head bolt hole

[siii8873]

anyone know of any reason not to helicoil an exhaust manifold bolt hole?
Putting my manifolds on tonight and isn't the last bolt hole I tighten stripped. Removed the manifolds and looks like I should do two holes.

[NC_Mule]

anyone know of any reason not to helicoil an exhaust manifold bolt hole?
Putting my manifolds on tonight and isn't the last bolt hole I tighten stripped. Removed the manifolds and looks like I should do two holes.

I would do it, can't think of any reason not to. I've had very good luck with helicoils in all sorts of places.
pb

[antichrist]

I've done it before without any problems later.

[brecon]

with most rover tech's there is a 6,8 & 10 mm helicoil kit in their toolbox. Installed correctly they really are indestructable. Good luck with your endevour.

[jac04]

You can also check with your local machine shop to see what they offer for thread repair. I work on utility coal pulverizers, and we almost never allow the use of helicoils for repair. You are much better off with a real solid threaded insert if room permits.

[greenmeanie]

You can also check with your local machine shop to see what they offer for thread repair. I work on utility coal pulverizers, and we almost never allow the use of helicoils for repair. You are much better off with a real solid threaded insert if room permits.

I'm interested to hear your resoning for this statement. I am familiar with the use of helicoils, keenserts and the like.

[jac04]

^^ Helicoils simply aren't as strong as solid threaded inserts. In high strength repair applications in steel & iron they are preferred. There are plenty of applications where helicoils are suitable (or necessary because of room), especially on non-ferrous metals and applications where the higher strength isn't required.

[greenmeanie]

Ah yes indeed. They are stronger but the question is not necesarily which has the greatest strength but merely which has adequate strength. In this case you are not much better off as the helicoil is adequate. I had approx. 100K miles on a manifold with helicoils and it was perfectly good.

In your application I agree but for a Rover manifold it is overkill. Not bad if it fits and the surounding cast walls do not become too thin but not necessary.

[jac04]

^^Agreed. The torque on the manifold bolts/studs is relatively low, so a helicoil should work. Just wanted to make sure Bob was aware that other options are available.

[siii8873]

Jeff,
certainly understand. went with the helicoils, do it yourself application.
We have used them in many places in the hydro plants I ran with good results. Just never used them in a high heat application before.
Those pulverizers are a different application one heavy duty machine in a very hostile environment. Understand why you would not use anything but the strongest item available in that application.
Bob