Head Studs Or Bolts

Duane WI

Member
I posted a few days ago about a Farmall Super C getting coolant in the oil. I had put air pressure in the cylinders and radiator trying to find a leak looking in the bottom of the engine with the oil pan off. I couldn't find anything but one of the intake valves was leaking air back into the carburetor so I decided to pull the head. No signs of a leak in the head gasket but did find that the one valve wasn't lapped in very well.

One thing I would like to do is replace the head studs. I suspect they are stretched and some have signs of corrosion pitting on them. I am thinking of going back with bolts. A grade 8 bolt is $2 and the studs are around $20 each if I can find them. I would be torqueing coarse threads into the block instead of fine thread nuts so I would have to increase the torque about 35%. I don't see any reason I can't do this. I think studs are better but not better enough to justify the cost. I have seen a lot of engines with bolts so I know it works.
 
I'd get the head checked for cracks. I'm not real familiar with that engine, but I would put in what it originally came with from the factory unless the threads in the block had been messed up ?
 
Studs are better because they can hold more torque. Many hot toddlers change to studs for that reason. I would clean those old studs up and coat them with rustolium paint.
 
I believe I would keep the studs.

Even if they have some pitting, as long as the treads are good they will work.

Another advantage of studs, they go deeper into the block, they are stationary once in, less chance of pulling the threads out of the block.

Wire brush the threads, but do not run a die over them!
 
(quoted from post at 13:38:52 05/07/19) I am going against the grain here. I put the head on my MF 65 diesel with grade 8 bolts 32 years ago and it is still running.

Bob, that is not really unusual unless your 65 has a history of blowing head gaskets prior to 32 years ago. Probably 99% of the time bolts will hold just fine, but here and there there are engines that just tend to have head gasket failures, so then you have to dig in to find any way that you can to make it more likely to last. I have a Powerstroke 6.0 and when I was getting the turbo, EGR cooler, and head gasket replaced, ARPS studs were part of the program. The shop owner had me run my thumb nail over the threads of one of the original studs, and then one of the ARPS studs. The difference was incredible! Arps studs are part of the program for a problematic classic car motor that I just installed in the car last night.
 
your way overthinking this. its a small gas engine. and not that much torque on those studs. you will feel if they are stretching when you torque them. , if you are experienced with that. most important is to have both surfaces clean clean. use Permatex high tack sealer on the gasket , or copper coat . torque in three steps. run it up to temperature for a few hrs.and retorque it and reset the valves. did you check the compression before disassembly? kind of a must, then you know what your dealing with and which cylinder or cyl's are lazy. the neighbor used to drain off his case 830 for years just cracking the oil drain plug and letting the antifreeze out. like just a few spoon fulls.
 
The studs were made to be reused. Most people don't even take them out of the block. It doesn't matter if they stretch or are stretched. No need to convert to bolts. In any case, the bolts are not your coolant leaking problem, and will not fix that situation.
 

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