What size are the exhaust manifold bolts???

[WC145]

I'm finally getting around to removing my cracked exhaust manifolds to install FPA headers but I can't figure out what size the bolt heads are - they're bigger that 1/2" but smaller than 9/16", bigger than 13mm but slightly smaller than 14mm - what am I missing?

[boaterbob]

I think there just 9/16 worn down from age and rust. Try using six point socket or wrench

[Alan H. Tast]

I think there just 9/16 worn down from age and rust. Try using six point socket or wrench

And plan on some bolt heads breaking off from the top row. You'd better do a Search of the Forum for broken exhaust manifold bolts before tackling this - there's a LOT of things you need to be aware of (and have on hand or at your disposal) before you start. In other words, making friends with a good machine shop may be a very good idea.

[RAVEN]

AND (poss old wife tale) when bolting up new stuff use pepto bismal (antacid stuff) to coat threads on new bolts. Several coats are best. The chaulk in the pepto leaves a residue which acts as a release agent or anti seize. Have done it for years and it has seemed to work up to now. Nothing ventured nothing gained. Was taught by an old mech that it was better than anti seize, as the oils in off the shelf non locking compounds actually became glues and made it worse. Best of luck.

[kevindeluca66]

If you break any off flush with the head you may want to try left handed drill bits. The set below is a bit pricey but worth every penny if you run into broken bolts often. The way they work is oppisite direction of regular drill bits and the hope is that they snag about 1/4" into the bolt and then twist the bolt right out. I have used these numerous times and had very good luck with them. I always use a bit smaller than the bolt so I dont damage the threads in the hole.


http://www.grainger.com/search?searchQu ... drill+bits

[tbird]

Another old trick is to carefully tighten the bolt about a 1/8 of a turn before attempting to back them out seems to work most of the time.

[WoodlandHills]

Depending upon location you can also heat the stud or bolt with a small torch (I borrow the creme br?l?e torch from the kitchen). Thermal expansion and contraction in conjunction with the other techniques can help. Giving the stuck item a good sharp rap with a hammer has helped before too......

[WC145]

Thanks for the tips and info. If I break any of them there's no room in there to drill them out, I'll end up having to pull the heads. Probably should have just done that this spring when I had replaced the intake.

[Alan H. Tast]

Thanks for the tips and info. If I break any of them there's no room in there to drill them out, I'll end up having to pull the heads. Probably should have just done that this spring when I had replaced the intake.

That's why it's a good idea for people to look through/search the VTCI Forum archives on a topic like exhaust manifold replacement before tackling it - after being online for over 10 years in its current iteration, the VTCI Forum has a tremendous amount of information from the "been there, done that" crowd. And it's also not bad that people bring up topics like this from time to time because someone may have come up with a new trick to use. But really, Wally, Pepto Bismol for the upper manifold bolts? That's a new one on me, and I'm sure my friends will be wondering for years to come why a bottle of it is on the shelf in my workshop (they already wonder why I have aluminum foil, used tooth brushes and dental picks out there).

I'm sure there are topics that haven't been covered here yet, but many of the most-common ones like broken manifold bolts, shifters dropping out of gear, sagging springs, convertible tops stuck in mid-cycle, etc., have numerous threads dealing with them.

[WC145]

Yes, the forum archives are a wealth of information. I've read everything I could find on exhaust manifolds, headers, loose shifters, wheels, brake calipers, etc.. I've found the answers to most of my questions without having to ask.

[RAVEN]

OK Alan, you may question my comment but it has worked. If I could get TUMS to spread on the threads I would try it too. Also having some antacid in the shop helps to relieve the pain that we all encounter when problems occur or other actions happen in the shop. I keep it on the shelf with the Tylenal and Advil!!!!

[Joe Johnston]

Also having some antacid in the shop helps to relieve the pain that we all encounter when problems occur or other actions happen in the shop.

Although that may work well for you, I'll stick to Manhattans!

[RAVEN]

Hey:!!!! Why do you think I have it in the shop MEDICINE cabinet, its not just for the exhaust bolt "heads". Another famous product was Plop plop fizz fizz oh what a relief it is !!!! Better stop or I will be paying royalties for advertising.

[RAVEN]

OK some more folly to add. I just unbolted my exhaust pipe flanges from my manifolds. After tightening them about 1/8 of a turn, then backing off after spraying ,with penetrating oil to lube the exposed threads, THEY JUST TURNED OFF. No fuss no muss.
When I bolted them up 20 odd years ago, I coated the studs and nuts several times with the great product of Pepto Bismal. Everyone chuckled when I said it, BUT it seems to have worked.
The next step will to be, to see if the manifold to heads will part with any challenges.
I will keep you posted, it may be awhile, but I will let you know what I find.
Maybe having it in the "Medicine" cabinet, to reduce other pains, in my shop, will be worth it.
No Martuneizes for me, they give me heart burn, lol

[Ian M Greer]

Raven , I don't doubt for a minute your secret formula's work , but I've got to admit your cracking me up . Are you sure you don't have a Pharmacy vs a garage out there. If so I hope you have flushing facilities close by ????