Removing An F 134 Exhaust Manifold

I am asking for a sanity check. My F 134 will be getting a new exhaust manifold. The current one is installed with bolts rather than studs and nuts, and you all know what this means. So my plan is to grind and or cut the bolt heads off to remove the manifold and have then remove the bolts using the stud removing methods (which are many and varied and interesting) that I have researched on this site. The reason is I want to avoid if at all possible breaking the bolts off flush with the block. So does this make sense and if not what suggestions can be offered.

Thanks

 

You’re assuming the bolts aren’t seized in the manifold holes, and the manifold will actually come off easily with the bolt heads cut off.

I’d suggest giving each bolt head a healthy whack with a hammer before you start the process. It might help break some bonds free.

 

Don't break the rear one. Access to fix it is obstructed by the firewall. DAMHIK.

 

Yep. Mine came that way.

 

The mechanics at the Jeep dealership would get exhaust manifold bolts rocket hot with a high-speed trip up and down the local highway. Obvious hazard, but apparently it worked.

 

I'm trying to picture in what universe a F-head is a "high speed rocket?"

 

That's called a "contradiction in terms."

 

Left hand drills work well too, I have had good luck drilling out broken bolts with them, they will spin the broken bolt out a lot of the time.

 

It has been a while so here is the best solution that I have found for removing the exhaust manifold bolts and or studs. First you soak them real well with the penetrating oil of your choice. Then you go to Florida for four months. While in Florida you have your son-in-law continue to soak them weekly while your grandson plows the driveway. After several weeks your son-in-law removes ALL the bolts and off comes the manifold with no broken bolts. Simple as that.

 

I Concur whole heartily..... FIRST : Soak the Liv'n piss outta 'em for a week. Then, if your Real Skilled with a torch, use a 6 point socket & a flex bar & a clean hit , like other's have mentioned . The key is clear access , the right ' Touch ' , rust desolve , & lubrication of those bolts that have 50 years or so of heat / cool / weather on 'em.
They'll break free.

Addendum : Late to the the dance here , as usual .

 

I have not been as lucky. On the recommendation of others here, I have successfully torched them out.
Picked the pieces out with dental tools, followed by a tap to remove any remaining debris. Good Luck!

 

I did like everyone suggested and all but two came out. They broke off at the block. I purchased left drill bits. Never used them before so it will be interesting

 

was it the one in back

 

Nope. One in the middle and the very front one

 

LUCKY!

 

Yes, very lucky. It seems like every other engine I work on has that back stud broken off.

One of the two engines I recently tore down for rebuilds had been repaired (rear stud) by drilling and tapping for a larger stud, and three of the head studs had Heli-coil repairs on the threads. When I encounter a stud or bolt that is stuck I almost always am able to get it to free up with heat, Kroil, a few raps with a hammer, and a stud removal tool. It is difficult to drill center, especially on small studs, and it is almost impossible to get a straight shot at that rear exhaust stud with the engine in the Jeep.

When I have to drill out one of the exhaust studs I will mount an exhaust manifold using the other studs to serve as a drill guide. I will just start a hole with a bit the size of the stud, this gives a cone shape making it easier to drill a pilot hole through the center of the stud. I then use a piloted counter bore to center a larger hole through the center of the stud, remove the manifold and then use a bit slightly smaller than the diameter of the stud. I work up until all that is left are the threads which will clear out with a tap.

If the rear one is broken off I will unbutton the engine mounts, drop the transmission cross member onto a wheeled jack, remove the fan, and move the power pack forward enough to get a straight shot.

One thing that can really make a mess is breaking off a hardened drill bit or an "easy out", which is something I avoid using.

I bought a Porsche once where both heads were ruined because the previous owner, who was supposed to be a good mechanic, had broken off most of the little bolts for the headers. He had then attempted to extract them with "Easy Outs" which he broke off in the holes he drilled, then he tried to burn them out with a torch. The alloy those heads are made from will burn so the end result was huge burned out holes around the still embedded Easy Outs. Bare heads for that car cost over a grand each and that was more than 30 years ago, but I was lucky enough to find a good pair of used ones.

 

Never mind - I was going to suggest you remove the head. The exhaust is in the block. Oh well.