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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Cheyenne1010 on August 12, 2022, 03:20:29 pm

Title: Starter bolts
Post by: Cheyenne1010 on August 12, 2022, 03:20:29 pm: I am a proud owner of a 1973 chevy Cheyenne longbed 5.7liter.the problem I'm having is the starter bolts are two different size.one is 3/8 diameter and the other is 1/2 diameter and when I purchase a starter the holes on the starter match up with the smaller diameter 3/8 bolt.thet last starter I bought I had to drill out the 3/8 diameter bolt hole to 1/2 diameter bolt hole.i have never see this before and if you have please explain what is going on and any suggestions on how to fix my issue will be greatly appreciated.

Thanks guys
Robert
Title: Re: Starter bolts
Post by: Shifty on August 12, 2022, 03:34:00 pm: It shouldn't be a 1/2....sounds like someone drilled/tapped your block at some point.
Title: Re: Starter bolts
Post by: bd on August 12, 2022, 03:39:21 pm: Someone may have stripped the threads out of the original 3/8" bolt hole then drilled and tapped for 1/2".

Can you post pics of the starter mounting surface of the block with the starter removed and pics of the starter showing the bolt hole layout? Some starters use a straight across bolt hole configuration while others are offset or staggered. Depending on how the block is drilled, you may be able to substitute an alternate style.
Title: Re: Starter bolts
Post by: Twosquarebodys on August 12, 2022, 06:11:58 pm: Will a Heli-Coil work??
Title: Re: Starter bolts
Post by: bd on August 12, 2022, 08:19:15 pm: No. The 1/2" bolt hole is already larger in diameter than the tap for the 3/8" Helicoil. If the substitute starter suggestion posted previously isn't workable, contact Timesert (http://www.timesert.com/) to see whether they offer a solution.
Title: Re: Starter bolts
Post by: JohnnyPopper on August 13, 2022, 10:03:11 am: Quote from: bd on August 12, 2022, 08:19:15 pm
No. The 1/2" bolt hole is already larger in diameter than the tap for the 3/8" Helicoil. If the substitute starter suggestion posted previously isn't workable, contact Timesert (http://www.timesert.com/) to see whether they offer a solution.

Did you mean the '1/2" bolt hole is larger than the drill size for a 3/8" Helicoil'? ;D
Title: Re: Starter bolts
Post by: bd on August 13, 2022, 02:23:53 pm: JP, I meant exactly what I wrote. A 3/8" Helicoil tap will fall through a 1/2" hole. ;)

I don't believe an off-the-shelf 3/8" Timesert will work either, but they may offer a custom solution.

Of course, the easiest solution would be to use a starter with the alternate mounting configuration if the block is machined to accept it.
Title: Re: Starter bolts
Post by: Shifty on August 13, 2022, 03:14:14 pm: OP, is this the "thru-hole" in the block? I've seen my share of longer bolts that just had a nut on them.
Title: Re: Starter bolts
Post by: zieg85 on August 13, 2022, 06:07:41 pm: https://www.emisupply.com/catalog/topaz-reducing-bushing-steel-male-threaded-p-39654.html
Title: Re: Starter bolts
Post by: Shifty on August 15, 2022, 09:13:19 am: Nice one Zeig! 8)
Title: Re: Starter bolts
Post by: Stewart G Griffin on August 20, 2022, 08:11:35 am: Now is also a good time to verify that you have the front starter brace installed. This sounds like a very precarious position to be in....