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Head stud bolts

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J

John_Progess

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Is it general practice to replace all the head stud bolts as part of the engine overhaul (64 BJ8)? If so, where are people buying their stud bolts? I don't know the condition as the head is still on the block but I was going to place an order soon. Thanks for your help.

John
 
Hi John, it certainly would give you peace of mind to use new studs and bolts to reassemble the engine. OTOH, I have no unique source for them and they probably all come out of the same bin.--Fwiw---Keoke
 
These are not torque to yield studs as found in more modern engines and I usually reuse them if they look OK (not pitted or covered with vise-grip gouges). If you want something "better", Denis Welch has "heavt duty" studs. Probably available from ARP too.

Marv James
 
I agree they can be re-used if they don't show signs of being over-tightened in the past. Signs would be necking (reduction) of the diameter or obviously stretched threads. They would have had to have been seriously mistreated not to be reusable.
 
[ QUOTE ]
I agree they can be re-used if they don't show signs of being over-tightened in the past. Signs would be necking (reduction) of the diameter or obviously stretched threads. They would have had to have been seriously mistreated not to be reusable.

[/ QUOTE ]

Yep /ubbthreads/images/graemlins/iagree.gif But if you don't know what the signs of wear are you are a lot safer just replacing with new.---Keoke
 
I bought my head studs and connecting rod bolts directly from ARP. They recommend retiring a fastener after it has been torqued 4 times.
 
ARP products seem to have a very good reputation, so no disrespect intended, but replace after four times? Sounds a bit too much. Studs do become elongated, with resultant decrease in diameter, and should be replaced if out of spec, but an arbitrary rule such as four tightening cycles then replacement seems a poor substitute for careful checking.
 
Hi Cutlass,
I hear what you are saying. I would guess that our low powered Healeys could get more life out of the fasteners. Their (ARP) recommendation may have evolved from feedback from race car builders, the majority of their customers. Who abuse engines much more than we do. /ubbthreads/images/graemlins/grin.gif
 
So where were you today Greg? It would seem that if ARP recommends a change in the subject bolts after a specified time in use.I feel that potentially 40 year old bolts that God only knows who and how they have been tightened in the past, will certainly increase your chances of success in an engine rebuild if replaced with new and the old ones given a rest.---Keoke
 
[ QUOTE ]
Is it general practice to replace all the head stud bolts as part of the engine overhaul (64 BJ8)? If so, where are people buying their stud bolts? I don't know the condition as the head is still on the block but I was going to place an order soon. Thanks for your help.
John

[/ QUOTE ]
Hi John,
I think it's a matter of how tight you are, how much reliability you want, & how willing you are to gamble.

All cyclically stressed parts are subject to cumulative fatigue failure. 40 to 50 years of this stress, you just don't know how much life is left in the parts. Inspection will not usually show pending fatigue failure.

I make it a point to replace head studs, connecting rod bolts, main cap studs, flywheel bolts, & a few others when doing a rebuild. Anything that might cause a disaster if it fails. Of course, the matching nuts & hardened washers as applicable. Despite the apparent extra cost, it is relatively cheap insurance against a disasterous failure. I don't want to take the chance.

I get quite a few parts from Denis Welch Motorsports:
https://www.bighealey.co.uk/catalogue.php?id=1

As others have said, ARP has a very good line of high strength fasteners if you can find what you need.
Back to my first line. It would be good to search out the parts & know exactly what you want to do before ordering, even if it takes a little longer.
D
 
[ QUOTE ]
So where were you today Greg?

[/ QUOTE ]
Hi Keoke,
WOT. I plain forgot until 8:30 this morning, still in my jammies. I kicked myself, twice.
 
[ QUOTE ]
[ QUOTE ]
So where were you today Greg?

[/ QUOTE ]
Hi Keoke,
WOT. I plain forgot until 8:30 this morning, still in my jammies. I kicked myself, twice.

[/ QUOTE ]

Well OK! See you another day.---Keoke- /ubbthreads/images/graemlins/driving.gif
 
Put new studs in myself, think they are grade 8.8, not sure what the originals were.
Now a Q for the experts amongst us!, will this reduce the inherent weeping if the studs are of a sturdier grade than original?
 
Hi zblu,
I believe a grade 8.8 stud has considerably less tensile strength than the original studs.
Some comparisons:
Metric grade 8.8 tensile strength = 116,000 psi
SAE grade 8 tensile strength = 150,000 psi
Original factory studs = 165,000 psi
ARP specialty studs = 190,000 psi

I think that with perfectly flat head & block surfaces, a good gasket, & good studs with hardened washers, properly torqued, there will be no "weeping" or other sealing problems. Cut any of these corners & the result may not be so good.
D
 
[ QUOTE ]
Put new studs in myself, think they are grade 8.8, not sure what the originals were.
Now a Q for the experts amongst us!, will this reduce the inherent weeping if the studs are of a sturdier grade than original?

[/ QUOTE ]

Well Maybe, But if you look at most original BJ8 engines that have not been taken to bits, they weep just behind the generator bracket and just above the heater shut off valve. Similarly, even if the engine has been rebuilt, if the engine runs hot they seem to weep there too.--Fwiw--Keoke-?
 
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