Technical Manifold Gaskets on FE keep blowing

Built my very mild 352, srock iron heads and manifolds last winter. Have about 1,000 miles on it. The LH manifold gasket blew at about 300 miles. And the RH blew last week at 1,000 miles.

I checked the manifold and the exhaust ports on the heads both are within 0.001" on all 4 mating surfaces.

These are FelPro gaskets, not impressed. The head side without the metal blows out. I used new grade 8 hardware when I build the engine. When I tore it down it was metal to metal, no gasket, original factory...no leaks. Removed the manifolds (and broke a bunch of bolts) to send the heads to the machinist for hardened seats to be installed.

Anyone have some advice, or a better gasket? I don't want to just keep throwing gaskets at it. Not the easiest job.

 

might try it without gaskets....Chevy never installed gaskets, but all the FelPro overhaul kits include them. But the folks who designed the engines knew that gaskets aren't needed, and they reduce heat transfer from the manifolds to the heads, resulting in overheated manifolds. I'm not up on Fords enough to remember if they used gaskets as original equipment, or not.

just make sure to use lock tabs to keep the bolts from loosening.

 

Factory had no Gaskets. And didn't leak.

 

there you go

 

Every time I tuned my Olds I had to change gaskets, it ate them just to be ornery. I put Remflex gaskets on it a few years back and have not had to mess with them again.

 

My FE had washers with ears that locked the bolts in place. Without them I would have to tighten them periodically.

 

The early FE motors used no gaskets, the later ones switched to a shim steel gasket. I've never seen that gasket for sale. Those manifolds for whatever reason are prone to warping and can be notoriously hard to seal sometimes. I've had very good luck with the typical gaskets but I lightly coat around the ports on both sides of it with Permatex Hi-temp copper silicon sealer and then carefully torque the bolts from the inner ones out like you would do for a head gasket so that you pull the manifold down evenly. I'll usually do this in two steps. I have yet to have a leak doing this.

A old Ford mechanic told me the trick to no gaskets is you need a freshly-machined surface on both sides. Over time and heating cycles, those surfaces 'wear in' to each other and once disturbed won't mate up properly. A light pass to clean up the head side is easy, the manifold not so much so few people do it.

The other trick to help prevent broken bolts in the future is to dip the threads on each bolt in Pepto-Bismol before installing. The aluminum magnesium silicate in it acts as an anti-seize after the rest boils out.

 

I had a 390 thst blew tons of gaskets
Finally got some copper gaskets and they worked great

 

Ck EGT

 

I’ve read a little red RTV is good.

 

I use high heat rtv, no gaskets . Just enough to color the port surface.

 

Just for shits and giggles check how flat the mating surface is, I’d bet a trip to the machine shop is needed…

 

Don't use exhaust gaskets in my super charged 8BA 14years now, never has leaked!

 

Toss the gaskets.

Use a thin coat of this: https://www.permatex.com/products/g...-ultra-red-rtv-silicone-gasket-maker-3-35-oz/

Allow it to cure for 24-hours after torqueing.

 

Also, double check your ignition timing, both at idle, and up the advance curve.

Make sure that you are getting all of the advance that you are supposed to.

Late timing sends still burning mixture out of the ports and into the manifolds.

I have seen headers glowing orange when the owner had the timing set wrong. That will give gaskets a rough go.

 

Welcome to FE's

I made gaskets out of 1mm aluminium, a smear of HT RTV on both sides and torqued the bolts upto 25lbft, would get 2 years out of these.

My feeling is the head exhaust surfaces get pretty hot and the faces warp slightlty.

 

leave the gasket out....seriously....

 

I have used a NAPA exhaust sealer on the FE with good sucess. Just use it to coat the gasket. Now for the bad part Napa sells 2 a #35958 and 35959 one is white and one is black you want the white stuff . If you are losing gaskets that fast is to remove the head and manifold and have them surfaced . It sounds like the gasket fail is in the same place every time.

 

I had several FE motors over the years, latest was a daily driver 63 with a 352, leaking exhaust till I got rid or it, used gaskets, no gaskets, grade 8 bolts with Lock washers, Locking tabs, had exhaust surfaced, heads surfaced, was a continual job to tighten bolts, hard to reach the two middle bottom bolts on drivers side. Had one in the 60,s for years with no problem. was told to use studs. Can't remove headers from heads with out picking the motor up for room for headers to clear studs. I never fixed leakers just kept tightening them.

 

I have a little experience with FE's, and have never seen stock manifolds that appeared to be warped- cracked yes. They typically came with no gaskets, and if the heads and manifolds are both cut flat, they will seal quite well with no crutches. Headers of course need a little help, but again, first you need straight flanges

 

No gasket was always the way when these were common in the shop way back when.

There was one guy in town that used a liberal coat of roofing tar on them! It seemed to work. I guess once the solvents cooked away (must have smelled awful), it left a coat of nearly pure carbon to fill any gap.

 

It's not warped so much as they kept driving with a leak and eroded away the metal at the leak Thats where I've had luck with the NAPA product.

 

FE Ford s have high egt,even stock. Make sure the tune up is good,timing correct for the engine and advance curve and is what the engine likes not motor manual spec.Make sure it has a working vacuum advance there are many different one. Adjustable one would be best,Gas has changed alot.

 

Yup. Not sure what he's running up there in Maine, but out here we have E10.

While the stoichiometric ratio of air-to-fuel for non-ethanol gasoline is 14.7:1, for E10 it is 14.2:1.

Without at re-tune for that, you are running lean across the board.

As lean mixtures take longer to burn than rich ones, an uncorrected lean condition from fuel type, with timing for a different fuel type, can result in late-burn.

Lean mixtures also lead to higher EGT. Just a few incorrect adjustments can add up to really hot exhaust. If an engine design is already prone to it, it will be exposed quickly.

 

Check to see if the head is straight and also the exhaust manifolds. If so, clean the surfaces with a body file with rough sand paper to a nice shiny surface. Coat the surface with mentioned high heat copper sealer. Torque the bolts in two steps from the center out to about 25 ft lbs. Let set over night. Start engine let it idle untill manifolds get hot. Let it set, till cool, check the torque on the bolts. You should be good!






Bones

 

My wife has a 63 tbird with a stock 390. It is a real pain to replace the gaskets as there isn't much room in there. I would be interested in having a crack at all0y gaskets like @BLACKNRED has suggested. I did work in a speed shop and we would get in the Remflex gaskets for people , but they are hard to get down here but most of the drag racers loved them,, cheers

 

I’ve got a 390 to go through soon. The plan is to surface all the mating surfaces and use a thin high temp sealant.
The worst thing Ive had on FEs was cracked manifolds and broke bolts.