Hi,

I have a Flowmaster 2" exhaust header and 2 - 1/2" exhaust

A coin sized section has broken out of the downpipe where it was bolted to the gearbox

I have decided to get my exhaust specialist to repair this, as he is only 5mins away, and a wizard at mig welding exhaust

This job could easily turn into a real ordeal at home

I want to put in a short 4" SS flex section. His foreman said this was not needed, as my setup has a sliding mount near the rear gearbox (I think that is standard)

The front section front section that broke being hard mounted to the bellhousing likely had something to do with the section cracking out (along with other factors)

I plan on deleting this front hard mount

It make sense to me to fit the short flex, should I just insist? (even though he is a trusted expert)

I dont want my headers getting stressed out by inevitable movement that constantly takes place with any engine, they always want to rotationally twist their mounts, apart from any other forces.
My mounts are all newish

I reckon the flex has to reduce stress on the headers, but I am not an expert

All opinions welcome.

I want to get this fixed asap, I cut a section of old exhaust pipe and wired it over the hole, which works satisfactorily, he gets back from his Xmas break on Monday

 

Do it!!

 

If the guy doesn't want your money, go somewhere else. There are very few, if any at all downsides to installing a piece of flex section.

 

I just got my exhaust hole repaired, and I asked the guy that was running the shop ( another guy as the owner is still on holidays)

He said..." if you want me to have to weld it up every six months cause they tear out, the XJ stock mounts are fine"

He also has many years experience

I just wanted it fixed quickly, so can think about the flex situation at my leisure

 

It's also worth taking a look at your motor mounts to reduce flex and stress on the exhaust system. If the mounts are stock and blown out you'll have much more movement that might necessitate a flex pipe.

The other thing to consider with a flex pipe is they don't last forever. Mine lasted only a handful of years on a jeep that only gets a couple thousand miles a year in a dry california climate.

 

My engine and trans mounts are newish

It was my opinion that the header is more prone to cracking if its stressed by the engine movement, including rotation and fore & aft movement

He said the slip joint on the trans is sufficient to allow for this, and the excessive heat is why they crack.

One of my other vehicles has a kind of "crinkly" bent section that seems designed to allow for slight flex

I will think about the matter for a while, I could fit flanges and a section myself

These 2 guys have over 80 years experience between them, exhausts is all the do, day in, day out

It cost me $50 to get my large exhaust hole have an insert section welded in, so much better than ****ing around with the *****

Flowmaster are high quality Australian made products, not Chinese rubbish