Bolt Spec Advice Sought

[Tom D.]

I'm about to help a friend by pulling his '74 350 and rebuilding it for him. I'm trying to get a few bolt specs to help the process go a bit smoother:

1. Bolt diameter and pitch of the holes used to pull the torsional damper in front of the crank.

2. Bolt diameter and pitch of the transmission to engine bolts.

Obviously, the first is to have the right bolts to pull the torsional damper and the second is for mounting the engine to my engine stand.

Thanks for any help!

Tom

[Gene M.]

Re: Bolt Spec Advice Sought

Your not going to mount the engine to the stand with the bell housing on? You gotta take off the bell housing, clutch and flywheel. Your engine should be mounted to the back of the block and the threads are 3/8 course.

[Gene M.]

Re: Bolt Spec Advice Sought

Your not going to mount the engine to the stand with the bell housing on? You gotta take off the bell housing, clutch and flywheel. Your engine should be mounted to the back of the block and the threads are 3/8 course.

[Tom Darone]

Re: Bolt Spec Advice Sought

Gene,

Had no intention of leaving the bell housing on for mounting to the engine stand. Most of the manual transmissions I work on (Datsun) have the bell housing as part of the transmission case, not separate. However, this '74 has an automatic transmission and I was guessing it was one unit on that also.

In any case, thanks for the data on the bolt. May sound like a dumb question, but how many threads per inch does "3/8 coarse" correspond to? My whole bolt stock is metric, which specifies in distance (mm) between threads. SAE bolts go by threads per inch, I believe.

Also, anyone on the torsional damper bolt hole specs?

Thanks!

Tom

[Tom Darone]

Re: Bolt Spec Advice Sought

Gene,

Had no intention of leaving the bell housing on for mounting to the engine stand. Most of the manual transmissions I work on (Datsun) have the bell housing as part of the transmission case, not separate. However, this '74 has an automatic transmission and I was guessing it was one unit on that also.

In any case, thanks for the data on the bolt. May sound like a dumb question, but how many threads per inch does "3/8 coarse" correspond to? My whole bolt stock is metric, which specifies in distance (mm) between threads. SAE bolts go by threads per inch, I believe.

Also, anyone on the torsional damper bolt hole specs?

Thanks!

Tom

[John H.]

Re: Bolt Spec Advice Sought

Tom -

The auto trans/bellhousing mounting holes in the back of the block are 3/8"-16; use Grade 8 bolts. Most balancer pullers use the pulley bolts in the center hub, which are usually 3/8"-24; make sure the center shaft on the puller has an adapter cap for the end so it doesn't screw up the start of the 7/16"-20 threads inside the crank snout for the balancer bolt.

[John H.]

Re: Bolt Spec Advice Sought

Tom -

The auto trans/bellhousing mounting holes in the back of the block are 3/8"-16; use Grade 8 bolts. Most balancer pullers use the pulley bolts in the center hub, which are usually 3/8"-24; make sure the center shaft on the puller has an adapter cap for the end so it doesn't screw up the start of the 7/16"-20 threads inside the crank snout for the balancer bolt.

[Clem Z.]

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[Clem Z.]

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[Clem Z.]

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[Clem Z.]

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[Clem Z.]

bolt sizes

SB puller size is 3/8"-24,BB is 3/8"-16 and install a short 7/16"-20 in the crank snout to prevent any damage to the crank threads. a BB will need a 1/2"-20 short bolt in the crank snout. use good 3/8"-16 to bolt the engine to the engine stand.no hardware store stuff,use grade 8. i have seen cheap bolts break and the engine ending up on the floor!

[Clem Z.]

bolt sizes

SB puller size is 3/8"-24,BB is 3/8"-16 and install a short 7/16"-20 in the crank snout to prevent any damage to the crank threads. a BB will need a 1/2"-20 short bolt in the crank snout. use good 3/8"-16 to bolt the engine to the engine stand.no hardware store stuff,use grade 8. i have seen cheap bolts break and the engine ending up on the floor!

[Tom Darone]

Re: bolt sizes

Clem,

Very good advice on sizes and precautions. I have a SB, so your info looks consistent with previous post. But now I'm adding a short 7/16"-20 to the checklist.

Thanks!

Tom

[Tom Darone]

Re: bolt sizes

Clem,

Very good advice on sizes and precautions. I have a SB, so your info looks consistent with previous post. But now I'm adding a short 7/16"-20 to the checklist.

Thanks!

Tom