[Gingervitis]

Hey guys.

New to me 1991 331 stroker Edelbrock Performer II upper/lower intake and heads.

Blew a gasket last week - I was getting on it hard in first gear and white smoke (I mean huge clouds of white smoke) started coming out of the exhaust. I limped home (6 blocks) - exhaust smelled like coolant and coolant was dripping out of my tailpipes. Coolant level was very low but temp gauge never got hot. Oil is not milky.

Side note: I was thinking that it was a blown head gasket due to pre detonation because my dumbass didn’t think about fuel octane with a stroker motor and filled up with 87 octane. This happened on my way home from the gas station after filling up. I haven’t done the compression ratio calculations (help would be appreciated on that) but I believe I should be running 91?

I started tear down and just pulled the lower intake to find a failed lower intake gasket as seen in the photo. The question is - should I assume that the failed lower intake gasket was the source of huge bellowing smoke out of my exhaust? Should I pull the heads to inspect and replace the head gaskets and bolts anyways since I’m this far?

Thanks in advance

 

[rob]

that happens a lot when using the gasket with rtv around the water ports on the heads and intake.

it is possible that a leaking intake caused your issues. order 1250s3 or 1262s3 which is steel reinforced and will not have that issues the current intake gasket are having.

as easy and cheap is an intake gasket sway is, i would do that first before changing the headgaskets.

 

[Blown85GT]

that happens a lot when using the gasket with rtv around the water ports on the heads and intake.

it is possible that a leaking intake caused your issues. order 1250s3 or 1262s3 which is steel reinforced and will not have that issues the current intake gasket are having.

as easy and cheap is an intake gasket sway is, i would do that first before changing the headgaskets.

Yes to all of this.

I has similar issue with my car, but my leak was more of a weep (at all 4 corners).
Ran that way for 15 years, but it never did run right and slowly drank coolant.
I didn't discover it until I pulled engine to rebuild.
New engine has 1250s3's that rob mentioned.

I'd say good chance it's the intake gaskets, but since you have it apart, just do a compression or leak down test.
Disconnect the serpentine belt so your water pump doesn't spin while cranking if doing compression test.

 

[90MarkVII]

And....once you have put it back together with the steel core intake gaskets, you should check the lower to head bolts after a few heat cycles. You will find they need to be snugged up.

 

[Killer95GT302]

I 2nd the leak down test

 

[Gingervitis]

Thanks for all the input guys. It would be easiest for me to do a compression test, but I have the fuel lines disconnected. What’s the easiest way to disable the fuel pump so I don’t pressurize those disconnected lines when I turn the engine over? Or should I go rent a leak down tool?

 

[Blown85GT]

Pull fuel pressure relay.
I think it's under driver's seat.

 

[Gingervitis]

Pull fuel pressure relay.
I think it's under driver's seat.

Thanks! Compression looks good, thankfully. I’m assuming high compression on 1/4/5/8 is due to coolant in those cylinders. They were spitting out coolant during compression test. You guys agree?

1- 205
2- 180
3- 180
4- 215
5- 205
6- 180
7- 190
8- 210

 

[strokeme]

Thanks! Compression looks good, thankfully. I’m assuming high compression on 1/4/5/8 is due to coolant in those cylinders. They were spitting out coolant during compression test. You guys agree?

1- 205
2- 180
3- 180
4- 215
5- 205
6- 180
7- 190
8- 210

Yes, and then use a 1262S3 intake gasket instead of that current 1262

 

[Gingervitis]

Yes, and then use a 1262S3 intake gasket instead of that current 1262

I had already ordered a 93334 - should I ditch that and order a 1262S3 instead? Not certain what material the 93334 is made of..

 

[strokeme]

I had already ordered a 93334 - should I ditch that and order a 1262S3 instead? Not certain what material the 93334 is made of..

That gasket is sized for a stock head, but it is steel core. Measure the intake port and use either a 1250s3 or 1262s3.

 

[Gingervitis]

That gasket is sized for a stock head, but it is steel core. Measure the intake port and use either a 1250s3 or 1262s3.

I apologize for my confusion - are you saying the 93334 is steel core, which is what I want?

My Edelbrock performer RPM head ports are 1.15” x 1.96” which matches the 93334.

 

[strokeme]

I apologize for my confusion - are you saying the 93334 is steel core, which is what I want?

My Edelbrock performer RPM head ports are 1.15” x 1.96” which matches the 93334.

If that gasket matches the port, good. Yes its steel core

 

[Gingervitis]

I got everything put back together with new lower intake manifold gaskets and a new upper to lower intake gasket. Engine started up and idled great, but I immediately had a lot of white smoke and coolant drips/splatter from the exhaust. I let it idle for maybe 2-3 minutes and still lots of smoke. At first I thought it might have been burning off residual coolant, but I assume that would not last that long, correct?

I’m a little confused as to what the problem could be. I thought the only way for coolant to get into the combustion chamber was from the intake or head (either gasket or crack) or a cracked block. The compression test tells me that the head, block, and head gasket are good, correct? Still no coolant mixed with the oil. Where should I test next? Looking for a little direction here, any help is much appreciated.

 

[96pushrod]

Do a combustion gas test on the coolant

Combustion Leak Detector

Amazing deals on this Combustion Leak Detector at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

 

[Ilusivefox]

Going to have to drive it to burn the junk out of exhaust.

 

[Gingervitis]

Do a combustion gas test on the coolant

Combustion Leak Detector

Amazing deals on this Combustion Leak Detector at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Just to clarify - a combustion gas test would indicate a blown head gasket (not intake gasket), correct? Wouldn’t this have been eliminated via my compression test?

 

[96pushrod]

Just to clarify - a combustion gas test would indicate a blown head gasket (not intake gasket), correct? Wouldn’t this have been eliminated via my compression test?

If there’s still a bunch of white smoke I’d just run the combustion gas test. At least you can for sure cross that off the list as the cause.

 

[Blown85GT]

Just to clarify - a combustion gas test would indicate a blown head gasket (not intake gasket), correct? Wouldn’t this have been eliminated via my compression test?

May not show up with a compression test.
Compression test is fairly quick (meaning the actual compression stroke is quick), so if the head gasket failure was small, it might not show low compression.

 

[Gingervitis]

Thanks for all the advice so far fellas. I just ran a combustion gas test and it passed. Fluid stayed blue (or at least very, very, very close to blue). I tested it after about 5 minutes of idling then again after about 10 minutes of idling. The white smoke didn’t show up until the car idled for about 90 seconds fwiw, not sure if that means anything. Attached a few photos.

Any ideas? Did I flub up the intake gasket install and it’s still leaking? Are there any other ways for coolant to get into the exhaust?