Unbelievable....broke an exhaust manifold

[Piece of Work]

In all my 30+ years of working on and driving old vehicles, I have never seen this. Today it was about 90 degrees outside and after work I went to pick up 2 of my grandsons. They got in and I took off, in there parking lot there is a low spot that retains water after a rain. When I hit this water, it splashed up and hit the hot exhaust manifold, breaking it in half!, right above where the down pipe attaches. Has anyone ever heard of this? Are these ram horns readily available? I find this rather unbelievable, but it happened.

-Mark

[cdowns]

yep it happens alot on the older stuff from the 30's thru50's it was a pretty normal deal// ramshorns are readily available (try ebay craigslist and the hamb)used and in fact they're repoping a new version for the rodders that speddway motors sells in either castiron or polished stainless

[d4xycrq]

Mark,

Been there, done that. I was able to get another manifold, no problem.

Ray

[Piece of Work]

That looks too familiar. Mine broke straight across.

-Mark

[PanelDeland]

Wow,one of the guys at work just asked me today if I ever heard of a manifold cracking.I said sure the old cast iron does that.He said no it's aluminum and it's cracked so bad the carb is the only thing holding it together.I haven't ever heard of an intake manifold cracking before have any of you?

[Select]

I had a 85 Turd Ranger in high school. It was a great beater. I had the driver side manifold bottom 1/2. not the flange area, break and fall off. It was only due to me making the straight exhaust backfire while going down the road, man was that loud.....Mikey

[Longhorn Man]

I know they'll break like that if you remove the tranny and let the exhaust hold all the weight.

[SideStepper]

I have broke several ramhorn exhaust manifolds (on both sides, but never at the same time) on my 68 over the last 2 years. I have replaced them with "junk yard finds" so I don't know if its due to age of the casting or some other reason. I have checked the engine mounts & all the hangers on the exhaust system without finding any obivious problems. Maybe new manifolds are the way to go. Any suggestions?

[longhorn71]

Originally Posted by Longhorn Man

I know they'll break like that if you remove the tranny and let the exhaust hold all the weight.

yep i had the same thing happen too.It also cost me a cap and rotor.It smacked the firewall dang hard

[WorkinLonghorn]

I have a big crack in mine. I didn't realize that the torque spec on these (according to the 1969 GM shop manual) is only 30 ft.lbs (inner) and just 20 ft. Lbs (outer bolts).
I read somewhere that it's good to check with a staight-edge and correct as necessary before installing a used rams horn.

[mrein3]

When my buddy that does machine work dropped off my 383 block he said to be careful not to torque the bolts on the exhaust manifolds too tight. They can break if too tight and then go through a few hot/cold cycles. I never broke one but it happens.

[rambler]

I've had one break to, on the surburban, and I was actually paying someone to rebuild the tranny, and he didn't remove the exhaust and it broke the manifold! of course, it was already broke according to him... I dont do business with him anymore...

[special-K]

Metal fatigue/old age.I`ve had more manifolds break than problems with headers,I don`t care who says what.True,a header would not last 30+ years,though.Today`s cast is nowhere as good as the older stuff,either.

[Sport/Truck]

So with this talk of cracking manifolds….I have some questions.
I plan on reinstalling my manifolds and was wondering what special steps need to be done. I think I have them marked from what side it came off, but do I need to have them checked for flatness or anything?
What torque should be used? I also plan on installing them without the gasket or heat riser. Good or bad?
s/t

[jamesroy9289]

It's okay not installing a heat riser, but you'll need the gaskets, or you'll definetally be hearing it when you start it up, they not like the new fords that run no gaskets on their 4.6's and 5.4's. If you don't you'll probably be hearing a ticking when you start it up.

[bad6772]

this is crazy, i have never heard of this . i have been hanging on to mine for 10 years, and 2 engines, i dont want the hassle of headers and everyone has told me that the (ram horns) are the fastest flowing stock manifolds out there. is there any way to make shure this doesnt happen (i e) coatings? or is it just luck of the draw??

[Sport/Truck]

Originally Posted by jamesroy9289

It's okay not installing a heat riser, but you'll need the gaskets, or you'll definetally be hearing it when you start it up, they not like the new fords that run no gaskets on their 4.6's and 5.4's. If you don't you'll probably be hearing a ticking when you start it up.

Do you have an OEM part #?
s/t

[lowrollin70gmc]

I cracked one a few years back, but replacements are easy to find and easy to put in, so I don't worry about it happening in the future. Just another querk of old stuff.

[Aarons72s]

I have done it to. Broke in about the same place as d4xycrq shows in his photo. Except mine was on the driver side. Hit a chug hole before a bridge back in 2000 and broke it. They are notorious for cracking there. And they are easy to find new or used ones.

[Truck Hippy]

This happens alot. If you look at a good one you will probably see alot of tiny cracks just above where it turns back. I had a 70' and the drivers side broke while I was going down the interstate. I have never had any problems with 4x4 manifolds.

[truckdude239]

www.partstrain.com has them pretty cheap

[Piece of Work]

Nothing like the feeling of not being alone.

I went ahead and bought a new one. I twisted the head off of the center rear bolt removing the old one, so out came the BFH and it came apart in no time! The bolt was seized in the old manifold, so I turned what was left of the manifold until the bolt was free. The break in the manifold looked like it had been cracked for a while, only part of the metal was shiny. Just for kicks I decided to check the plugs while I had such easy access, and I found the worst looking plugs I have ever seen in a running engine. So tomorrow it's new plugs and new bolts. Maybe I'll have this "easy" repair done soon. Thanks for all the replies.


-Mark

[72swbcamo]

Don't mean to be a wise guy but the bracket in the picture holding the A/C compressor look like the wrong one for the exhaust manifold. It looks like the bracket that is supposed to be on the intake manifold that supports the compressor. Could be the wrong bracket put too much stress on the exhaust manifold. If you look at the pic you can see that the compressor is not directly bolted to the bracket. Looks like they used the A/C compressor bracket shims to make up the difference.

[tx71smallblock]

yeah me and a buddy of mine broke one when we hit a bump in a field in his 67. we found new ones for his and my 71 in an LMC Truck catalog

[mfarmer]

Broke one once when I was driving down I35 and an 18 wheeler blew a tire in front of me. It was about 11:30 at night so I ending up running over it. The exhaust pipe fell to the pavement and was throwing some nice sparks back at my wife who was following me. I had to pull over, and on the side of the road with 18 wheelers passing by close enough to shake the truck, I tied the driver's side exhaust pipe up with a coat hanger that I surprisingly found in the bed. I then drive another 150 miles home with the complete understanding of why they invented mufflers. It was very loud to say the least. I was able to find one a a junkyard. Took it to a machine shop to have it surfaced and was good to go.