[guitaristanime]

I have a 4-2-1 Toyosports exhaust manifold on my VVT swapped mk1 and it's stress cracked badly where the arrow is on the following picture because it doesnt have a flexi on, had worn exhaust rubbers for too long and its slightly too long for the car (was readjusted from a mk2 car)

I was planning to put a flexi pipe in on the right before the 2 bolt cat flange and then weld up the crack however, I've been told that the crack will just crack again if I do this as it will be too weak.

If I buy a new manifold (for instance the 4-2-1 from MX5 Parts) and get a flexi in on that, is the weld on that gonna crack the same as the repair would on my current one?

 

[BlueFive]

My suggestion would be to also upgrade engine mounts in an attempt to minimise stresses of the assembly.

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[Martin Y]

I might be inclined to try to to improvise a version of the clamp which holds the stock downpipe to the gearbox to stop it flexing. I had a stock manifold crack right round the 4 into 1 collector after I failed to replace that clamp.

 

[guitaristanime]

The garage that did my engine swap (and modified the toyo downpipe that's broken) is supplying and fitting another off the shelf with a flexi due to the initial mistake of not fitting a flexi which was agreed on prior to proceeding with the job, which is great and I'm glad I went back to discuss to give them an opportunity to make things good.

I went back through my photos and the downpipe had infact already started cracking weeks after I picked it up, I expect the mild steel was already starting to weaken due to rust and heat cycling having looked at the photos.

Gotta give garages credit where due, I normally do everything myself but I can't weld very well, and I don't have room to do an engine swap

 

[Zed.]

I expect the mild steel was already starting to weaken due to rust and heat cycling

stainless suffers from that.........

stainless work-hardens & cracks for fun, I despise the stuff 🤨

Rich.

 

[guitaristanime]

stainless suffers from that.........

stainless work-hardens & cracks for fun, I despise the stuff 🤨

Rich.

You saying you prefer to just make a mild steel exhaust?

On my turbo car I have the cast Kraken manifold and stainless there after...

 

[Zed.]

You saying you prefer to just make a mild steel exhaust?

yup

cheap stainless is dreadfull stuff, unfortunately most exhausts will be made from cheap / low quality materials🤨

stainless has its benefts but I'm not convinced the heat & vibrations in car exhausts are suitable without serious thought...


Rich.

 

[guitaristanime]

yup

cheap stainless is dreadfull stuff, unfortunately most exhausts will be made from cheap / low quality materials🤨

stainless has its benefts but I'm not convinced the heat & vibrations in car exhausts are suitable without serious thought...


Rich.

Thanks - maybe I'd better learn to weld after all then if I can mig some mild steel at home, nothing stopping me really