1994 3.1 Oldsmobile LIM question

[Jesuscookies]

I also found this document and am assuming the same thing. They meant 1.75 and 1.85 respectively for each type of engine gasket.

OK... I think the PDF that I linked to has innacurate measurement info, but it's still useful.
The Dorman gaskets that I posess have the locating pin in the center of the middle port... just like the Small Port gaskets are supposed to.

The PDF says that the Small Ports are 0.75 inches tall and the Large Ports would be .85 inches tall
I think that is wrong because mine measured out to exactly 1.75 inches tall.... but that DOES jive with the .75 measurement.

I cannot find anything that indicates the Dorman gaskets are wrong.

I look forward to your comparison of the Dorman and FelPro gaskets... I suspect that they are the same.
And of course a picture of the gasket laid on top of the head would be great.

[Penglii]

So that's like a defective Dorman gasket?
Because it sounds like mine are likely to be fine.

[Century7667]

What does the intake port itself measure on your motor?

Ken T.

[bszopi]

What does the intake port itself measure on your motor?

Set the gasket on the head and take a picture, then post it on here.

This is why I asked for a picture of the gasket on the head itself. If the gasket still covers the port area and seals, then it really shouldn't matter how much bigger than stock it is.

[Century7667]

This an important question, and if answers could clear up quite a mystery! For instance, my '95 A-body was build in June of 1995 according to the a VIN decoder sight. I looked inside the oil filler cap the best I could, an it appears to me that I've got a ball stud setup. But, what kind of head is it? Could it be the same as my '96, which presumably is roller rocker and take the 98004T intake gasket? ...or does it matter? Do all the VIN M engines take the 98004T like Fel-Pro claims? It's interesting that Fel-Pro says that you can't trust the head casting number.

Ken T.

[tractorman]

For what it's worth, I did this same job a few years ago on my '94 Corsica with a 3100. It had the ball & pedestal rockers. I used the MS98004T gaskets- they worked fine for about 3 years & 40,000 miles until the vehicle's transmission gave out. And yes, according to the place I bought these gaskets, this set fits all VIN M engines- regardless of rocker type. For the later 3100's (VIN J, I think), you use MS98003T.

From what I'm seeing on this thread, I think either set would work for your engine. Though personally I'd go for the MS98004T's simply because I KNOW they will work. But I personally wouldn't worry about a .1" difference in port size. I'd lay the gaskets on the head surfaces and the intake surfaces. If the sealing breads line up with the surfaces, then it will work. It's not like you're doing port-matching on a top-fuel dragster.

Whatever you do, don't use the plastic-frame gaskets again... for obvious reasons.

[Jesuscookies]

Yeah, I ended up using the 98004T for the same reasons, and sent the dorman gaskets back. Pain in the ass job for sure, but it's done now, and she is running like a champ...Except for the starter that just took a crap on me

[Century7667]

For what it's worth, I did this same job a few years ago on my '94 Corsica with a 3100. It had the ball & pedestal rockers. I used the MS98004T gaskets- they worked fine for about 3 years & 40,000 miles until the vehicle's transmission gave out. And yes, according to the place I bought these gaskets, this set fits all VIN M engines- regardless of rocker type. For the later 3100's (VIN J, I think), you use MS98003T.

From what I'm seeing on this thread, I think either set would work for your engine. Though personally I'd go for the MS98004T's simply because I KNOW they will work. But I personally wouldn't worry about a .1" difference in port size. I'd lay the gaskets on the head surfaces and the intake surfaces. If the sealing breads line up with the surfaces, then it will work. It's not like you're doing port-matching on a top-fuel dragster.

Whatever you do, don't use the plastic-frame gaskets again... for obvious reasons.

Thanks! This is what I just had to know. There just seems to be all this uncertainty about the gasket set to use on the early 3100. So, it would appear that the Fel-Pro document is correct after all. MS98004T is good for all Vin M 3100 engines, whatever the subtle differences might be.

Which is a good thing, since this '95 has low miles, and I wasn't looking forward to finding new heads and an intake.

Ken T.

[tractorman]

Yeah, I ended up using the 98004T for the same reasons, and sent the dorman gaskets back. Pain in the ass job for sure, but it's done now, and she is running like a champ...Except for the starter that just took a crap on me

Be sure to check the cables and test the battery- those are more likely to fail than a starter, and it can be hard to tell the difference.

A reall simple test that I like to use is this: take a volt meter and put one lead on the hot STUD of the battery (not the cable end- the stud). Put the ground lead on a clean part of the starter case. Have somebody crank the engine while the ignition is disconnected so it will just crank but not start. You should see AT LEAST 10 volts while cranking. If you see less, then you have a problem with either the battery or cables.

Now make sure your cable connections at the battery are clean and tight. Hook up jumper cables and repeat exactly the same test. If the engine cranks good, then you've got a bad battery. If voltage is still low, you have a bad cable or cables.

Thanks! This is what I just had to know. There just seems to be all this uncertainty about the gasket set to use on the early 3100. So, it would appear that the Fel-Pro document is correct after all. MS98004T is good for all Vin M 3100 engines, whatever the subtle differences might be.

Which is a good thing, since this '95 has low miles, and I wasn't looking forward to finding new heads and an intake.

Ken T.

Glad I could help. I ran into the same issue around maybe 2008 when I did the intake gaskets for a SECOND time on my '94 Corsica.

The first time I did the LIM gaskets, the only ones available were the old style plastic ones- this was in maybe 2004?. At the time I learned that it mattered which type of rockers I had- the plastic gaskets were visibly different depending on rocker type. Anyhow, I put the correct plastic gaskets in and they lasted for maybe 30K miles and then I found that one was leaking externally.

By that time (2008?), the metal/rubber gaskets had come out, and I knew that's what I needed. Problem was that FelPro made no distiincton between the different rocker types. Turns out that there are little metal studs made onto the MS98003T gasket designed to hold the pushrods in place- instead of those molded plastic guides on the gaskets for the VIM M engines with roller rockers. Anyhow, the gaskets worked. It matters which rocker type you have if you use the plastic-frame gaskets. But with the metal-frame gaskets, it doesn't matter (at least with FelPro).

But now sadly that '94 Corsica is gone. The transmission failed suddenly and completely at 182,000 miles. No warning whatsoever... stranded me 800 miles from home. The car was rode hard and put up wet anyway- with the body and suspension in such condition that it really wasn't worth the tow bill back to Kansas. So I got the wife a pretty nice 2004 Accord (blasphemy around here, I know), and I've inherited her 2001 Lumina. So there's still one 60-degree V6 in the stable.

[pocket-rocket]

Now make sure your cable connections at the battery are clean and tight. Hook up jumper cables and repeat exactly the same test. If the engine cranks good, then you've got a bad battery. If voltage is still low, you have a bad cable or cables.

I can't support the clean cables part enough. I've seen plenty of GM cars that had corrosion in the cable where it hooks to the + on the battery and the corrosion actually snaked it's way down the cable INSIDE the insulation about 3-4 inches giving a high resistance reading on that cable causing hard starts.

[Penglii]

Just to squash any uncertainty... I used the Dorman LIM gaskets and they work perfectly.

[Century7667]

Be sure to check the cables and test the battery- those are more likely to fail than a starter, and it can be hard to tell the difference.

A reall simple test that I like to use is this: take a volt meter and put one lead on the hot STUD of the battery (not the cable end- the stud). Put the ground lead on a clean part of the starter case. Have somebody crank the engine while the ignition is disconnected so it will just crank but not start. You should see AT LEAST 10 volts while cranking. If you see less, then you have a problem with either the battery or cables.

Now make sure your cable connections at the battery are clean and tight. Hook up jumper cables and repeat exactly the same test. If the engine cranks good, then you've got a bad battery. If voltage is still low, you have a bad cable or cables.



Glad I could help. I ran into the same issue around maybe 2008 when I did the intake gaskets for a SECOND time on my '94 Corsica.

The first time I did the LIM gaskets, the only ones available were the old style plastic ones- this was in maybe 2004?. At the time I learned that it mattered which type of rockers I had- the plastic gaskets were visibly different depending on rocker type. Anyhow, I put the correct plastic gaskets in and they lasted for maybe 30K miles and then I found that one was leaking externally.

By that time (2008?), the metal/rubber gaskets had come out, and I knew that's what I needed. Problem was that FelPro made no distiincton between the different rocker types. Turns out that there are little metal studs made onto the MS98003T gasket designed to hold the pushrods in place- instead of those molded plastic guides on the gaskets for the VIM M engines with roller rockers. Anyhow, the gaskets worked. It matters which rocker type you have if you use the plastic-frame gaskets. But with the metal-frame gaskets, it doesn't matter (at least with FelPro).

But now sadly that '94 Corsica is gone. The transmission failed suddenly and completely at 182,000 miles. No warning whatsoever... stranded me 800 miles from home. The car was rode hard and put up wet anyway- with the body and suspension in such condition that it really wasn't worth the tow bill back to Kansas. So I got the wife a pretty nice 2004 Accord (blasphemy around here, I know), and I've inherited her 2001 Lumina. So there's still one 60-degree V6 in the stable.

That's a great story. One reason I consider renting if I leave the state. Thanks for sharing the story!

Ken T.