Cylinder Head Studs

[AUSMHLY]

Hello,

Reference BJ8:
My understanding is ARP studs/washers/nuts are an upgrade vs the factory/stock cylinder head studs/washer/nut.
The stock stud for the BJ8 is about 5 1/8" long.
I purchased ARP studs that are 5" long.
The stock stud 7/16-14 thread for the block is about 5/8" long.
The ARP stud 7/16-14 thread for the block is about 1" long.

I've read the studs should be installed finger tight into the block.
The stock stud is finger tight when the shank makes contact with the block head at 5/8" depth.
The ARP stud is finger tight when it makes contact at the bottom of the hole, more then 5/8", because the threads are 1" so the shank doesn't make contact.
Because the ARP stud is lower in the block, it doesn't extend enough into the cylinder head nut to use all the threads.

Would it be safe acceptable to hand screw the ARP stud 4/8" into the block and stop there?
That will allow the APR stud threads to protrude the nut about 1/8".

Photos attached:
1. Stock stud next to ARP; notice the length of the threads.
2. Both studs taped to show how far they enter the block.

3. Stock stud inserted finger tight until shank. ARP finger tight to bottom of block thread hole.
4. How far ARP stud extends into the cylinder head nut.

5. Stock stud inserted finger tight until shank. ARP finger tight 4/8" into block.
6. How far ARP stud extends into the cylinder head nut.

Stock stud inserts 5/8 into block.
ARP stud inserted 4/8" into block, OK?
I've added a thin silver washer to compensate for the gasket thickness.

Thoughts?

 

[John Turney]

The general rule is to insert the studs so that the top of the stud extends about one thread beyond the nut when tightened. You will need an Allen wrench to adjust the stud height.

 

[Randy Forbes]

The extra washers (zinc-plated, pic #5) are those to account for test assembly without the head gasket in place?

Frankly, I'd be disappointed, and be making phone calls to 1st) ARP to express my concerns, and 2nd) to (vendor) for a refund...

I also read your thread about the reduced-shank studs, but I have no experience/opinion on those.

I use ARP studs on all the BMW I-6 engines I've built (they were originally fitted with TTY, or one-time use bolts) and with those I am always able to hand thread them in until the non-threaded shank stops on the top thread in the block, same as what I'd expect to do with your Healey.

 

[AUSMHLY]

The extra washers (zinc-plated, pic #5) are those to account for test assembly without the head gasket in place?

Frankly, I'd be disappointed, and be making phone calls to 1st) ARP to express my concerns, and 2nd) to (vendor) for a refund...

I also read your thread about the reduced-shank studs, but I have no experience/opinion on those.

I use ARP studs on all the BMW I-6 engines I've built (they were originally fitted with TTY, or one-time use bolts) and with those I am always able to hand thread them in until the non-threaded shank stops on the top thread in the block, same as what I'd expect to do with your Healey.

Hi Randy,
Yes, zinc washer to compensate for HG.
Another Healey guy who was putting together a cylinder head kit posted on the AHX forum the ARP # for the stud that should work.

ARP Head Stud Kit : Motorsports Forum : The Austin-Healey Experience

I am a new member to this forum, but not new to Austin Healeys. I have owned mine since 1968. I am currently modifying the engine for fun...not racing, but I noticed that there were several references to ARP bolting products for Austin Healey 3000 engines. I found that ARP does manufacture a spe

www.ahexp.com

Once I received it, I found the threads 7/16-20 and 7/16-14 plus 5" length was good, even though the stock stud is 5 1/8". Issue is the 7/16-14 thread was too long at 1", should be 5/8". Not ARP or seller fault being I didn't speak with them prior to purchase. I'm trying to figure out if I can use the ARP studs I have. If not, lesson learned.