Hi - Just bought an '04 trailblazer that I was informed doesn't run or barely starts up and runs (which is true). I was told next to nothing for compression and it needs a top end. From what I've read this may be a common thing with these. What should the compression be for this machine?

I guess I am going to tear it down and put a new piston kit in it. Not sure if I can just get away with a hone or need to bore over. I took the head off and everything looked OK. Cylinder walls looked real good. Obviously I couldn't see the side of the piston. Do I have to take the cylinder in to get rebored or do it myself? or should I just hone it myself?

I did get it running and it sounds......ok (I guess) but it has NO guts! So far he is right - maybe a piston ring or something to give it low compression
any help would be great. I will check the compression tonight. Thanks!

From the rookie in west MI - Johnnie

 

Comp needs to be over 100psi.If not take the cylinder off and take it to the shop that you want to rebore it and get the correct size of piston.It will most likely need bored out ( every one I have done has needed it)

 

Hmm, it is right at 100 cold or hot.........It runs like a dog...............Like my 2 cylinder snowmobile running on only 1 cylinder............I guess it has to be, no ?

what should they be? 120, 150, 180 ??????

Thanks!!!

 

yeah I just rode it like 5-7 miles and was OK - just a dog.........It will idle OK when in nuetral but wants to die when I put it in gear. and it clunks hard into gear.............

 

if it has 100psi it should run alright. guessing around 130 psi is stock(not sure) but maybe you want to check and clean carb and maybe check the clutches,belt as well. make sure the belt isnt bad and the secondary buttons arent worn out which will make it seem to have no power. imo.

 

Probably carb. I just picked up a 2000 Trailblazer. Power seems fine. but a lot of dead spots in throttle and terrible throttle response. So, ordered a carb rebuild kit. will see what happens with that

 

Hmm, so 100PSI should be OK stendori? The dealer told me that's way too low.
So stock is only 130 ? I thought it woul be more..........
Hmm, dang.... I think it does look like it could use a new belt....

brian - please give me an update after you put your carb rebuild kit in it. Mine doesn't have any dead spots. Just has NOOOOOOOO power.................

Anyone have dimensions of what the piston / cylinder should be at ???

Man - I am really stuck here...............

Any more opinions would be great!!!! Thanks!!

 

i have had my fair share of crank seals and intake gaskets on the last 2-250 trailblazer and trail boss..just a thought

 

Check the secondary buttons

 

OK will keep you updated. Also, found online that stock compression is 126psi