my manifold cracked twice already??

[IMAQL8]

just wondering how i can prevent it from happening again, its annoying!! its cheap to repair.. just getting it welded up again but is there anyway to stop my exhaust manifold from cracking a third time??

its stainless steel by the way...

and pic just incase you need to see it..

[Bigelboe]

Once you repair a crack its always very likely to crack again, especially around the weld point because welding adds tensile forces into the steel making it easier for it to fail by fatigue.

And if your manifold is made of the wrong alloy or is too thin there isn't much you can do about it.

Where is it cracking? Down by the collector? Is the second crack right beside the 1st?

[b16a2]

brace it in 2 or 3 different point back to the block, do you know thickness/gauge of stainless used??

whered you get the manifold from anyway, its not a xs power or anyhting stupid like that is it?

[itekdu]

I have read that after a while heat wrap can make the steel brittle if its cracking under that?

[IMAQL8]

im pretty sure the old owner said ronnie made the manifold, and the first crack was near the first bend from where you bolt too the block...
second crack i cant fine yet but i can hear it so im taking it to someone to find where it is and weld it up again...

not sure of thickness of s/steel..

so best bet would be to get ronnie to remake the manifold but with a thicker s/steel??

yeh heat wrap will breakdown the metal faster because it keeps all the heat in..

[Cyclone21]

maybe its time for a steam pipe manifold ?

[agroek]

your turbo mite be to big

[Hayce]

Running open gate? If yes then brace the mani better. Also are the welds ground down?

Mine cracked when I plumbed my gate back in and didnt add a flexi in the dump pipe.

[IMAQL8]

its an external not plumbed back in..
and the welds are ground down... but not where the other guy welded the first crack... all the other welds are ground down though..

so better bracket's and bracing...

has anyone got a pic of there manifole thats well braced so i can sort of get an idea of what to tell them when i get mine re-welded and braced..

[Bigelboe]

Originally Posted by IMAQL8

its an external not plumbed back in..
and the welds are ground down... but not where the other guy welded the first crack... all the other welds are ground down though..

so better bracket's and bracing...

has anyone got a pic of there manifole thats well braced so i can sort of get an idea of what to tell them when i get mine re-welded and braced..

Mnn grinding welds off on something like that is never a good plan, my guess is the first crack was on a weld.

[IMAQL8]

Originally Posted by Bigelboe

Mnn grinding welds off on something like that is never a good plan, my guess is the first crack was on a weld.

Yeh the first crack did happen to be on a weld ops:

[BTLF3D]

Turbo flange - Head Flange


Turbo flange - WGate Flange


these might help

[IMAQL8]

cool thanks for that man.. i will use these to help me tell the guys how to brace it a little better..

along with trying to find an engine damper as that helped another member on these forums as he had the same problem as me..

[VTAKYO]

Uneven heat wrapping can lead to cracking as parts of the manifold end up heating up more than others, causing parts to expand more than others, and cracks develop. Based on that pic, I'd either remove the heat wrapping, or have it done properly.

[IMAQL8]

didnt know that and thought it was okay from seeing other cars do it but i will most likely remove it after reading that theory haha

[VTAKYO]

...wrapping a header GREATLY increases the chance of cracking. The header gets ALOT hotter being wrapped if done correctly. Each heat cycle the header will slighly loose mass. I.E the metal decaying.

Thats just a quote from another thread. So, pretty much the parts that aren't heat wrapped will be decaying at a slower rate than the parts that are. When they heat up they heat up at different rates anyway due to the insulative qualities of the heatwrap, and you are ending up with two sections decayed one more than the other, you are only asking for cracking.

[IMAQL8]

sweet as cheers i will look at removing the heat wrap thats on there..

[Bigelboe]

Originally Posted by VTAKYO

Thats just a quote from another thread. So, pretty much the parts that aren't heat wrapped will be decaying at a slower rate than the parts that are. When they heat up they heat up at different rates anyway due to the insulative qualities of the heatwrap, and you are ending up with two sections decayed one more than the other, you are only asking for cracking.

I dont think the decay rates are particularily important, especially with stainless steel, but what you said about uneven heating is bang on the mark. Steels tensile strength goes down markedly with temperature so it makes it much more supsceptable to fatigue failure, IE cracks. Fatigue resistance is where mild steel (steam pipe) absolutely kicks stainless steels ass.

Personally I would bin that manifold, your just going to be pushing shit uphill, doesn't sound like it was made with longevity in mind.

[b16a2]

^^ youll also find stainless has far greater expqansion rates, so it wants to move alot more than MS, so there alot more internal stress when it cant move,

[IMAQL8]

Originally Posted by Bigelboe

I dont think the decay rates are particularily important, especially with stainless steel, but what you said about uneven heating is bang on the mark. Steels tensile strength goes down markedly with temperature so it makes it much more supsceptable to fatigue failure, IE cracks. Fatigue resistance is where mild steel (steam pipe) absolutely kicks stainless steels ass.

Personally I would bin that manifold, your just going to be pushing shit uphill, doesn't sound like it was made with longevity in mind.

cool thanks i will ask ronnie if he can make same manifold with mild steel/steam pipe.. as the car wasnt really a daily driver before and now it is...

thanks guys for your input.. helped in different ways... i'll try the bracing methods first and damper, and if still happens then new manifold it is haha

[BTLF3D]

Originally Posted by Bigelboe

I dont think the decay rates are particularily important, especially with stainless steel, but what you said about uneven heating is bang on the mark. Steels tensile strength goes down markedly with temperature so it makes it much more supsceptable to fatigue failure, IE cracks. Fatigue resistance is where mild steel (steam pipe) absolutely kicks stainless steels ass.

Personally I would bin that manifold, your just going to be pushing shit uphill, doesn't sound like it was made with longevity in mind.

why? its a manifold built over in the states isnt it? im sure WATUGT bought it in?

IMAQL8, you shouldnt need to buy/get a new manifold made if this one is made from the right material and welded correctly, mine has cracked once and has now been fixed and braced and i havnt had a problem since. try and reweld/brace it first before spending the $$ on a new mani!

[Bananaman]

Just my 2c

(he said it was made by ronnie lim Hayden)

I would just enquire as to what it is worth to get a MS one first. By the time you by an engine dampener ($250 min) and get the crack fix ($50???) then you already have $300 towards the new manifold.

Just my take on things. Find out replacement cost first then way up your options.

[Hayce]

if this one is made from the right material and welded correctly

If it was it wouldn't have cracked in the first place. Just cos it came from the states doesn't make it good.

Stainless is an inherently weak material to make a mani out of period. If you want no dramas get a mild steel one. If you want to keep fixing a stainless one do so.
I have a stainless one as well and it very rarely cracks but at some point it will

[BTLF3D]

Originally Posted by Bananaman

Just my 2c

(he said it was made by ronnie lim Hayden)

I would just enquire as to what it is worth to get a MS one first. By the time you by an engine dampener ($250 min) and get the crack fix ($50???) then you already have $300 towards the new manifold.

Just my take on things. Find out replacement cost first then way up your options.

ops: didnt see that, i would just go back to ronnie and let him have a look, he would know what to do with it :wink:

[Coupe-R]

Depends how the Stainless manifold is made also, when it expands if its fighting against itself then it will crack everywhere. It depends how its made.
THEN what grade of stainless and what sort of welds are used.

Id scrap that and get a Mild Steel one, however it will be expensive to coat again rust.
(Will take YEARS to rust out tho!)