L-134 exhaust manifold

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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Chuck W.
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L-134 exhaust manifold

Post by Chuck W. » Fri Feb 16, 2018 3:21 pm

it appears that the exhaust manifold is cracked on my M38. Looks like reproduction exhaust manifolds are available, and I want to reuse my correct M38 intake manifold. Is it a good idea or even necessary to have the two manifolds surface ground where they mate to the engine block as a unit after they are bolted together or do you just leave the four bolts loose where the manifolds bolt together until the manifold assembly is bolted to the block? I am concerned that I might crack one or both of the manifolds during assembly. What is the best assembly order? Thanks!


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Re: L-134 exhaust manifold

Post by JMZ421 » Sat Feb 17, 2018 6:20 am

I had to change out my exhaust manifold last yr and I found a NOS. It was cracked and rusted out where it meets the intake. The gasket is designed to to make up for a difference and I tightned everything up then attached to the block. I lightly sanded the surfaces. Maybe that is not correct but I have no leaks at all. I did not use any sealer or anything just the gasket. John

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Re: L-134 exhaust manifold

Post by Wolfman » Sat Feb 17, 2018 6:45 am

Depends on what has been done to the old manifold in the past.
"If", the original in/ex manifold has ever been resurfaced, the over all width of the manifold assembly will be less.
Not a problem when the assembly was resurfaced but now that you are replacing the exhaust manifold, with the original, resurfaced intake, the intake gasket surface may be low, in relation to the new exhaust manifold gasket surface.
You can assemble the intake and exhaust, then check the gasket surface with a straight edge or bolt the manifold ass. to the block, without the gasket. Leave the four bolts that hold the two manifolds together snug, but not tight.
If both manifolds fit squarely against the block, tighten the four bolts between the two manifolds. Remove the manifold assembly. Install a new gasket and put it back together.
If there are any gaps. any where, in the intake or exhaust gasket surface, you will need to tighten the four bolts to hold the two manifolds as close to being in alignment as they can be, and then have the manifold resurfaced as an assembly, to square up all the gasket flanges.
Mike Wolford
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Re: L-134 exhaust manifold

Post by artificer » Tue Feb 20, 2018 12:50 pm

That issue is easily fixed with a thick washer & using a file to step same....then both manifold 1/2's will will contacted & evenly torqued. I'm sure Mike would have been aware of this approach as he's an experienced tradesman.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: L-134 exhaust manifold

Post by Joe Gopan » Tue Feb 20, 2018 3:43 pm

And do not forget the two WO-344732 Special"Stud Washers" that share the same studs at that location.
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Wolfman
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Re: L-134 exhaust manifold

Post by Wolfman » Wed Feb 21, 2018 5:59 am

I ain't never changed half of a split manifold before.
Well. Maybe once . :roll:
I'm an old farm boy.
Women in high heels with wonder bras, out here, are about as useful as teets on a (bore ?? ) Boar Hog. 8)
Now give me a good looking lady in blue jeans and a t-shirt.
I'll shut up before I get in trouble ! :D
Slipped that one through. But I fixed it !! :lol:
Last edited by Wolfman on Wed Feb 21, 2018 10:33 am, edited 1 time in total.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

Wolfman
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Re: L-134 exhaust manifold

Post by Wolfman » Wed Feb 21, 2018 10:36 am

Nice work !!
Too bad you are so far away.
I know a lot of people around my AO, in antique tractor clubs, that would love to have some one available that can do that kind of repair work.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB


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