LT1 - leakdown test, headgasket replacement advice, etc

[Pranav]

Quick background, got a LT1 motor along with the car with somewhat unknown history, I had my cage guy handle the driveline install. Had the heads taken off and resurfaced, valves were checked, LT4 valve springs put in, threw it back on the block with those super awesome Cometic gaskets.

Cooling system seemed to do well but got worse over time. Boneheaded mistakes on my part led to it running hot too many times (not bleeding air bubbles correctly, not sealing off the radiator soon enough, stupid ducting decisions, not backing off when it got hot, etc), and now I suspect a leaking headgasket, motor will not stay cool on track. The crankcase is collecting a lot of steam during idle that does not "go away", I am losing coolant somewhere inside the motor, pressure testing to 20lbs with hot coolant shows no hose/fitting leaks, and i swear i saw a few drops of oil in the radiator.

I borrowed a leakdown tester and will test some or all of the cylinders before I go ahead and pull the heads next week.

I had done some reading up and see that the Cometic gaskets require a VERY smooth finish? I've got a spare set of regular Fel-Pro 9966pt that I understand to be more tolerant of rougher deck surfaces/finishes. Would it be worthwhile for me to just slap those on and continue on?

I've got a pretty good idea of what all it would take to R/R the heads, but where I am fuzzy is the best procedure to prep the block deck surface while it is still in the car, and whether or not I should apply any copper sealant to aid in sealing.

Any tips/advice on what else I should be doing?

[Pranav]

Oh and who can I trust in Houston with a reasonable rate and turnaround to resurface the heads and check the valves for me?

[ShadowBolt]

Some gaskets say "use no sealant" but if not I cover both sides of my head gaskets with spray coppercoat. After using a gasket scraper on the block I will use sand paper on a sanding block. I have never had a head gasket fail.

JJ

[Pranav]

Do you rinse the block off with anything before assembly? Worried about the sand paper particles getting in there. When I replaced my wiped cam I gave everything a rinse of acetone before re-assembly...

[ShadowBolt]

Do you rinse the block off with anything before assembly? Worried about the sand paper particles getting in there. When I replaced my wiped cam I gave everything a rinse of acetone before re-assembly...

I blow the pistons off prior to installing the heads. I'm sure a little sanding dust gets in but I only sand the parts I can't get the old gasket off.


Jerry

[Pranav]

Thanks, the Felpro permatorque gaskets I have on hand say no to any additional sealant. Will post up once I pull the heads and have em looked at next week or so...

[Dulaney]

Oh and who can I trust in Houston with a reasonable rate and turnaround to resurface the heads and check the valves for me?

I asked HK Enterprises, and they recommended Westside Performance Machine for your heads.

[Pranav]

Thanks Jim!

[Pranav]

Got the exhaust and intake off, found some drops of water in the oil in the intake valley. Oil that came out of the pan was not milkshaked, looks like it was just steam collecting in the intake valley from the gasket(s).

Got halfway thru unbolting the driver's side head before I crawled into bed and passed out. Hopefully should have both heads off tonight and dropped off in the morning.

Has anyone tried to remove and reinstall the factory exhaust manifold heatshields? Going to to give them and a few other parts an electrolysis (rust removal) bath and paint them inside/out now that we can paint them.

[Pranav]

Got the heads and everything back on, just been slowed down by a million "while you're in theres"

Gotta get the new oil cooler mounted and plumbed then I can fill it up and start it!