Exhaust manifold cracks?

[Guest Anonymous]

I asked an earlier question regarding the various degrees of cast iron webbing found in stock 02 exhaust manifolds. It has been hypothesized that the webbing was added to bolster the manifold and prevent cracking. I have owned and observed many cars including some of the earliest 02's but I have never seen a cracked or broken exhaust manifold on an 02. Maybe I am just lucky or blind and I have no doubt one could break a manifold with a sledge hammer. Nevertheless, IF there is no particular problem with cracked manifolds, why the improvement/webbing (assuming it is an improvement)?

Anyone out there experience cracks in their "early" non-webbed cast iron exhaust manifold?

Thank you in advance.

[wegweiser]

Yep!

On my way home from a cross country trip (Pennsylvania to Arizona, then Wyoming and back) Solo, no gas gauge, no clock, no speedo, in a 71 2002 for 3 weeks.

Mine cracked outside of Ogalala Nebraska - and I got a friggin' TICKET for noisy exhaust (and doing 72 in a 65 zone!) as I was exiting the highway to check out the horrendous NOISE the car suddenly produced. Windows shook in downtown as I drove by....unbelieveably loud.

It was 20 years ago...and I still hate Nebraska.

Paul

[Guest Anonymous]

Does that mean you favor the "webbed" tii manifold? Could you not have "wrapped" the manifold with "muffler bandage/tape" as a short term fix?

I did not mean to suggest it could not happen, I just have never seen it. I have had e9's crack just not 02's. ON the E9, I brazed the crack.

Six or so years ago I broke off the top of the plastic timing chain guide. Its still running. The one ordered from you is still in the trunk and may be installed . . . someday. })

[asvander]

On the tii I just bought, it has a crack, and some deep pitting towards the front. I think I'm going to have someone try to weld it up, and see how it goes...

[jerry]

i have seen several exhaust manifolds with cracks. i believe all were of the webbed type referred to above. anyhow, i had a coworker weld one up for me. it took several attempts before he was able to eliminate weld cracks. he 'stop-drilled' the crack tips prior to grinding a vee along the length of the crack. what finally worked for us was heating it up in a furnace to 700F and stick welding with a high-Ni rod then returning it to the furnace and allowing to slow cool to room temperature. he's welded several manifolds before but remarked that this particular BMW manifold was very difficult.

btw, every crack i've seen has been at the No.3 outlet.

[Guest Anonymous]

I had an MGB that went through 3 exhaust manifolds. Each would crack at the same place. When my manifold supply ran out, I took the last one to a welder who preheated the piece and used a high nickel rod as you describe. UNfortunately, the manifold would crack elsewhere. Out of utter frustration I took my oxy-acet torch and brazed the cracks- with the manifold on the car. Ran the engine before brazing to preheat. Cant recall if it was silver or higher melting bronze rod, but it worked on all of the cracks. Filled the joints. It looked weird, but it worked.

Good luck.