5 1/2" Starter Bolt is stripped. How to tap something that deep?



After a 30-year hiatus, I successfully completed an auto repair task. (I was always a weekender type, figure-it-out sort of novice.) 5 hours, start to finish, one trip to the parts store, and my new alternator was a shining success. But…then the starter died the following Feb. I am still wrestling with it!!! Problem, the 5 1/2 inch long bolt stripped as I initially removed the old, worn out starter from this aluminum engine. Because it is so long, I cannot figure out how to tap new threads to then insert a helicoil and new bolt. No one makes extensions for a STP (Self Threading Insert) type of tap. HELP!!! I will probably try to attach the starter without repairing the threads and inserting the new bolt. Again, HELP!!


You seem like a person who is willing to take on a challenge. But before you can get help here, you have to treat us as if you were going into a parts store to get a part for your vehicle. And what’s the first thing you tell the counter person?



It’s a 51 Henry J. with a 65 Mustang 289 bored .030 over with a Crower cam and Holley 650, Tester. Can’t you read between the lines?


If the bolt hole goes all the way through the flange, use a longer bolt and put a nut on it.


surely a 5 1/2 inch bolt doesn’t screw in any farther than a 2 inch bolt. The hole that you need to tap surely is no more than 3/4 inch deep, is it? By the way, I bought a 51 Henry J new. It was white with red alligater-grain upholstery, a trunk (some did not), a 6 cylinder engine, I put a sunvisor and dual exhaust on it. It sounded goooood! Oh, it had big wide whitewalls too.




I’m trying to visualize this, and I can’t quite see why you are having a problem. The bolt goes through a flange? Then through the starter? Then into a hole that used to be threaded? With the starter out, don’t you have access to that hole so you can rethread it in some appropriate fashion before putting the starter back in?

What obstructs your access to the once threaded hole if the starter is not in the car?

Even assuming that my imagination is letting me down, why can’t you slip a twelve (or eight if you can find one) point socket over the drive end of a standard tap and tap new threads using a normal socket extender? You will probably need to drill out the hole through the starter a smidge to use a slightly oversize mounting bolt that matches your new threads?

Anyway, good luck.


2000 Honda Accord, V-6, 3.0 liter. The 5 1/4 inch bolt is smooth except for about 1 1/4 inches at the tip.


The hole terminates inside the engine, otherwise a nut on the end is not always good (look at me).


I typed out a response but don’t see where it went. So this may be a duplicate for you.

The 5 1/4 inch bolt inserts through a 1 inch starter then 4 1/4 inch of the engine (2000 Honda Accord, V-6, 3.0 liter). The threads in the hole and on the bolt are the last 1 1/4 inches. So, with the starter removed, my M12 x 1.25 STI tap, at full insertion into the engine, maybe just starts to touch the should-be thread region. No one can tell me how to extend an STI tap…regular taps yes, but not the STI which creates new thread for a Helicoil insertion.
Also, cannot place a socket on the tap because the socket is too wide to insert into the hole.
Finally, I may do as you suggest and tap a somewhat bigger hole, use an oversized bolt, but not one so long.


I would get a 7" bolt of the same diameter and threads and quality, and cut the head off the bolt a 1/2 inch of the shank,then using a die put the same threads on the end you just cut the head off.Put some JB Weld as deep in the hole as the threads,use a plastic drinking straw and coat the new threads with JB Weld.Thread into the hole as deep as you can and let dry overnight. You now have a stud to put the starter with a nut.


This is great!! I’ve only read it twice, so I’m still trying to get the full picture, but this sounds very doable, and easy!

Not here, but a tool vendor, was just telling me to scrap the Helicoil idea and its persnickety STI tap, and go for a KEYSERT that requires a normal tap that can be extended.

Now, this is a little tough for me, but I have to choose between these/you two. I’m laughing because both ideas are good, especially yours! I will order the KEYSERT and try to make my decision either this weekend or the following (when I’ll also have the KEYSERT).

Thanks a bunch!


If I had to this repair, I’d take the tap and weld a 1/4" drive extension of the proper length to it. Now you can reach in and cut the new threads. Don’t forget to blow the chips out of the hole after cutting the new threads.



Hmmm. Can you install a somewhat larger helicoil at the “top” of the bolt hole in the engine then use a 2 inch or so bolt screwed into that helicoil to hold the starter?

I’m a little leary of that though. There must be a reason that Honda used a five inch bolt. I can’t think what it would be, but you don’t want to find out the hard way the reason that the starter fastener has to be four inches deep in the engine.