Alpine Bell Housing Bolt Size?

[tylerite3124]

A friend has a Series IV Alpine being restored that has an overdrive trans that is missing the bolts needed to bolt it to the block.. Does anyone know the size of the bolts he needs? Thanks for any help.

Rick

 

[hartmandm]

The Parts Manual shows three bolts that are 3/8 UNF x 1-1/4" and one bolt that is 3/8 UNF x 2-1/4".



I think the three bolts at the top of the bell housing are the shorter length. These are bolts into blind holes.

I think there may be two longer bolts that are on the right side. They go through the block and have nuts. The oil pressure line clamp attaches to one of them. I attached a clamp for the OD wiring harness onto the other one. Picture of the right side on my series 5:



I think the higher of these two longers bolts, with the wiring harness clamp attached, is the 'dowel bolt' listed in the Parts Manual.

Mike

 

[tylerite3124]

Thanks Mike. Very helpful.
Rick

 

[Barry]

A friend has a Series IV Alpine being restored that has an overdrive trans that is missing the bolts needed to bolt it to the block.. Does anyone know the size of the bolts he needs? Thanks for any help.

Rick

I think your friend would benefit from having one of these thread checkers:

https://www.amazon.com/gp/product/B08L38BJDS/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&th=1


Your friend can buy a fancy thread depth gauge for blind threaded holes, but a 3" 10d (aka, 10 penny) nail, a thumbnail and a ruler will do nicely for the vast majority of situations.

 

[tylerite3124]

I think your friend would benefit from having one of these thread checkers:

https://www.amazon.com/gp/product/B08L38BJDS/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&th=1


Your friend can buy a fancy thread depth gauge for blind threaded holes, but a 3" 10d (aka, 10 penny) nail, a thumbnail and a ruler will do nicely for the vast majority of situations.

Thanks, Barry. I’ll forward this info to him.
Rick

 

[Tom H]

Don't miss the point that one of the bolts is a DOWEL bolt and uses a nut on the end. That's the bolt that Mike highlighted in his photo where you can see a nut on the end. The dowel bolt is a snug fit to provide critical alignment of the bell housing to the block. I think there is also a plain dowel, no thread, at some other point to assure alignment.

 

[tylerite3124]

Thanks Tom. Point noted.
Rick

 

[sunalp]

Hi Rick,
The three threaded bolts on top are 3/8-16. Two are 1 1/2" long , the smaller (middle one) is 1 " long.
Cheers!

 

[hartmandm]

Hi Rick,
The three threaded bolts on top are 3/8-16. Two are 1 1/2" long , the smaller (middle one) is 1 " long.
Cheers!

Hmm... those specs are not aligned with the info in the Parts Manual. I think most of the fasteners on the car I have seen are Fine not Coarse...

It is best to use a thread checker of course.

Mike

 

[sunalp]

Well, those just came out of the SV I have in the shop. Seen them on a couple of others as well.
I've also seen the fine pitch which is usually 24. Same lengths though.