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Need some expertise, broken exhaust maniford

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J

Jerry

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I took the exhaust maniforld off the TR3A engine today. It came away in two pieces. The rear segment broken about 7 inches from the head. I know this is cast iron and that can be welded, but will it be strong enough?
Other alternatives:
1. I happen to have an exhaust manifold from a TR4A. IE: it ends in two pipes rather than one. It will fit the intake manifold. Can this be used on a TR3A? Might need a TR4A downpipe?

2. I also have the intake manifold for the TR4A, and it is very different from the 3A. It is longer away from the head. Will this fit, and is there any advantage to the manifold? Although I am betting it is for a Zenith Stromberg carbs.

Any advice would be appreciated.

jerry
 
Jerry-

TR3 exhausts are very common, don't even try to weld the old one up it just won't be worth it. Yes, the 4A manifold will just bolt right up, you'll have to get a 2 into 1 connect from a 4A to splice it back into your single pipe exhaust. Or you probably can sell the 4A manifold if you have no use, and buy a 3 style manifold and keep the profit, the 4A manifold commands a higher price.

Randy

If you were closer I'd suggest dropping by and grabbing a manifold, I probably have half a dozen spare ones - but shipping would be dear I think.
 
Have a competent machine shop fix the old one (flange alignment, preheating and proper rod) or find a new 3 manifold.
Bob
 
While it is possible to weld cast iron I understand it is quite difficult> (I am not a welder!)

As time went by the four cylinder engine was developed and improved, so later parts are generally better than earlier and can usually be retrofitted. Your car should have the later high port head with a log type inlet manifold.
The exhaust manifold from the TR4a should be useable with the secondary pipes for a TR4a, you will obviously have to make some adjustments to the rest of the system, so do some measuring first.

The long branch inlet manifold may put the carbs too close to the inner fender to allow clearance for the air filters, but pancake filters may solve this problem.

I am sure others have made these mods and can give more detailed answers.
 
Jerry, my suggestion would be to scrap the old manifold and look for a TR3/4 exhaust manifold. The TR4A manifolds (as a pair) will bolt up to the engine & carbs, but you'll have body clearance problems with both intake and exhaust; plus have to re-engineer the throttle and choke linkages. And I don't believe the 4A exhaust can be used with a 3A intake without some modifications.

Yes, it can be welded, and lots of welders claim that they can do it. But I have never seen one welded that lasted more than a few years before breaking again. Be sure to ask the welder how long he will guarantee that his weld will hold (including paying the labor to R&R the manifold yet again). He'll either just stare at you, or laugh hysterically!

And doing it right is going to cost a LOT more than finding another manifold. As Randy says, they are pretty common. Check with your local club, I'm sure several people have them collecting dust in the shed.
 
Hey Jerry,

Welding cast iron is tricky at best, and usually reserved for high dollar specialty parts not easily obtained, like say, a head that has a couple thousand $'s in port work done to it. The pre-prep and post-prep adds a lot to the time and cost. You can find gobs of welders who will do it cheap, but they either do not plan to do it right, or do not know how to.

I have been welding since I was 8, and still wouldn't consider welding a '3 manifold. It is too easily obtained at a reasonable price to make it worth my time. Give it a couple more decades, though, and it may be worth it when they are rare! I am sure someone here will lead you to a reasonable used one.

Best of luck,

John

PS-this site keeps locking up on me...had to put this in 5 times. Anyone know if I need to change a setting from my end...or is it still some bugs in the new format?
 
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I just sent a note out to our club asking people to check their parts bin. We will see how lucky I get! I was also looking in the book "How to Restore TR 2,3,4 and 4A. He lists 6 different intake manifolds. According to his book, I have one for an early TR4, but who knows if that is right. The extra intake manifold is not even in the pictures but does fit the head on the engine. After 52 years, who knows what combos were replaced. I know the manifolds that came with the car fit in the engine bay, so I will look for those.
 
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