Engine Nightmare - Part II

[Robert G.]

After getting out the nail that I dropped into my engine, I was attempting to put on the intake manifold and it looks like there is a large gap (1/16-1/32 inch) at both ends of the manifold. I believe the heads were 'trued' during a rebuild a very long time ago. If I used no gaskets at all, the manifold might sit down properly. Other than getting the intake milled down, are there any other options available? Thinner gaskets? The strange thing is I replaced the intake gaskets 20 years ago, but due to very liberal use of gasket sealer, I never noticed the gap. Suggestions?

[John H.]

Re: Engine Nightmare - Part II

After getting out the nail that I dropped into my engine, I was attempting to put on the intake manifold and it looks like there is a large gap (1/16-1/32 inch) at both ends of the manifold.

Bob -

Is that with or without the side gaskets in place?

[Robert G.]

Re: Engine Nightmare - Part II

I just realized that what I wrote wouldn't make sense. John, I had the side and end gaskets in place and have my doubts that torquing the intake down will close the gap on the ends. That's what I am really asking. What should I do if I still have a gap? Sorry, but it's been a difficult day and that manifold weighs a ton.

[Bruce B.]

Re: Engine Nightmare - Part II

A bead of silicone sealer will fill any gap and help keep the end gaskets in place.

[Joe L.]

Re: Engine Nightmare - Part II

I just realized that what I wrote wouldn't make sense. John, I had the side and end gaskets in place and have my doubts that torquing the intake down will close the gap on the ends. That's what I am really asking. What should I do if I still have a gap? Sorry, but it's been a difficult day and that manifold weighs a ton.

Robert------


This kind of a situation can occur when block decks or heads are machined ("milled"). Usually, though, it ends up with too little gap at the end rails and, thus, over-compressing and squeezing out the end seals.

The way to deal with the immediate problem is simple. Just replace the end seals with RTV sealer. I prefer Permatex Ultra Copper. Later GM engines all used RTV instead of rubber end seals. Personally, I would not use the end seals and then add RTV to fill the remaining gap. I would use RTV to fill the entire gap and eliminate the rubber seals entirely.

The above will solve the immediate problem. However, very often when this problem occurs there can also be problems with side gasket sealing which are not so obvious. So, after you get the engine all back together and running, observe carefully for vacuum leaks and/or high oil consumption due to oil being drawn into the intake ports from the lifter valley.

[Edward J.]

Re: Engine Nightmare - Part II

Joe, not to knock the ultra copper, but I perfer the prematex sealant, Its called ( the right stuff) it is black and maynot show up as much as the copper stuff. and has excellent sealing capabilites, I have used in my automotive repair business for may years with great results.