Welding the manifold crack (Page 2/2)
jelly2m8 JUL 08, 11:56 PM

quote
Originally posted by Spadesluck:

I would tack weld it while it is bolted down in a couple spots you can reach. Then when you remove it, you can weld it all the way around without the metal warping on you. This way it eliminates you needing a jig.



Yep great advice, to add to this,

I always kept an old 2.8 and 2.5 head around to bolt them to while welding them up

When you get them off you will see the flanges are welded fast from inside. What I do once removed is reweld the tubes to the flanges ( if the flange is already broke free then tack weld that on the outside first)

I would bolt them to the head and weld any cracks, once they are hot from welding a section, I retighten the mounting bolts in that section. After its completely cooled down then remove and a couple minutes on a belt sander cleans the flanges right up, then port the flange openings, you will see in the 2 ports closest to the manifold exit what can be ground out. I believe the exhaust heat hitting those protruding areas is what causes the manifolds to crack, as that's where usually crack.

Never ever had one return for re-cracking after doing that, and the exhaust manifold gaskets seem to last forever after wards of the porting.

Regular steel wire in a mig welder works great on these manifolds, don't need nothing exotic. Just clamp your ground to the manifold, as close to the area you are welding.

[This message has been edited by jelly2m8 (edited 07-08-2024).]

handymanpat JUL 12, 12:08 PM
Great news!
I soaked the bolts each night and gave it a try.
I could not believe it when each bolt popped and broke loose!
I really expected that at least I e would be seized or break but it actually came loose!
I will either weld this one or put one on without a crack.
Thanks again for the help

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pat moody

Yellow-88 JUL 12, 01:37 PM
My manifold crack story is a little different. We got a good deal on our first Fiero, a second owner 86 SE because it had a ".... cracked head and would cost more than the car was worth to fix... ". We drove it home. The first listen with the hiss tube revealed leaks at both ports #2 and #6. I soaked the bolts for days assuming the worst. 2 of the 6 bolts were finger tight and the others came right out. ( !!?? ) The gaskets were completely blown out on ports #2 and #6 with port #4 lookin fine. The 3 flanges were on 3 different planes and #4 was proud of the others by about .030". This would require a flycut on a mill not just a belt sander.

This is my theory. The first owner had a classic crack, welded it and bolted it back on. The new owner put about 50k on it before it failed.
The bottom line, as has been stated here is clear. Wild on a jig, either bolted to an old head or a solid piece of steel.
When finished the 3 flanges MUST be on the same plane. A belt sander can do it but do check it on a surface plate or granite countertop.
theogre JUL 12, 07:50 PM

quote
Originally posted by handymanpat:
I will weld up the cracked ones and use those, it makes sense that the welded ones would be stronger.

Sadly often Not. Oh The welded area maybe stronger but often can/will crack somewhere else. More so when have overheated exhaust pipes because iffy ignition timing or running lean/rich because that makes more stress from each heat cycle. Or just open the wet/snow covered deck lid dumping water/ice on the exhaust that crash cools the pipes.

4 cyl E-man has those same problems or other issues causing E-man cracking or even breaking.

Have good used or brand new E-manifold have same problems & can Fail too.

& not just a "Fiero problem." Some other models from other brands have similar problems. Some Jeeps w/ 4 cyl & cast E-man likes to crack @ a deep Y in the casting because of heat cycle stress. 1 neighbor broke 3 of them over a few years before sold/traded for another car.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Spadesluck JUL 14, 10:25 PM

quote
Originally posted by handymanpat:

Great news!
I soaked the bolts each night and gave it a try.
I could not believe it when each bolt popped and broke loose!
I really expected that at least I e would be seized or break but it actually came loose!
I will either weld this one or put one on without a crack.
Thanks again for the help




I can only imagine the sigh of relief when they broke loose.
handymanpat JUL 14, 10:32 PM


I really did not think they would.
As they came loose one by one I was expecting the last couple to snap but they came out fine
I did soak them with ob blaster each day
QUOTE]Originally posted by Spadesluck:


I can only imagine the sigh of relief when they broke loose. [/QUOTE]

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pat moody

jelly2m8 JUL 15, 02:09 AM
delete

[This message has been edited by jelly2m8 (edited 07-15-2024).]

jelly2m8 JUL 15, 02:11 AM

quote
Originally posted by theogre:Sadly often Not.



A welded crack is not stronger but letting it air cool normalizes the material, which in this scenario is what you want

[This message has been edited by jelly2m8 (edited 07-15-2024).]

cartercarbaficionado JUL 15, 03:23 AM

quote
Originally posted by handymanpat:
I really did not think they would.
As they came loose one by one I was expecting the last couple to snap but they came out fine
I did soak them with ob blaster each day


yeah they actually tend not to break in my experience. I even have 3800 exhaust bolts in a few holes to make them easier to remove in hard to reach places and those have been fine too
jelly2m8 JUL 15, 03:49 AM

quote
Originally posted by cartercarbaficionado:

yeah they actually tend not to break in my experience. I even have 3800 exhaust bolts in a few holes to make them easier to remove in hard to reach places and those have been fine too



Huh What? Fiero manifold bolts are metric, 3800's are ISO standard....

[This message has been edited by jelly2m8 (edited 07-15-2024).]