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Is it common for Ecotech Exhaust manifolds to crack ?

losh1971

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Can't you just use the VT-VY ones and put a plug in the EGR port?
IIRC the VT on have a different shape and won't fit earlier models.
 

Whiteshark68

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it would seem from what i can find there are 3 exhaust manifolds for the 3.8
1 for the buick another for the early ecotechs vs only and the third for the later ecotechs vt to vy but as i said earlier i have never heard of the vs ecotech manifolds cracking i guess i was lucky i skipped from vr to vt
 

Aussie Trev

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Firstly thanks to all who've responded but I guess I'm going to answer my own question after experiencing it first hand.

I ventured down to the infamous U-Pull-it yard this morning and ended up pulling 5 LH Exhaust manifolds off only to find every single one is .............................. you guessed it...........cracked between 3 and 5. Some more severely than others but it's a real PITA having to do it 6 times all up to find one that hasn't.

I'm wondering how long it's going to be before the welding of these manifolds becomes a standard practice as you can't use the later VY manifolds on a VS due to the EGR pipe being fitted into the later units. I guess they can always be plugged but welding should eliminate the issue pretty much for life. Welding of cast iron isn't a back yard operation and as such most people will have to pay for that to be done correctly.

Anyway I guess this topic has now been well documented for all future questions.
Welding cast is not a big deal, you just have to get it hot first to do the job right. Any stick welder will work once you have the crack cleaned and heated with oxy or even an LPG torch. That's assuming you can weld using good old stick that is :)
 

vs-lover

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That makes 4 then I guess ;)

Honestly I couldn't believe it when I pulled the first one off then the second, then third, fourth and finally struck gold at the 5th. I just couldn't believe that these are such an issue, but in saying that I've changed the cracked one out on my lads VS and put the good one on and truthfully ??? No difference at all as there was no sound leak from the cracked area. Also I've always found that the way that the manifolds are simply a straight up fit against the side of the head with no gasket is odd. If you did that with a 186 Holden motor then you'd have hideous sounds coming out all over the place with it farting and burping. same with flange gaskets made of straight steel against steel pipe.
 

Whiteshark68

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Vy are different to vt
from what i found it was vt on were supposedly the same just going on ebay sellers though
but in saying that my best guess would be vs to vt series 1 would be the same and vt series 2 through to vy would be the same but like i said it would be a guess
 

Immortality

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A crack may not make noise but if it's letting fresh air in it will give false readings to the O2 sensor and upset the tune.
 

woteva

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Also I've always found that the way that the manifolds are simply a straight up fit against the side of the head with no gasket is odd.

Exhaust gaskets are available and I have always installed them after doing any exhaust manifold work on the VR's and VS's I have owned.

Have never bothered fitting headers to a stock V6 as dyno figures show only very marginal gains of less than 5kW.
 
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