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BJ8 Cylinder Head Installation

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AUSMHLY

AUSMHLY

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Healey BJ8, cylinder head ARP stud/washer/nut procedure.

I'm installing a new head gasket on my BJ8. Decided to use ARP studs/washers/nut that I purchased separately. (Moss doesn't use ARP nuts in their kit.)

Moss's kit instructions: Coat the coarse threads with a light oil or ARP Assembly Lube for Threaded Fasteners (Moss 322-815) and install them in the block finger tight. ARP studs have a hex recess in the top for an Allen wrench, which facilitates installation.

Moss: Tighten the nuts on the studs following the procedure given in the factory workshop manual. Note that the upper end of the stud is left dry; the threads are not coated with oil or ARP Assembly Lube and therefore the torque specification in the workshop manual can be used.

YouTube videos about using ARP say to coat the coarse threads with a little oil, finger tight.
Using ARP’s washer, bottom of washer dry, top of washer use ARP Assembly Lube. Fine treads on top of stud, use ARP Assembly Lube so ARP nut has smooth movement. Torque will be smooth until torque wrench clicks.

Spoke with ARP, they say the same, except torque to 80 ft/lbs, not 75 ft/lbs per shop manual.

Moss say when using their ARP kit, torque to 75 ft/lbs.

NOTE: Moss’s kit does not us ARP nuts. Moss doesn't lubricate the washer or nut. Not sure if that has bearing on why Moss says torque to factory 75 ft/lbs.

Those who use ARP studs/washer/nut, what is the procedure you use and what value do you torque the nuts on a BJ8 cylinder head?

Thank you in advance.
 
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I can't help you directly, but am a bit puzzled. The idea is to stretch the studs a given amount to develop the desired preload. Part of the torque applied overcomes the friction of the nut to the washer and between the threads. The use of the ARP lube should reduce the amount of friction. So I would have thought that the torque with the lube would be the same or less than the torque dry.

ARP's instructions for rod bolts is to torque/loosen three times. Do they say the same for the cylinder head studs/nuts?
 
How good are the threads in your block? Was your block decked as a part of the rebuild? Assuming the threads are sound (did you run a thread restorer into each stud hole? How tight was the hole after this exercise? Do the threads look good?) and the deck is flat (check around the stud holes with a straight edge if the block was not decked) I would follow the ARP instructions. If you are unsure then go to 75 lbs. Lubricating the fine threads and washer face reduces friction and allows a greater percentage of the twisting force to stretch the stud. The ARP studs are much harder than the stock studs, so the higher torque recommendation may be to create a bit more stretch/tension. Also, higher torque should reduce the chance of a head gasket failure.
 
ARP recommends, torque 30, 60, 80.
After the initial final torque, when do you re-torque?
Soon after running the engine or X miles later?

Has anyone hear that ARP studs/washer/nut do not need to be re-torqued?
 
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Legal Bill said:
How good are the threads in your block? Was your block decked as a part of the rebuild? Assuming the threads are sound (did you run a thread restorer into each stud hole? How tight was the hole after this exercise? Do the threads look good?) and the deck is flat (check around the stud holes with a straight edge if the block was not decked) I would follow the ARP instructions. If you are unsure then go to 75 lbs. Lubricating the fine threads and washer face reduces friction and allows a greater percentage of the twisting force to stretch the stud. The ARP studs are much harder than the stock studs, so the higher torque recommendation may be to create a bit more stretch/tension. Also, higher torque should reduce the chance of a head gasket failure.
Click to expand...

Hi Bill,
I haven't taken the head off yet. I'll clean the thread hole with a small wire brush, spray parts cleaner then compressed air to clean out. Then I'll gently hand twist a stud in to determine the resistance and use a thread chaser if needed.

I'm replacing with the gasket with a high quality one from Moss or AHS, which I think maybe the exact same gasket.
I plan on spraying Permatex Copper Spray-A Gasket on both sides of the gasket.
With quality parts and using an accurate torque wrench, hopefully the head gasket will not leak.

Is there a chance that some damage could be directed to the block or cylinder head with higher torque of 80 vs 75?
 
AUSMHLY said:
Hi Bill,
I haven't taken the head off yet. I'll clean the thread hole with a small wire brush, spray parts cleaner then compressed air to clean out. Then I'll gently hand twist a stud in to determine the resistance and use a thread chaser if needed.

I'm replacing with the gasket with a high quality one from Moss or AHS, which I think maybe the exact same gasket.
I plan on spraying Permatex Copper Spray-A Gasket on both sides of the gasket.
With quality parts and using an accurate torque wrench, hopefully the head gasket will not leak.

Is there a chance that some damage could be directed to the block or cylinder head with higher torque of 80 vs 75?
Click to expand...
Your plan raises some concerns. Maybe I’m missing something. Please tell us why you are doing this job in the first place.
 
So AUSMHLY, Why are you installing a new head gasket on your BJ8? Are you going to take your head somewhere for a valve job job?
Also, why are you replacing your studs, nut and washers with ARP products? Seems like a waste of money to me - unless you are bumping the compression to 12:1. The original components are more than adequate for re-use. Over and over. They are quite robust and torqueing the nuts to 75, or more, with or without a touch of oil is no big deal. These are low tech motors. I believe you are over thinking all of this. My understanding is that Roger Menedue never used a torque wrench on a Healey cylinder head. Do you think he got all the nuts just right at 75? Gasket failure on the 6 cylinder motors are not an issue. BJ8 motors are the same as every 6 cylinder Healey motor that came before it. There's nothing special about a BJ8 cylinder head or block.
 
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