Bolt size?

[Bucketboy]

If anyone out there has a timing gear bolt, I would like to know the dimension of the shank of the bolt. I know it's a 5/16 - 24 thread, but I need to know what the the diameter of the un-threaded shank, under the head, measures.
Thanks!

[19Fordy]

If you can post a photo of the bolt, I will look through my "stuff" and "mike" one.

[51 MERC-CT]

All 4 of a set that I have measure .3105" to .3107" dia.

[V8COOPMAN]

Are you possibly thinking about the distributor mounting bolts that are slightly bigger than normal (shank diameter) to precisely mount the distributor? DD

[russcc]

The Green bible lists them, with dimensions.

[19Fordy]

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Bucketboy: What engine are you dealing with?

[paul2748]

shouldn't it be 5/16 ?

Originally Posted by Bucketboy

If anyone out there has a timing gear bolt, I would like to know the dimension of the shank of the bolt. I know it's a 5/16 - 24 thread, but I need to know what the the diameter of the un-threaded shank, under the head, measures.
Thanks!

[DavidG]

With respect, they are not 5/16-24, but rather 5/16-18.

[51 MERC-CT]

Originally Posted by russcc

The Green bible lists them, with dimensions.

Originally Posted by paul2748

shouldn't it be 5/16 ?

Originally Posted by DavidG

With respect, they are not 5/16-24, but rather 5/16-18.

All engines that have a bolt on camshaft timing gear use a generic rolled thread 5/16-24 bolt. The shank dia. will fall within whatever tolerance spec. that is assigned to the bolt.

[Bucketboy]

Thanks 51 MERC-CT, as well as all the rest of you that responded.
Was curious due to the fact that the timing gear has 1 hole that measures about .310" diameter, while the other three measure a little over .340" diameter. Since the timing gear apparently locates on the cam using the shank of the bolt that goes through the small hole, instead of being keyed, I was just wondering if there would be enough slop between the bolt diameter and the hole diameter to affect the cam timing. Thanks again.

[DavidG]

Oops, I misread the question and thought it pertained to the timing gear cover bolts. Sorry.

[51 MERC-CT]

Originally Posted by Bucketboy

Thanks 51 MERC-CT, as well as all the rest of you that responded.
Was curious due to the fact that the timing gear has 1 hole that measures about .310" diameter, while the other three measure a little over .340" diameter. Since the timing gear apparently locates on the cam using the shank of the bolt that goes through the small hole, instead of being keyed, I was just wondering if there would be enough slop between the bolt diameter and the hole diameter to affect the cam timing. Thanks again.

Reply removed because of incorrect information

[Mart]

Ford probably reckoned that the degree of rotation controlled by the bolt in the one tighter hole was within tolerance for the power output of the engine.

If the bolts are .3105 to .3107 they appear to be tightly controlled. If the hole is "about .310"" diameter that would suggest it is a close fit (theoretically slight interference, but the one dimension is approximate)

I feel it is a non issue for a stock build. If building for power with a hot cam, some method of degreeing it in would probably be advised.

I just bolt em up.

Mart.

[51 MERC-CT]

Originally Posted by Mart

Ford probably reckoned that the degree of rotation controlled by the bolt in the one tighter hole was within tolerance for the power output of the engine.

If the bolts are .3105 to .3107 they appear to be tightly controlled. If the hole is "about .310"" diameter that would suggest it is a close fit (theoretically slight interference, but the one dimension is approximate)

I feel it is a non issue for a stock build. If building for power with a hot cam, some method of degreeing it in would probably be advised.

I just bolt em up.

Mart.

Reply removed because of incorrect information

[Mart]

It's located on a diameter, ain't it? Not just the bolts.. I'll have to go and have a look.

Mart.

Edit: just checked a French gear - it locates on the large diameter on the front of the cam. Two of the holes on the French gear are smaller than the others I'm getting .307, .310 and then two at .340. this is with calipers so will be a little out due to the square edge on the blades.

I can't find any bolts to measure.

[51 MERC-CT]

Originally Posted by Mart

It's located on a diameter, ain't it? Not just the bolts.. I'll have to go and have a look.

Mart.

Edit: just checked a French gear - it locates on the large diameter on the front of the cam. Two of the holes on the French gear are smaller than the others I'm getting .307, .310 and then two at .340. this is with calipers so will be a little out due to the square edge on the blades.

I can't find any bolts to measure.

You are 100% correct, the gear mounts on the O.D. of the cam ( don't know how I missed that but I sure did )

[V8COOPMAN]

Don't forget guys, that the oddball sizes should index the timing mark on the gear at the proper "timing location" on the cam itself. DD