Slight wiggle in block studs

[sphanna]

I will probably purchase new studs, but there is a slight looseness in 2 of my studs in the block. I am wondering, if I buy new studs, could I put a little JB weld on the coarse threads and install in the block to strengthen the block threads? I am concerned about stripping the block threads. I did have the same situation when I put the new head on and torqued to 55 pounds. They torqued up OK and did not leak. This time I am wondering if i should try to fix the looseness.

[Jim Brierley]

You could do that, and it would work but that sort of repair becomes quite permanent so could be a problem down the road??? I would install a repair like a heli-coil. If you do the JB trick, immediately after installing those studs, slip a head on so the studs will be fully vertical, do not tighten anything until the JB sets up.

[CarlG]

Originally Posted by Jim Brierley

... I would install a repair like a heli-coil...

On mine, the studs that have been helicoiled are the loosest ones.

[Russ/40]

You can use a release agent on the stud, and it will work, and also be removable. JB actually sells a product for that labeled a thread repair.

[sphanna]

When you say a "release agent", I am not sure what you mean. Thanks for your help. I will check on the Thread Repair by JB

[callcoy]

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You need "Full Torque" thread insert by Stitch Lock, google them!

[Craig Lewis]

Originally Posted by sphanna

I will probably purchase new studs, but there is a slight looseness in 2 of my studs in the block. I am wondering, if I buy new studs, could I put a little JB weld on the coarse threads and install in the block to strengthen the block threads? I am concerned about stripping the block threads. I did have the same situation when I put the new head on and torqued to 55 pounds. They torqued up OK and did not leak. This time I am wondering if i should try to fix the looseness.

New studs may or may not remedy your problem.
I ordered a set from a well known Model A cylinder head manufacturer advertised as "high strength, close tolerance threads"
They rocked back & forth more than the cleaned up originals. He said "use them it's OK"
....they took the torque, although I've not started the engine yet....
While it's hard to compare interpretations of 2 people in regards to "a slight wiggle" ... I would describe my new close tolerance studs as having a significant wiggle. In fact I used heli coils in two holes and even then the new studs rocked back & forth a bit.
The number 1 worse thing you can do with block threads is to run a threading tap into any hole. The correct tool for this job is a thread chaser which must be used with lubricant. I prefer to clean the threads with a miniture bottle brush and carb spray, being sure to insert an air nozzle to the bottom and blow the crud out into my eye
I screwed my studs in with a light film of motor oil and twisted them "just snug" with pliers.
If I ever went shopping for new studs again, I'd want to see them first & would use a dial caliper across the threads of my best original...then compare to the new.

[mot]

stainless steel gun bore brushes work great for cleaning threads
38 , 45 caliber or 9mm
the bronze one wont work after the first hole,

[Tom Wesenberg]

Originally Posted by mot

stainless steel gun bore brushes work great for cleaning threads
38 , 45 caliber or 9mm
the bronze one wont work after the first hole,

You sure have that right about the brass or bronze cleaning brushes. They bend over like a wet noodle and stay there.

[George Miller]

The problem is people use a regular tap to clean the threads. They were originally a closer class thread. If you can screw the stud in without much effort , why clean the threads. You will do more damage to the threads than you will good. If it goes in real hard then that is another story.

[CarlG]

Originally Posted by George Miller

The problem is people use a regular tap to clean the threads. They were originally a closer class thread. If you can screw the stud in without much effort , why clean the threads. You will do more damage to the threads than you will good. If it goes in real hard then that is another story.

The problem I have is that obviously a regular tap was used sometime in the past to clean up the threads, and now they are loosey-goosey. Just trying to come up with a solution that would remedy that without having to get into a lot of remedial work and cost. It seems to torque down and hold OK. Maybe I'm just being paranoid?

[Old182]

George has it right. I just posted on another thread that studs have 2 different classes of fit. The coarse end should have a Class 5 fit which is an interference fit. The studs I've seen from the Model A supply houses are not Class 5 on the coarse end and can be easily screwed into the block - studs should have to be "driven". After 80+ years of heating, cooling, corrosion and erosion, it's no wonder the threads are somewhat loose, particularly if the new studs are rolled to a Class 2 fit. Perhaps a "real" fastener supply house would have the correct fit studs for our applications. All that said, I replaced a worn (loose) stud with the 1/2-13 repair kit from Snyder's and it's worked quite well for several years now; you might consider that route if nothing else sounds reasonable.

[1931 flamingo]

Loctite??
Paul in CT

[sphanna]

I thank everyone for your suggestions and advice. This is a very valuable Forum.

[callcoy]

I gave the wrong info in an earlier reply, The Co. to contact is Lock n Stitch in Turlock CA. They repair and provide their patented products those that also repair cast iron castings. They have products to repair cylinder heads, manifolds, sparkplug threads, stud holes and etc, alum. and cast. The key to their success is their patented thread that actually pulls the casting together. I am suprised that I haven't seen them mentioned on this sight before, in my 58 years of wrenching I have never seen a product nearly as good as theirs. Google them they have quite a website!

[Russ/40]

Originally Posted by sphanna

When you say a "release agent", I am not sure what you mean. Thanks for your help. I will check on the Thread Repair by JB

The release agent allows for removal of the stud without damaging the newly repaired threads. You mentioned the block held torque on this stud, that is why I feel this repair is a sound idea. If the existing threads would not hold torque, I would then go the insert type repair.