I have had a really difficult time tuning my 383 and because it keeps sucking oil into the intake runners via the bottom of the intake gaskets.

I have AFR 195 heads, a Weiand Action plus intake, and I am using Fel Pro #1205 gaskets.

When I initially assembled the engine, other than the RTV on the water ports and end walls I did not use any sealer on the on the intake gaskets, and I torqued the bolts in the proper sequence.

The black soot coming from the exhaust told me that something was wrong, and the tiny bit of oil pooling on the gasket between the intake and the head gave me a good idea of where to look for the problem.

I replaced the gaskets, but this time I used a thin coat of Permatex #2 around all the intake runners between the gasket and the head (no sealer on the intake side).

It seemed to seal for a short time, but I was soon seeing more black soot and recently started seeing oil seepage at the gaskets again.

From the pics you can clearly see that there is oil seeping past the gaskets, and although they are a little blurry you can see some buildup on top of several of the intake valves.








The #5 valve has the worst buildup on it.






It appears that the gaskets are compressing a little more at the top than at the bottom, so I might need to have the intake milled in order to get it to seal.
Is there an easy way to determine the angle and amount to have the intake machined?

Does anyone have any good tips for getting a stubborn intake to seal properly?

Any and all advise is appreciated.

Thanks

 

If the heads were milled (making them shorter) this changes the relation with the intake.
or...
If the block was decked this has the same effect.
There was another post about this same problem recently and there is a formula for the amount to remove from the intake.
Sorry I don't have a link for that on hand right now.

 

On my 396 in my Chevelle I had the heads cut and my intake gaskets let loose and dumped water in the oil! After I had the intake cut to match the heads never had any more problems.

 

I had a problem like this on a 350 with an edelbrock intake. Sealed it twice and it still sucked oil into the intake. What I did the third time is I took some sandpaper and block-sanded the gasket surface of the intake to "scuff" it up a little. The gasket and sealer always came off nice and clean, so I figured this would help. Seemed to, I haven't had the intake of in probably 5 years now. Maybe you could find some thicker intake gaskets and try those two. I used the blue fel-pro's.

KC

 

The heads are fresh from the factory AFR 195's, and unfortunitely I do not know the deck height. I bought the block from a local machine shop that did the machine work on it. I remember asking them questions about deck height before deciding to purchase (the answer was "we only take off enough to make the deck true"), but I failed to get the exact spec. from them when I picked up the block and I didn't have a practical way to measure it when I started assembly.

 

Luckily I have not had any trouble with the water passages (knock on wood). The RTV that I used around the water ports seems to stick very well to both the head and the intake, unlike the permatex #2.
Is it OK to use RTV on the intake runners too, or should I try some other type of sealer like the spray on copper stuff?

 

Others have reported similar problems using those 1205's. Try using the el cheapo blue Fel-Pro Permatorque type gaskets you can buy at AutoZone (and other places).

Sometimes, it seems we outsmart ourselves buying the fancy stuff...

 

I've been following oil consumptions posts for awhile now and most members say to use the 1205's and Not the 1204's...I believe I have a similar problem and I have the 1204's on now. I'm looking into the 1205's or Mr. Gaskets Ultra Seal...

 

There's an angle gauge available for checking Intake to Head angles. It's part# 2520 for SBC(pre'87), #2521 for SBC(from '87), #2522 for SBC 18°, and finally #2525 for BBC. These gauges are designed to provide (to aid in machining) a 1° interference angle, which results in approx. .005" more gasket compression along the floor of the port when tightened.

The angle difference between manifold and heads can be off by as much as 5°. On a 2.75" tall Intake flange, this would create a .025" mismatch from top to bottom, and create less load required for sealing at one end.

Intake leaks seem to be more of an issue when combining different manufactured parts together that are "supposed to fit". Different manufactures have different tolerences, and the "stack up" of these variances effect sealing. So basically the "height" and "angle" between the Heads and Intake needs to be checked for correct sealing.

Hope this helps,
Later.

 

Believe me I know where you're coming from. I'm now taking my son's 327 apart for the third time. We bought ProComp Aluminum heads for it and the Edelbrock Tunnel ram intake just will not seal on them. It's creating one hell of a vacuum leak. First I used trim to fit Fel Pro's. Then I used 1205's. I gave in and bought a set of Camel Back Double Hump's and plan to use the Edelbrock recommendation of their intake gasket #7201. When I bought the heads the description didn't say anything about the intake runners not being stock. I've never run into a problem like this before. Good Luck on yours.

 

That sounds like what I might need. Who is the manufacturer and where do I purchase?

Thanks

 

Kevin,

Sorry to hear about the problems. Did you actually have oil visible between the head and intake from the top?

Any idea on what your going to do? You might want to call DES and see what they think or if they have a recommendation.


Tim

 

Tim,

The gaskets were oil soaked on both sides, and there is a little oil buildup on top of the intake valves (some worse than others).
I used no sealer on them during the initial assembly, and Permatex #2 the last time I put it together. It sealed a little better last time, but the Permatex had obviously hardened and allowed the leaks to re-emerge. I think I have decided not to cut the manifold at this point, but I will use RTV when I assemble it and I might use different gaskets. Hopefully it will solve the problem.
I have a few days before my transmission get back from the rebuild to decide, so I will be calling several different sources for more suggestions.

 

Those are Fel-Pro part#'s.

Need to change my profile name to Ex-GasketDude! As they've been doing head count cuts in June and I just got my walking papers yesterday (6/13) after 15 yrs. At least I'll get more time on the Jet-Ski with my 7yr old this summer

Anyway, borrow, scam, or buy this gauge. Split the cost with a buddy or have your local club buy it for future use. I don't know the cost off hand (as I got my back when it was a future release) but they will save you headaches in the long run. Maybe the local machineshop will let you borrow theirs for the night? Knowing you'll be bringing your manifold in for machining.

The more I read these Intake leak issues the more it makes me think about writing a paper and posting it here or on the other forum for those to read and download. All the sealing "rules" apply no matter who's gasket you use. And I see the same mistakes being made here, repeatedly.


Oh yeah, don't dis the gaskets if its a hardware issue on your end .

Good Luck,
(sorry for the rant)
Later.

 

Kevin sorry not trying to highjack this post.

G.D sorry to hear of the job problem. I know it doesn't help but that happening all over the country these days but not much is being said or done about it.
I would sure like to read your paper if you write it.
Good Luck,
Gary

 

Question: Are you applying any thread sealer to the intake manifold bolt threads? I use the black rtv and have eliminated the seepage around the bolts that caused pooling on the intake. I haven't driven the '80 enough since my installation of the latest set of Printoseal gaskets (1256) from Fel-Pro to know if oil consumption has improved or not. Had the standard 1204's on prior installation. Similar to prior installation, I applied Gaskacinch on the underside of the gaskets but this time, I allowed them to cure for about 1 hour before I installed the end gaskets and torqued all bolts. Hoping this makes a difference. Oh, in both cases, I thoroughly cleaned all block, head and intake mating surfaces.

My combination: OEM L48 block (no decking as far as I know), DART Iron Eagle 180cc heads, Edelbrock Performer Intake (3701).

Noticable changes so far: quieter on top side of engine. I suspected some leakage that contributed to what I thought was valvetrain noise. Still some noise but quieter...

 

Gasketdude,

I'd like to see that paper also. Would help a lot of people on the forum.

Sorry about the job. Hopefully you will find a better one.

Cheers,

Pete

 

I got the intake back on earlier this week, and after finally getting the transmission put back in today it is running again.
After thouroughly cleaning all the gasket surfaces I checked the fit of the intake to the heads using my Mark1 eyeball, and a set of feeler gauges. It appears that the intake fit slightly tighter at the top than the bottom (0.005" or so) but I don't think that is enough to make that much of a difference.
While I was looking though I noticed that several of the bolt holes in the intake had impressions of the bolt threads on the top side. It appears that the bolts had been supporting the intake and preventing it from being squeezed down far enough onto the heads.

I went after all the bolt holes with the die grinder and opened them up enough so that I could easily thread all the bolts though the intake into the heads even without a gasket in place (just to be sure that there would be no problems once the gaskets were installed).
Since the permatex #2 didn't appear to work worth a flip the last time I opted for RTV (Utra Grey) on both sides of the entire gasket this time, and also used the same RTV on the bolts instead of the permatex.

It started right up and once I got the timing back where it is supposed to be it ran much smoother than it did a week ago. The manifold vacuum is up 2" from where it was, so I feel pretty certain that the intake is sealed now. Only time and miles will tell if I have solved the problem for good but I am very hopeful. I am going to work on tuning the carb again tomorrow, maybe a have more of a fighting chance now that it the mixture is not being screwed up with all that oil mist getting into the cylinders.

Oh yah, It sure is nice to have a transmission that shifts properly now too!!!!

 

One more question on this subject...if the intake gaskets are the problem, will you see a ton of oil in the intake when you pull off the carb???

 

I did not see any oil in my intake either under the carb, or in the runners. I could only see oil on the gasket surfaces, in the intake runners of the heads, and lightly baked onto the top of several of the valves.

I did search the forum archives before posting this though and I recall seeing at least one thread where the guy was getting oil pooling in the intake under the carb and he suspected that it was coming from the intake gaskets.