Exhaust Manifold Leak

toadpad

New member
I have a leak on the exhaust manifold gasket in the center on cylinders 3 and 4. i flatened a copper wire and pushed it int the space, this worked pretty good until I had time to have replace the manifold and gasket which I did, but the problem came back after 1000 miles, I noticed manifold needed to be re tightened. but even after re-tightening the problem came back. Now I tried pushing silicone into the hole but it burned away after a few days. I am considering using something stronger like JB weld or some exhaust patch compound but I'm concerned about damaging the head or not being able to remove the manifold in the future.

1. Has anyone solved this problem before?

2. Should I try another new gasket, or even install 2 gaskets?

3. Can it be fixed without removing the head?
 
Hi, NO on the double gasket it well blow out soon.. If the bolts/nuts are coming lose then make sure to put new lock washers on it and are tightening it to specs. Use a new High quality gasket, make sure every thing is clean of any old gasket. When tightening start in the center and work you way outward. Wouldn't hurt to use a thin film of high temp gasket sealer.
good luck
tim
 
seems like in this above named work around process U could also put a strait edge acc. it to see if it's flat enuff to stand up (ie BOTH sides). If not some type of heat proof jb might help. If blowing out again yes - may be it's time for new parts or machining…

How many mi on it?
Which yr is it? (some ex mani were better than others).
_______
Let us know how it wrks out.
 
as I seem to remember after a certain yr. the manifolds got better, can't recall in what yr. but I think after '64 or '62 it had more meat on it or some improvement that could help in ur type of predicament
also
20 - 24 ft.lb tq to bolts
and
"Hi, NO on the double gasket it will blow out soon.. If the bolts/nuts are coming lose then make sure to put new lock washers on it and are tightening it to specs. Use a new High quality gasket, make sure every thing is clean of any old gasket. When tightening start in the center and work you way outward. Wouldn't hurt to use a thin film of high temp gasket sealer.
good luck
tim"
 
Are you sure its an exhaust leak? may be a ticking lifter? an exhaust manifold leak sounds like a ticking lifter so a ticking lifter could sound like an exhaust leak.. Yes NO??
good luck
tim
 
toadpad":34notzoa said:
I have a leak on the exhaust manifold gasket in the center on cylinders 3 and 4. i flatened a copper wire and pushed it int the space, this worked pretty good until I had time to have replace the manifold and gasket which I did, but the problem came back after 1000 miles, I noticed manifold needed to be re tightened. but even after re-tightening the problem came back. Now I tried pushing silicone into the hole but it burned away after a few days. I am considering using something stronger like JB weld or some exhaust patch compound but I'm concerned about damaging the head or not being able to remove the manifold in the future.

1. Has anyone solved this problem before?

2. Should I try another new gasket, or even install 2 gaskets?

3. Can it be fixed without removing the head?

These are Answers from tried and true experiences.

1. Yes put a straight edge like a framing square across the exhaust manifold and use some feeler gauges to test its flatness using a FelPro type gasket the surface tolerance is few thousands. But if it's not flat enough then there's no getting around it will need to be resurfaced on the exhaust manifolds matting surface to insure that it's flat. Even though you are using a new reproduction manifold you should not assume that it is flat quality varies widely with repro parts depending on who made it. Since you are blowing the gasket out quickly in the center ports something is wrong there so check if it's warped (i.e. not flat) or there is damage to the mating surface in that area.

2. If your already using a FelPro gasket thats about as good as it gets, no on using two gaskets. Many of the old ford engines used a metel shim gasket for the exhaust or no gasket that also works but the manifold and head surface have to be very true / flat. The hi temp Silicon can work without a gasket also, if you use with a gasket use it sparingly and let it sit long enough to cure (overnight) or it can cause the gasket to side out. A header gasket might also work they are a bit thicker, if you can find one that it will line up properly with the exhaust manifolds ports.

3. Yes usually, most of the time the head surface is not the problem though sometimes the heads machined surface has gotten damaged or its not flat enough (within spec) so examine that area good and also use a straight edge and some feeler gauges to find out if it's true. If it tests out as not flat or is damaged in the center ports area then it would also need to be resurfaced. Most any good auto machine shop can quickly resurface a head or exhaust manifold for a reasonable price.

Also X2 on the other suggestions like tightening to corect spec and working from center out etc. Good luck, :nod:
 
If it is the original manifold, when you take it off, you will probably find that it is curved outward on both ends, when using the straightedge. But even with a new one like you have, that is why you start from the middle outward, in a circular motion. Those original manifolds get punky and brittle. Plus, the divider between the 3 and 4 may be perforated, which blows extra heat and burns the gasket.
 
I am going to remove the manifold again and check both sides with a straight edge as recomended. Then I may simply re-install it with a different brand of gasket "Victor Reinz" http://www.amazon.com/gp/product/B007ZJ ... 393O04YIYG. Last time I did not re-tighten the manifold for 2000 miles, and when I did the gasket had shrunk and the bolts were loose. I'm hoping that this time if I re-tighten it after the first 500 miles it will keep pressure on the gasket and solve the issue by preventing it from blowing out the gasket.

If the head is warped I may try to grind and shape the reproduction manifold to match it. I think it could work and I'm not ready to remove the head and get that deep into the engine just yet.

Any thoughts???
 
Just make sure you proceed out from the middle one bolt at a time - one on one side and one on the other all away to the ends. And don't yank them down too fast all at once. Take a few passes to get up to full torque spec, again working stepwise, out from the middle. You might want to use hi temp gasket seal too.
 
i finally got the manifold off. it was hard to work around the ac bracket, but its off.

I cut a straight edge to 25 inches and checked for straightness. Bolt sides look incredibly flat.

The gasket white/grey material was blown out in a few places.

i noted that there is nothing dividing port 3 and 4 on the head side so there is no point to having the gasket in the center.

is that normal???
 
That is the 'siamesed' exhaust port and there is no gasket between the two. The space between them has a hollow for air to enter the choke pull off tube.

It may be that the tube area is burned through. This is normal for the engine of this age. I plugged it top and bottom with brass screws so the exhaust would not come out the holes in the top and bottom.

You might want to do a search on 'exhaust port divider' with the search function at the top of the page. This is a plug that makes the 3 and 4 outlets the same size as the others. Opinions are divided as to whether it does much good, but many guys do it - including me.
 
There very few Ford heads that came with the individual ports in the center most are the siamese. So make sure you are using the correct gasket that fits your head by its port openings or year etc. someone may have swapped a different head on your engine you can check that by the casting / design code numbers. Good luck :nod:
 
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