Dreaded 460 Exhaust Manifold Leak

[Biggyniner]

Well I have the dreaded "tap tap tap" noise that pretty much guarantees an exhaust leak. More or less making this post to vent and to get tips from anyone who has done this before... At least the noise pretty much goes away when warm...

So far my plan is:
-Soak the studs for a few days with penetrant oil.
-By some miracle, if the engine Gods allow it, I will then attempt to remove the manifolds without busting the studs.
-I will inspect them/hone them and if any cracking is found I will replace them
-When I re-assemble I will use a high performance copper gasket. This will be very unlikely to deteriorate and will expand/contract better than the cheaper gaskets. Probably these ones

Did I miss anything? Any other advice? Sigh... I really dread this job, there is hardly any room to work and I have a trip to Northern California planned for the first weekend in May... 😞

[T18skyguy]

Biggyniner wrote:

T18skyguy wrote:
Here's the story on exhaust manifolds. We didn't have warping manifolds(or brake rotors) back in the 60's and 70's. The reason we have problems now, is that to save money, the manufacturers eliminated the nickle content from the metal, which really gave it it's strength. With the heat they stretch, warp, and break the bolts, most commonly the back right. The best permanent cure is headers. I went with Banks. Did the job myself. Yea it was a hard job, but your problems will be over for good. When you plane the manifold, it removes metal, and the manifold just runs that much hotter and warps again. Here's how you test a warped manifold. Take the manifold and put it on a perfectly level surface. Usually a supported piece of glass will work fine. Take a feeler gauge and measure the gap(warpage) all around the whole thing. If the gap is any larger than .01 inche, no gasket will seal it correctly, then you can try and plane it. But having been there done that, the Banks with it's 5/8 thick stainless flange is the best. Thorleys are good also, but never put cheap headers that have a flange less than 3/8. I wouldn't even do that myself. If you go with the Banks, save some money and skip the Ram Air part. It does nothing but make you feel good. If you have to drill out a broken bolt, they sell drill guides that keep it straight. However, you need to use a drill stop, because if you go too deep you get into the water jacket which is only 3/8 thick. Particularly on the back right. There are multiple threads on this issue if you search it. Good luck with it.

I looked at Banks, but they don't offer any headers for the 460 on the E350 platform, at least for my year. I'm assuming this is due to the tight space constraints. Thorley did have a ceramic coated set for a little over $800.00 ...

I'm sure they use to. My rig was a 96 with a 95 chassis. My guess is they probably stopped production as it was no longer cost effective since the 460 being phased out. Mine was an E-350. I suppose they sell a bunch for the V10 I bet. Poor quality OEM exhaust manifolds literally gave birth to Banks exhaust. I would go with the Thorley's then. Depends on your budget and how long your going to keep the rig. If you can get new Thorley's for $800 I would guess that would be competitive with new Ford exhaust(but whats the point just gonna warp again).

[Biggyniner]

T18skyguy wrote:
Here's the story on exhaust manifolds. We didn't have warping manifolds(or brake rotors) back in the 60's and 70's. The reason we have problems now, is that to save money, the manufacturers eliminated the nickle content from the metal, which really gave it it's strength. With the heat they stretch, warp, and break the bolts, most commonly the back right. The best permanent cure is headers. I went with Banks. Did the job myself. Yea it was a hard job, but your problems will be over for good. When you plane the manifold, it removes metal, and the manifold just runs that much hotter and warps again. Here's how you test a warped manifold. Take the manifold and put it on a perfectly level surface. Usually a supported piece of glass will work fine. Take a feeler gauge and measure the gap(warpage) all around the whole thing. If the gap is any larger than .01 inche, no gasket will seal it correctly, then you can try and plane it. But having been there done that, the Banks with it's 5/8 thick stainless flange is the best. Thorleys are good also, but never put cheap headers that have a flange less than 3/8. I wouldn't even do that myself. If you go with the Banks, save some money and skip the Ram Air part. It does nothing but make you feel good. If you have to drill out a broken bolt, they sell drill guides that keep it straight. However, you need to use a drill stop, because if you go too deep you get into the water jacket which is only 3/8 thick. Particularly on the back right. There are multiple threads on this issue if you search it. Good luck with it.

I looked at Banks, but they don't offer any headers for the 460 on the E350 platform, at least for my year. I'm assuming this is due to the tight space constraints. Thorley did have a ceramic coated set for a little over $800.00 ...

[ernie1]

gkainz: The driver's door was not loose until AFTER all the mechanical work was done and I returned the rv for body work and ,so, it's really obvious what happened and who did it.

[T18skyguy]

Here's the story on exhaust manifolds. We didn't have warping manifolds(or brake rotors) back in the 60's and 70's. The reason we have problems now, is that to save money, the manufacturers eliminated the nickle content from the metal, which really gave it it's strength. With the heat they stretch, warp, and break the bolts, most commonly the back right. The best permanent cure is headers. I went with Banks. Did the job myself. Yea it was a hard job, but your problems will be over for good. When you plane the manifold, it removes metal, and the manifold just runs that much hotter and warps again. Here's how you test a warped manifold. Take the manifold and put it on a perfectly level surface. Usually a supported piece of glass will work fine. Take a feeler gauge and measure the gap(warpage) all around the whole thing. If the gap is any larger than .01 inche, no gasket will seal it correctly, then you can try and plane it. But having been there done that, the Banks with it's 5/8 thick stainless flange is the best. Thorleys are good also, but never put cheap headers that have a flange less than 3/8. I wouldn't even do that myself. If you go with the Banks, save some money and skip the Ram Air part. It does nothing but make you feel good. If you have to drill out a broken bolt, they sell drill guides that keep it straight. However, you need to use a drill stop, because if you go too deep you get into the water jacket which is only 3/8 thick. Particularly on the back right. There are multiple threads on this issue if you search it. Good luck with it.

[pnichols]

I had the related thing of broken manifold bolts on the passenger side of our 2005 E450's V10 around three years ago. Our shop removed (how ... I don't know ... as it looks like a nasty place to get access to in a van) and installed new mainifold bolts.

I "HOPE" that they may have also resurfaced the manifold .... as Gary says above. Unfortunately the excellent heating up and retightening that Gary recommends didn't get done, and I hope that I don't live to regret it.

Our mechanic recommended doing nothing about the broken bolts as I didn't hear any manifold leak sounds or smell any fumes. However I had them fix it anyway, just to be proactive.

[garyhaupt]

Thru very costly trial and error..I can tell you how to fix that manifold properly.

The engine was not built with manifold gaskets so reverting to them is just going to allow the warping/tapping to recur.

Once you have the manifold off, have it resurfaced properly then install it without gaskets. Torque to it's proper point..start it and let it warm up. Shut it down for 24 hrs..let it coool....no cheating. In the morning, re-torque again..start and let it come up to temp..shut down and let'r sit 24..hrs..re-torque,.repeat this 5 time..5 days. That will have your manifold seated properly and no gasket troubles 2 or 3 yrs down the road.


Gary Haupt

[j-d]

crasster wrote:
I will probably catch some "heat" for this but you could always try:

Blue Magic

If used right it's supposed to seal cracks and gaps and keep them sealed. MAY be better to use and see if it works before a huge job.

Sure worth $10 to try. I tried "Victor (gasket company) Muffler Mender" with no joy. The Blue stuff might work awhile. I'd be afraid the expansion/contraction would do it in.

An OP here, DaHose, wanted to put Headers on his old Class C. What Jose did, was destroy the manifolds in place. Cutoff Wheel, Die Grinder, Chisel, etc. This left the fasteners completely exposed for removal efforts, and he got them all out. Expensive to trash a set of manifolds, but any "parts cost" will be less than pulling the head(s).

Dealer might have had a hard time handling that 460 Intake Manifold. My Haynes manual suggests lifting it with a Hoist.

[gkainz]

ernie1 wrote:
I had the same problem on my 1989 E350 Econolpne with a 460 engine. My problem was that one of the heads on the manifold bolts was sheared off and there was nothing but the stud left. I tried gripping the stud with a vise grip and, when I turned it, the stud broke again till it was just about even with the head. I then tried to drill the broken stud out but the clearance was way too tight. Soo, after spending about $1900 at the Ford stealership to have the intake manifold and head removed to drill out the stud I got my rv back with a big dent on the rear of the vehicle. Apparently the tech that was working on it backed into a lift and hoped I wouldn't notice it. I went back and complained to the Service manager who said they would repair the damage. When I went to pick up my vehicle, I noticed while traveling on the freeway that there was a lot of wind noise coming from the driver's door and it seemed loose. When I got home, I found out that someone loosened the striker pin thing on the door so that it would not close tightly. CAN'T IMAGINE HOW THAT COULD HAVE HAPPENED! Anyhow, good luck on repairing the manifold.

Your door striker was probably loose because they probably removed the door in order to more easily remove the head thru the door opening.... my guess, anyway.

[crasster]

I will probably catch some "heat" for this but you could always try:

Blue Magic

If used right it's supposed to seal cracks and gaps and keep them sealed. MAY be better to use and see if it works before a huge job.

[Hondavalk]

My opinion Kano Aerokroil or Kroil is the best penetrating oil on the market. let it soak at least 2 days.

[ernie1]

I had the same problem on my 1989 E350 Econolpne with a 460 engine. My problem was that one of the heads on the manifold bolts was sheared off and there was nothing but the stud left. I tried gripping the stud with a vise grip and, when I turned it, the stud broke again till it was just about even with the head. I then tried to drill the broken stud out but the clearance was way too tight. Soo, after spending about $1900 at the Ford stealership to have the intake manifold and head removed to drill out the stud I got my rv back with a big dent on the rear of the vehicle. Apparently the tech that was working on it backed into a lift and hoped I wouldn't notice it. I went back and complained to the Service manager who said they would repair the damage. When I went to pick up my vehicle, I noticed while traveling on the freeway that there was a lot of wind noise coming from the driver's door and it seemed loose. When I got home, I found out that someone loosened the striker pin thing on the door so that it would not close tightly. CAN'T IMAGINE HOW THAT COULD HAVE HAPPENED! Anyhow, good luck on repairing the manifold.

[j-d]

I did this job on an older E350 with a 460 in it, specifically 1983. On the Driver Side, I sprayed the fasteners with penetrant daily for over a week. Then I found I could loosen all the fasteners with a 3/8" breaker bar. All eight came out.

I had my manifold re-surfaced at an automotive machine shop that had a "belt sander." This sander is a machinist's tool, and it dresses to a tolerance close that of a cylinder head re-surfacing machine. A head machine can't do an exhaust manifold because the pipe connector part interferes with getting the manifold flat on the surfacing "surface" of the machine.

An old mechanic suggested this: Use stamped steel gaskets, NOT the fiber ones. The gaskets you linked look better to me than the steel Fel-Pro's that I used. Then Kent's advice continued: Apply NeverSeez to the head, manifold, and gasket surfaces. Then, torque NEW bolts till the stampings are crushed and STOP. The lubricant, and the lower-than-spec torque, allow the manifold to expand and contract differently from the head, without shearing the gasket.

A couple years later, it needed the passenger side done, and what I found was the bolt heads were wasted away, to less than their original 9/16" size. On the older chassis, I found I could force a long extension bar between Frame and Fender Liner, then put a 13mm six-point on the extension and pound it onto the bolt heads with a hammer from the fender well. Then Voila! Epiphany! They were all nearly Loose! From there, I did the same process as driver side.

It was clear to me that the beating I gave the passenger side was far more effective than my patient spraying the driver side.

I also replaced the OEM exhaust with a Flowmaster Cat-Back exhaust kit. We had a forum member awhile ago who did a Flowmaster kit AND an aftermarket high-flow cat converter. The 1983 wasn't built with a cat, so all I needed was a piece of pipe. Flowmaster kit was 3" diameter with very smooth mandrel bends and an enormous "big block" muffler.

I've added the Flowmaster part of the story because I believe part of keeping the manifolds from warping is getting rid of as much exhaust heat as possible and that high flowing exhaust system just had to help.

I also believe we can "abuse" our manifolds by coming down off the interstate, ducking into the first gas station, and shutting down right away. Slowing down, and idling a couple minutes, helps things to cool down gradually, and hopefully, together.