TR2/3/3A TR3B Exhaust Manifold Gaskets

[af3683]

I brought my TR3B to my mechanic to replace the entire exhaust system. While removing the exhaust pipe, 2 of the 3 nuts broke and the end of the exhaust pipe is still stuck on the end of the exhaust manifold. He has tried heat and various lubricants but it still won't budge. So now he has to remove the exhaust manifold. Would someone be kind enough to tell me exactly which manifold / carb gaskets I need to replace. I looked on the TRF and Moss web sites but I am really confused. Thanks so much for your help. Art

 

[TR3driver]

Here's the TRF/factory numbers:
(2) 113122 gasket, manifold to head
(1) 106958 gasket, exhaust manifold to head pipe

I usually find it possible to leave the carbs attached to the intake manifold (both manifolds must be removed together). But if they have to come off, you'll need
(4) 112867

Usually, the insulators can be reused. But if not,
(2) 112866

As long as you're ordering, might as well get the new studs. Sounds like 2 of the 3 are already ruined, and I'm guessing the third one is in bad shape.
(3) 101442

As a side note (your mechanic probably already knows this), I find it very helpful to coat the studs with copper-based anti-seize, every time I have the nuts off. It works really well at ensuring the nuts will come off next time with a minimum of fuss. I've tried brass nuts and so on, but ordinary steel nuts plus the anti-seize work the best of anything I've tried.

PS, be sure he uses new split lockwashers on the nuts holding the manifolds to the heads. The heat seems to make them lose their spring, which lets the nuts work loose later on. I also find it helps to use a heavy flat washer (aka setup washer) on the outermost studs (the ones without the bridge pieces) in addition to the split washer.

 

[af3683]

Randall, thanks so much. I guess I might as well get the #WL208 Washers from TRF as well. He did remove the carbs for better access, but it didn't seem to help. Do you know if it is common for these studs to break off? I don't think the head pipe is original, but that doesn't mean it hasn't been on there for many years. I wasn't expecting this be such a big job. Art

 

[BillyB62]

Art, most TR3 items ar on sale this week at TRF.

 

[TR3driver]

Do you know if it is common for these studs to break off?

Quite common, I'm afraid; they lead a really hard life down there. I twisted them off just about every time before I discovered anti-seize. Haven't had one twist off since then, but they are still frequently bad enough to be worth replacing.

I've had the same problem with other old cars as well, it's not just a Triumph thing.

 

[CJD]

Yep! 2/3 is my usual batting average.

The routine usually goes: Twist them off, remove the manifold, ground the end of the broken stud flat, drill the center of the stud, try to use an extractor (which never works), re-drill the stud completely out, run a tap through the manifold.

After a while working on old cars, you expect to go through the routine, and feel REALLY excited if you don't!

 

[af3683]

Thank you all. This is probably a dumb question, but I assume that the 2 manifold gaskets do NOT require any cement. Also, why are 2 required? Thanks. Art

 

[Geo Hahn]

I have never used any sealant on those gaskets.

You need two as each gasket is for a pair of cylinders, i.e. one for 1&2 and another for 3&4.

 

[TRTEL]

The copper anti seize is a good idea. If you can't find that molybdenum disulfide base works almost as well. I've had luck with higher grade stainless nuts. You can usually find them at nut and bolt specialists or aircraft suppliers close to airfields.

 

[Don Elliott]

My 1958 TR3A came with brass nuts on the ends of the studs for the manifolds. Don Elliott, Original Owner

 

[mgedit]

PS, be sure he uses new split lockwashers on the nuts holding the manifolds to the heads. The heat seems to make them lose their spring, which lets the nuts work loose later on. I also find it helps to use a heavy flat washer (aka setup washer) on the outermost studs (the ones without the bridge pieces) in addition to the split washer.

My car had no split washers at all when I got it. I plan to use new ones now. Question ... why not use setup washers on all the studs (that is the ones with the bridge pieces too)? Was concerned that lock washers would some how interfer with proper operation of bridge pieces, but perhaps flat washer might as well. Just curious as to how the manifolds should be reattached and what combination of nuts and washers works best. Thanks for the help. Cheers, Mike

 

[vivdownunder]

The bridge pieces taper so the front flat is about the same diameter as a split washer. A flat washer would overhang and look out of place.

I too have found a flat and split washer works best at the outer ends of the exhaust manifold (in my case Triumphtune extractors). Adding a flat washer tends to hold the flange tighter against the head and lessen the risk of gasket leakage.

Viv

 

[Geo Hahn]

On the TR3A I use longer nuts, I think these are easier to work with especially under the manifold as they are not as deep a reach for the socket & u-joint I usually use.

I have some that are steel but have only been able to find them in brass at the local FLAPS.

On the TR4 I am using brass nuts as an experiment.

BTW I find that I have to get the bridge piece on the lower studs before the manifold is up against the head. If I wait until the manifold is fully home then there is not enough room between the end of the stud and the manifold to get the bridge piece on there -- but that may just be a function of stud length on my head.

The key to this exercise is to pull the head off every year or so -- that way everything comes apart quite readily and the procedure remains fresh in your mind.

 

[mgedit]

Thanks for the additional information. Cheers, Mike

 

[TR3driver]

Original setup was tall steel nuts and spring washers on all 8 studs. The tall steel nuts are available from TRF under PN 56675. As Geo noted, they are easier to get a socket or wrench on, even if they don't help keep things tight.

Question ... why not use setup washers on all the studs (that is the ones with the bridge pieces too)?

I don't know of any reason why not, they just don't seem to be needed.

Just curious as to how the manifolds should be reattached and what combination of nuts and washers works best.

Well, obviously I think my setup works best, but your mileage may vary

Years ago, I had trouble with the exhaust gaskets blowing. (Don't recall offhand if that was with a stock manifold or cheap tubular header from JCW. Probably the latter.) I got in the habit of checking the nuts at every oil change, and they frequently moved by a half flat or more. Replacing the lock washers helped, but the outer nuts still worked loose over time. So I added the heavy flat washers there, and the problem seemed to go away. I haven't had a gasket blow for over 30 years (and don't even bother to check the nuts any more).

My theory is that the exhaust manifold flange winds up expanding faster than the head does, every time it gets hot (meaning every time you start the engine). So it has to move a little bit against the head. I'm guessing that it winds up moving a little bit against the nut & washer as well (instead of just bending the stud). Since the lockwasher tends to dig in, the setup washer gives it a joint that can move. I could be way off base, but it worked for me.

 

[mgedit]

Randall ... Thanks for the explanation. Sounds like good advice. Cheers, Mike