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Post by kru251 on Jan 7, 2013 21:27:26 GMT
Blimey, am I the only one getting confused? We are going here from a piston clear of barrel by 5.5mm (not possible IMHO) or 0.5mm below. Depends on the head recess too or does it fit flat with no lip on this kit.? I was always taught to use two or three starands of solder wire ideally set in a position to go either side & inline with the gudgeon pin (wrist pin in Americana). That reduces the rocking issue giving potential false readings.
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modpx
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Post by modpx on Jan 7, 2013 22:18:23 GMT
I would like you to try to measure the squish again. With the piston higher than the barrel at the top and the head you showed a picture of yesterday the squish will be very small. Under 1mm. This would certainly explain why it overheated. It also explains why it doesnt pull the standard 4th gear I just made some rough calculations for you. The numbers are even worse than I thought but the good news is it's very easy to put right. Ok that sounds cool (the easy to put right part i mean...) ! Have you cosidered, thou, the possibility that the pinasco head might have been calculated for that high top TDC in order to keep a very low squish? hmmm... .... anyway tell me about the calculations... ;D
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Post by modpx on Jan 7, 2013 22:31:40 GMT
Blimey, am I the only one getting confused? We are going here from a piston clear of barrel by 5.5mm (not possible IMHO) or 0.5mm below. Depends on the head recess too or does it fit flat with no lip on this kit.? I was always taught to use two or three starands of solder wire ideally set in a position to go either side & inline with the gudgeon pin (wrist pin in Americana). That reduces the rocking issue giving potential false readings. I'm confused too but i never said the piston was 0.5mm below, the yesterday picture has just been taken from adifferent angle thats why gives the impression of being below, today's pic it was taken exactly from the side to give the right perspective instead. I couldnt calculate perfectly the distance from the piston TDC to the top of the barrel cause the piston is curved so i (super) roughly measured it by putting a straight and flat stick on top of it and i calculated the distance of the corresponding height from the edge of the stick to the top of the barrel, i hope it's clear..
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Post by modpx on Jan 7, 2013 22:46:54 GMT
Blimey, am I the only one getting confused? We are going here from a piston clear of barrel by 5.5mm (not possible IMHO) or 0.5mm below. Depends on the head recess too or does it fit flat with no lip on this kit.? I was always taught to use two or three starands of solder wire ideally set in a position to go either side & inline with the gudgeon pin (wrist pin in Americana). That reduces the rocking issue giving potential false readings. I'm confused too but i never said the piston was 0.5mm below, the yesterday picture has just been taken from adifferent angle thats why gives the impression of being below, today's pic it was taken exactly from the side to give the right perspective instead. I couldnt calculate perfectly the distance from the piston TDC to the top of the barrel cause the piston is curved so i (super) roughly measured it by putting a straight and flat stick on top of it and i calculated the distance of the corresponding height from the edge of the stick to the top of the barrel, i hope it's clear.. pretty much like this Attachments:
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Post by joey on Jan 7, 2013 23:20:20 GMT
Pinasco have always had a generous squish, in fact I don't think I've seen one below 2mm on either the 213 or 225 (long stroke,) and seeing as they've carried out years of R&D who am I to argue?
I think your best bet is to lap the head (on the wet &dry,) slap a SIP road on and refit the standard P2 4th gear. It's not going to be a racer by any stretch but should give plenty enough torque to pull. By downgearing all you're really doing is reducing top end and paying handsomly for it. Acceleration will be no different as your primary and 1st/2nd are untouched???
If what you're after is a fast AND torquey motor then you're better off looking at the Polini.
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Post by modpx on Jan 7, 2013 23:35:57 GMT
Pinasco have always had a generous squish, in fact I don't think I've seen one below 2mm on either the 213 or 225 (long stroke,) and seeing as they've carried out years of R&D who am I to argue? I think your best bet is to lap the head (on the wet &dry,) slap a SIP road on and refit the standard P2 4th gear. It's not going to be a racer by any stretch but should give plenty enough torque to pull. By downgearing all you're really doing is reducing top end and paying handsomly for it. Acceleration will be no different as your primary and 1st/2nd are untouched??? If what you're after is a fast AND torquey motor then you're better off looking at the Polini. I agree every word, as a matter of fact i already have a sip road (actually a Megadella that is much better, hand made by an italian tuner) and i originally didnt plan the short fourth gear. I just ported the case (a more experienced friend did it for me). But once the 4rth gear exploded (lost 2 teeth!!) and so did the cruciform i thought of making something more racey, fun to ride in and out the city but still with a good top end for touring, so i put the long third and short fourth and the special cluster by DRT and i decided to make it even more torquey with the RZ exhaust. The set up you suggested is certainly good but very traditional... i picked Pinasco and not Polini cause it's generally considered more reliable, at least in Italy. In fact i only seized after 30 km with the new set up ;D
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Post by pxguru on Jan 8, 2013 0:26:49 GMT
Based on the rough measurements stated and norms. With the 0.25mm base gasket you will currently have 166 degrees exhaust duration and 118 degrees of transfer duration. This will begin to pull in top from 4500rpm and max out in gear at 6500rpm. Somewhere in your parts from Pinasco they gave you a 1.5mm base gasket like this one www.sip-scootershop.com/en/products/gasket+cylinder+base+th+15mm+_90760000if they didn't you need to buy one! The 0.25mm base gasket they gave you was for the standard 57mm crankshaft. The 60mm crankshaft needs a 1.5mm base gasket (half of the extra 3mm). In a kit they should have included one. When it is all assembled the piston will be 1mm down from the top of the barrel. The piston should NEVER be poking out of the top of the barrel with a Dykes ring piston! And with normal rings, a very custom head (which yours isn't). When you get your new piston and re assemble, only fit the 1.5mm base gasket. You will then have 172.3 degrees exhaust duration and 125.5 degrees of transfer duration. This will begin to pull in top from 3500rpm and max out in gear at 7500rpm. I guess the squish will be about 1.7mm but you will need to measure it to be sure. 140 main jet to start with. Don't touch the timing. You don't need to change anything else. See how It goes but I think it really will pull like a tractor this time and you will be putting the standard gearbox back in!
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Post by sbwnik on Jan 8, 2013 1:09:35 GMT
Did no one notice the question about putting extra base gaskets on? This would increase the squish, not lower it. Just thought I'd throw that in for the sake of it
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Post by pxguru on Jan 8, 2013 7:06:41 GMT
Nik, you can't skim read a thread like this one! Did you see the photo where the Dykes ring is poking out the top of the barrel? He didnt fit the 1.5mm spacer for the 60mm crank!
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Post by joey on Jan 8, 2013 9:17:30 GMT
I think he's measured the dome and not the deck............ I can't see any ring sticking out............ mind you I haven't got me glasses on.
Now assuming that he's measured (or at least attempted,) correctly then he presently has more than 2mm squish, if he then adds another 1.25mm I can't see how that's going to help?
As for the timing.... I'll reiterate that the IT mark is not necessarily 18deg BTDC, it's a guide only and should be used as such. You'll need to strobe it to be sure.
My opinion due to modern sh*te fuel is that if a kit states 18deg then knock it back to 16 in order to reduce pinking, let's not forget that most manufacturers haven't changed their literature for years and modern fuel has a much higher tendency to knock.
Modpx, just clarify for us, as I can't really see from the pic.......... at TDC is the extreme edge of the piston below or above the top of the cylinder?
And I know we're going back over old ground but when trying to measure your squish it's the extreme outer edge between piston crown and cylinder head that you're trying to measure. As guru has said if you don't get any squashing of the solder with one or two strips then keep adding until you get a measurement, even if you end up with 4 or 5 lengths of solder twisted together.
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Post by pxguru on Jan 8, 2013 9:38:26 GMT
If you look at the picture of the head and the picture of the piston at TDC the squish will be less than 1mm. He is just not measuring it right.
Do Pinasco make a special longer barrel for a 60mm crank or is it the same barrel as the 57mm with the Pinasco 1.5mm spacer? ;D
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Post by joey on Jan 8, 2013 11:25:02 GMT
Well according to SCK the only difference between the two kits is that the head on the 225 accomodates the additional stroke, no need for 1.5mm packer.......... again who am I to argue? Perhaps Pinasco think adding an extra 1.25mm to the bottom isn't the best way to go?? They recommend the SIP Road too. CLICK FOR LINK
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Post by modpx on Jan 8, 2013 11:43:22 GMT
Well according to SCK the only difference between the two kits is that the head on the 225 accomodates the additional stroke, no need for 1.5mm packer.......... again who am I to argue? Perhaps Pinasco think adding an extra 1.25mm to the bottom isn't the best way to go?? They recommend the SIP Road too. CLICK FOR LINKExactly like i said before i was sure that when i bought the kit that wouldnt need any spacer cause the pinasco head had an already calculated squish for the 60 crankshaft cylindrer kit... but i'm also hearing from others that the piston shouldnt be above the cylinder head... im really confused on this one.. PMS (punto morto superiore) =TDC (top dead center). pxguru: in case a spacer is needed that should be put at the base to diminish the squish not between the head and the cylinder to increase it, right? But if instead the squish is already good cause the pinasco head is made appositely for that than i coud "space" the cylinder head and increase the squish? what benefit would i get? I gave up on the squish calculation, i tryed for hours yesterday and nothing comes out... if you can make me a drawing of the strands how they should be twisted and so on... im sure iis the easiset thing to do but for my little experience i know that what comes to Vespa even screwing the simplest nut can make your life a hell and slow down your job for days!!
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Post by joey on Jan 8, 2013 11:48:43 GMT
As i asked before fella....... is the EDGE of the piston protruding above the top of the barrel or just the dome?
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Post by modpx on Jan 8, 2013 12:26:47 GMT
As i asked before fella....... is the EDGE of the piston protruding above the top of the barrel or just the dome? just the dome..you are making me doubt thou... i have to go and check again but looking at the pic that shouldnt be the upper ring for what i recall
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Post by modpx on Jan 8, 2013 14:22:34 GMT
just checked it again. Definitely just the dome.
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Post by joey on Jan 8, 2013 15:57:21 GMT
And the edge of the piston is below the top of the barrel?
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Post by modpx on Jan 8, 2013 17:35:09 GMT
yes is below.
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Post by joey on Jan 8, 2013 18:05:02 GMT
Okey doke, that means that if you've got the new Pinasco head then you have a massive squish........... You can mess about forever trying to get everything right to give top performance but at the end of the day it's a Pinasco (not my cup of tea due to only one transfer same as standard....... we've moved in the last 20 plus years since the kit came out ) If you were happy with the performance prior to your seize then leave it alone, just lap the head and refit............ As i said previously it looks as though your head was blowing which may be the cause of the seize........ Make sure you torque tighten the head when refitting, warm the motor up and then retorque. To check for any further leaks just spray a little WD 40 around the cylinder base and head with the engine on a high tickover....... if there are any leaks the WD40 will bubble up and show where the leak is. Just a quick tip for lapping your head.......... colour the sealing face with black or blue permanent marker pen which after a few seconds lapping will give you an indication of any high, or low, spots.
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Post by modpx on Jan 8, 2013 18:21:12 GMT
do you think that is why i couldnt find any squish? so you say that by spacing the base or between the head and the cylinder i wont get any better performance (more torque/top end etc..)Just a quick tip for lapping your head.......... colour the sealing face with black or blue permanent marker pen which after a few seconds lapping will give you an indication of any high, or low, spots. Read more: vespa.proboards.com/index.cgi?action=display&board=general&thread=3135&page=3#ixzz2HPPWYFGDok so no spacers? at any level? nothing like more torque/top end/acceleration? thanks for the tips.
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Post by pxguru on Jan 8, 2013 18:38:34 GMT
Joey, check the head picture he sent (on the 1st page). Doesnt look deep dished to me. Looks just like the old Pinasco head for the 57 crank.
What would you guess the squish is with that head?
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Post by joey on Jan 8, 2013 19:07:15 GMT
I wouldn't like to take a guess kid, if he says it's the new style head for 60mm then it should be about 1.5 to 2mm. Seeing as he already has neg deck the squish is going to be massive, borne out by the fact that he had no compression on 2mm solder.
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Post by pxguru on Jan 9, 2013 9:05:47 GMT
If is the big question I checked the part number of the head in the picture modpx posted and it it confirms what I thought, the head he has is for the 57mm crank. The deepdish Pinasco looks totally different and has a different number. I still dont know why he cant tell us exactly what the squish is now Modpx, Put it back together as it is, if you want it to overheat again. Or put the 1.5mm base gasket if you want it to go faster and have more torque without overheating. Or buy the Pinasco deep dished head and have it no so fast and highly reliable!
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Post by modpx on Jan 9, 2013 10:50:28 GMT
If is the big question I checked the part number of the head in the picture modpx posted and it it confirms what I thought, the head he has is for the 57mm crank. The deepdish Pinasco looks totally different and has a different number. I still dont know why he cant tell us exactly what the squish is now Modpx, Put it back together as it is, if you want it to overheat again. Or put the 1.5mm base gasket if you want it to go faster and have more torque without overheating. Or buy the Pinasco deep dished head and have it no so fast and highly reliable! Hi guru, which part number are you talking about precisely? I can't see any number in that picture apart "Gruppo Pinasco Genova 810"
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Post by modpx on Jan 9, 2013 11:04:00 GMT
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Post by sbwnik on Jan 9, 2013 11:39:48 GMT
I'm out of this conversation, I've passed the limits of my knowledge on tuning I know some things, I don't know other things, I know when I'm at the limits of my knowledge. I just ask one thing... when this is resolved, can someone please put up a brief, plain English, explanation of the result?
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modpx
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Post by modpx on Jan 9, 2013 16:02:18 GMT
The kit i bought is for longstroke, confirmed. If it wasn't i couldn't be running at all, you can't run a 57 stroke kit with a 60 longstroke without those 1.5 mm. cause the piston would bang against the head. In the Pinasco kit the cylinder is the same either for 57 or 60, is the head to be different so i dont know what numbers Guru checked before but they are irrelevant...(or so it seems).
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Post by pxguru on Jan 9, 2013 18:50:40 GMT
Don't you just love buying stuff of ebay
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modpx
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Post by modpx on Jan 10, 2013 1:49:42 GMT
Don't you just love buying stuff of ebay Alrite, after many researches i came to the final conclusion that the my head is for longstroke 60. In the first the cylinder head of an italian guy from an italian Vespa forum who has the same cylinder head as mine, the model is vrh c60 (c60 stands for corsa60=longstroke60) and the code is 810. The second picture is the "vrh pro candela centrale" (central spark plug) version , it's still for longstroke and is code is A3610. The third pic instead is a 215 cylinder head. The code 810 is the same as the longstroke. If anyone from this forum has a pinasco 225 with a different head and can prove it i'll be glad to change my mind Alternatively can contact Andrea Pinasco in person! ;D ;D That said I'll lap tand seal he cylinder as i was told before, i'll tighten the head harder than before and upgrade the mainjet. I'll check the spark plug colour and avoid squeezing the gas too much till the end of the running in. I'll keep you posted. Attachments:
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modpx
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Post by modpx on Jan 10, 2013 1:51:08 GMT
Don't you just love buying stuff of ebay Alrite, after many researches i came to the final conclusion that the my head is for longstroke 60. In the first the cylinder head of an italian guy from an italian Vespa forum who has the same cylinder head as mine, the model is vrh c60 (c60 stands for corsa60=longstroke60) and the code is 810. The second picture is the "vrh pro candela centrale" (central spark plug) version , it's still for longstroke and is code is A3610. The third pic instead is a 215 cylinder head. The code 810 is the same as the longstroke. If anyone from this forum has a pinasco 225 with a different head and can prove it i'll be glad to change my mind Alternatively can contact Andrea Pinasco in person! ;D ;D That said I'll lap tand seal he cylinder as i was told before, i'll tighten the head harder than before and upgrade the mainjet. I'll check the spark plug colour and avoid squeezing the gas too much till the end of the running in. I'll keep you posted. Attachments:
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