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Post by sime66 on Nov 23, 2016 18:01:09 GMT
I was holding on to this one because I’m not sure it’s ready to post yet, but I’ll be tied-up until Friday now, so I want it off my desk and out of my head for a bit. Here’s where I’m at with Crank Timing; I’ve done a little calculator, which needs (i) pad opening degrees and (ii) crank degrees to calculate Inlet Timing, then will show (iv) cuts needed for the (iii) desired Inlet Timing. It’s still rough – (to be tested a few times before adding to my Port Timing/Gears-Speed/Gearbox Visualiser Spreadsheet at some stage), but it does seem to be working properly – it gets a bit fiddly with the +/- where the ‘I.o’ on crank crosses TDC though. Anyway; that’s not the point of this post; having a quick look at Race Crank Timing is…… We have to remember that on my 150 casings, I expect to need to open the inlet sealing pad to the maximum width and length to get the area bigger than the carb outlet. We also have to remember that I have not yet measured my pad, but I know what I had last time, so for now (because the result doesn’t have to be precise to prove the point I’m coming to) I’m going to use a 60° opening 60° before TDC (90° in the middle – this is very close to actual on The Beast, which ended up at 61° & 62°). With race crank timings, using Mazz Crank 6°/138° as first example, that 138° (as opposed to about 110° on a standard crank), gives a large ATDC I.c., and we can’t really keep the pad small to reduce it because we need the area there. My initial thought is that opening the 150 pad for area/volume and a Race Crank don’t go well together. Standard crank example (5°/110°):
Mazz Race crank example (6°/138°):
I’m still trying to find Tameni / MEC EUR crank prices and timing data; I believe they are similar to Mazzucchelli, but seem to have a better reputation lately - there’s been talk of Timeni on here recently.
….You’ll see that ATDC I.c. is already long – though we haven’t yet established where we want it.
This Pinasco Race crank example is better (6°/123°), but they start getting more expensive too (at £190 this one isn’t on my price breakdown):
www.sip-scootershop.com/en/products/long+stroke+crankshaft+pinasco+_46006000
I’m beginning to think a standard, not race, 60mm crank will be better, and I think the reason is the size I need for the opening on my Inlet pad – unless we want around I.c. @ 70°/80° ATDC?
(Or unless my numbers are wrong, but I spent last night trying to remember it all, and then simplify the job of playing with lots of different cranks without getting mistakes or muddled-up, so I hope not).
I was reading last night about the long ATDC closing issues, but I can’t find it now; I might add it in later if I find it again.
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Post by pxguru on Nov 24, 2016 7:03:42 GMT
Not much time this morning but a fair amount to think about. I did think you had a big shopping list in mind but its not needed. I do think the engine should be sold. Is being built as an exercise and not your kind of thing but it is what most scooterists aspire to. The manky old flywheel will work ok with the ring taken off. Will need a new piston. And a nine ball main bearing. Crank is as you wish (if you can find an old original crank, that will be fine). An expansion will only be needed for testing (advertising), I was thinking you might borrow one. Clutch should be a banded basket with a race circlip and heavy springs, this cost is unaviodable unless selling without a clutch. Fancy CDI is not needed here. The inlet calculator shows the Mazz crank to be the best one. Edit; You will find a lot of conflicting information about ATDC inlet timing. It is hard to understand the concept, as it sort of doesn't make sense. Why would you keep the carb inlet open when the piston is already on the way down and starting to initiate what could be blow back? What actually works is, the higher the rpm the more ATDC open inlet gives more power (even more than a reed inlet by the way) but at lower rpm too much ATDC will make it run inefficiently. The question for us is how much ATDC is best, as this is a static duration and the engine won't always be at max rpm. The easy answer is less than 90
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Post by sime66 on Nov 25, 2016 15:29:05 GMT
Thanks for your quick post yesterday, which I chewed-over for a while before posting; I really do find it all very interesting, but I think I’m best to shelve this build notion for a while and decide how best to proceed. The shopping list aside, which after clarification, seems not to be such an issue now anyway (I have no problem with buying crank or clutch); there are a couple of points, important to me and already mentioned in previous posts on this thread, that we haven’t got past, which still seem to me to make Screamer not right for my next project (though I understand why you’re keen on it):
1) I do not want to build something to sell; it just doesn’t interest me at all to do that, in any case, but not the most important point, I don’t think something I’ve built would be anything anyone would be interested in – the engine I build has to be something I want to ride, not sell. As I don’t need it now, and have another one under the bed already, maybe now is not the time to build after all. – Just set the parts aside and keep them together, as originally planned as part of my tidy. 2) Screamer does not sound like something I would want to ride; designing with more ATDC because it gives more power at high revs, but at the expense of efficiency at low rpm, when I don’t want the emphasis on high power at high revs sounds the wrong choice for me. I understand what you say; that it is a balance to set ATDC somewhere lower because engine won’t always (in my case hardly ever) be at 9,000rpm, but the concept of wanting it based on high power at very high revs, just seems wrong for my scooter. When I read that explanation in your post, it confirmed my creeping doubts. I’m much happier with the long, pretty decent, power band I already have with the plateau torque and the climbing power, with only small low-end losses – for me, we got it right first time. 3) I won’t jeopardise the arrangement I have here by antagonising my neighbours with a big loud pipe, nor do I want to draw attention to my scooter by riding around with one on it. You might not understand my situation or why that matters so much, but it is an important point to me, and I really don’t see me changing my mind on it.
You may not agree with those three points, but that’s the finance, design, and personal factors all telling me ‘No’ – to this particular design.
I accept the notion of building it as an exercise, but maybe what we are trying to achieve from the exercise still differs too much. I built the first one because I was persuaded I couldn’t do all the theory without a practical example, so we did it on an bare engine from scratch, so I could keep my scooter on the road; and it was a really good process and an excellent result; I don’t think that means the next practical example needs to be something faster/more powerful that I don’t actually want to ride though. I think, as it is at present, Screamer is not for me, and as I’ve already built something that is for me, maybe I’m better to sit on my stuff for longer until I have a better plan for using it. I’ve given it lots of thought, I’m not making the point clearer by writing more, and I’m repeating myself, so I’ll leave it there.
For interest, and because it was the original topic of the thread, the stepped Input shaft arrived and fits with no apparent problems; the casings go together and an EFL Primary cluster spins freely in the, quite tight, gap between the outer casing and the inner crankcase/clutch bearing casting; I can build a decent EFL, tuned engine, based on a Malossi 166, and p150x casings, with the parts I have, and a couple more decent, missing parts. I’m still going to put the driveshaft in to check that aligns with the position of the Input Cluster, but a couple of other important things have been taking my time over the last few days, so that’ll have to be weekend or next week now. After that it might be time to box it up for a bit, and measure when I have a better idea of a plan.
I appreciate the thought and time you’ve put into it this past week, but I have to make my own decisions, and I just can’t bring myself to like this option.
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Post by pxguru on Nov 26, 2016 11:31:33 GMT
I felt that this wasn't what you wanted all along. I did think you wanted to build it to understand the theory difference between what you have with the Beast engine and what could be done with a different way of porting. Which is I why I have kept on saying build it to sell it. I do think someone would buy it, especially as a tried and tested lump. There is no way I was thinking you would like to ride this kind of engine for long. The Beast engine turned out like it did, with the very long torque curve and comfortable riding power because that is what a decent touring tune gives. A high rpm road racing engine would be quite different. Harder to ride but way more responsive, with a very noticable power band (like a 2 stroke sports motorbike usually has). Would have had bad economy and been jumpy in traffic. It is what most scooterists hope to achieve by tuning an engine but rarely what they actually want when they get it This is why the remit of my Polossi 225 was to be a practical fast tune, a 30bhp fully panelled scooter, that does ride in traffic, not terrible economy (if crusing) and will still manage a GPS 80mph wide open the motorway. This has not been easy task. I still have its next barrel on my shelf gathering dust, while I am waiting for it blow up. If you are not going to sell the 166 engine then you could make another tourer but you might as well make it for someone else as the Beast engine will be running for a very long time yet
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Post by sime66 on Nov 27, 2016 8:17:43 GMT
Thanks pxguru, Even mulling over your posts and a bit of background reading for a week is a bit of an eye-opener about how much of a different animal you can make out of a 2-stroke with a few changes, and also the balance involved, and maybe compromises that might need to be made. I am keen to continue to pick up the theory and understanding more; it’s more complicated and versatile than people think. I also take the point about maybe some not getting quite the ride they thought when buying a big barrel, matched casings, race crank, big carb, big pipe – bolt it all together, put it on a Dyno, get a big number, and think that’s the job done. I also still hope that what I’ll do is interesting enough to make it worthwhile posting, and maybe there are some tweaks (compromises or improvements) that could be made, so it isn’t too same-again; I have started a list for that, which I’ll post when I’ve given it some more thought. I’ll still post my measurements when I have a crank, which now won’t be a race crank, but might still be 60mm; I’m going to do a proper barrel measure and then a rough Port Timing for 57mm and reduced durations too, see what that suggests, and will keep an open mind, and one eye out for a bargain too. I’d rather buy a long crank or raise the ports myself than have a big lathe bill, but I expect there are more important factors than just that. You made the point before about the 30bhp, 80mph Polossi 225 being a hell of a lot more effort to get another 8mph. The complexity, expense, effort, potential poor ride in traffic, poor low-end and poor economy of a high rpm, road-racing engine sounds like it could really be enough to put a chap of 2-stroke tuning – a time and money pit; but a challenge to tackle for your own satisfaction. I think I’ll keep it simpler, and for me at least, it’s reinforced what I’d thought, which is that max power at highest revs isn’t what I wanted before or now. – The Beast really isn’t such a beast, but it is what I like.
So, not quite a Screamer, but something still worthwhile from my stash……….
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Post by pxguru on Nov 28, 2016 13:58:30 GMT
Still amazes me how a few millimeters here and there on the barrel ports makes so much difference. So sad that 2 strokes are slowly being outlawed.
If you want the limitations to be the SIP Road II and an SI carb, could be made into a similar Touring tune to the Beast but with a 60mm crank. Would probably be a little more powerful with better torque overall, as the Malossi has better ports and more tunable piston to start with. Will still make interesting reading whatever you decide.
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Post by sime66 on Nov 29, 2016 9:32:43 GMT
I’ll try to keep it interesting and not wander off-topic too much, and continue to post as long as it seems worthwhile doing so. Definitely SR2 or maybe a Bix-Box next change (but not a big pipe), probably Si carb; just to avoid another expense of loads more jets, and another year playing with carbs, but I’ll keep an open mind on the carb to a point. I still have an open mind on the crank, but I did win an original 57mm on the weekend, which should be here early next week. It was £25, so as long as it’s OK (I’ll check end-play etc) I’m happy with it, whether I use it here (which was sort of the intention) or not. I’m happy to put this in ‘spares’ and get a 60mm for a bit extra power and torque, and depending on how each look from point of view of packer, skimming and port heights, which I’m going on to next job. I started doing comparison port timings for 57 & 60mm the other day, but binned it with a fuzzy head, and because it’s a bit premature without proper measurements. Yesterday I measured Casings, inlet pad and barrel to get as much accurate info as I can without crank, which was probably enough to have a stab at that now. Below the dimensions in Blue are measured and Red are calculated:
I then measured the Ports accurately and calculated the area of the exhaust port (need to keep an eye on Exhaust port at BDC):
I did notice that the Main and Boost Transfers are a different heights, so we might have to have a chat about that:
With that info I can do some port timing calcs as next job (tonight probably), but it will need checking thoroughly when I have a Crank and definite Deck Height – I get +0.3mm, but within the tolerances I’d say it’s fair to reckon on about zero with a 57mm Crank.
[I’ll add some Port timing calcs below, later....]
During my evening’s Net Wandering I’ve had a look at a few Malossi 166 threads and images of barrels and casings, and I’ve gone through the Malossi instructions a few times too (I suspect we'll go beyond that, but for reference). I had a quick inspection of barrel, and did a quick mark-up of likely mods to it and casings, so here’s a few photos just to start the ball rolling. I’ve got the Transfer cut marked perpendicular to the circumference of the skirt and about 5mm from stud holes, then followed line of barrel and limit on the casings edge to give a similar shape to those I’ve seen, but I suppose I need to round my corners a bit.
I’ve also noticed the Boost Transfer has the middle channel blanked-off behind the ‘V’ shaped channel splitter, so that might be somewhere to open, and I’m pretty sure we should lose the bit with ‘?’ marked on it too:
That’s me for now; now/next I’m waiting for Crank and doing some port timing calcs for 57 & 60mm with the info I have……………….
(I guess for now I’ll use a transfer duration around 123 - 124°).
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Post by pxguru on Nov 29, 2016 12:05:58 GMT
That 57mm crank looks ok apart from the slight surface rust. Hopefully it's not got in the big end bearing but if it has you could get a 60mm conrod kit for it. Even fitted will be way cheaper than a new 60mm crank. Plenty of work to do on the casings and barrel. Exhaust port will go at least another 4mm wider without any concern. Shape now is not bad for general economic running. Those boost ports need lots of work. Great place to start but by the end they will look quite different. Depending on what type of tune you want there are a many ways of working them, all are a lot of work
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Post by sime66 on Nov 29, 2016 14:25:26 GMT
Lots of work is good; it’s sort of what I was thinking for this project – making something out of what is available with a bit of thought and effort – and your expert guidance. I think I’ve stumbled across those eccentric bearings before, but not taken much notice; I’ll see if I can find it again. That’ll depend on this crank too, which was listed as having a good, tight big end, so doubt it’s worth dismantling if it is good. I thought we’d be playing a lot with the exhaust port (top, bottom and sides); it doesn’t have those boosts like you liked on the DR177 – wider sounds good to me. I also meant to say or show how un-clogged it is in the exhaust stub; it looks like it’s been barely used – sooty, but no solid crud; I expect I’ll be in there for days widening and smoothing all that anyway. I’ve marked-up the boost transfers as best I can with what I anticipate you’ll suggest (it’s a bit tricky for me to picture it, let alone try to mark up a photo, but I’ve had a bash – I got my little narrow bridge tops upside-down on the bottom image); I’m thinking that the ‘V’ centre becomes another channel and two posts with a pointed leading edge and a narrow top – we tried for 1mm wide on the DR, but I ended up making them a bit too sharp. I've made it wider too, maybe deeper is also possible; is this anything like you have in mind?
….I found some eccentric crank pins (only a quick search). I found a 2mm offset one which makes a 57 into a 59mm, but at £67 plus bearing and shims, and labour (I don’t imagine it’s a home DIY affair), if I wanted 60mm it would seem sensible to buy a 60mm crank and keep this crank in spares. – Only first impressions after a very quick search and before I get hold of the crank anyway.
What type of tune?? There’s two main things I’d like to have improved on The Beast, but they are probably more to do with weight, gearing or more precise (localised to the point in the rev-range) carburetion than port timing or anything at engine build stage – gearing maybe though. 1) My 3rd gear with the big long torque was excellent to about 7800rpm peak and just over 100kph GPS, but my 4th never really got going (yet), and got hotter at the lower revs. I’m sort of picturing an earlier and longer peak power rev range, rather than just the local peak and sudden drop off. If there was peak power earlier and longer, it would still be there to pull 4th a bit to get it going when the revs dropped when I changed up. 2) My low revs torque is pretty important to me. I do a lot of narrow, windy, hilly lanes where there isn’t any chance of building up speed to get revs up to overcome hills; they are short straights, rev and gear drops for blind bends, accelerating again from low revs on the incline, getting revs up long enough to change up before the next bend/sheep/tractor/Emmet in the road. Pretty heavy on the clutch too, but a lot of work at low revs on the engine. Again, on my previous dyno, I see this as the high torque coming in earlier, and reducing the low-end losses we identified before. I did a quick mark up of my previous dyno (yellow dots); it sort of gets rid of that little later start and dip and has the peak power starting earlier and lasting longer, but not higher. That may be nonsense, but it’s how I picture it, and probably not to do with porting anyway.
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Post by pxguru on Nov 29, 2016 18:57:18 GMT
I think the beast will improve yet, once you have sorted the jetting. How did the BE2 and AC185 go? It may not be so easy to make a fuller power corve without being less. I would go for more power which will still improve on the Beast everywhere. The main and secondary transfers will just need a lot of work but nothing so special. It's only when you analyse a kit like this that you actually see that they come out of (in this case) the Malossi factory as a pretty rough job. And the Malossi is better than the DR The main and secondary transfers are not even sqaure. I'm sure it can be made better than the beast but will take some more effort without the barrel shortening. Especially if it ends up as a 57mm crank. That 166 boost port is going to need a lot of work. I don't think that the port at the base gasket is big enough for 3 ports in the barrel, even after it is fully opened up. Just leave that port feeding the 2 outer boost ports. The centre boost port should be made twice as long, wider and deeper. Will need a bit more hole in the piston there too. You will need a few more tools for this, like, long shank burrs and some right angle head to get inside the main transfers.
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Post by sime66 on Nov 30, 2016 8:57:43 GMT
With The Beast, I hope/expect the 4th gear issue will improve with jetting – BE2, AC185 not yet played with due to wet and windy weather. It’s low-end torque is good; I think there I was more making the point that I didn’t want to lose any more, compared to that, whilst trying to get more top-end power. (I sort of realise I can't add at both ends). I do seem to need more power to make use of 4th gear though, the rev drop seems to put me where the 4th is struggling. Anyway that’s The Beast and this is a new baby, so we have a blank canvass. I suspect something will have to give: · 57/60mm · Barrel skim · Lots of raising of Transfers within the Barrel I reckon I’ll have to be sensible there; I can’t just raise the barrel and leave a big squish and rubbish compression ratio, so probably can’t get my ports where I want them with a 57mm without a load of cutting of all the Transfers. I haven’t done the calcs yet, but that’s how I picture it. If that is the case, I’d rather go to 60mm than getting the barrel skimmed, but if I end up having to have the barrel skimmed anyway, I might as well stick to the 57mm, (there is only about 1.5mm raised surface on the barrel to skim before we're into the first fin too; we've been there before) Having said that the 60mm gives me a bit more volume and power. It seems a bit of a chicken and egg situation, and I feel I need to know more to help me decide. I’ll do my tables and see if I can get a better picture of it. Of the 60mm non-race cranks I’ve found so far, the BGM Pro 60mm 105mm seems favourite, but €180 is a bit scary, so I’m still looking for alternatives (They generally seem to go ‘race’ timing when they go 60mm). This is the BGM one anyway (says 58° ATDC, mine would probably be more because I’m opening the Inlet pad right up): www.scooter-center.com/en/product/BGM031121G/Crankshaft+BGM+Pro+Touring+rotary+valve+60mm+stroke+105mm+conrod+Vespa+PX125+PX150?meta=BGM031121G*scd_ALL_en*s19861358297328*bgm%2060%20105%20crank*1*1*1*16To this boost port then; keep to two ports, and make deeper and wider at the area at base gasket – OK; that’s understood. I’m not sure where you mean twice as long though; cut back into casings? The port and part of skirt I marked with ‘?’. The length of them in the vertical face of the barrel? I got a bit lost picturing where you mean. I have had a look at the piston, and I see holes that could be worked, In the skirt and within the piston, some depending on barrel port heights though?. It’s on my list to clean it up so I can read the stamps on the crown (to check it’s an ‘A’), so I’ll do that and take a few photos of the piston ports before finishing this post:
No problem buying tools at all; it’s an investment (as long as I don’t break anything with them). The 90° fitting is about £22. I looked at long shank burrs before, but got stumped because I could only find 6mm ones and I think my Dremel only takes 3mm, so managed without them. A set of seven 6mm is about £60, I expect there’s some in the set I don’t need. Individually they’re £10-15, so maybe three or four specific ones might be better. Do you use 3mm ones? Is there a supplier you’d recommend, rather than taking pot-luck on Ebay?
Anyway, Port timing calcs will follow (I said that yesterday, but was brain-faded by evening), I’ll post this once I’ve had a scrub and taken some photos of piston for discussion……………..
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Post by sime66 on Dec 1, 2016 7:20:23 GMT
This is probably my last morning on this for a few days, so I wanted to compare crank strokes to try to get a better picture in my mind; it seems to be as I thought it would, which is that a 57mm Crank will need a big packer, which gives me problems with the exhaust port height, AND the strong likelihood of the need to skim more than there is available; but the 60mm crank seems to fall into place perfectly for a Transfer Duration around 124°. Bearing in mind I still don’t have a definite Deck Height yet, but have my last measurements to work with, which was +0.3mm. I’m using the measurements I took earlier in the week: Transfer height = 47.42mm Exhaust Height = 35.43mm (Deck Height = +0.3mm) With the 57mm Crank, setting the deck height at –2.4mm would give:TD – 123.68° ED – 177.75° BD – 27.03° That seems to mean: 1. I’d need to skim the barrel 2. There’d be more than the 1.5mm available to skim 3. The exhaust would be too high anyway I guess the alternative would be setting the exhaust height and cutting all the transfers, which is doable, but I doubt is sensible. With the 60mm Crank, setting the deck height at 0.1mm would give:TD – 123.90° ED – 175.69° BD – 25.89° That seems to be pretty close to spot-on, within the accuracy of the measurements I have without any crank in the casings to measure exact deck height yet. I suppose the deciding factor would be whether or not a a 60mm crank with a deck height of pretty-much zero would require any skim or gasket combination to get the squish and compression ratios right. If buying a LS crank means I have no out-of-house work for Lathe Man, then I’d rather spend my money on the crank; especially as, unless I’m missing something (which is fairly likely because the '+/-' tweaks get me a bit muddled with this), the exhaust is going to be too high with a 57mm Crank anyway. I’m putting these below in case we need to find any errors in my working, or if some fine-tweaking might be needed:
If that’s correct, I think my next job is to look at volumes to see what skimming or packer would be needed in the head, and if no skimming is needed, I’m leaning towards to 60mm crank, especially if it’s going to give me a bit more volume and power too…..
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Post by pxguru on Dec 1, 2016 8:48:28 GMT
I don't think either would require shortening the barrel. If you do end up with a 57mm crank then all the ports would need to be ground up 2mm or more. This gives a nice opportunity to change all the port angles etc. The 60mm crank would require less work and be more cc.
How does the inlet timing work out on the Mazz 60mm without cutting the casing?
On the boost port. I was talking about the centre boost port notch in the barrel. It will need to be twice as long. the base port for the other two will need to be a bit bigger but not so much.
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Post by sime66 on Dec 1, 2016 12:57:22 GMT
At this point then, I’d favour using the 57mm crank I (should) have and raising and adjusting the angles of all the Transfers, over the expense of a LS crank; the build wasn’t intended to be based on buying flash bits, so I would prefer to limit that as much as possible (piston, chunky clutch, main bearing with extra balls, hard crux.....). However, let it remain undecided until all consequences of the decision are known for sure. Those main factors being (not really questions; just things I’m still thinking about or don’t know yet) – · Is the power due to volume increase so great between 166 & 175cc, and what other differences in performance does LS give? · Is that more important than getting the angles of the Transfers correct? · Will there be no barrel skim? (More investigation required to be sure – volumes check). · Do I now have a good 57mm Crank? (To be confirmed next week). A quick look at doing that with the 57mm crank gives me, at Deck Height = 0mm: Raising Transfers 2.5mm Raising Exhaust 1.75mm Gives: T.D. = 124.10° E.D. = 174.99° B.D. = 25.44° (I can’t set the barrel for the right Exhaust duration because it would then need skimming for squish, so would have to raise Transfer and Exhaust ports.) To the question of the LS Mazz Race crank on an uncut inlet pad; I’ve done the numbers, but two points first: 1) We need the bigger inlet area we get from cutting the inlet pad opening long and wide. 2) My numbers seemed a little out from what I’d expected; maybe by a few degrees – I’d already made a mental note to check my 64° & 61° again. (pic)
From my rubbing, Inlet is at 76° BTDC and is 37° long as it is (magenta on pic). Mazz Crank timing is 6/138° Cutting nothing would give Inlet Timing 107/68° Cutting just I.o. on pad could give 117/68° (there’s about 10° more both ends on the pad) For more than that BTDC I’d be cutting the Mazz Crank (8-10° giving 195°ish total). I think you like the Mazz Crank for this one; it’s cheaper too (£130-ish)
I think I’ll worry about the boost port nearer the time, when I’m measuring and marking-up precisely; for now the words aren’t really making pictures in my head yet……….
Just to finish the original subject; the Chinese bearings arrived – I didn’t need them, but was curious. Dimensions as expected, achieved by bigger inner section, not bigger ball bearings (which would have made them wider – I was wondering). I don’t know how you’d judge quality without trying them, but they would also get an EFL gearbox in p---x casings without stepped input shaft (though stepped shaft is a better idea), but these bearings were US$0.90 each (for 10, so US$9.0), and US$15 for TNT tracked airmail, so about £2 each – considerably cheaper than the shaft. Needless to say if any of the regular contributors/engine-dissectors fancy inspecting them or having a play (pxguru, bryno, vespasco, henri, ……..), I’ll send for goodwill and karma. If not I have a plenty for myself, and a wider range of manky old spares I know I can re-use now. Here’s some pics:
Left to right: Original Ø12mm input shaft and 401/P4 bearing, Stepped input shaft and 6302 bearing, Ø15mm input shaft – all work with EFL cluster:
I'm tidying this away and a couple of busy days now, then maybe some progress on The Beast jetting this weekend. I think it’ll be muffs-on too, which is pretty good; leaving them off until December; I had them on in September for Tour of Britain last year.
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Post by pxguru on Dec 1, 2016 15:33:10 GMT
Those Chinese bearings look just fine. Would need to run them for a while to see if they were any good. The OEM ones can last for 50,000 miles If these ones do half of that, then that's plenty good enough. So, from no solution to two perfectly good solutions in a week. Thanks but I have no need for one but any non purist out there with an P___X/E needing a more efficient gearbox might want to think about it.
I think overall the 60mm crank would make a better job. Would be easier for you to get assured results. More CC is more torque and longer stroke is more torque too. Will be missing out with a 57mm. I am sure we could make something that really goes with either crank though. If you were making a screamer it wouldn't really matter which crank as we could port it to do similar with either but as you have an affinity to tractors, we could try to make it pull better than the beast. And with the big Malossi secondaries it will probably have more power too.
Edit; here is a use for some of those bearings. Should check that 57mm is true before using it.
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Post by sime66 on Dec 1, 2016 19:32:38 GMT
I'd already thought of doing that with them! (Hadn't seen the film either - my cunning plan had a spring mounted digital caliper to save buying the gauge).
For a better job, more torque and easier to get it right; I’m happy enough to spend the extra on LS Crank - (plenty of time to decide - and after the 57mm crank arrives anyway). What’s the plan with Inlet timing and pad area, given that 60mm are race (long ATDC) timings, though? I put some numbers in my previous post, but I still can’t quite see what you have in mind there. I can see 68° being OK, (-ish, as long as I don’t lose any bottom-end), and I can get the I.o. up if I cut the crank too, but what about the pad area? I haven't yet seen a good combination of crank and pad cutting that solves it.
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Post by pxguru on Dec 2, 2016 8:20:33 GMT
Not sure if its too early but I get 119/62 on the uncut port and Mazz crank
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Post by sime66 on Dec 2, 2016 8:27:32 GMT
...Been up for hours; have to go out soon, will check first.....................
I have checked mine and get the same result; 107/68. I’m using 76 & 37 on the casings and 6 & 138 on the crank. I doubt you’re wrong, so will check better later to see why I'm different – I'm a bit rushed now. As a double-check I always check that the result I get is the same as the two openings, in this case: My 107/68 timing = 175 Crank opening + case opening = 138+37 = 175
The total has to be 175.
I'll have a better look at it this evening; no need to rush now.
(It 's to do with how we're reading 6 & 138; I'm reading 6 then 138, and you're reading 138 BTDC and 6 ATDC, so you get the extra 6, and the 138 in a different place - I'll check it later where the 6 is - thought I had it right, but have a doubt now).
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Post by pxguru on Dec 2, 2016 9:08:02 GMT
Seems like the 6 is the issue. I have always assumed that if a crank is specified as 138/6 it is 138 BTDC and 6 ATDC. Therfore the following would appear to be true. 119+62=181 138+37+6=181 And that being all possibly correct, then a Mazz race crank will be ideal for this purpose
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Post by sime66 on Dec 2, 2016 9:12:26 GMT
I will check it for certain later; I did just quickly re-check myself on SIP and SC. SIP states valve timing: "138°/6° post TDC" (I read that as: in the direction of the crank, the 6 is after it is past TDC) I grabbed an image of the crank from SC to check as well, and it does show it to be as I thought, which is 6 after TDC then 138:
I'll look at it later; I do have to rush out now.......
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Post by pxguru on Dec 2, 2016 11:44:37 GMT
This crank is not quite as "race" as it would have you believe. I just read up on it too. The 6 is the issue. It is stated as open ATDC but in reality it works as BTDC in terms of the port timing. It is open 138 degrees, so the timing is only 175 and your 107/68 is correct. This is why I always measure mine with a degree wheel (several times) before cutting anything This crank will still be just ok but something like 125/65 would be better for this. Would mean nothing could be cut from the IC end.
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Post by sime66 on Dec 2, 2016 13:56:26 GMT
I need to get my head into this better later, but the 6° wasn’t a problem – on the Beast I cut it about that past TDC (from roughly 5° to –7° from memory). It is the 138° that messes up the inlet timing, and I’m concerned more about not being able to cut the inlet pad than I am concerned about having to cut the crank, which was surprisingly straightforward. I quadruple-check everything; I’ll have the crank and the casings precisely measured before cutting, but this is making a selection based on the crank spec. I wonder how any of these L.S. more open cranks that limit what I can cut on the pad, will allow me enough cutting to have a big enough inlet area; (ie. Bigger than the carb) that’s the one that’s bothering me. The 57mm, standard timing, crank will be here early next week, and I’ll have both items to physically measure precisely, and know what cutting would be needed on crank and pad to get 125/65, then calculate an inlet area on the pad, then see if any L.S. crank can do a better job than that, without compromise – then weigh it up again. At the moment I'm seeing the volume from long stroke as a power/torque benefit, but the crank timing it gives as being a problem. Edit This working shows cutting a 60mm Mazz ‘Race’ crank and the Inlet opening on pad to get as near to 125/65 as possible:
With my pad opening of 76° and 37° (acknowledging that this is imprecise until I fit a bearing and crank to measure accurately), and with crank 138/6, we agree that my timing is 107/68 (175°). Given the target of 125/65, the first obvious point is that the pad can’t be cut at I.c. because it's already 68° – we agree on that too. (I think that gives us a problem with the final area of the Inlet opening). There are about 10° more available on the pad for I.o., so taking that all, my ‘A’ can increase from 113° to 123°. So using ‘A’ = 123° (measured and calculated), ‘B’ = 76° (measured), ‘C’ = 6° (now agreed), and ‘D’ = 138°, the timing is as follows (117/68 = 185°):
Another 8° is needed on the I.o. on the crank to achieve 125°, so ‘C’ (was 6°) becomes –2° (that IS now BTDC on crank - like I did before), as shown above in magenta. Timing then becomes 125/68 = 193° (47+146 = 193°), BUT (and I think this is important)
The area of the inlet opening on the pad is compromised because with this crank the I.c. is already too great, leaving none that can be cut from pad. We’re using under 50° of pad when we could have more like 60°.
I think that pad inlet opening needs to be as long and wide as possible, so I think this crank is not ideal. This is the same conclusion, for the same reason, as The Beast; standard, non-race cranks seem to suit the smaller inlet pad on these engines better – I suspect it isn’t the same for 200s. - That’s why I was trying to find a less-‘race’ 60mm crank, and why I’m still not convinced that standard timing, with cutting pad and crank like before, won't be better than compromising the Inlet opening on the pad.
(But that’s why we’re doing the sussing out now; so I buy the right bit when we’ve finished kicking it about).
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Post by pxguru on Dec 2, 2016 16:07:48 GMT
I am thinking that the area of the pad is not as important as getting the timing correct. There will be sufficient area with what is available. The 125/150 pad is straight down at the front anyway. Increasing the I.c area will make it look better. Remember we are going for a lower rpm high torque motor, where high flow is not so important. Should be able to get a bit more out the width to compensate too. For the cost/benefit I think that this Mazz crank will do just fine with 125/68 timing.
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Post by sime66 on Dec 2, 2016 17:26:26 GMT
The mazz crank has become a strong favourite then, but let me make sure we’ve considered everything……. Inlet timing:O.K., I take the point, but is that better than using a standard-timing crank (I checked my previous as 110/5°), and achieving exactly 125/65° by opening the pad right up to give plenty of volume, and cutting I.o. and I.c. on the crank? Like this (standard crank for 125/65):
‘A’ is still 123°, ‘E’ is another 10° wider to 57°, ‘B’ is 10° shorter to 66°. On the standard crank, I.o. gets cut by 7° to –2°. I.c. gets cut by 16° to 133° total.
133 + 57 = 190° 125 + 65 = 190°
The questions are: 1) Is or isn’t the smaller Inlet pad area a problem or compromise? 2) If any problem exists, is it outweighed by the benefits of the long crank volume/power increase?
And not forgetting another £130 on the cost of the build; I’m happy to do it, but I’d like to be sure we’re sure. But also not forgetting the easier job I have in the barrel with the L.S. crank, so maybe that swings it, when all weighed-up together........?
Areas: A 28mm carb is 615mm² A 26mm carb is 530mm² A 24mm carb is 450mm² My wide-open Inlet pad before (width and length) was 630mm², so maybe it isn’t such a problem; I don’t actually know the answer to that; the criteria was bigger than the carb. I can see that 50° not 60° on the pad will be about 5/6ths of the area though, which is 525 mm², and with L.S. the volume is 175cc, just about same as DR was.
Revs: Another question that arises from all that as well then, is what max power revs are we basing the port timings on? I’ve been using 124° TD for max power at 8,000rpm, but your last post said lower rpm high torque motor; which is good, but do you mean lower than The Beast (123° TD for 7,500rpm)? That makes a difference to the barrel stuff I’ve been doing. Or do you mean lower than the Screamer’s 9,000rpm we talked about initially?
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Post by pxguru on Dec 2, 2016 19:03:13 GMT
I think on a lower rpm motor, the pad length will not be such any issue. I would say to aim for 7500 rpm for max power same as the Beast and aim for max torque, which should be more on this one. As this will be your second try with a faster barrel to start with, it is possible it will have more power too. Everything should be done during the porting to achieve torque. This will then fit with the SI carb and SR2. As it doesn't have the extra exhaust ports, with a 60mm crank it will definately have a better bottom end. Overall like this the result will be similar but fingers crossed better.
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Post by sime66 on Dec 2, 2016 20:08:20 GMT
This is great progress; thanks for your patience – after a quick couple of weeks to-and-fro the numbers and parts are falling into place nicely, so a quick summary: Target timings:TD = 123° ED = 171° BD = 24° I.o./I.c. = 125/*65(8)° (*T.B.C. by precise measurement). Engine:Malossi 166 (175) with L.S. Mazz ‘Race’ Crank, EFL gearbox (gearing T.B.A., esp. clutch/primary ring), Sip Cosa2 ‘Sport’ (banded, 16 spring, wide circlip) clutch, SipRoad2, Si26 (probably), standard elec-start flywheel without starter ring, Ducatti CDI, static timing 18°, max power at 7,500rpm, tuned for max torque. - That might seem a bit ‘standard’, but the magic’s gonna be in the barrel! Main stuff to buy:Mazz Crank (£130):www.sip-scootershop.com/en/products/long+stroke+crankshaft+mazzu_46000000Malossi Piston and rings (£75):www.wasp-performance.co.uk/onlineshop/prod_4033075-Malossi-166cc-610mm-Grade-A-Piston-Kit-Standard-Size.htmlClutch (not added up all the bits, but this basket – total about £150+):www.sip-scootershop.com/en/products/clutch+basket+sip+sport+cosa_93402000Bearings and seals esp. stronger main bearing (9 ball) Hardened crux and conn rod.…..that’s about £500, and I’ve spent about £200 on casings, barrel and gearbox, so a bargain for another excellent engine and lots more revision and learning; and maybe something to keep this forum lively too. Anyway, once the dust has settled, and any afterthoughts are thought of, if there are any; I’ll be wanting to get the crank next. With the crank I can check all the inlet and port timings, and pin it all down precisely; packer, deck height, squish, volumes too - that’s got to be next move. I will recheck my pad as best I can without bearing or crank, and do a quick port timing for TD 123° before buying, just to be sure it all looks sweet. A good place to leave it on a Friday night…………………………..
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Post by pxguru on Dec 3, 2016 9:12:51 GMT
I was going over the numbers to check everything with the concept of max power at 7500 rpm. Looks like you might be saving yourself £130. Hopefully I got something wrong but to achieve 171 degrees Ex it will need a negative deck of -1.4mm. This is just about possible but not a good idea. To make matters worse I would prefer to aim for these numbers, as it will be a bit stonger low down and there is scope for going over.
Target timings: TD = 123.5° ED = 169° BD = 22.75°
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Post by sime66 on Dec 3, 2016 9:15:42 GMT
Good morning......I was just about to post something very similar; let me post mine just as it is, then I'll compare my findings with yours, and post again later when both make sense. Before my head cluttered up with other stuff, I had another look a port timings this morning. A quick observation on the L.S. Crank with the Malossi 166 Barrel is that it seems to be much better suited to 124° – (going by the distance between top of Transfer and Exhaust ports). If you aim for 124° it all falls into place with just a precision tweak after proper in-situ measuring, but if you try to get 123° with the Transfer height it makes the Exhaust well-out (which can’t be dropped), and if you set the Exhaust at the right height (for 171°), all the Transfers need cutting for 123°, and the probable squish/compression/skim problem arises again. I think this shows L.S. and 124° makes more sense:
This raises a couple of questions: 1) Am I right? – I’ll check myself and see if I can find a better way later, but I’m not really intending getting into it this weekend. 2) If I am right, is it such a bad plan to aim for 124° (8,000rpm max power), or am I risking losing my low power/torque?
If I am right and 124° will give me a problem, and 123° might mean I still need a skim, then last nights joy needs to be tempered with a bit of caution before I get my wallet out.
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Post by sime66 on Dec 3, 2016 10:38:51 GMT
….so, still not yet having spent long enough on it to be confident without double-checking when time allows, but seeming to confirm what you say, I did 57mm crank at: Target timings: TD = 123.5° ED = 169° BD = 22.75°This gives me a deck height (set for Exhaust) at pretty much where my measurements say it will be (0.3mm), and a cut of 2.1mm on all the Transfer ports (which gives the room to adjust the angle). As previously found by us both, trying to achieve the same with 60mm crank does get tricky. The left-hand one of the two below, is my first quick bash at achieving the target timings with 57mm crank and barrel as previously measured:
I have to check my deck height +/- because I get it muddled there until I’ve drawn it (to picture it better for myself; I can’t think this stuff as quickly as you do), but so close to DH = 0, when my best measurements say that’s what I’ll get with 57mm crank, it looks like 57mm crank has become firm favourite for TD=123.5° – and more work with Transfers in barrel will be needed to achieve target timings, which might actually make a better job anyway.
(I’ve quickly got TD=123.58°, ED=169.03° & BD=22.72° – all subject to fine measurement with crank in-situ, and tweaking of numbers).
…and I’ve quickly re-measured the inlet pad and redone the pad and crank-cutting for 125/65° (if we still want /65°). As previously found, cutting 10° both ends of the standard Inlet opening, and cutting the crank I.o. by 6 to –1°, and I.c. by 16 to 132° (total) will give 125/65° (132+58=190°).
I will check everything again thoroughly when I have some quiet time to concentrate on it better - probably when I have the 57mm crank to do it all properly in a few days.
Edit:
A quick bash at squish, volumes and compression ratios – As it is – all numbers are fluid until pinned-down better; this is pretty much Out-the-Box; just for starters, to get a feel for it.
Head Dims: (at present squish would be 1.5=0.3 = 1.8mm)
Head Volumes:
Calcs based on current measurements and volumes: – All subject to change (Malossi say 11:1)
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