How to Drill, Tap, & Helicoil stripped Chevy Crankshaft Threads at home

This video shows you how to repair stripped out threads for your harmonic balancer bolt. These techniques apply to all threads and helicoils. Save yourself some money and do it yourself at home!

[@khmkhm23]

Was able to retap the hole without using a helicoil. But thanks for the tips. I followed them and it worked

[@murraymcleod7605]

I did everything this lesson describes and it worked perfect. Thank you.

[@morydinx6546]

Good job!

[@morydinx6546]

Did you buy a tapping handle?

[@murraymcleod7605]

@@morydinx6546 Yes, what you said about even pressure on both sides made too much sense. It's a '99 Jeep and the engine is in the vehicle. I removed the transmission cooling line and both fans that gave me clearance. Had to get a right angle adaptor for the drill and a stubby bit to get behind the radiator, it was slow but it worked. Your info saved me probably quite a bit of money and I learned. 👍

[@johnhanson974]

I know this is an old video but had to comment on the way the helicoil installation tool was being used. The way he did it is certainly an effective way to do it but here is another. The inside of the larger part of the installer is threaded for that specific size helicoil. Using the driver, start the coil inside the larger part of the installer using the access hole on the side. Turn the driver and coil through the installer until the coil just starts to peak out of the front of the tool. Place the tool onto the hole and continue to turn the driver so the coil begins to enter the tapped hole. The larger part of the installer is designed to keep the coil wound up. In the coils relaxed state it is larger than in its final installed size. Sometimes it can be difficult to get it started into the hole with just the driver part of the tool.

[@garrettsoler7290]

Yup great explanation this is exactly how I use the tool too, makes installing the helicoils a breeze

[@jonalarcon8564]

You did a good job either way , infact my engine ran for 35 years with no harmonic balancer bolt and I never had any issues on a built engine around 400 hp

[@JulianCDalida]

How😭

[@dickeymoore7365]

The bolt on sbc engine is 7/16-20 so what size tap do i need to rethread the threads?

[@gtojohnny3242]

What’s size bit did you use and what size helicoils

[@a.f-body1vids655]

I tried to line up two helicoils once, but I couldn't get a bolt to go through both. Is it pretty easy lining up two helicoils?

[@joey2shots260]

Good lube... How about grease? Like chassis grease or wheel bearing grease?

[@lordsauto]

great job

[@sk8n854]

I may have to do this. Same bs. Stripped out the first few threads trying to pull the harmonic balancer on with an install bolt. I got it on there and torqued down with the install bolt and a couple of washers but idk if it's a good idea to leave it like that with the install bolt instead of the factory bolt. 😅

[@scottyfixer452]

What kind of tap/brand and what kind of drill bit

[@ALLCOMPTON]

How exactly are you suppose to install multiple thread inserts? I bought a kit that doesn't give directions for installing more than one coil.

[@EcFlipz]

How much did you have to torque the pulley? I stripped the internal threads on my crankshaft. Thinking about helicoils but doubt the strength since it needs to be 180 lb/ft.

[@PhantomX3K]

I believe helicoils are supposed to make the threads stronger since you’re replacing them with stainless steel instead of the regular aluminum threads, so torquing to 180 shouldn’t be a problem

[@Compumon27]

How did this workout for you? Does the engine run without issue?

[@morydinx6546]

Yep, works fine

[@jeremyelford7926]

PB Blaster is a good cutting oil, too...

[@timgroot4231]

What size coils were they? What size kit am i supposed to be getting, and why did you have to hone the balancer? Would it be smarter to just go one bolt size bigger?

[@wburke8628]

Tim Groot why didn't you measure the depth and put a drill stop on the bit or even a piece of tape at the correct depth. That would enable you to drill all the way in one smooth motion.

[@wburke8628]

He honed the balancer to make it easier to pull the balancer up tight.

[@morydinx6546]

Sorry I just saw this. I don't recall the size off hand. Pretty easy to search what you need online. I stopped to get chips out and apply cutting oil to the drill. You know when you hit the bottom so no need for a stop. You could use a BBC bolt, but you wouldn't want to drill that much out by hand. This is fairly easy because the drill size is hardly bigger than what was already there.

[@lawrenceunkart1474]

That is why you do not use the bolt to install the balancer, you are lucky it did not break. You use the install tool made for installing the balancer.

[@jonalarcon8564]

Exactly ! I bought one too at harbor freight it was cheap in price!

[@mitchdropps6856]

I just broke the install tool off in my crank last night.... There's gotta be a better way

[@soufyanedz9688]

Tap with large than 7/16 coil will broke

[@Randy4662]

way way too fast on that large of drill bit. The larger the bit, the slower the rotational speed of the drill is needed. good job. unfortunately, mine is still in the car. ugh.

[@jonalarcon8564]

So was mine i just removed the radiator and anything in the front of the engine , I actually got into the engine compartment and did the work easily, I used a makita cordless drill set on slow , it came out perfectly!!!!!!