Manifold issues

[Dodgeb4ya]

You've got to get past all the carbon infiltration in the cast befroe even attempting to weld. Used exhaust manifold cast is a mean metal to weld.

I wouldn't bother to weld it either- get another one-better way to go-just make sure the heat riser shaft and bushings are not worn out or severely frozen up.

[greg g]

That angle shows the crack better and I guess I would search for a different manifold also. Yes that is your heat riser and it is in the position to feed heat tot he manifold all the time. So thats not good also. The flap wants to be horizontal whent he engine warms up.

[ggdad1951]

The crack is right where this flapper thingy is which I assume is this infamous heat riser mechanism. It is of course tight and does not move. Can I just leave it the way it is or must this be fixed and loosened before I install it?

torched up my manifold today to loosen the heat riser and guess what I found? Almost the same crack noted here....several here said to get a diff (non cracked) manifold...how easy is that gonna be to find?

Edited September 7, 2010 by ggdad1951

[Aaron]

I couldn't find a welder in town that would weld on it. One guy said if I absolutely could not find a replacement to bring it back and he would try, but would not guarantee anything.

I found a forum member that was generous enough to sell me an extra one he had.

Aaron

[Bradley S.]

Over many years of high heat cycless, the cast iron manifold parts pick up and retain carbon that is a normal part of the combustion process and the exhaust gasses. After years of this activity, the cast iron changes metallurgically, and becomes quite brittle.

I seem to remember this very thing in one of my engineering classes. I was thinking about ripping off my intake and exhaust, making them pretty and re-installing. On second thought, I will leave them alone. Just try to wire brush them up a little.

Brad

[ggdad1951]

alright , anyone have a spare manifold? Second HUGE crack as well (3/4 around)

[Young Ed]

See if you can still get into Sonnys junkyard. They had a ton of them.

[ggdad1951]

I doubt I can, she was pretty firm about wanting to get "out" of having to be there all the time...I SHOULD be able to "order" one from her possibly tho, but no way then since I wouldn't be pulling it to make sure it wouldn't have a crack as well....I'll drop a call today and find out, where were they that you remember JIC?

[Young Ed]

Lots of the dodges and plymouths all had manifolds. Otherwise try french lake. They have a ton of flathead mopars too. There's gotta be one in there somewhere. You can use one off a dodge or plymouth car engine as long as its the same length block.

[ggdad1951]

ok thanks for the tip(s)! Biggest problem I no weekends free till October!

[ggdad1951]

and this thread comes back....

ok, was getting ready to paint manifolds and was prepping them today and lo and behold, my buddies snapped off all 4 of the bolts between the intake and exhaust manifold flush with the intake manifold (w/o telling me). So before I chuck it up in the mill and machine out the old bolts and try retapping them, a few questions.

1. NO way I'm going to be able to line up the old threads with a tap now...unless someone has a magic trick they'd like to share

2. overdrill and helicoil?

3. other?

ah...the best layed plans for Thursday night go awry!

[Merle Coggins]

If they're flush there's 2 things to try.

1. Take a 5/16" nut... set it on top of the broken bolt... weld the inner bore of the nut to the top of the bolt... let it cool... now heat the corner of the manifold around the bolt... put a wrench on the nut and work the bolt loose.

2. Drill the center of the bolts as close as possible... get a screw extractor set into the bolt (notice I didn't call it an "easy-out")... heat the manifold and back the bolt out.

These methods were successfull for me.

Merle

[Young Ed]

Do you have any stub sticking out? Had good luck with cutting a screw driver slot into the remaining stub and using heat to get them out. Otherwise you can try welding a nut to whats left. If neither of those work then you are down to trying to drill it out and retapping or drilling it and helicoiling. FYI this is VERY common for these bolts to break.

[Dave72dt]

Weld a WASHER to it first. You'll get better weld penetration to the stub than with a nut, you'll put more heat into the area that needs it most and you can always weld a nut to the washer afterwards if you feel it necesary. Even if the stub is flush, you can usually weld a washer to it. I can usually turn them out with a regular non-locking pair of pliers. If the washer, manifold heat doesn't work, you can still drill.

Edited October 28, 2010 by Dave72dt

[ggdad1951]

1/4 SUCCESS! Welded a washer on, took it to the fab shop and begged the maintenance guy to torch it...and it came free! Now other question is this, how hot should I/can I get the casting? I'm afraid of cracking/deforming it. Red hot? Not red hot?

[Young Ed]

always a nice orange glow. let it cool naturally. Dad and I have done many this way and never had an issue. Now my question has always been is it better to use grade 8 bolts and hope they will come out next time in 1 piece or to use soft grade 2 so they'll be easier to drill when they break next time.

[Dave72dt]

Grade 5, strong enough to hold and soft enough to drill.

[ggdad1951]

no dice on the last 3...the first gave me hope....now dashed as bad as the Vikings' Superbowl dreams! I'll take the studs out the carb side and chuck her in the mill after work tonight and drill out the bolts for helicoil...I just don't want to snap and easy out off in there as well!

Edited October 29, 2010 by ggdad1951

[Dave72dt]

Just as easy to snap a tap off. I've welded washers on several times to the same stud to get them to come loose. You can put more heat into the stud by putting more weld on it after the first initial weld, heating it up to cherry red, concentrating the heat in the center. When it cools to blue, grab it with the pliers and wiggle it. If it doesn't move, heat it again with weld. You're trying to drive the heat all the way to the bottom of the stub. without transferring all the heat to the cast and welding is the quickest way to heat it without massive heat transfer..

The stud/stub should shrink more than it expands allowing it to turn through the rust or corrosion. Getting the cast hot around the stud allows it to expand and do the same thing as long as the heat doesn't transfer to the stud and expand it also. Ability to heat quickly is essential.

Also, the weld won't stick to the cast so you can get pretty aggresive with stubs even partially recessed.

[ggdad1951]

Just as easy to snap a tap off. I've welded washers on several times to the same stud to get them to come loose. You can put more heat into the stud by putting more weld on it after the first initial weld, heating it up to cherry red, concentrating the heat in the center. When it cools to blue, grab it with the pliers and wiggle it. If it doesn't move, heat it again with weld. You're trying to drive the heat all the way to the bottom of the stub. without transferring all the heat to the cast and welding is the quickest way to heat it without massive heat transfer..

The stud/stub should shrink more than it expands allowing it to turn through the rust or corrosion. Getting the cast hot around the stud allows it to expand and do the same thing as long as the heat doesn't transfer to the stud and expand it also. Ability to heat quickly is essential.

Also, the weld won't stick to the cast so you can get pretty aggresive with stubs even partially recessed.

tried welding on two times...all three still broke off the bolt stub...spun off...the one that did came out came out like a dream....there is always helicoil....maybe I can talk the maintenance guy into running the torch ONE more time tho....

[Dave72dt]

This method doesn't always work, I'll admit, but I've had really good luck with over the years, better than with the nut welding by far, it's usually faster than with drill. I've also lightly run a flat punch in an air hammer over the cast area the stud is in to help loosen the rust inside before attempting to remove them. Tricks of the trade. I hate drilling and it's my last resort but I have done it. Good luck with it.

[ggdad1951]

Lunch time play at work:

well, welded on 3 more washers went down to maintenance, torched it, took a swing at it...and one more free....other 2 twisted off the nubs. He welded on washers this time and just twisted free again....I'll drill and try an easy out (GENTLY) next and if still no dice...I've got the helicoil set.

[Young Ed]

Are the remaining pieces down below the surface now? If so you can use a transfer punch in the hole to get the drill nice and centered.

[ggdad1951]

Are the remaining pieces down below the surface now? If so you can use a transfer punch in the hole to get the drill nice and centered.

Lined up off of the exisiting holes w/o stubs and went 2.625" over on the Bridgeport and dead center for the hole. Right now I milled in 3/16" holes and will try the easy out, if not, heli...

[Reg Evans]

If none of that works hows about drilling on through to the other side, like the big block engines, and installing 4 new nuts and bolts.