ineedboostbad

Just tested the compression on my 97 d16y7
# 2,3,& 4 were 155~160 but #1 was 130...
I put a little oil and checked again and it was the same. 5 tries, all 130~133ish
I have ran about 2 1/5 bottles w/ the 50 shot nossle. fuel pressure was bumped up about 5 psi @ idle before adding the NOS kit.
How bad is this?
Is #1 notorious for going lean due to the poor design of the d16y7 intake mani?

MooreBoost

Did you CP test the engine before you added the nitrous?

ineedboostbad

Nope. but that was about 30k mi ago. 104 on the clock now.

Phase Change Racing

If the comp didn't come up with oil in the cyl your problem is North of the rings. Most likely a valve sealing issue and most likely not nitrous related unless you ran the poor thing *** lean and cooked an exhaust valve a lil.

ineedboostbad

I only put about 1/2 a teaspoon of 20w in... I've never done a valve job on the motor either.
are the numbers low for the rest of the cylindars?
I'm supprised that my 8:5:1 comp 2jz has about the same compression as the 3 good cyls' in my honda

Phase Change Racing

I don't have too much Honda experience but most of the DOHC engines I have worked on squeeze out between 180-210. Some of the oddballs like the GM Quad Four will squeeze as high as 240.

The 155-160 does seem a bit low. How many miles are on this thing? Did you do the test after running it while it was warm?

ineedboostbad

Tested while warm 90 deg out w/ 100 % humidity Was at WOT, w/ 15 amp igintion fuse pulled, all plugs removed, 5 cranks per cyl. went up to like 8 trying to squeeze a few more out of #1. like 104kmi I belive on the odo. I've only sprayed like 23lbs of n20 through the setup over 30kmi.

Somthing may be up w/ the guage as the high 155's is all my supra and the civic have produced. but numerous attempts, cleaned around where it threaded in, put a bead of oil around the gasget on the comp checks threaded bit..

Any info appreciated! Thanks in advance
-James

Phase Change Racing

Compression tests can often be misleading. They do provide useful info but take it for what it is. The best way to determine sealing problems is by doing a leakdown test on all 4 holes.

It sounds like you did your comp test right so like I said before, i'd put my money on a valve sealing problem in that hole.

cubish

considering compression on a single cam will yeild low numbers anyway. compression is only around 9 something and the motor is not very new...

ineedboostbad

Would adjusting the valve clearences be enough to fix this, or might it be a seal?

Phase Change Racing

9 something? You mean 90 something? Either you have a paperweight for an engine or you have no idea how to do a compression test?