Ok guys, I need some help here. I know for sure I put the head gasket on correctly, torqued to proper ARP spec with the ARP bolts, and this motor was just rebuilt with a nice .017-.018 piston ring gap all around. I couldn't figure out why the car won't run, so I did a compression test.

Cylinder 1 - 70 psi
Cylinder 2 - 130 psi
Cylinder 3 - 0 psi
Cylinder 4 - 133 psi

I am baffled here. I was expecting really good numbers since we built the motor right, but could it possibly be cam timing related? I don't see how it would be head gasket since 2 and 4 have great compression and the other two suck.

 

With a number like 0psi I would look towards issues with the cam timing or valves. Try a leakdown.

 

shouldnt the gap be around .0035-.004? it seems the ring gap is to tight, and causing excessive blow-by.

 

Just to clarify, are you measuring in inches or metric measurement? When I looked around, I saw about .010" for an N/A build and .020" max for a boost build...I went with .017-.018" because my boost build isn't excessively crazy. I hope I wasn't supposed to use .040-.045, that's significantly wider than what I used. I just posted on the LS-T thread to see what they say.

 

check your valve lash.... you have some valves not closing

 

This or bent valves. You would have to forget to install the rings or have a hole in the piston to get zero compression.

 

I know I should search this, but does anyone have a known good link to describe how to do this? I don't want to do something horrible to the engine because I didn't follow a good set of instructions.

I had the head rebuilt when we were putting the motor back together, so the valves were straight at the time, but that's not to say I didn't bend the valves with this problem. I checked my cam timing and it seems to be spot on though.

 

yea it would have to have no rings on the pistons for it to have 0 compression.

 

yea if the cam timming was off and you tryed starting the motor with v2p contact, it would bend the valves.

 

For what ever reason. Be it cams out of time or just hanging valves.

Your ring gap is fine.

MB

 

http://lmgtfy.com/?q=how+to+check+va...honda-tech.com

 

Did you look around the garage? You might have forgotten to put a piston and rod in the number 3 cylinder.

LMFAO… How did you build the motor but don’t know how to set valve lash?

 

timing....

 

LOL that's awesome.

Satisfied, I really don't know what to tell you lol, I've never built a motor before this one, so I had help from a master tech at the Toyota dealer I used to work at...plus lots and lots of searching. I didn't even think about valve lash adjustment.

Rechecked the timing, it's dead on. Hopefully valve lash it is.

 

I got the same issue with a b16 60/150/60/150 new piston rings. I don't know what can be the problem, I took the head to the shop and they check it and said it was ok. I also have white smoke coming out of my oil cap any suggestion????? please help driving me crazy.

 

Whenever you get your head back from the machine shop the valve lash are usually loose and you must set the valve lash to spec after assembling the head and setting the cams at tdc im assuming you diddnt.gl

 

went to check valve lash today, and cylinder 1 was tight, but cylinder 3 is extremely tight on the exhaust side...to the point where I can't adjust them loose enough to hit the oem gap. All I can think of is that maybe the machine shop put intake valves in the exhaust side on that cylinder...but I don't see how that's physically possible to make it seal since the diameter is so much different.

I really don't know what to do now aside from parking the car and waiting until I can afford to rebuild the head.

 

did you go in the correct order to set lash? if the cam lobe is not on the smallest part, you will not get it to loosen correctly. make sure you go 90 deg and check that the valves have closed for the cyl your working on.

 

 

LoL you can't just go down the line to adjust the lash... You have to make sure the cylinder you are working on is at TDC (on the compression/power stroke) to make sure the camshaft lobe is not touching the rocker arm. You set valve lash off of the base circles of the camshafts.

Just get a cylinder at TDC then follow the firing order from there you can watch the camshafts to see if the valve is on the lobe or base... You will be turning the crank 180* (the cams 90*) after every cylinder until you finish.

 

OK here's what I did.

Put motor at TDC, adjust valves on cylinder 1. Intake and exhaust valves were all a little bit tight. That cylinder was the 70 psi cylinder.

Turn crank 180* to BDC, go to adjust on cylinder 3. I went out and looked again, and at BDC, the exhaust valves are open. I can't figure out why they're open however. I double checked and I don't have an intake cam in the exhaust side or anything...I may have one cam from a b18a and the other from a b18b however, since I have two sets of cams. I can go take a picture of how open the exhaust valves are if anyone needs to visually see. I'm baffled as to why it is that way. Cylinder 2 has the Intake valves partially open at BDC, and 3 has the exhaust partially open.

 

I just re-read satisfied's post, and I think I found what I'm doing wrong. I wasn't watching how far I'm turning the crank...I'm turning the CAMS 180*, so that's my problem hopefully.

Sorry for being such an idiot guys...thanks for all of the helpful posts however.

 

you go by the cam gear marking not crank pulley when doing valve lash

 

http://www.c-speedracing.com/howto/v...alveadjust.php

 

this should help set you straight.. from what it sounds like valve lash is your problem