M5 Manifold Replacement Dilema

FarmallPaul · Feb 7, 2012

Hi All- I'm replacing a broken manifold on a model M5 that I just bought and as I was cleaning up the ports on the heads, I noticed that the front of the front exhaust port and the back of the back exhaust port had burned thru the gaskets. I don't know any history, but this ole girl's been apart and back together a few times! I put a straight edge against the ports and it looks like there is about 0.080" gap from front to back. The ports are true for each head, it's just that the heads aren't in line with each other. I have gathered from other posts here that the proper way to mount the manifold is to torque it down with the head bolts loose and then torque the head bolts down. My problem is, is this OK to do without tearing into it and replacing the head gaskets? Would it be OK to just loosen the head bolts, install the manifold and then retorque the heads? I'm not working on a show tractor or anything here, just trying to get back to feeding hay to the cows. Any input will be appreciated! Thanks-

Dieselbear · Feb 7, 2012

Put some high temp RTV in those spots , tighten down, let it cure. and go back to work. It will last a long time

FarmallPaul · Feb 7, 2012

Dieselbear- I might have to just break down and do that. Is there any chance I might crack the new manifold? Do you happen to know the torque settings for those 4 nuts?

Dieselbear · Feb 7, 2012

I guess it's always a chance. Sung them up good run it so it's warm and give it a little more. Don.t go crazy just use some common scene Most of the pressure is where the clamps are. good luck

Kevin Moschenrose · Feb 7, 2012

Is this a new manifold or a used one you are installing?

FarmallPaul · Feb 7, 2012

It's a new manifold. I got it on Ebay!

mightymolinekid · Feb 7, 2012

If you are going to loosen all the head nuts, be sure to drain the cooling system first or you will get leakage into the gasket surfaces and then will not get a proper re-torque

Anonymous-0 · Feb 7, 2012

Just fix it right and be done with it. Loosen the head bolts.
I have seen new manifolds crack because the heads were out of line.

Kevin Moschenrose · Feb 8, 2012

Six of one and a half dozen other! You might get by with out busting the new one you might not. Loosen the heads up and then install you might be replacing head gaskets then again you may not. If it was mine I would see what it would do with new manifold gaskets and just install it first. .008 out really isn't that much that a gasket wouldn't fix. Make sure and use new ones though.

FarmallPaul · Feb 8, 2012

All- Thanks for the input. I think I'll go ahead and loosen the heads. Kevin, the misalignment is .080, not .008. That is, if the gaskets were crushed completely on the inside ends, they still wouldn't seal at the outside edges!
MMkid, good point! I'll drain the coolant for sure. I have to pull the radiator to fix a small leak anyway....
I'll let you know how it goes!

M5 Manifold Replacement Dilema

FarmallPaul

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Dieselbear

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FarmallPaul

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Dieselbear

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Kevin Moschenrose

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FarmallPaul

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mightymolinekid

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Anonymous-0

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Kevin Moschenrose

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FarmallPaul

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