Projects Mid Life Crisis 62 Vette

If the intake manifold is dry and only the intake ports on the head is oily, it has to be the mating surface IMHO. Has anyone ever doubled up the intake gaskets? I know that doubling the gaskets might cause port misalignment but this might be a cheap and easy way to determine if the mating surfaces are the cause. IIRC way back in the day when guys angle milled heads I think they used 2 gaskets to a side.
Dan

 

"If you go back several pages you’ll see the new heads and aluminum intake unpainted on the engine. The fit looks spot on."
Looks good from on top & on ends, but you can't see the bottom of the ports & valley & that's where it would not be sealing ...............................

 

The intake manifold ports would naturally be dry, sucking oil from valley would go straight to head port where the vacuum is the strongest.

 

If it is a milling of block & or heads problem see if these gasket port would work. Gasket is thicker thats what you would need.
MR GASKET #116 INTAKE SET SMALL BLOCK CHEVY LARGE PORT | eBay

 

Jim, have you considered just swapping back to the original cast iron intake manifold to rule out the porosity issues with the aluminum one? It might not run worth a damn with the heads and cam change, but it would run good enough to see if that was the problem.

 

Went back reading Friday posts but not clear if all plugs oily & all head intake ports oily or only a few. Has to be problem fit between new heads & intake not just gaskets. Try a new ( different ) intake manifold. If head was off & intake off, prop them up & bolt together see if any gap on underside but not the same as manifold wedged between two heads. Strange problem & pain in butt

 

Post 1646.

How about the Valve Guide Seals.

 

If the intake valve guides and seals are badly worn I'd expect the problem to show up as intermittent valve train noise. Or maybe blue smoke out the tailpipe after prolonged idling or during closed throttle de-acceleration while still in gear.

 

Have you ruled out aluminum intake manifold interference to soup can? You have the shortest can they make but it's worth a look.

 

I have hade that issue with a low Edelbrock Streetmaster. JW

 

The question is where is the oil coming into the heads from. Even if the mating surfaces of the heads and intake were off, there should be some evidence as to the seal being off. If the oil was pooling in the heads and washing down past the valve seals I could see it. But I wouldn’t think just bad seals would cause that kind of consumption. Maybe pull a head and set it with the rocker valley level. Fill the valley and see if you can see where it leaks through. Might cycle the valves if you have the tool to do it manually.

 

If it’s the intake gasket letting vacuum suck the oil into the head, does it get worse if you stuff a rag down the oil fill breather cap tube? (I believe I read the pcv is already plugged )Or can you feel vacuum at the oil fill tube with your hand?

 

the machined surface around the head ports looks quite slick, maybe too slick to seal without some kind of sealant.
I would clean all gasket surfaces with lacquer thinner and use a non hardening gasket compound like Permatex 2 on both sides of the new gaskets, toss the end gaskets and apply a nice bead of RTV Black silicone in their place. (looks like that is what you did there)

 

If you're still considering some porosity in the underside of the intake manifold, would this maybe tell you anything?

Invert the manifold and remove the heat shield under the carb. Clean the hell out of it and paint the underside with some form of Glyptal. At least if the porosity was near the outboard intake ports it might explain why the oil only shows up in the cylinder heads.

Yeah, I'm just grabbing at straws here . . .

 

Yes, I thought about that, it's one thing I can do pretty easily.

The intake a factory 1962 340 HP 327 intake, it clears the can just fine. The heat shield from the 250 hp intake fits this 340hp intake. There's no soup can interference.

I just did this yesterday, no help.


Thanks for all the suggestions!

 

Wasn't there a "stump Squirrel" thread a few years back? I think Squirrel just did it.

 

Some ideas for quick checks.
For mounting surface angles, bolt cleaned manifold to cleaned head with out a gasket. Check for even gap across the ends.
For a warped manifold:
(1) Bolt manifold to a head on the bench and use a feeler gauge to check for gaps at bottom of ports.
(2) Coat mounting surface with marker
On a hard flat surface, place stickit file paper (220?), or discs with opposite sides cut straight, in an area large enough to accommodate the manifold.
Carefully hold the manifold flat on the abrasive and work it back and forth several times.
This will also tell you how flat the mounting surfaces are.

 

Well, what's the verdict?

 

@tomcat11 he mentioned pulling the engine in this thread.
https://www.jalopyjournal.com/forum/threads/sick-66-drag-drive-oct-2024-mo-nm.1305132/page-2

 

It actually looks like it's sealed up now...no oil in the intake, the gaskets looked good.

But there were some other reasons I wanted to take it apart again...one was the main bearings, the other is that the performance is not quite what I hoped...I think I will be happier with a smaller cam. I'm thinking about swapping the valve springs, and maybe finding a different intake, and planning to do some tinkering with the carb.

Mean while, I'm replacing the main bearings, which I noticed were kind of rough looking when I had the engine out last time. I had got new bearings for it, but they were the wrong ones, so this time I have the right ones, and am replacing them. Oil pressure would get pretty low when it was hot, like 30 psi at 3000 rpm.

I'm going to put the flat tappet cam and original heads and intake back on it for now.

Another thing is that it's been getting pretty bad mileage with the new stuff, it was getting around 18 before, now around 12...and this trip I'm taking isn't going to require the car to be quick, just make a long drive and be able to race every day (1/8th mile).

So expect more changes as time goes on.

 

What intake are you wanting to run?

 

Not sure yet....

 

I have a performer that was on a 350 I bought to build for a boat. If you’re not looking to really rev that high, they work pretty well. I’m probably putting something a little more vintage on the boat. It was cast in 98.

 

Late idea but…pcv baffling leading to oil consumption?

https://mewagner.com/?p=1221

 

It has baffling....

Anyways, I pulled the engine, put the flat tappet hydraulic cam back in, as well as the power pack heads and iron intake and WCFB. It is back to it's old self, for now.

I'm considering changing the valve springs in the Trick Flow heads, and putting them on later this fall. And playing with different intakes and carbs.

I welded an O2 sensor bung on the pipe while the engine was out, so I can check the mixture. I think the AFB was running kind of rich, although I put stock size jets/rods in it.

 

Can you tell us what O2 sensor and gauge (kit?) you installed?

 

I just put the bung in the pipe, haven't screwed in a sensor or plugged it into anything yet. I was planning to just put in the temporary setup, which is a very old Innovate LM-1 handheld system, it plugs into a cigarette lighter, and the wideband sensor, and displays AFR or lambda on an LCD display.

 

I like it, looks basic.
The Ededlbrock carburetors seemed to rich out of the box for me. The one thing is getting the idle with no ported vacuum signal at that port. If your lucky it's only a metering rod change.

 

I think all Eddy's run rich out of the box, they don't want you leaning out and have to buy you a motor!