The Stovebolt Site Forums The Shop Area Engine Shop Removing the manifolds. Am I opening a can of worms?

Hi all. The exhaust manifold on my 41' 1 1/2 ton is a rusty mess. I would like to remove it along with the intake manifold. Fix the heat valve and reinstall them after they are cleaned up.
Is this something that is better left alone or left for someone with more experience than me, or is it something a weekend hack like me could tackle?

Let me know what you think

Thanks
Andy

What is wrong with the heat riser valve?

If it is a looseness in the pivot shaft, here is an over-sized shaft.

If you want to separate the manifolds, you most likely will break a mating bolt. Then, you (or a machine shop) will have to carefully drill it/them out and clean the threads (or, drill out and thread for larger bolts).

Clean and gently blast the manifolds. If the seal between them looks good, maybe you will not have to separate them.

Others with more experience will post better advice.

If you decide to take them apart, do all of the refurb, new bolts if necessary, new gasket, etc. But I always take them and have them surfaced at the machine shop after messing with them. To surface them, they need to be together with gasket in place, torqued together properly, then they are surfaced as one. I paid $50 to have that done recently. It just ensures you won't have any leaks afterwards. This of course in addition to fixing the heat riser properly.

Riser valve is frozen with rust.

If the manifolds did not leak prior to removal, there is no need to have them machined. If you separate the intake from the exhaust manifold, make sure to leave the fasteners loose which hold them together at the heat box while you tighten the manifold assembly to the head. Once the the manifold assembly is torqued to the head, you can then tighten the fasteners which hold the intake to the exhaust manifold.
A tip to loosen up any of the bolts without breaking them is to actually tighten them slightly until some movement is felt, or a sound is heard. Don't ask why it works. It may well be magic.
Carl.

Excellent advice from Carl.

However, I do not gamble, but I bet a ride in my Suburban to Carl and Andy if Andy can separate 1941 manifolds without braking at least one bolt.

On 250's, the intake/exhaust mounting bolts are staggered across the head. I always tighten the upper bolts first so the weight of the manifolds is hanging off them. If you tighten the lower row, the upper bolts have to pull all the weight up which puts a lot of extra pressure on the threads. Yours may be the same way.

Joe

Thank for the vote of confidence

How much is the wager Tim? I do reserve the right to coach Andy along as he works the bolts loose.
Carl

The heat riser was frozen on my '57 when I bought it. I didn't want to separate the manifolds for fear of breaking bolts. I followed the following advice that I got from this forum.

I removed the carburetor to get access to the inside of the heater valve. I liberally sprayed Kroil on the inner and outer pivot points every morning and evening and gently tapped the weighted and unweighted ends of the heater valve shaft with a hammer each time I sprayed with Kroil. After a couple days, I grabbed the weighted end of the shaft and tried to turn it. I made progress in very small increments then after about ten days, it magically broke free and has worked fine ever since. I give both sides of the shaft a shot of Kroil for good luck every time I change the oil.

Patience paid off for me doing it this way.

Matt

I used the Kroil too, and heated the bolts with a torch, and also shocked the bolts with a hammer. It took some time and patience over about 90 minutes. Was able to get the bolts out in one piece. Mike