Can i use the head studs from my donor engine to rebuild my block already in the car or should one always use new studs?

I see they are expensive (each), from Moss Motors - anyone know of a reputable supplier who wont break the bank if the answer to the above questions is NO.

P

 

Use your old studs if they are the correct length, they are not torque-to-yield.

 

If you do change the studs, be sure to use the slightly longer ones if/where the lifting eyes sit and not to use the longer ones where they don't.

 

Use Thread sealer on them as well when you install them! Note that the stud marked as number 8 in the torquing sequences is specific to that hole. It has a collar on the bottom that is larger than all the rest of the the studs. Studs 7,8,9 and 10 are longer than all the rest as well since the lifting hooks are mounted on them. I have a full set of used ones if you need any. I opted to replace all of mine since I was going for a full rebuild.

 

Thread Sealer = Thread Lock?

And thank you - may take you up on your kind offer, im ready to pop the head off my seized block ready for cleaning and lapping, once I have the head off I will be in a better position to see whats what - i do know the head and block are different serial numbers - my Jag is becoming a frankenstine under the hood.

I saw a trick on youtube to use 2 bottle jacks to lift the head off of the block.. i gave it a tug and its not budging.

 

You might try spraying some lubricant in between the studs and the head and let it soak in a day or so. If they are corroded then it will be difficult to remove the head. My head gasket failed and the head came off real easy.


The stud in the foreground is the number eight stud with the larger collar

 

I used Form A Gasket Sealant number 1. There are thread sealers as well. Locktight may work but not thick enough I think. Sealing the threads on the studs was recommended by an XKE restorer. He uses the Form a Gasket.

 

theres a chap on youtube with a channel called living with a classic (or something) and he said water can get up past the studs as they pass through to the water core in the block - so i can see the appeal of Form A Gasket Sealant number 1...thanks for the nod.

 

The studs only need replacing if they are damaged. They can be damaged in a couple of ways. The studs can rust into the block especially if you have had a head gasket go and water has seeped into the thread holes. I have seen studs snap off when trying to be removed from the block due to corrosion. The shaft of the studs can become corroded due to the chemical reaction between the alloy head and the iron of the stud. This is generally the alloy that furs up locking the stud in the hole in the head making the removal of the head almost impossible. Not heard of using bottle jacks to get the head off but I used an engine crane to remove mine. The block was held on an engine stand and I then attached the engine crane to the head using chains to give an even pull. I then put pressure on the engine crane to lift the head and with some suitably directed hits with a nylon hammer the head eased off the block. Photo below.

If you do want to remove the studs heat is your friend and I was given a tip to free up any stubborn or rusted in studs. Using a hot gun or a gas flame heat up the stud and block which normally breaks the rust lock but whilst it is still hot get a wax candle and press it against the stud so the wax melts and runs down the stud into the threaded hole. The wax lubricates the thread and you should have no trouble turning the stud out.

 

Here's a good disassembly video.