Fel-Pro 1250 intake gasket set

blubuckaroo · Jan 22, 2010

For the second time now I have had issues with the Fel-Pro 1250 intake gaskets. The first time it leaked around the rear coolant ports within a year. Now after a year the things have squished out and caused a vacuum leak on #2 cylinder. You can actually see the blue "printoseal" line above the intake manifold. I have retorqued to the Edelbrock specs of 18 ft lbs three times. Now after googling these gaskets, I find that they have caused a bunch if similar issues mostly in the Mustang clubs. These are the gaskets recomended by both Edelbrock and World. These gaskets are different than the stock type in that they don't have the steel reinforcement laminated inside. Edelbrock specifically recomends against using those with the steel reinforcement because aluminun manifolds can't be torqued tight enough to seal them properly without damaging the manifold. Has anyone here had similar problems with them, and how did you remedy it?
I'm about to go back to an iron manifold so I can use the good gaskets again.

broncnaz · Jan 22, 2010

I've never had any issues with them But I have also retorqued them after a week or so just to make sure things are tight. Sounds like your block or heads have been milled? Gasket shouldnt be sticking up that far. Or you may need to glue them on in postion. Usually if the block or heads are milled the intake manifold also needs to be milled to correct mismatch and ensure the sealing surfaces are parallel.

iwlbcnu · Jan 22, 2010

You need a 1250S-3, it has a thin steel core to keep the gasket from pushing out. My fathers 514 did it 2 times before we found the S-3 sets.

NJB71 · Jan 22, 2010

When I swapped my stock manifold for edelbrock a year ago or so I used fel-pro and never had a leak, and as broncnaz has said I retorqued everything over a weeks driving span from the initial install, btw since that was my 1st big job I ever tackled I was suprised how much give thier was in the original torque in the bolts.....

fromme · Jan 22, 2010

I know this song, been through it before with Mustangs. I'll never use the 1250s again. The best intake gasket is the 93334 and it'll come with the rubber ends.
http://www.summitracing.com/parts/FEL-MS93334/

blubuckaroo · Jan 22, 2010

This is the first time I left the sealant off the intake runners. Maybe that had something to do with it.

Viperwolf1 · Jan 22, 2010

The intake ports are a little bigger on the 1250's than most other gaskets. It could lead to leaks if your intake does not meet the heads just right due to decking/milling.

blubuckaroo · Jan 22, 2010

Well I know the gaskets were lined up when the intake was installed. I used guide pins. I think expansion of the motor somehow made it crawl out.

iwlbcnu · Jan 23, 2010

My 306 in my stang has been together over 10 yrs and never pushed out the standard 1250. Dads FRPP 514 pushed out the same type gasket twice, the factory one in a yr, and then we switched to the S-3 4 yrs ago with no problems since. I'm sure it comes down to tolerances.

blubuckaroo · Jan 23, 2010

iwlbcnu said:
My 306 in my stang has been together over 10 yrs and never pushed out the standard 1250. Dads FRPP 514 pushed out the same type gasket twice, the factory one in a yr, and then we switched to the S-3 4 yrs ago with no problems since. I'm sure it comes down to tolerances.

I really don't think tolerances could be the issue since I used RTV at the valley ends instead of geskets ant that isn't even close to bottomed out. Do you use the 1250S-3 gaskets with an aluminum manifold?

broncnaz · Jan 23, 2010

Hard to say as on my 73 I also use RTV on the ends and its pretty close to the bottom. I cant use the cork seals as they really push out. You may have clearance issues and the intake is moving around during the heating and cooling cycles due to too much clearance. That said I'm pretty sure I've used stock type gaskets before with a aluminum intake and I didnt have any sealing issues. The torques for cast iron intakes is not that much higher than the aluminum intakes.

iwlbcnu · Jan 23, 2010

If the heads have ever been shaved, you may have created a sealing problem. The S-3 is just adding a very thing lining to the reg 1250 gasket, so it is still soft for the aluminum, but the ports have strength. Both 306 and 351 are using them with aluminum heads and intakes, running 1262 on the 351.

blubuckaroo · Jan 24, 2010

I just pulled the motor down. I guess this explains the dead #2 cylinder as well as the oil consumption. What could heve caused this gasket to slip and only on the passenger side?

broncnaz · Jan 24, 2010

Hard to say but looking at the pics I would say that the gasket wasnt quite lined up when installed. I can see where the intake bolts kninda tore into the gasket. Heck I dont think I've even seen a old stuck gasket tear up that bad. You seemed to have researched this enough but I have to ask did you use the recommendeed tightening sequence on the bolts?

fromme · Jan 24, 2010

Looks like overtorque and/or improper torque sequence. And a crappy gasket. That gasket does not look like a good match to those head and intake port sizes either. Too big.

blubuckaroo · Jan 24, 2010

broncnaz said:
Hard to say but looking at the pics I would say that the gasket wasnt quite lined up when installed. I can see where the intake bolts kninda tore into the gasket. Heck I dont think I've even seen a old stuck gasket tear up that bad. You seemed to have researched this enough but I have to ask did you use the recommendeed tightening sequence on the bolts?

Yes, and retorqued several times after assembly. This gasket was fine and the problem didn't occure until I took it on a trip of about 150 miles. Sort of makes you wonder about the intake gaskets without steel reinforcement, doesn't it? I didn't put any adhesive or sealant on the runner area of the gasket this time. It is still in place around the coolant ports where there was RTV. It is pushed up in the middle of the head.

Viperwolf1 · Jan 24, 2010

fromme said:
Looks like overtorque and/or improper torque sequence. And a crappy gasket. That gasket does not look like a good match to those head and intake port sizes either. Too big.

Yes, gasket too big for those heads.

fromme · Jan 24, 2010

blubuckaroo said:
Yes, and retorqued several times after assembly.

That's most of the problem right there. Several times is too many. That just kept cranking and compressing, then it'd heat up and retorqued again. Not good.

blubuckaroo · Jan 24, 2010

fromme said:
That's most of the problem right there. Several times is too many. That just kept cranking and compressing, then it'd heat up and retorqued again. Not good.

But it was loose. You can't leave it loose. I only retorqued it to 18 ft lbs.

blubuckaroo · Jan 24, 2010

Viperwolf1 said:
Yes, gasket too big for those heads.

They are the standard Fel-Pro 1250s that Edelbrock recomended. The reason they look too big is they have split and spread out.

Fel-Pro 1250 intake gasket set

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