89 Iroc Z

My brother(UVA3rdGen) and I were replacing my busted lifters when we realized that air and oil were leaking up through to of the intake valve seats on #3 and #7 when we turned over the engine. They have practically no compression. I sprayed intake/throttle cleaner on them in a hope to clean off some debris that was preventing a good seal but that only made things much worse. Other then taking the heads off and have a machine shop redo the valve seats and valves is there anything that can be done to regain compression? Also how the heck was my engine running like that before, all it had was a rough idle. I am trying my best to make this engine last till spring, but I am losing hope. Thanks in advance.

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1989 Iroc-Z 5.7 350, Blue, T-Tops

Lightly Moded:
Edelbrock Headers, Rebuilt B&M 700R-4 Tranny, Higher Stall Torque Converter, Airfoil, 3.4 w\posi, K&N's, Ported Plenum
-- Blue LED Bakelite Dash & Climate Control
"Just some 17 Year old spending every dollar I make on my car."

SoCo80p

iTrader: (5)

nothing you can do outside of rebuilding the engine, just drive it like a granny and only when you must and keep your fingers crossed.

TomP

What about a junkyard head, just for now?


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-Tom P (Hot rodded 1986 Firebird 2.8l)

a73camaro

If the heads are off, goto Sears and get a valve spring compressor or rent one from Auto Zone/Checkers. Disassemble the heads and keep the springs with the associated valve. Punch 16 holes (two rows of eight) into a cardboard box (case of oil) and place the valve and spring gear in each hole to keep organized. Clean up the heads and wire wheel the valves.

Get a valve lapping kit, either at Sears or an auto store and follow the directions on how to lap valves.

If you can relap a good seat onto the heads, then reassemble and reinstall the heads. If not, maybe you can take the heads to a high school with an auto shop and have the kids to you a valve job.

If you get a "valve job" gasket set, there will be vale seals that need to be installed.

If none of this makes sense, don't bother.

[This message has been edited by a73camaro (edited November 16, 2001).]

UVA3rdGen

Ya, I am his brother, and I have rebuilt and port and polished my LB9 heads. I did not know you could clean up the vavle seats yourself. I was always told that if you nick the valve seats good, your in trouble. That is good news, I am sure the springs and everything else is on it way out, but i need to just keep the heads going till spring time. even if the seals are leaking I am just going to put on some of those cheap umbrella seals if the old seals are bad, not those awesome ones that have to be pressed into the head. Thanks for the advice, I am going to go see if I can find that kit you are talking about.

Xenodrgn

Redoing seats is easy, but, DO NOT wire wheel the valves....!!! Put them in a drill press and turn them slowly and take off the carbon at the base if you must, but don't touch the stem. Clean up the face and head an everything (this is all optional)...

then go out and buy valve lapping compound (actually it probably comes in a kit, I'm telling you how we used to do it in my mech shop class) then get a suction cup (a -good- one)... run a bead of compund around the face (the part that you need for a good seal) and then press the valve in, and stick the suction cup to it... then turn the valve in there, and turn it good... what we did was like starting fires indian style, put your hands together around the suction cup and rub back and forth, pressing against the valve, hard but not hard enough that the valve won't turn. When your hands got to the bottom, lift the valve out a little to let the compound move around better, and start over... you will see when a seat is forming on the valve, do this until there is a slight indentation, or follow the instructions with the kit. take the valve out, and clean everything up -REAL GOOD-... valve lapping compound is exremely abrassive. If you've got the money have them tanked afterwards to be sure you got it clean... (heck just let the machine shop do everything for you)

Do this to at least the low cylinders, all of them if you want (up to you), keep the parts for each valve together, and good luck.

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1985 Camaro SC - 2.8L, auto.

C'mon, spin 'em for papa...
http://www.xenodrgn.f2s.com/Frontright.jpg

killer305

iTrader: (1)

are use sure you did the correct valve lashing, that couldbe leaving the valves slightly open. if you thought the engine was running good before you replaced the liffters than thats the only thing i can think of besides waht everyone else said

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90 RS 305 tbi, 4 3/4" cowl Hood, Edelbrock TES headers, Flowmaster exhaust, Crane roller cam, comp roller rockers, vortec heads/intake, ported tbi, w/new injectors, MSD probillet Distributer/ coil, 1 inch tbi spacer, air foil, 14x4 k&n flat base air cleaner, Rebuilt 700r4 w/ B&M shift kit, B&M Megashifter, 3.23 posi, 2 12 RF's with mtx amp, top of line alpine cd player, soon to have 90-91 gfx, z-28 wing, new paintjob, rims, and all new lowered suspension.