Instead of having a head pressure tested by a machine shop ($35 or so), I've heard that you can turn the head upside down and fill the combustion chambers with water or windshield wiper fluid to check for leakage.

If the valves are seated correctly will it not leak any fluid at all? If so this indicates a good head, right?

I tried this water leak test on a d15b7 head that had horrible compression #s after mating it to the block. Compression was 30 psi per cylinder, however the valves "visually" looked like they were seated correctly. I took the head off again, left the spark plugs in and put fluid into the combustion chambers... it leaked the fluid. TIA

 

what i do is rub some bluing ink on the valves seating angle ever so lightly and tap it quickly against the seat...you can usually see any mis-contact but you can only put so much blue otherwise it will smudge against the seat...this is assuming of course the valves are still moveable otherwise no go...

 

Another thing you can try with the head off the car is put water in the exhaust or intake ports and see if it comes out between the valve seats and the valve face. the best way would to have a machine shop check it out, but u could try that out GL

 

i use tranny fluid to fill up the combustion chambers. that's what the machine shop told me to use.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ctr83 &raquo;</TD></TR><TR><TD CLASS="quote">i use tranny fluid to fill up the combustion chambers. that's what the machine shop told me to use.</TD></TR></TABLE>

Tranny fluid is oil. That's the last thing you want to use. Even water is too viscous, and it leaves behind surface rust.

Alcohol is what you should use. And no, it shouldn't leak at all. Sometimes the carbon buildup is enough to interfere with seating. If I have a cylinder head apart, I usually lap the valves in until the ports can retain alcohol without a single drop getting through to the chambers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Legion &raquo;</TD></TR><TR><TD CLASS="quote">

Alcohol is what you should use. And no, it shouldn't leak at all. Sometimes the carbon buildup is enough to interfere with seating. If I have a cylinder head apart, I usually lap the valves in until the ports can retain alcohol without a single drop getting through to the chambers.</TD></TR></TABLE>

Yep, I used brake clean, but same concept..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dmotoguy &raquo;</TD></TR><TR><TD CLASS="quote">

Yep, I used brake clean, but same concept.. </TD></TR></TABLE>

+1

 

rubbing alcohol always works great. and its usually about $1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Legion &raquo;</TD></TR><TR><TD CLASS="quote">
And no, it shouldn't leak at all. Sometimes the carbon buildup is enough to interfere with seating. If I have a cylinder head apart, I usually lap the valves in until the ports can retain alcohol without a single drop getting through to the chambers.</TD></TR></TABLE>

Well I picked up another d15b7 head that's in better condition, but it only leaks fluid in the #3 and #4 combustion chambers. The fluid is leaking past the exhaust valves on those chambers and flowing into the exhaust ports.

I'm trying to avoid spending money at the machine shop to correct the issue. It's a beater car, so I'm not concerned about performance, however compression numbers need to be adequate enough for the motor to run well.

Would lapping the valves seal the leak? If so, is lapping valves a fairly easy procedure? I've assembled bottom ends in the past without issues, but have always had cylinder head work done professionally, so this is fairly new to me. Any help is much appreciated.

 

it does not matter how much a valve is bent, it's bent...lapping valves is a final procedure after everything has been rebuilt with fresh new parts and to tolerance to give fresh contact surfaces a massage...so no you cannot lap them to seat correctly you will need to check the guides as well you will need to acquire a new valve set and some bluing ink for checking valve seating...if you do this procedure use a light amount around the valve seat contact angle if you smudge it you wont get an accurate reading...

I apologize if I'm making more work for you then I should or if I'm not making any sense lol...