low compression piston

[Juggalo]

does anybody out there make low compression pistons for a 416ex? im talkin like 8:1 compression. does somebody make them or am i gonna have to get some custom made?

[TC426EX]

WHy you want to go lower than stock?

[6858-400ex]

i have heard u can run up to 11:5:1 compressin on pump gas

[hart]

He probally dosent want the Higher compression of the 11.1, my guess is that he wants to put a Tubo on, and u need low compression or you will detonate your motor just because compression creates heat and such.I belive you can have JE custon bulid you a piston for yor needs..

[Juggalo]

hart guessed it correctly...its for a turbo application. so sounds like a custom made one then eh? pricey...

[cals400ex]

i bet you will need something custom. i don't even know if JE likes to do that unless you buy 4 or more pistons. i have heard CP does though. their pistons are supposed to be awesome so i wouldn't have a problem using one.

[Craig02]

You could try stacking base gaskets and using a stock thickness head gasket to lower the compression some.

[frosti108]

i like craigs idea. thats what i was thinking...

but you never know how stacked gaskets would hold up...

[2muchquad]

well if your thinking about a turbo,i would imagine you would need a 6.5 or even 6 to 1 compression piston for turbos.with even as little as 6 pounds of boost you will have astronomical cylinder pressures with 8 to 1 piston.400ex s break studs with simple 12 to 1 setups..:(

[rneal]

If you start stacking gaskets it will turn into a point of failure. Not to mention, you may need a custom cam sprocket made to correct the timing. Most adjustable sprockets are intended to go the other direction.

[Juggalo]

Originally posted by 2muchquad
well if your thinking about a turbo,i would imagine you would need a 6.5 or even 6 to 1 compression piston for turbos.with even as little as 6 pounds of boost you will have astronomical cylinder pressures with 8 to 1 piston.400ex s break studs with simple 12 to 1 setups..:(

we've already had it running at 8 PSI with 11:1 compression. it ran good too....just not very long lol. it was expected tho. where can i find more info about these CP pistons? i have never heard of them. a phone number or a website would be nice :)

[ja400ex]

have you cosiderd how much you can lower your comp. by creating a larger combustion chamber by openning up the head. Not sure how much diff. you can acheive with this but it can be done. Talk to someone who does custom head work

[nakomis0]

call cosmetic gaskets, they have different size head gaskets that could get you a lower comp. Go bigger on the head gasket not the base

[Craig02]

Adding thicker gaskets to the head and base do the same thing, you should not get the head gasket too thick or it will blow. You could probably get a good machinist to cut down a normal piston to lower compression, but you would have to do the calculations to find out the ratio.

[wilkin250r]

Originally posted by nakomis0
call cosmetic gaskets, they have different size head gaskets that could get you a lower comp. Go bigger on the head gasket not the base

Why the head gasket? The head gasket is directly sealing combustion pressures and heat, and thus is subject to WAY more stress than the base gasket will ever see.

The base gasket is little more than an oil seal. The only problem I can see with a thicker base gasket is flatness. If one side gets compressed more than the other, the cylinder will tilt slightly. Forward or backwards isn't a huge problem, but side to side will cause the piston to walk the pin, and even a few thousandths will cause problems.

Me personally, I say perish the thought of adding gasket thickness. It's a band-aid, a cheap solution that will cost you in the long run. Yes, custom pistons are expensive (especially if minimum orders are involved), but repairs tend to be even MORE expensive.

[F-16Guy]

Originally posted by wilkin250r
.... Yes, custom pistons are expensive (especially if minimum orders are involved), but repairs tend to be even MORE expensive.
And if you're installing a turbo, you can't be that broke!!:D :D