question on exhaust valves

[mk3sons]

Ok guys.. i have a compression problem with my 2jzge, every cylinder is ~40 psi with the exception of 1 being even less. I added oil to the cylinders and saw no change.

So i pulled the head off, cant even tell if the head gasket was blown (i'v never ran the engine).

Then i decided to check the valves.. so i added some liquid to them and none leaked. good! but then i tried blowing air into the exhaust manifold and the second picture is what i found.. yet no liquid leaked through...

so i guess the real question is: is it normal for air to flow through backward or do i need some valve work?

 

[Suprapowaz!(2)]

It's your bottom end. Piston rings are worn out. Apparently all of them.

Excuse me, I take that back. For some reason I misread that you saw a change rather than no change in compression. In that case that is a mystery. Cause usually when you add oil and see no chance it's the top end. But you say no leaking valves, and no sign of BHG. Sorry for the confusion.

Unless of course your piston rings are SOOooo worn out that the wet test wouldn't make a difference. No major scoring in the cylinder walls? Possibly it overheated and collapsed your piston rings? I just guessing here.

 

[mk3sons]

i could be the head gasket i couldn't tell from looking at it.. there was air coming out of my radiator though with no coolant in it. witch made me think it was super blown, but i cant tell.. I'm still confused about the valves still because the fluid isn't leaking out yet i can blow air through them the other way with my mouth.. so valves.. good or bad?

added notes.
-compression test was done with throttle open.
- full battery hooked up to a charger
- has cross hatch in cylinder walls still but engine condition is otherwise unknown

 

[IBoughtASupra]

What you should do is get gas, fill up each port on the head and watch for leaks.

Place the head on its side, intake or exhaust side up. You can only do one side at a time.

Six cylinders, one port on each side per cylinder and two valves on each side per cylinder.

Fill each port with the gas and then watch all the valves on that side for a leak. You are filling it up through the intake port/exhaust port and watching the valve seats to check for leaks. The cams have to be out to do this.

 

[mk3sons]

whats the difference between that way and the way i did it?

looks a little blown between the cylinders?

 

[hvyman]

Since the head is out. Why not get a valve job and replace the gasket and call it a day.

 

[mk3sons]

Since the head is out. Why not get a valve job and replace the gasket and call it a day.

i wish there was a shop around here i trusted.. or i would. I'm 1 7m and 3k down after i trusted the only one around here with that.. but i guess since it has to be ether the head gasket or valves (right?) that's what ill have to do eh?

 

[suprarx7nut]

I'll second the recommendation to send to a good shop for a head job. If you can't find one locally, you can always ship it out to somebody. It wont always be cheap, but think of the cost of your time and effort putting it together and ripping it out again if something else isn't quite right.

I used to be astounded with the cost of good machine work, but now it makes perfect sense and I'm happy to pay the price for good machine work.

 

[Poodles]

Could also just lap the valves yourself and call it a day. It's not fun though...

 

[IBoughtASupra]

I agree with poodles. Lapping the valves is not bad, just a little timing consuming. I did lap the valves on a 1JZ head I sold, completely rebuilt with seals, a mill and just a lapping job with valve adjustment. I used Permatex valve paste BUT there is a better one but I cannot find it at any parts stores. It comes in a tin and has coarse and fine, the Permatex one is a fine grade.

That head is now on a SupraForums members' car who did 581 on the dyno.

 

[mk3sons]

Could also just lap the valves yourself and call it a day. It's not fun though...

i did not know this could be done yourself.. i looked into it and i think i'm going to try it! Thanks for the help thus far guys!

Am i stupid to think/hope there's nothing wrong with my rings though? considering i only have ~40 psi across the board? even though it didn't change more than a couple psi adding oil and the cylinder walls have no scoring just a cross hatch. I know "while the head is off i might as well bore hone and rering" but i have no money for that..