bigdsz

iTrader: (1)

When my friend was ccing his intake and exhaust runners water leaked between the valve and valve seats on a few of the valves. These are newly ported heads with new larger valves, will the valves seat themselves and not leak after the engine is run for a while? I this anything to be concerned about?

Taspeed

iTrader: (1)

might want to lap the valves a little and have them pressure checked to see if they are seated. They should not leak if they were redone.

M6HuggerSS

depends on your method..... did you use a little grease between the valve and seat?
if not, do it again .....if so. than you missed a spot!
-spread grease around seat and rim of valve
-install in head and spin a few times..
-wipe away any excess in chambers

this should work perfect.

now when your all done with assembly be sure to VACUM TEST your heads to asure proper seal!
if a port is leaking, just hand lap that valve, and try again! and try again untill ALL
ports are vacum tight!

THIS IS VERY IMPoRTANT!!!!!!!!!!!!!!!!!!! be patient.

bigdsz

iTrader: (1)

Ttttt

Grimes

iTrader: (3)

yeah, use grease or some vaseline you can wipe off later. Also, you can use alcohol, so you don't have to worry about water sitting around for so long.

bigdsz

iTrader: (1)

The point is, is this leakage going to stop once the engine gets running and the valves have a chance to "seat" themselves. I'm worried about power loss because I don't have a good seal between the valve and seat.

M6HuggerSS

how do you know if you have a bad seal? did you vacum check them? thats the only way you can really tell for SURE....
and yes you can loose power! fix them before you install them!
give some more info on your method of cc'ing and vacum testing first!

bigdsz

iTrader: (1)

Three intake valves are leaking, the worst valve is forming one drop between the valve and valve seat every 4 seconds. Water was used instead of light oil to CC to avoid a mess.

M6HuggerSS

im guessing the heads are fully assembled and you are only cc'ing the CC?
you need to seal the valve with grease to properly cc the chambers.....

if they are allready assembled and they are still leaking! than you need to hand lap what ever valves are leaking untill that are all vacum tight!!!!!!

so are they assembled allready?

bigdsz

iTrader: (1)

Yes the heads are assembled. The intake and exhaust runner volume is what was being checked. My argument to my buddy is that it's nothing to be concerned about, but he doesn't agree with me. Probably shavings or dirt between the valve and valve seat.

FASTONE

If those are newly machined heads they shouldn't leak, the builder should have done a vacuum test on them before you got them,I"d call and talk to the shop that built them.Also use rubbing alcohol to cc with it is cheap and easy to clean up afterward plus you can save it and re-use.Use the colored alcohol its easier to see.

MelloYellow

What kind of heads? Patriot had some bad valve seals 6 months back.

bigdsz

iTrader: (1)

The leaks are between the valves and the valve seats, not up by the valve seals. The worst one is only leaking one drop every 4 seconds, which is not very much. I don't know the history on the heads other than they are 5.3's and are new with larger that OEM valves. I'm just looking for someone to tell me this is not an abnormal situation and that the valves will seat after the engine has been run.

2xLS1

iTrader: (25)

The force of compression and combustion is going to be pushing the valve against the seat and sealing them tighter when they are on the car.

M6HuggerSS

its true that after running the car a while the valves may create a better seal by them selves but its not for sure!
id re- vacum test the heads!

M6HuggerSS

when finishing up my heads, while vacum testing them we had 2 valves that had a minimal leak.... so we hand lapped them both, took only an extra 20 min. and now i know for SURE that there good.

best to do it now.

bigdsz

iTrader: (1)

The head was taken to the machine shop and the problem valves were reseated. Interesting point, the porter we were talking to said that he avoids lapping the valves because it messes up the sharp angles of the valve job. Go figure. Never heard that one before.

Pro Stock John

iTrader: (34)

Yeah you needed to fix them, otherwise you would second guess that decision to ignore it down the line.