Raising compression using Jb Weld?
 

Alright so I've seen Jb weld used to fix holes in pistons before, I've also seen it used to fill gaps in the cylinder wall. Than I began to think what if you used Jb weld to create a dome on the piston only about a mm or so high. Could this be done if the jb weld was made sure to be uniform all around and still have the valve seats in the piston? Just wondering because I have an Atv and the compression ratio is only 7.6:1 and well I'd like to have it a little higher.

Re: Raising compression using Jb Weld?
 

what kind of atv is it. what engine.

Re: Raising compression using Jb Weld?
 

200 cc honda 4-stroke.... It's surprisingly quick as it stands but as with everything you always want more. I have a few spare engines so if this seems feasible I may try it out on one of them and hopefully I will get a deacent amount of time on it.

If it doesnt seem feasible I may still do it anyways lol get 15 minutes of fun....

Re: Raising compression using Jb Weld?
 

yeah it works just fine. i have jb welded cylinders and a nice size dome i have been runing 12.5:1 compression for almost 3 months now.

Re: Raising compression using Jb Weld?
 

excellant >:D what kind of prep work did you do to the piston and what kind of finishing did you do to the jb weld... any tips?

Re: Raising compression using Jb Weld?
 

no ------- way, the jb weld doesnt melt? if you do this you better ------- clay it to make sure it clears

Do atv motors not run nearly as hot?

Re: Raising compression using Jb Weld?
 

id think it would melt also, i used it on a radiator preped correctly and it melted off :l. just go bigger displacement.

Re: Raising compression using Jb Weld?
 

well i've seen it used to fix holes in pistons and it actually stood up to the abuse. I would guess it would work.... hmm I hope so

Re: Raising compression using Jb Weld?
 

no way this would work. The jb weld will melt right off. I tried to use jb weld on my friend oil feedline on his turbo once and that ---- melted off into a bubbly mess of liquid in about 5 minutes lol.

Re: Raising compression using Jb Weld?
 

I don't think you did. It is not possible. maybe some ass hole told you they jb welded their pistons, but they were ------- with you. this is todays dose of reallity

Re: Raising compression using Jb Weld?
 

it works. my pistons were milled so to reraise the compression i applied some jbweld. it works well and gives that extra power

Re: Raising compression using Jb Weld?
 

http://jbweld.net/products/jbweld.php

good up to 500 degF

avg. ATV cyl. temp on fairly hot day 230-240 degF

If it will hold up to the pressure the I don't see why not.

In my experience, JB weldi s terrible on radiator applications or other liquid applications because the liquids eat through it and soften it up. Plus it's hard to properly prep an area that has liqud going through it so that gets half assed most of the time.

Re: Raising compression using Jb Weld?
 

Ya I tried fixin a radiator with jb weld it craked in the same place 3 days later

Re: Raising compression using Jb Weld?
 

I used JB weld on my header and it melted/burned right off.

Re: Raising compression using Jb Weld?
 

my dad once used some JB weld in his exhaust port on his suzuki LT500 quadracer.. the jbweld charred...
in the cylinder the jbweld will be exposed to high heat.. even if the head doesnt get as hot.. the JBweld isnt a head... it wont last long and will probably cause detonation

Re: Raising compression using Jb Weld?
 

you all are clearly retarded

Re: Raising compression using Jb Weld?
 

Maybe not JB weld...but there may be an industrial "liquid steel" that can withstand the heat and pressure. At least on smaller engines that don't get very hot. I doubt it would work on the cyl walls because of the added friction, but maybe adding a little on top of the pistons?!? I've never heard of it being done before and there's probably a good reason why it's not commonly done. I wouldn't do it but I could see how it would be feasible if you found something tougher than JB Weld.

Re: Raising compression using Jb Weld?
 

Not recommended for use on manifolds, exhaust systems, and other engine components which normally operate at temperatures above 500° F.
http://jbweld.net/products/uses.php
yet they reccomend it for cylinder heads

I love the stories they have on there
"I own a dragster. During a competition, the cylinder head cracked. I didn't have time to repair or replace it, so I filled the crack with J-B WELD. Well, I made my time trials, and took second place! The head still works great, and I'm not going to order a new one."

"My pickup threw a rod and tore a hole in the block. I plugged the hole with large washers bolted together and sealed it with J-B WELD. That was over 50,000 miles ago; still with no loss of oil. Thanks for a remarkable product!"

Re: Raising compression using Jb Weld?
 

engine temperature =/= combustion temperature

Re: Raising compression using Jb Weld?
 

ok so final answer is........

Re: Raising compression using Jb Weld?
 

try it and let us know.

Re: Raising compression using Jb Weld?
 

It won't hold up to the heat. I've JB welded body panels together, and the grinder made enough heat to melt the weld.

Re: Raising compression using Jb Weld?
 

Where in the ---- did you get that info from? ::) The average cylinder temperature on an "ATV" is 230-240? Are you talking about the outside of the cylinder as in the part that's exposed to air(that won't raise compression, dipshit)? ::) There is no ------- way the inside of the cylinder is "on average" 230-240 degrees. I've seen plenty of exhaust systems glowing red hot so there is no fuckign way the combustion chamber is that cold. :1 Punch yourself in the nuts.
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Re: Raising compression using Jb Weld?
 

Agreed. :3
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Re: Raising compression using Jb Weld?
 

No you haven't. ::)

No it's not. :3 Even a highly modified 200cc 4 stroke is slow. :l
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Re: Raising compression using Jb Weld?
 

LOL....seriously? LOL

Re: Raising compression using Jb Weld?
 

Also agreed
So much so that reading this post has made my head hurt

I started to make an actual reply, but then was like WTF. It isn't even worth it. The whole idea is idiotic at best.

Later
Randy

Re: Raising compression using Jb Weld?
 

there really is only one true way to find out yourself.

Re: Raising compression using Jb Weld?
 

if metal pits in combustion chambers how would jb weld survive

Re: Raising compression using Jb Weld?
 

personally i prefer piling up the Weld on my piston with a mig. I made a 25:1 compression piston once....................... :6

Re: Raising compression using Jb Weld?
 

of couse dude all serious engine builders use jb weld to raise compression

Re: Raising compression using Jb Weld?
 

it would serve like a little detonation pillow ;D

Re: Raising compression using Jb Weld?
 

exactly. so OP go and jb weld your stuff and it will be fine!. please let us know how much faster your quad is because of it

Re: Raising compression using Jb Weld?
 

:y

Re: Raising compression using Jb Weld?
 

Re: Raising compression using Jb Weld?
 

[hit in the nuts] :X 240 deg... I was thinking more along the lines of sealing up a crack on the side of the block or something that's seeing coolant temperatures. Inside cylinder temps. are def. much higher.

If you want to try it, go for it. It's your engine not mine ;)

Re: Raising compression using Jb Weld?
 

And real men don't ever raise compression anyways... just add more boost.

Re: Raising compression using Jb Weld?
 

i would like to confirm that statement! why tear apart a motor to jb weld the piston dome. ------- replace the piston!

NEUMAN

Re: Raising compression using Jb Weld?
 

Well the motor is already apart so applying the jb weld would be no problem at all..... and the reason I asked is for some cheap power, if I remember the roots of HMT was to do everything as cheap as possible and I thought to myself perhaps this would be a cheap alternative since I cannot afford a high compression piston right away, plus machine shops are pretty far so I pretty much have to do everything low budget.....

Re: Raising compression using Jb Weld?
 

There is the HMT style of doing things and then there is this.