whats my compression psi supposed to be? is there any online resource that provides this info? does compression decrease drastically over the course of a year, from wear and tear?

I cant find enough online reading material to educate myself on this subject...kinda frustrating, looks like only experience can tell you these kind of things.... keep the comments comming, i cant get info info!

 

ok, so i tore my engine apart. the cylinder walls look just fine.

Do I need to bore out just because or do I order a standard wiseco piston as a replacement and just hone the cylinder? I dont know what I should do please help. I want to get to ordering the parts so please help me out with some answers!!!

I would like to save some money and not bore the cylinder but what is proper practice in this situation? Will my compression go up once I have new piston and rings?

 

piston to cylinder clearance should be less than .004
Best bet is to take the piston and cylinder to a shop and have them measure it.

 

my piston broke on my 250, but it was my fault probably not supposed to hold it wot for 2.5-3 miles, has an aaen stage 5 kit, it sure ran great!!! if I was you, I'd just buy another piston/rings/ set, get it bored and have it done right, then, heck keep it for a couple more years. I would not sell it, just keep it as a back up for when your NEW one breaks or a friend or wife, etc wants to go out for a ride.

 

Did you find out what the compression should be? I have a Trailblazer 250 that is only registering 90 psi.

 

Well, I just rebuilt the engine, bored out, new piston, ported, and milled the head. Wow this thing has some awesome power to it now!!! My compression is now at 135psi, with all the new mods.

 

If i may i have a 89 trailboss always looking for more umph how much did you mill the head?

 

I milled the head .025", that was recommended by Rick Ridder, so that I dont have to run higher that 93 octane gas. I know others who have milled the head .040" but it required race gas.

I have to say I have no regrets spending the $$$ money on all the recent work, I got a real good power gain and I am just loving it!

 

ive looked at all gas stations around and the highest octane is 91.just wondering
what brand of gas you get? but yeah just recently rebuilt mine too wiseco 0.60 over
ported-clutched-k&n air filter and love my ole beater its really a monster if you get on a open road but anyway thanx

 

i put a DG exhaust on my\ine and didnt jet it and i think i blew it up, but i would go 40 over to start, and next time 60. 20 over is a waste of time.