Yesterday I started car and it made a noise and starter bolt fell out. Stripped. 3/8-16 into an aluminum block. Pulled the motor out and was going to put Heli-Coil in it but I really do not like the way it fits.

I am thinking of tapping it all way through and reaming starter block for a 7/16-14 bolt. I could then use a longer bolt with more thread engagement and not have to worry about integrity of the Heli-Coil. I would have over an inch of thread engagement with the 7/16-14 bolt. That would mean the starter block is for only on that motor but if I had to I could always get a new starter block for another motor.

What is your opinions? Heli-Coil or larger, longer bolt?

You might look at a Keensert or Timesert instead.

the od on sertss are different i would and have lately chosen a sert with a 9/16 od to do that job.most serts are stainless but not all ,i suggest cabon threads.i am cuurently doing this not on starter but aluminum as we speak

I used a time sert when I had to do mine, worked out good. They actually have a kit for Chevys, comes with everything you need. I would think SB and BB kits are the same

This is the Timesert kit I used, I bought it from Amazon but they are showing out of stock right now

https://www.threaddoctor.com/p...NTt7fWGz9-iRIMrfE2Hg

If it was mine I'd drill and tap the h0le for 7/16" and use a proper length head stud. A stud makes installation super easy. Drill and tapping the existing h0le keeps things very accurate. Get the stud (head studs work great) and drill the h0le deep enough so the stud runs out of threads right when it bottoms so it tightens up in the block. Drill/ream the starter h0le for the 7/16" stud, slip the starter up in place over that stud and start the other 3/8" bolt. You'll never be happier installing a starter while laying on your back under the car...And the extra clamping force of the 7/16" is nice also..

X2

Bob

quote:

Originally posted by imakehp:
If it was mine I'd drill and tap the h0le for 7/16" and use a proper length head stud. A stud makes installation super easy. Drill and tapping the existing h0le keeps things very accurate. Get the stud (head studs work great) and drill the h0le deep enough so the stud runs out of threads right when it bottoms so it tightens up in the block. Drill/ream the starter h0le for the 7/16" stud, slip the starter up in place over that stud and start the other 3/8" bolt. You'll never be happier installing a starter while laying on your back under the car...And the extra clamping force of the 7/16" is nice also..

Stud will not work on this motor, I have a large kickout on oil pan and the frame is very narrow there so I can not slide it straight up from bottom. And my chassis has a diagonal right there so starter barely goes in from side.

If I ever built a chassis from scratch I would definitely make it a few inches wider. That could make several things so much easier.

Is it the inside h0le or the outermost?

inside hole.

quote:

Originally posted by Curly1:
inside hole.

Couple of things then.....

I THINK some of the mini-starters us short bolts instead of the 4-5" standard bolt..

If not....
If you're stuck with the traditional long bolt(s) either milling the starter bolt boss down to about an inch and use a 1-1/2" long stud.... OR instead of milling the boss down, mill/slot the entire length of the side of the h0le so it will slip right over the longer stud when you install the starter from the side....Make sure to use a beefy head stud washer for support..

One thing to be careful of if the bolt shank is knurled it would probably be better to helicoil or keensert the knurled bolt is important in keeping the starter from moving around.Its a pretty snug fit between the knurl and starter holes.

Timesert or Kenesert, don't use helicoil the thread inserts are just way better options. If you go up to 7/16" you'll have the same problem later down the road and will have to go up antoher bolt size. The problem you have is the steel bolt up against the aluminum threads of the block (assumes block was not helicoiled or thread inserted from factory). With a thread insert you won't have steel bolt vs. aluminum thread situation. While you are at it, I'd put an insert in the outer bolt as well.

I do think you'll run into some challenges as the helicoil and threadserts I have used, if I'm not mistaken utilzie the same thread pitch and drill size. I'd guess there are multiple OD options out there so you may be able to find something that works.

Good luck!

I recently used some advice I picked up in here and used a pipe plug as a thread insert. I did one where I drilled and tapped then installed. Second one I drilled and tapped in place. So far it seems to be a good fix. This was on rocker stand hood down bolts for me.

Thank you for all of the good advice. I decided to go ahead and step it up to 7/16 mainly because I was able to pick up over a full inch of threads. Got 19 threads on one bolt and about 17 on the other. Should never pull out again.

While I was at it I went ahead and did the other bolt to. That way both are the same and I know it will not pull out.

I think they probably should have had a Heli-Coil or what ever from the factory in an aluminum block.

Thank you,

One more thing, I had pulled motor out a few weeks ago to Dyno it and try some things, rebuild transmission and check out converter. Put it all back together and was trying to start it to check transmission fluid. Rats! Motor had to come back out! Going back in now.

Buy a race car, it will be fun they said.......

Just make sure your spare starter for at the track is also drilled out

Those starters move around dontcha know.
After experiencing issues with starter bolts and gear teeth I took a cue from Chevy and made/mounted a bracket to the front of the armature casing. Everything stays put and gear life improved.