Stripped threads on cylinder head for the rocker

[INF3RN0666]

Hi

I overtorqued a rocker bolt until the cylinder head threads came out. I've read that a heli-coil kit would be a cheaper alternative than replacing the head.

1st question: do you think it's a good idea? Is it going to hold under the constant movement of the push rods? Second, where would I buy a heli-coil kit. I don't think Canadian tire carries it...

Thank you

[MagicRat]

Heli coil or a Timesert is the way to go. I have heard that Timeserts are better, but have never used one. Look: http://www.timesert.com/

As for helicoils, you would be surprised how many applications they have kits for. I have used them in the past and they have always worked well.

IMO the best solution is to take the entire head to a decent machine shop and have them repair the thread. This is less risky than you using the valuable head as practise for installing a helicoil.
Or find a decent auto parts store..... Napa, Carquest, AC Delco etc as a source....

[Mavrick14]

You can buy them at NAPA, carquest, canadian tire etc.

Depending on the engine your working on, if the stripped hole is easily accessible with a drill then i would recommend installing a heli-coil yourself.

Heli-coils are in fact stronger than a tapped thread. Making this repair stronger than it ever was. What you do is drill out the hole to larger diameter, tap threads in the head with a tap, and install the heli-coil into the threads you just tapped. It's pretty straight forward, and a pretty easy task if you have room to work with.

[INF3RN0666]

Thanks for the advice guys.

I was wondering what the best way is to figure out the thread size and pitch on this bolt. Should I buy a thread measuring kit?

I went to canadian tire today and asked the first two guys at automotive counter, but they didn't even know what helicoils were. The third guy said the hardware department should have it. The hardware department has no staff and I couldn't find it. I called up partsource, they don't have one either LOL. Guess I'm going to napa.

[MagicRat]

Originally Posted by INF3RN0666

Thanks for the advice guys.

I was wondering what the best way is to figure out the thread size and pitch on this bolt. Should I buy a thread measuring kit?

I went to canadian tire today and asked the first two guys at automotive counter, but they didn't even know what helicoils were. The third guy said the hardware department should have it. The hardware department has no staff and I couldn't find it. I called up partsource, they don't have one either LOL. Guess I'm going to napa.

In general, forget Canadian tire for auto parts. Nobody there knows anything about parts at all. Also, they often have little in stock, and going back the next day to pick up minor parts they had to order gets very old very fast.

As for the pitch....... it's likely the Helicoil catalogue specifies a kit for your particular problem, to take the guesswork out of it. Otherwise, take a rocker bolt into napa with you and they can specify the correct kit.
Try getting anyone at Canadian tire to do that!

[Blt2Lst]

Originally Posted by INF3RN0666

Thanks for the advice guys.

I was wondering what the best way is to figure out the thread size and pitch on this bolt. Should I buy a thread measuring kit?

I went to canadian tire today and asked the first two guys at automotive counter, but they didn't even know what helicoils were. The third guy said the hardware department should have it. The hardware department has no staff and I couldn't find it. I called up partsource, they don't have one either LOL. Guess I'm going to napa.

To figure out thread size you need to:
1. Measure the bolt diameter with a micrometer to get an accurate measurement.
2. Use a thread gauge to determine the thread pitch
(Thread gauges usually come with tap and die sets, I am guessing you will need a metric gauge)

or
3. Take the bolt to a parts store and have them do it and tell you what you need.