Manifold repairs - what's possible, not possible?

[S Works]

Morning all. Say I had a cracked manifold, the crack being in one of the pipes on the 4 part of a 4-2-1, would it be possible to repair rather than replace?

It's a custom made jobbie from Simpson race exhausts from what I recall.

In this day and age of chuck away and replace, it pains me to see a good piece of kit thrown when only one section has a small failure, so I'd rather get it repaired if possible.

Cheers,
SW

[stevieturbo]

Almost anything can be repaired.

if you think its a Simpson exhaust, why not contact them ?

Photos would help too. If some sort of welding machine can physically gain access to it, then it can be fixed.
And even if it cant, often you can cut it up to get access, then weld it back together.

[S Works]

Stevie, thanks for the info, I wanted to get some opinions from people who know better than I (not difficult, I'm a mech-numptie!) before I called anyone. I pretty much figured it could be repaired. Unfortunately I can't take pix of it as it's not on the car at the moment, but your advice helps. Thanks.

[K13 WJD]

here i am

whats the manifold made off ????

if its cast iron, its a tough one, you'll need a very good blacksmith, NOT a welder, it'll need to be put in a furnace, and heated to silly temprature, before being filled....any other trys will hold, but not for any great length of time. remember that a manifold gets subjected to repeated heat and cooling.....not ideal

if its mild steel, then you'll be able to mig/arc it fairly well...if its a fine crack, id advise making the crack WIDER before welding it, to stop the crack growing as it cools......OR find someone to fillet it.

if its stainless, you'll either need someone who's VERY good with a mig and stainless wire, or a tungsten inert gas (TIG)

to save the manifold cracking again, it may be worth using a speed saw, or hack saw, to cut gaps inbetween the ports.....this allows for SOME expansion and contraction.....

hope this helps, if you tell me what mainfold it is, i will help more.

I had a cracked C20LET manifold, which is acutally a manifold AND the exhaust housing of the turbo, and i managed to weld it in a furnace, and it lasted for around 20,000 miles !!!

[stevieturbo]

K13 WJD said:

here i am

whats the manifold made off ????

He said he reckoned it was a customs Simpson racing item, tubular design, so it will likely be stainless.

Either way, repairs should be straight forward.

Edited by stevieturbo on Saturday 17th November 19:05

[S Works]

stevieturbo said:

K13 WJD said:

here i am

whats the manifold made off ????

He said he reckoned it was a customs Simpson racing item, tubular design, so it will likely be stainless.

Either way, repairs should be straight forward.

Yep, as far as I know, that's the spec.

[Steve_D]

Have to tell someone this.
Took my RV8 stainless headers to a local exhaust manufacturer (didn't even know they were there) to see if they could weld in some O2 sensor bosses I had bought.
They drilled the holes and welded them in.

Cost £2.

Gob smacked or what!!

Steve

[Mr2Mike]

K13 WJD said:

I had a cracked C20LET manifold, which is acutally a manifold AND the exhaust housing of the turbo, and i managed to weld it in a furnace, and it lasted for around 20,000 miles !!!

The cast iron manifold on my Fiat Coupe 20VT cracked (they all do) and I simply Vee'd out the crack, stuck it in the oven for an hour on maximum temperature, then MIGed it with normal mild steel wire while still hot. Has lasted for around 5k so far, but the manifold on a friends Volvo V70 I did a couple of years ago is still holding with lots of mileage on it. It's certainly not the technically correct way of doing things, but if you bodge it "properly" it can last.

A Simpson 4-1 is going to be a tubular manifold, so repair should be far easier than a cast item.

[BB-Q]

I've repaired plenty of Volvo cast iron turbo manifolds. All I do is heat the affected area with a blowtorch and then MIG the cracks up. Never had a problem so far.

[leorest]

I repaired the cracks in my tubular manifolds on the RV8. Used the smallest gas nozzle available. Put it back on and all looked good. Fired her up and the cracks came back almost immediately... Did this twice and the same thing happened again! I presume that the stresses from bolting it up caused the cracks so the next attempt was to weld up the cracks with the manifold bolted in place. Not a lot of fun to do (complete and utter pain in the bum in fact) but it did the trick and has lasted for almost a year to date.

[K13 WJD]

think the repair of cast iron depents on its use.....fair enough a vovlo turbo manifold will last well if its heated and miged.....but what about a cossie manifold that glows bright red under full load ?????

just my 2p worth.

[S Works]

Right, so if I read these correctly, welding it up is going to be a bit of a hit-n-miss affair. BUT if the offending tube was removed, and a brand new one put on in it's place, that would be possible, right?

[stevieturbo]

S Works said:

Right, so if I read these correctly, welding it up is going to be a bit of a hit-n-miss affair. BUT if the offending tube was removed, and a brand new one put on in it's place, that would be possible, right?

Welding should not pose any problems if done correctly. It also depends on the extent of the crack, and the chances of warpage when welding.
Contact Simpson Race exhausts...given they made it, they would seem the obvious choice, unless you are miles away.