CHT rings

[vespasco]

Im getting bored of changing the broken CHT sensor gauge rings on my sip speedo after every 500-1000 miles so want to weld one onto the cylinder head. No more p,i.t.a. especially when ill have a few plug readings to do.
Has anyone tried doing this.?   I will post a pic if i could.
I can really only see one place to put it,  on the extremely short fin between the spark plug hole and the stud hole right next to it (1 o'clock).  
If i routed out a small piece to fit the adapter it should be a good fit and give faster readings.
Its an odd size thread too?! 4.28mm!?. I was thinking of buying/making a long nut instead of the flimsy adapter but with that odd thread?
(Its a Koso adapter for SIP speedos)

I'll hopefully be able to edit in pics later , to help make more sense!

[vespasco]

Ok. Im replying to myself here! O f
I found a solution today!
Time will tell just how effective it is
But it is possible.

[henri]

is that a blob of weld ,or ali brazing ,H

[vespasco]

A blob of weld. There aint much room to get your bits inbetween the fins. It just about penetrated the cht adapter. Feels solid.
Oh er

[henri]

from what ive seen on other forums under a spark plug or on a fin gives diff temps ,with the fin being bout 15-20 degrees lower coz of the heat loss from head an distance from hottest spot the plug,so i'm hoping your aware of this n are taking it into consideration .
am interested coz have been wanting a cht for easier jetting setting but been put off by tales of broken senser rings , an asked bout weld/braze as ive had a kit to solder ali in my shed since my dad gave it to me 10 years ago ,jus never found a use for it yet n thought it might do , but can see it would be hard to use as youve got to have shiny ali to get solder to work. h

[vespasco]

This will be the 3rd time i try to post this reply!! Its different everytime i type it too! Bloody technology!! I wish i had a desktop pc with proper keyboard n mouse!

Yes, i can confirm, with sensor under the plug i got readings of around 230°f when cruising/wot
With sensor moved to under cylinder stud nut readings were typically around 215°f

So i will expect different readings with this newly positioned sensor. Probably around the same 215°f -ish. Unfortunately,theres no weld on the other side of the sensor.. The better the heat transfer to the sensor , the better/quicker the readings would be.

The sensor rings break at the joint of the ring/threaded section, so ive eliminated this weak point!!! They break, due to being bent when installed (weakens it) ,the heat from engine but mainly because of the vibration of the motor.

Would an EGT gauge be better suited for jetting, especially alongside a CHT gauge?!

Cht gauges do work as a warning.
I forgot to torque down my carb top once.. The cht picked up on this about 2 miles before i would have noticed. So you could say it saved my kit!!


(I asked the welder about brazing/soldering but he simply shook his head). Im sure you could prepare the surfaces ok..just not much room to work in!!

[sime66]

Nov 9, 2014 22:20:38 GMT vespasco said:

This will be the 3rd time i try to post this reply!! Its different everytime i type it too! Bloody technology!! I wish i had a desktop pc with proper keyboard n mouse!

Off topic – sorry, but for vespasco really:

You can use your Android’s Bluetooth for a keyboard and mouse.

My P.C. and my laptop are both due for renewal soon, and I’m way off making decisions about what to get (and M’lady needs a tablet), but at present I use an extra Bluetooth mouse and keyboard when the laptop is on my desk:



(In fact on weekends I have the laptop plugged into the HDTV via HDMI and use the Bluetooth keyboard and mouse from the sofa)

Those are old now, and if I go for a tablet I’ll be looking at getting something like this, which would work with an Android tablet/smartphone – it has a keyboard and numeric pad, which is also a mouse/touchpad:



I know it’s off-topic, and I know there’s experts on everything here who’ve got/done better, but just trying to help; my point being it’s quite simple to get a mouse and keypad for your Levono 5500 tablet if you need to.



CHT/EGT is something I looked into before, but gave up on then because of mounting a suitable display without going SIP Speedo, but I’m following your thread with interest.

[henri]

the better contact area was why i considered ali brazing ,with the idea of having the sensor lying horizontal at the bottom of 2 fins ,so as not to block air flow in the area too much .but as i said above the difficultys of preparing the area well enough an then getting enough heat in to do the job put me off .
an yes a cht alongside a egt would be a even better set up ,but only really neccesary for a dyno/rollin road session ,
my idea was to use a cht like it worked for your carb top loosening,as a early warning system whilst in early stages of dialing in jetting in a new engine .
as i'd be moving it from engine to engine i'd be more likely to suffer sensor failures ,no matter how careful you are tightening it down puts stresses into it an as you say vibration finishes the job .kru251 mentioned his cheaper multimeter came with a temp setting an probe that seems accurate ,so ive been thinking of getting one an sussing out a temporary way of attaching probe on a known good engine to see what its reading .an then transfering to new engines as needed ,bit seat of the pants stuff really but hopefully good enuff to spot a temp spike n kill engine before seizing .
thats why i'd be interested in the temp readings from your moved sensor ,to give a wider variation in my base-line , as reckon with it vertical in the cooling air stream you readings are going to be lower again than under the stud ,should just be a case of care n learning the new temp range as in safe/not safe . H

[vespasco]

Good morning chaps
If youre playing with engines and tuning i would recommend a cht (and egt)?! But on a stock i think its a bit overkill for stock engines but not totally unnecessary as proved above.

Off piste.....
I bought a bluetooth keyboard a month or so back. Its really nice to use a keyboard you can actually feel, especially the spacer bar. This is where i end up editing...words all joined together. Its the cursor that a pita...if i move it to a word i need to edit, and then edit it, it very often goes somewhere completely different without me realising, deletes other words and it takes a while before i realise where the cursor actually is or where it was. Then i forget what i was typing so have to start again. I should slow down when typing i guess!! Other than that it works well and i even bother to connect it and use it sometimes!! I do have a laptop but it only comes out for my work, for reasons stated below...
Along with a smaller screen it can get tricky. Im actually 'fairly ok' with technology. Ive built a few pcs, mostly for recording music/instruments/sounds. Ive also used HTML to write websites. Im usually the one in the family who has to set up pcs, tvs, sky dishes etc etc but am hoping my teenage nephew will take over from me soon!!
I do love the tabs, quick and easy normally but as a 'main computer' its a bit fiddly compared to a desktop. You may have noticed i dont often copy n paste links very often. With a mouse it takes nano seconds...with my tab it takes ages.

Even more off piste and on the black run....
Im not sure if you will believe me or not but its true........ I dont have the luxury of mains 240volts!!! Hence no more desktop, or wide screen tv to double up as a monitor. I live off 12v !!! And everything i use has to be super effcient and absolutely necessary and generally mustbe able to recharge from a 12v car cigar lighter/adapter. No im not a 'kin pikey and i dont live in a caravan or own a whippet on a piece of string! (I didnt know how long it should be! Hehehe)!
You could say im off setting my 2 stroke carbon footprint , hehehehe!

[henri]

i lived "off-grid" for a bit ,whats the wind speed like in your area , as a car alternater with propeller blade on a scaff-pole charging as many old car/truck batterys as ya can scrounge an a 12v/240v converter ,like the ones for caravans an canal boats ,so long as youve enough battery reserve to "buffer" the 12volt you can run computers ok without voltage spikes/lows crashing them all the time .just hang some wind chimes on it an call it " eco" /" green" an also "renewable" ,ya might get a eec grant on it . h

[vespasco]

Ive often considered doing just that. And now the winters approaching and the wind gets up and the sun dont shine its time to go wind power. A veggie diet should help
I use a large solar panel to charge leisure batteries. Running a pc is possible but @ 300watts thats a luxury i can well do without.
I have an invertor but never used it. Everything is 12v !!

[henri]

inverter is what i should of typed instead of "converter" , an the veggie diet will help, i dont carry spare fuel anymore ,just a length of pipe an a quorn sausage butty (missus is veggie) , if i run out just eat butty ,wait 30 mins ,insert pipe n go LPG, H

[vespasco]

Back on track again....
Cht readings so far with new sensor posistion....
Cruising at around 50mph, 9°c ambient temp, misty too,
185°f.
Normally, with sensor under plug it would have read around 215°f +\-10°

Im thinking of ways to improve the heat transfer from the head to the sensor...(to get hotter/quicker readings)
Any ideas appreciated

[henri]

only way is more contact area ,but as ya photos show an ya mention there aint much room to work in there , maybe suggest to ya welder to use a mig set n take off the gas shroud an up the gas flow to max,an flood the area with gas ,maybe rags or cardboard baffles inbetween fins to give a space you can purge with argon whilst welding ,without the shroud he might be able to build more weld around the connecter giving a better transfer of heat .
also the connecter is in the "forced air" cooling flow ,a heat saving coating will give you hotter/truer readings,more close to actual temps inside the head , ceramic coatings not feasible ,but what about "lagging" it with something, cooking foil or exhaust wrap, ive some offcuts of wrap in my shed i think if you want to try it ,H

[vespasco]

Plan B


I had a practice run on a redundant Pinasco head, pictured above.

I ground out a little of the fin, tapped an M5 hole @9.5mm deep. The sensor is a little sloppy but loctite should keep that from vibrating loose.

Ive got some plug chopping to do soon so next will be to do it for real on my current head and see how long it lasts...hopefully longer than those crappy rings which break so quickly...

[henri]

nice change of direction ,should work well, i thinks it loctite 207 ya could use or permatex copper gasket goo, not thread locker but would do the job an is suitable for high temp jobs like cylinder heads , H

[vespasco]

Oh crumbs! Id better not destroy this head too much in case you want it H!! I think its the one you picked up on in another thread.
Its still usable! But take into account its a 69er
(Diameter)!
You may just get away with skimming your existing head (is that the central plug)? Youve room to skim 1.5mm off, which will also achieve a nice squish too. This would loose you upto 5cc by my reckoning (if you dont use a base gasket)


That mod' above would be better if i was to tack a few blobs of weld there, to build it up a bit, to give the sensor more of a bite...and not go so close to the inside of the combustion bowl

[henri]

destroy away mate ,its all good research an theres other heads , its all still in my head/planning stage at moment ,that an i'll prob have to sell a scoot to finance it ,always a "emotional" moment, it helps that i look a bit of a dick on a smallframe but its still 1 of my babys . H