Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
kstanley44
Member
Offline
-
Hi Guest!
You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
There are some perks with a member upgrade!**Upgrade Now**
(PS: Subscribers don't see this gawd-aweful banner
TR2/3/3A Broken exhaust manifold TR3b
- Thread starter kstanley44
- Start date
-
- Tags
- exhaust system tr3b
Share this page
Brinkerhoff
Jedi Knight
Offline
It could be fixed, but finding a good used manifold might be more cost effective.
CJD
Yoda
Offline
It's toast.
Exhaust manifolds get so hot in use that the metal structure changes. The carbon turns to graphite and makes the metal hard as rock. Welding will not work.
Fortunately, TR3 manifolds are both plentiful and cheap. I think I still have the one from my donor car if you'd like me to check.
Exhaust manifolds get so hot in use that the metal structure changes. The carbon turns to graphite and makes the metal hard as rock. Welding will not work.
Fortunately, TR3 manifolds are both plentiful and cheap. I think I still have the one from my donor car if you'd like me to check.
I have welded lots of cast iron,from vintage motorcycle cylinders to coal stove shaker grates,and agree with Randall, not worth the time to grind back to clean metal,build up with weld and machine hole and flange if replacement is available.
Tom
CJD
Yoda
Offline
I'm not saying it can't be welded...I'm saying the weld won't hold. Think of it this way: the manifold gets heat treated every time the engine starts. It amounts to thousands of heat treats, and eventually the grain structure reaches a point that the original grain lattice cannot be recovered with further heat treating.
I've also welded blocks, heads, crankshafts, intakes, you name it. As a young gearhead teen I could not figure out why I could never weld exhaust manifolds with any success. Weld looked beautiful...and cracked. Do it again...cracked again. Later, I studied metallurgy in school, and learned that exhaust manifolds are hardened to the point of no return! The grain structure of the weld can never be matched to the over-treated structure of the manifold, no matter how much you preheat, cool controlled, or otherwise prep the weld. It will end up brittle. A brittle weld may, possibly, last on a grate, but it will never take the load of that stud on the manifold.
Another way to put it...I could weld that for free...and I have saved many a lost part from the grave for no other reason than the challenge of trying it...but I still would not attempt Welding your manifold. It has no chance of success.
I've also welded blocks, heads, crankshafts, intakes, you name it. As a young gearhead teen I could not figure out why I could never weld exhaust manifolds with any success. Weld looked beautiful...and cracked. Do it again...cracked again. Later, I studied metallurgy in school, and learned that exhaust manifolds are hardened to the point of no return! The grain structure of the weld can never be matched to the over-treated structure of the manifold, no matter how much you preheat, cool controlled, or otherwise prep the weld. It will end up brittle. A brittle weld may, possibly, last on a grate, but it will never take the load of that stud on the manifold.
Another way to put it...I could weld that for free...and I have saved many a lost part from the grave for no other reason than the challenge of trying it...but I still would not attempt Welding your manifold. It has no chance of success.
Luckily I sourced a supply while employed so cost wasnt a factor.Indian flathead exhaust port nipples get hotter than auto manifolds and I have successfully welded both.
Multiple passes you have to peen the bead to stress relieve.Lowest heat otherwise porosity.My guess is you would get the hang quick.
If you sent me a self addressed envelope I will put a few rods in for you to try or have on the shelf.
Multiple passes you have to peen the bead to stress relieve.Lowest heat otherwise porosity.My guess is you would get the hang quick.
If you sent me a self addressed envelope I will put a few rods in for you to try or have on the shelf.
OP
kstanley44
Member
Offline
Thanks all for the metallurgy lesson!!! It sounds like I should be looking for a replacement manifold. John, you mentioned you may have one. Did they change any over the TR3 run? Mime has the following casting number: DA14221 and under that 304164.
Take care,
Kerry
Take care,
Kerry
Offline
If John doesn't have one, I have several.
Marv
Marv
CJD
Yoda
Offline
Just got back in town...I'll check and PM you...