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TR2/3/3A Blown Exhaust Manifold Gaskets

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mastaphixa

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I have about 1200 miles on my engine rebuild. I have blown 2 exhaust manifold gaskets, one stock, one the improved offering from Moss. It keeps blowing out at the #4 exhaust port although the first one was starting to go at #1 as well. I ran a straight edge across the manifold as best I could after the first time and didn't notice anything out of the ordinary. I installed the upgraded set and ran the engine thru a heat cycle and snugged the nuts up again and repeated that several times. Does anyone make a dead soft copper exhaust/intake gasket? I have another exhaust manifold and I may try that on my next attempt. Any thoughts? I have posted this question on another Triumph forum as well. Thank you for your time.
Steve Baker
 
Dead soft graphite by Remflex:
Remflex TR2/TR3 Exhaust Gasket

I've recommended them on another thread. Super-thick, super-soft graphite that can fill up to (IIRC) 1/16" of warpage. I used to blow out header gaskets on the FF1600 engine at least 2-3x a season (badly warped header flanges) but I never blew out a Remflex. Can't recommend them highly enough.

They also offer bulk sheets if you had a desire to cut your own, but since they have the TR2/3 pattern there's not much need.
 
The only thought I have is the 2 studs that are supposed to hold the exhaust and intake together might be holding the 2 manifolds out of line. The metal gasket looks like a quality fix.

Steve
 
If you are having gasket blow-outs, there is something wrong with the studs and/or nuts clamping the manifolds. You are not getting full clamping force on the manifolds. I would run the nuts down the studs fully without the manifolds, and if there is any resistance at all, either chase the stud with a die, or replace the stud. Once you are certain the threads are in good shape, then be sure to check the manifold and head mating surfaces (as it sounds like you have), and look over the manifold assembly to ensure there are no issues preventing both manifolds from seating fully. This include making sure the hold-downs are able to rock easily.

I would not tighten the bolts holding the manifolds together until after installation, to be sure the intake is not holding the exhaust manifold up.

If you check all this, and use a decent gasket with a little high-temp gasket goo, you will be good.
 
If you have a leak at one of the two center exhaust ports, you might double-check to make sure that you do not have a TR2 exhaust manifold. They're interchangeable with TR3/3A and TR4 manifolds, but have less metal on the manifold where it meets the center two exhaust ports on the cylinder head - which results in the gasket blowing out more easily. This applies to both high-port and low-port heads. The TR2 exhaust manifold part number is 301144. Exhaust manifold part # 304164 is the later (better) TR3/3A type, which continued into the TR4 era. The TR4A exhaust manifold was, of course, different, but can be retrofitted to an earlier car.
 
Thank you all for your responses. I swapped to my spare manifold in case there was some deformity I couldn't pick up with my eye. The exhaust down pipe was misaligned at the box section of the frame causing a twisting moment on the exhaust manifold so I relieved the three holes in the down pipe a bit allowing the exhaust to fit better. John, I checked and I am not bottoming out on any of the studs. I did order the above mentioned upgraded gaskets. I've driven it once and tightened the nuts. I keep doing that for a while and see where I get. I'll report back.
 
mastaphixa said:
Thank you all for your responses. I swapped to my spare manifold in case there was some deformity I couldn't pick up with my eye. The exhaust down pipe was misaligned at the box section of the frame causing a twisting moment on the exhaust manifold so I relieved the three holes in the down pipe a bit allowing the exhaust to fit better. John, I checked and I am not bottoming out on any of the studs. I did order the above mentioned upgraded gaskets. I've driven it once and tightened the nuts. I keep doing that for a while and see where I get. I'll report back.
Click to expand...
Is it possible for loose manifold bolts or a poor gasket seal to carbon up the plugs and intake manifold ie. exhaust gases being sucked into the intake?
 
I am going to call this one fixed. I guess there was something amiss with my original exhaust manifold.
 
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