ok heres the deal..my buddy has a turbo GSR that has CP 9.8-1 pistons stock bore on a sleeved block..his rings went south on him so we rebuilt it..we used CP rings along with all new bearings and seals..well (the first time we did the rebuild) we start it and its got alot of vapor coming out of the valve cover breather..so we give it a day thinking it just needed to has some load and use to seal (bores where honed by a local shop) and it just smokes like crazy (also had a real shitty leak down on 1,3,4 cyl 2 was great)..so we took the engine apart thinking we did something wrong..well we rering it (used the old bearing because they looked new) and install a new head gasket (re honed it again..this time ourselfs with a ball hone) after we had a nice cross hatch we then mic the bores and find that cylinder number 2 had .002 piston to cyl clearance and that 1,3,4 had .0015 (as per CP's piston spec sheet) well we say its only a 1/2 thou screw it..well we get it all built and the same **** over again..we made sure everything was great..rings where gapped at .017 top and .019 second and oil ring left untouched..but this is where things get real funky..we leak down the engine and it has..25%=1 3%=2 22%=3 26%=4..so I guess my question is this..could it be that the pistons need more wall clearance? cyl #2 is great and its a lil over spec but the ones that are at spec are hurt..

my buddy is getting really fed up with buying rings and gaskets and would like to only do this one more time before he bash's the car in and goes postal!

 

how do you know its the rings??? the leakdown can indicate faulty valves as well. just a thought....

Landon

 

100% the rings..during the leak down no air came from the intake or exhaust valve but alot of air from the valve cover breather..and I mean alot.

 

hmm did you oil the walls and the pistons before placing them in the block. I know some guys who dip the entire piston in oil before putting them in the cylinder. I just coat them with oil and the same with the cylinder walls. You could also bring the block to someone who can do plateau stlyed honing and maybe that will help next time.

 

everything oiled and everything 110% clean.

 

My guess is your bore is egg shaped and no amount of honing or re-ringing will fix that.

 

when the block went to the machine shop he checked all that and everything was great..we even checked it the last time we re ringed it and with a piston and a .001 for 1,3,4 and a .0015 for 2 feeler gauge it was the same all around (piston upside down from the bottom to the top)..I thought the same till we checked it..but here is some news..we just did a compression check and it has 210 all the way accross..no ups no downs and we used to differant gauges to confirm this..Iam starting to think it may have a flat spot or low spot up near the top of the sleeve where the rings sit while performing a leak down..dunno Iam just trying to figure it out.

 

the only things i can think of are:

1. possible installed a ring or 2 upside down
2. out of round cylinders
3. ring positioning is wrong

goodluck man, that sucks either way

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99Hybrid_Hatch &raquo;</TD></TR><TR><TD CLASS="quote">I am starting to think it may have a flat spot or low spot up near the top of the sleeve where the rings sit while performing a leak down..dunno Iam just trying to figure it out.</TD></TR></TABLE>

Now, that is some good logic. Hope everything works out for the best with your boy's car.

 

What did you use to oil the walls?

 

i know the 1st time you said it was blowing smoke, how does the car behave now does it still puff smoke from the breather, exhaust, dip stick? I dont want to insult you but could there be a chance your doin the leakdown wrong. 25% leakage in 3 cylinders would show signs of burning oil if indeed it is the rings.

 

since the lastest set seem to have done better have you actually gone out and flogged the car to seat the rings?

 

we put some rislone "ring seal" in it and have been boosting it all day..car has great power but still has a lil smoke..oh well..if it doesnt seat after a few 20 psi pass's we will get oversize pistons and bore and hone it.