Questions: Arrow on piston, Milling cylinder head, stock washers

[HeadSmess]

teflon gasket jointing material...

it is the engineers choice of material for high temperatures and high pressures... non reactive, doesnt stick, easily dismantled, squishes to minute clearances...

from memory...300C+ at about 4000psi.

your (worked, high compression, high performance racing) engine will be lucky to get a peak pressure of 1000psi

there is a "special" teflon string available, but as mentioned..teflon tape, twisted into a string works fine. and is a lot cheaper.

if you want pink or yellow, go for it, ive always just had white stuff on hand. its still teflon.

it may take a few goes to get the technique down pat. dont worry about popping the head off again to make sure, practice makes perfect!

they (?) also recommend very minute grooves cut into the sealing surfaces...a dead smooth, flat surface has no "grip" so to speak. think of an LP record sorta thing. as the head comes stock, is fine. unless there are any obvious gouges in it...leave it alone.

 

[Neufcruz]

Just got my windowed piston so ready to put that in and head on. So I remove the metal gasket and replace with Teflon. And pics of how to? Even a sketch would work for us slow learners.lol
I bought the heavy duty bolt kit. There's 4 large Allen head bolts the size of the studs. Do these replace the studs? I don't see where else they would go. Never seen a head go on with bolts and not have studs. If so, every time you pull the head the entire jug comes lose?!!!
Do I use Teflon on the jug Tom case?
I'm getting close!
Mike

 

[HeadSmess]

pic...tures? what eez zis peec-ture?

sheesh, you only gotta make it into a donut sort of shape...not that hard! as long as its a few mm in diameter bigger than the piston/bore, she'll be good. the trick is to not move it out of line when installing the head! personally i couldnt care less if its overlapping anywhere...

dont even contemplate doing it for the lower gasket...unless you have a LOT of patience that spot, good old cardboard from a cereal box, the standard gasket as supplied, expensive gasket paper from an auto spares shop, or if youre into experimenting with port timings and compression ratios, alloy shims, all do the job

bolts? no studs? no comment... i have seen it but i cant say id ever design it that way... definitely more likely to strip the threads in the case if you plan on dismantling it fairly often.

there should be a spigot on the base of the cylinder that keeps it lined up anyway... just doesnt keep the holes and gaskets lined up but hey, just a little wiggle will cure that.

 

[Neufcruz]

Thanks Headsmess.
Just making sure I do it right.
You answere a bunch of question regarding the bolts and lower gasket as well that I just posted.
Appreciate the clearing up.
I'm very new to this and don't plan to have apart that often. I hope!
Mike

 

[canalcat]

Tore my cylinder apart , pins for rings were on exhaust side!! Well that's how I reassembled it ( new rings and honed cylinder. ) , now she fly's about 32 mph!!! GO BIKE!!!!!!!!

 

[Neufcruz]

Tore my cylinder apart , pins for rings were on exhaust side!! Well that's how I reassembled it ( new rings and honed cylinder. ) , now she fly's about 32 mph!!! GO BIKE!!!!!!!!

So now we have 3 on here that say ring pins on intake and 1 says exhaust side.
I'm assuming the intake side unless corrected! My windowed piston was the wrong one so now going to drill myself.
Mike

 

[sbest]

Luckily Mike, due to my Army experience my vision of you drilling yourself involves a lot of fancy marching.
I hear others have different interpretations...

Canalcat: These engines have small intake and exhaust ports so no danger of snagging the ring end on the exhaust port with the piston backwards (on these engines only). There are 2 other possible problems. The piston pin is slightly offset in most pistons, not it is on the wrong side. This may or may not be the case, many cheap pistons have the pin centered. The worst worry is the end of the rings and their locating pins are subject to the exhaust heat and may fail early.

Steve

 

[crassius]

any mention of port mapping on these should be considered 'rude humor' - not sure if I've ever seen two barrels with exact same dimensions of port machining - I have seen kids put pins at exhaust side & snag a ring in the port

 

[butre]

So now we have 3 on here that say ring pins on intake and 1 says exhaust side.
I'm assuming the intake side unless corrected! My windowed piston was the wrong one so now going to drill myself.
Mike

yeah ring pins go on intake side. I've seen plenty of engines destroyed by putting the ring ends on the exhaust side

 

[Neufcruz]

Thanks butre.
Going intake side.