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Cracked Exhaust Manifold

1.4K views 8 replies 5 participants last post by  **DONOTDELETE**  
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#1 ·
I was just wondering if any of you guys have any suggestions as to how to fix a passenger side cracked exhaust manifold on a 90 351W. The crack is just in front of the #4 cylinder and it runs about half way around the diameter from the bottom back side to the top. Any thoughts would be great. Thanks.

~Mike

 
#2 ·
You can drill two holes

each just past where the crack ends and filet grind a grove all along the crack and send it in for TIG oven welding or......... You could call the nearest wrecker and have him hunt you down a used one on-line. Chances are good he'll even install it for you for a little extra tacked onto the negotiated price.

Deal goes like this " $40 for the manifold". You reply "I was hoping for $25, say can you guys handle installation too?". He replies "yes we can, tell you what, $75.00 installed". You say "deal, I'll be right over on pay day".

Sixlitre

 
#3 ·
or you could grab a set of cheap headers if that option doesn't work out. speaking of which, my pass. gasket appears to be leaking, am i gonna have problems with broken bolts and such when i pull it off or does that usually go smoothly? if it's going to be probematic then i wont even worry about it. and does anybody make a cheap header for a 93 351 with the o2 hole? i might as well upgrade while i've got them off.

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S H O U L D A G O T T A F O R D!

www.ArkansasMud.com
 
#5 ·
We used to repair manifolds when i worked in the machine shop (cast iron spray weld). Its an acetylene torch with a powdered metal resevoir mounted on it. Works great if you preheat the work first but anytime you weld a manifold, everything twists so you then need to resurface it or you`ll have a leak.

$50.00 to weld $25.00 to resurface, might as well get a junk yard piece or a new one since they offer new castings in the aftermarket now.

Muddy, you could get Summit racings #G9036 Shorty headers. Should bolt right up and i believe it comes with a Oxy. sensor attachment(might want to check first though) for $160. They say smog-legal so it must have some provision.
 
#6 ·
Hmmm... sounds familiar. I had the same problem until one day when I was trying to remove my muffler. Somehow the exhaust manifold ripped off instead of the muffler. I replaced mine with FlowTech headers. They really haven't made much of a noticeable difference, except they make it impossible to remove the spark plugs and wires without haveing to remove the headers.

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90 BRONCO Custom
 
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#7 ·
This is a ridiculoulsy common problem on stock Ford truck manifolds. My driver's side manifold on my '90 developed a crack which eventually spread all the way around. When I removed it it came off clean in two pieces. I got some manifolds for free from a buddy who had installed headers. As for leaks/gaskets, at the advice of an experienced mechanic I took the new manifold to my local machine shop and had the mounting surface planed. No gasket, no leaks. As mentioned above, was about $25 in labor.

 
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#9 ·
This is not real common in my experience, and I would just go hunt another one in a junkyard. I would take the old one with me, since many of these look alike but are different. '

Been there, done that.

I agree that headers are a lot easier to install, remove, maintain, etc, also.