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A friend at work has a 1999 F-250 with a 5.4 litre,and one of his exhaust manifolds has a hole in it just at the bend on cylinder one. The nuts,and bolts holding on the manifold are all crusty,and rusty,and he doesn't want to risk breaking a stud/bolt(lovely New England winters). Is there a substance that can be used to block up this hole for a few years? He tried Marinetex,but that doesn't seem to be working. Any help would be appreciated.
There are several...
Welder + scrap sheet metal. I welded my vitara manifold a couple years ago and its still holding up just fine.
Time for headers?
A hole or a crack? Cracked manifolds are very hard to weld without taking them off and getting them to someone who can weld cast iron. Now..if it's just a hole from an EGR pipe or something, I've JB welded bolts that nearly thread in--and that's worked out ok.
It is a hole the size of a pencil eraser.
If you can't braze it, there are some 'muffler cement' type products that will stand up to the heat.
In my experience, JB weld or the like won't work. It melts away in the high temps.
Could it be brazed?
brazing might be the only alternative.. besides R&Ring them
JB Weld won't take the heat. But there is a similar product that does. Most auto stores have a little tub of the stuff. Goes by various names like liquid manifold weld, etc.
You can get buy for a surprisingly long time by carefully stuffing steel wool into the hole as well.You've got to pack it tight. Any exhaust gas coming through it will promptly burn it out.
If you can wrap wire around the back side, you can patch it with a piece of metal, some Permatex Ultra Copper, and tie it all down well.
Cast iron can be difficult to weld. Certainium makes rod/wire specifically for it.
....but before I did that I'd drill it to 1/8", 1/4" or 3/8" m.p.t. tap size, thread it and put a pipe plug in it. You may need to use a right angle drill, or carefully use a burr on die grinder. It's a tapered thread so i'd be pretty hard to screw it up too bad.
You can weld cast iron with regular mild steel wire on a MIG. I've done it before and so has my brother (on turbo manifolds) and both of our welds have held up just fine over time.
The pipe plug idea isn't bad, either, though. I like welding whenever possible because assuming you have a piece of metal to bang over the hole (unless you just fill it with weld) its basically free.
If you can get at it, the drill-tap scenario is about the easiest way out.
Promise not to laugh...
we used high temp (gray) furnace cement to patch a manifold on a ranger we had...it worked until we were able to get another one (probably about 3 years)
andrave wrote: You can weld cast iron with regular mild steel wire on a MIG. I've done it before and so has my brother (on turbo manifolds) and both of our welds have held up just fine over time. The pipe plug idea isn't bad, either, though. I like welding whenever possible because assuming you have a piece of metal to bang over the hole (unless you just fill it with weld) its basically free.
A simple trick I have never tried but seems perfectly plausible right now as I have just thought of it (I am sober too). Preheat the cast iron - start the truck and let the manifold get hot... clean the hole up quickly and weld it. Let it cool naturally and slowly...
MedicineMan wrote: Promise not to laugh... we used high temp (gray) furnace cement to patch a manifold on a ranger we had...it worked until we were able to get another one (probably about 3 years)
actually not a bad idea!
I've MIG welded cast w/o problems. I welded some weld-els to a factory exhaust flange (cut the manifold off), welded cracks on manifolds, and even welded a downpipe to a hacked-up RHB5 O2 housing (flange wouldn't clear the x-member on a CRX).
AFAIK, all are still working.
+1 for filling the hole with a bolt of some sort.
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