1960 318 Exhaust Port Issues

Kapt

Member
Joined
Dec 1, 2018
Messages
77
Reaction score
42
Location
Northern CA
60 Dart, 318 Poly. Three broken exhaust manifold bolts. I took the manifold off to actually see what's going on. Two of the bolts broke off flush, maybe a little bit inside the head. The third one is a disaster. Someone broke it before and tried to drill it out. They missed and drilled crooked into the head a little, then it broke again. I can see it with a mirror, but cannot really get into it to do anything.

So here's my dilemma. Do I pull the head off a 60 year old motor and take the head to the shop? Or do I pull the whole motor, take it to the shop, and hope the head doesn't need to come off anyway? Either way, this cannot be repaired while in the car
 
Less likely to have major problems just pulling the head, these heads have steel shim gaskets and the heads, block and gaskets were pretty much bullet proof. I would suggest pulling both heads as this is an excellent time to do both head gaskets. The head that has been drilled crooked might have to be replaced. Any good automotive machine shop can remove the broken studs and evaluate the head to see if it is repairable. If not, 318 poly heads are still pretty available. This would also be a good time to check the timing chain.

Dave
 
Just curious as to why the bolts keep breaking? How many miles on the motor?

IF the head gaskets are orig, it might be a good idea to change them anyway. Reason? The flow restrictor holes in the gaskets might have been degraded/enlarged with time/use and possibly marginal coolant conditions over the years. Which might contribute to "running hotter" situations.

With the removed head chucked-up in a drill press mechanism, then the drill should be able to be aimed at the offending broken bolt. When removed, then the hole can be drilled for a HeilCoil insert, or possibly a "permanent stud" could be installed in that location?

Just some thoughts,
CBODY67
 
Just curious as to why the bolts keep breaking? How many miles on the motor?

IF the head gaskets are orig, it might be a good idea to change them anyway. Reason? The flow restrictor holes in the gaskets might have been degraded/enlarged with time/use and possibly marginal coolant conditions over the years. Which might contribute to "running hotter" situations.

With the removed head chucked-up in a drill press mechanism, then the drill should be able to be aimed at the offending broken bolt. When removed, then the hole can be drilled for a HeilCoil insert, or possibly a "permanent stud" could be installed in that location?

Just some thoughts,
CBODY67

Mopar exhaust studs got brittle over time from the repeated heating and cooling. Usually a good idea to replace all of them while the engine is apart.

Dave
 
They've been broke for the two years I've owned the car. The leak was getting worse and worse the more I drove it. It is time to fix it, and fix it right this time
 
They've been broke for the two years I've owned the car. The leak was getting worse and worse the more I drove it. It is time to fix it, and fix it right this time

Check the mating surface of the exhaust ports and the manifold for erosion. Sometimes when they have leaked for a long tome there will be some loss of metal on the sealing surface that will need to be re-machined to get a good seal.

Dave
 
Good call! I looked at the manifold, it looked good. A little dirty, but looked good. The head? That'll be up to the machine shop
 
Back
Top