V8 Stripped Exhaust Manifold Thread

[doris]

Passenger side, one of the top row middle exhaust manifold bolts will not fully tighten..... goes so tight, then spins.

Are there any other options than head off and helicoil??

Damon

[muddydisco]

Passenger side, one of the top row middle exhaust manifold bolts will not fully tighten..... goes so tight, then spins.

Are there any other options than head off and helicoil??

Damon[/quote

Tap it out with the next size tap. Put a bigger bolt in
Theres no need to take the head off than

[doris]

Thanks for that....

I thought that might be an option but then thought of the manifold hole.....  guess I could always enlarge that too.

D

[hobbit]

The manifold hole will be bigger that the stripped hole in the head anyway, if you drill  the manifold be careful, you will be drilling steel with ally behind it

[doris]

I have discovered that there is 1/2+inch of thread beyond where the bolt reaches, and reckon if I can get a longer bolt that may sort it.....

What say you  all?

What thread is the bolt?  

(its 9/16 socket, which I am led to believe is 3/8 thread, but I don't know what pattern)

Damon

[Range Rover Blues]

A tip, been there and done that.

There is indeed a length of thread unused inside the head.

Get a new machine bolt or stud.  If a bolt then put a nut onto it first, tighten it into the threrad as far as it will go without going crazy, it should go infurther than the old one by a good 4 turns or so.

Once the bolt is tight, use the nut to tighten the exhaust manifold.

That way you are not asking the wael thread to dleiver a clamping force whilst you are turning the thread too, so it's less likely to strip out any good threads left at the bottom of the hole.

Oh and BTW, some companies will come out and helicoil a thread in-situ for you, it was an option I was looking at for something and a mate of mine had had it done before on a similar job.

[doris]

Wow............  that is a good tip.  I will remember that one.

I have in fact managed a bodge................  got a new bolt of the same thread, which appeared to have much better threads thatn my old bolt, and was also about a 1/4inch longer.

A combination of the better threads and longer bolt seems to have gained a purchase.  

It is now clamped up good and tight........... but the b***ger still seems to be leaking somewhere!

Damon

[Range Rover Blues]

Downpipe gasket, these are poo and I'm swapping them every 6 weeks or so at the moment.

[landandy]

When i had RR classic had same prob. I used therded rod with som loc tight then a nut so i had as stud sticking out easy fix. hope this helps.

[doris]

Bang on the money Mr Blues.........

Have now done the downpipe gasket on the same side and its much quieter.

Noticed while I was under there doing the gasket, and my lock stops, and diff oil changes and breather servicing that the middle and rear sections of my exhaust are full of pin holes now........  they weren't like that a fortnight ago!!

It never ends.

Many thanks for all yours help as usual


Damon