Looking for some Help...SBC Oil fouling plug

[Horder]

Very thankful for the help from all of you that replied.

I will reply with pictures when the intake gets pulled.

I think I was extremely careful with the gaskets and install??

Used a Fel-pro 1256 gasket. A nice bead of The Right stuff on the China walls which appeared to have a perfect gap with the intake sitting on the gaskets. Used a sealer around the water jackets etc

I’m expecting an angle issue with the intake vs the heads....maybe. Haha

[Tom68]

The old manifold might be warped.

[dannobee]

Or the deck and or heads have been milled enough to where the intake no longer fits correctly. You might need to have the intake machined.

[Horder]

I did check mating surfaces for flatness. Checked gap at China wall and it looked to me to be a good fit. My last engine had a manifold that needed milling because of head milling and decking etc so I am somewhat familiar....

I will certainly be looking at this in depth. I’ll measure the gasket thicknesses, top and bottom when I remove to look for variances.

The drivers side gasket does appear to be sitting 1/16” lower in relationship to the intake manifold than the passenger side upon further inspection...

I’m a rookie at this obviously. Lol

Enjoying doing it myself and learning

[1980RS]

Doesn't the PCV pull vacuum form No. 8 runner on a Dual plane intake? I would check that 1st.

[Tom68]

The drivers side gasket does appear to be sitting 1/16” lower in relationship to the intake manifold than the passenger side upon further inspection...

That could do it with that light weight manifold, not lot of surface area to help it pull down flat.

Sounds like a sweet little motor.

[travis]

I am not familiar with the felpro 1256, and it may be fine, but I've had trouble in the past using a harder intake gasket made for an iron intake with an aluminum intake. Something like a felpro 1204 may be a better choice.

When you pull the intake look at the impression left in the intake gasket surface. That can tell you a lot right there.

[rgalajda]

I am not familiar with the felpro 1256, and it may be fine, but I've had trouble in the past using a harder intake gasket made for an iron intake with an aluminum intake. Something like a felpro 1204 may be a better choice.

When you pull the intake look at the impression left in the intake gasket surface. That can tell you a lot right there.

1256 fel pro Port Height (in.):
1.990 in.
Port Width (in.):
1.230 in.
Gasket Material:
Composite with coating and Printoseal
Thickness (in.):
0.060 in.
Port Style:
Stock

1204 fel proPort Height (in.):
1.990 in.
Port Width (in.):
1.230 in.
Gasket Material:
Steel core laminate
Thickness (in.):
0.060 in.
Port Style:
Stock

[Horder]

Attached is a picture of the 1256 gasket.This pics were taken when building the engine. I have not pulled the intake yet

[rgalajda]

Here is a picture of a BBC intake gasket that I drilled holes in to insert a lead shot held by grease . I then tightened the intake down progressively and torqued it. Then removed intake to measure lead shots. Gasket was .060" thick. Some of the lead shots measured around .062" while others measured around .092". The worst one wasn't squished at all.
Motor used a litre of oil in about 350 miles before we had the intake machined.
This was one of those OEM "winters snowflake" aluminum intakes. Thinner surface . I also bolted a newish aftermarket aluminum intake on with the lead shots (as a test ) and all the lead shots compressed to aproximaely .060".
By the way it took the machine shop twice machining to get it right.

This is the tool they should have had
http://www.bhjproducts.com/bhj_content/ ... ng/iag.php

[Horder]

My intake is a "winters snowflake" factory intake as well.

That is great info!

I have an original 66 327/350 HP L79 winters intake as well. I used the Z28 winters intake instead as it is widely considered to be an excellent dual plane intake and much better than the L79. With the carb and air cleaner installed they are hard to tell apart.

[Schurkey]

the PCV system is the stock looking system as used on the L79. It was referred to as a closed system
The 1966 "closed" PCV system had a PCV valve that was threaded into the oil filler tube on the front of the intake manifold and a hose that ran to a vacuum port. Another hose went from the back port in the block and ran to the air cleaner.

When engine was running I pulled off vacuum line to PCV in oil fill tube creating a major vacuum leak. Engine RPM picked up.

Engine is running too rich, at least at idle.

I shut off the engine, capped the vacuum line, removed the cap on the oil fill tube. Started the engine. RPM was lower than when PCV system was fully functional.

Totally normal.

I then checked to see if I could feel any vacuum on the oil fill tube. I did not. A piece of paper did not seem to stick to the opening. Even so, I sprayed the carb cleaner down the tube... RPM dropped. Repeated 3 times. Dropped each time. A 5 second shot would stall the engine. Keeping in mind that the cylinder I am having trouble with is a straight shot to the oil fill tube.

Did you disconnect the hose from the back of the engine to the air cleaner? Was the air cleaner still in place?

We know the engine is overly-rich at idle. You spray burnable carb cleaner into crankcase, where it's heated, expands, and is drawn into the air cleaner--which makes the engine EVEN RICHER. So, sure, the idle dropped, and too much aerosol carb spray caused it to stall.

1256 fel pro Port Height (in.):
1.990 in.
Port Width (in.):
1.230 in.
Gasket Material:
Composite with coating and Printoseal
Thickness (in.):
0.060 in.
Port Style:
Stock

1204 fel proPort Height (in.):
1.990 in.
Port Width (in.):
1.230 in.
Gasket Material:
Steel core laminate
Thickness (in.):
0.060 in.
Port Style:
Stock

I'm having problems with the 1256 distorting over the course of several months. Is the `1204 REALLY a steel-core gasket? I don't think it is--I think it's got a sheetmetal section to block the exhaust crossover, but not a steel core. I can't find out for certain.

If the 1204 is genuinely a steel-core gasket, that'll be what I use next time--after getting the manifold planed.

1256 after about ten months:

2022_K1500_Intake _Gasket (5).JPG

[rfoll]

I have had valve guides go bad in 500 miles for various reasons. You could bring the piston of the offending cylinder up to tdc and pull the spring.

[Horder]

I did have the air cleaner on and the hose attached.

I will redo the test right now and post the results

[Tom68]

When engine was running I pulled off vacuum line to PCV in oil fill tube creating a major vacuum leak. Engine RPM picked up.

Engine is running too rich, at least at idle.

He added a massive amount of air, it would then be lean but still has to pick up speed.