Unbelievable....broke an exhaust manifold - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Piece of Work · 07-12-2007, 08:04 PM

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 · 07-12-2007, 08:15 PM

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 · 07-12-2007, 08:16 PM

Mark,

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

Ray

Piece of Work · 07-12-2007, 08:18 PM

That looks too familiar. Mine broke straight across.

-Mark

PanelDeland · 07-12-2007, 08:20 PM

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 · 07-12-2007, 09:56 PM

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 · 07-12-2007, 10:56 PM

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

SideStepper · 07-12-2007, 11:13 PM

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 · 07-12-2007, 11:26 PM

Quote:

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** · 07-12-2007, 11:45 PM

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 · 07-13-2007, 07:17 AM

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 · 07-13-2007, 08:06 AM

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** · 07-13-2007, 08:23 AM

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 · 07-14-2007, 10:07 AM

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 · 07-14-2007, 10:59 AM

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 · 07-14-2007, 03:07 PM

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 · 07-14-2007, 03:16 PM

Quote:

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 · 07-14-2007, 05:36 PM

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 · 07-14-2007, 06:53 PM

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 · 07-14-2007, 08:11 PM

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** · 07-14-2007, 08:15 PM

www.partstrain.com has them pretty cheap

Piece of Work · 07-14-2007, 08:29 PM

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 · 07-14-2007, 09:15 PM

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 · 07-14-2007, 10:13 PM

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 · 07-14-2007, 11:10 PM

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.

07-12-2007, 08:04 PM	#1
Piece of Work Cultural Infidel Join Date: Jan 2007 Location: Clearwater, FL Posts: 668	Unbelievable....broke an exhaust manifold 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 __________________ posted via La-Z-Boy -Mark 1972 C-10 Fleetside 350/TH350 PS PB A/C Cab Sadly....Sold 1968 Short Fleet 350/TH400 PS PB Delivered by Fine69 Also sadly Sold! It may be that your whole purpose in life is simply to serve as a warning to others. A man is not complete until he is married -- then he is finished.

07-12-2007, 08:15 PM	#2
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Unbelievable....broke an exhaust manifold 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 __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

07-12-2007, 08:16 PM	#3
d4xycrq Registered User Join Date: Apr 2006 Location: Boyertown Pennsylvania Posts: 37	Re: Unbelievable....broke an exhaust manifold Mark, Been there, done that. I was able to get another manifold, no problem. Ray

07-12-2007, 08:18 PM	#4
Piece of Work Cultural Infidel Join Date: Jan 2007 Location: Clearwater, FL Posts: 668	Re: Unbelievable....broke an exhaust manifold That looks too familiar. Mine broke straight across. -Mark __________________ posted via La-Z-Boy -Mark 1972 C-10 Fleetside 350/TH350 PS PB A/C Cab Sadly....Sold 1968 Short Fleet 350/TH400 PS PB Delivered by Fine69 Also sadly Sold! It may be that your whole purpose in life is simply to serve as a warning to others. A man is not complete until he is married -- then he is finished.

07-12-2007, 08:20 PM	#5
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Unbelievable....broke an exhaust manifold 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? __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 07-12-2007 at 08:20 PM.

07-12-2007, 09:56 PM	#6
Select Friday's Toy Join Date: Nov 2006 Location: Ovilla, TX Posts: 574	Re: Unbelievable....broke an exhaust manifold 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

07-12-2007, 10:56 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Unbelievable....broke an exhaust manifold I know they'll break like that if you remove the tranny and let the exhaust hold all the weight.

07-12-2007, 11:13 PM	#8
SideStepper Registered User Join Date: Jun 2002 Location: Southern California U.S.A. Posts: 279	Re: Unbelievable....broke an exhaust manifold 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?

07-12-2007, 11:45 PM	#10
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,883	Re: Unbelievable....broke an exhaust manifold 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. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme. Last edited by WorkinLonghorn; 07-12-2007 at 11:47 PM.

07-13-2007, 07:17 AM	#11
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	Re: Unbelievable....broke an exhaust manifold 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. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

07-13-2007, 08:06 AM	#12
rambler MOVE OVER Join Date: Jun 2002 Location: Warrensburg, MO Posts: 5,470	Re: Unbelievable....broke an exhaust manifold 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... __________________ No matter where you are..... There you are... Buckaroo Banzi

07-13-2007, 08:23 AM	#13
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Unbelievable....broke an exhaust manifold 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. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

07-14-2007, 10:07 AM	#14
Sport/Truck Sierra Grande Club Join Date: Jan 2007 Location: New Mexico USA Posts: 2,433	Re: Unbelievable....broke an exhaust manifold 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 __________________ 1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

07-14-2007, 10:59 AM	#15
jamesroy9289 Registered User Join Date: Apr 2005 Location: Brookings_South Dakota Posts: 43	Re: Unbelievable....broke an exhaust manifold 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. __________________ 01 Pontiac Bonneville SLE 62 Studebaker GT Hawk 72 GMC C20-327/th350 81 Chevy c10 84 Monte Carlo SS 70 Ford 3/4ton 4X4 Highboy 390/bedhoist 68 Mercury Cougar GT

07-14-2007, 03:07 PM	#16
bad6772 Official Site Guitar Shredder Join Date: May 2006 Location: Oz Posts: 3,955	Re: Unbelievable....broke an exhaust manifold 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??



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07-14-2007, 05:36 PM	#18
lowrollin70gmc Too many projects Join Date: Mar 2004 Location: Fargo, ND land of the flat hills Posts: 1,147	Re: Unbelievable....broke an exhaust manifold 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. __________________ Andrew 84 GMC C1500 SWB 6.2 Diesel/700R4/3.42 "Grandpa's odd duck" 70 GMC C1500 LWB My first truck: shaved, bagged, and more: the lowrollin70gmc 68 K20 Suburban 12V Cummins/NV5600/NP205/D60/11.5AAM 3.73s "Dakota Cadillac" 63 Chevy II Nova Coupe 250 I6/T56/4.56s "Economy car" 53 Willys Wagon 350/NV4500/BW4401/HP D44/9inch “Winter Wagon” 30 Model A 16 Focus ST

07-14-2007, 06:53 PM	#19
Aarons72s Registered User Join Date: Apr 2006 Location: oklahoma Posts: 10,669	Re: Unbelievable....broke an exhaust manifold 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.

07-14-2007, 08:11 PM	#20
Truck Hippy Registered User Join Date: Aug 2002 Location: Hickory, NC. Posts: 776	Re: Unbelievable....broke an exhaust manifold 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.

07-14-2007, 08:15 PM	#21
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: Unbelievable....broke an exhaust manifold www.partstrain.com has them pretty cheap __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

07-14-2007, 08:29 PM	#22
Piece of Work Cultural Infidel Join Date: Jan 2007 Location: Clearwater, FL Posts: 668	Re: Unbelievable....broke an exhaust manifold 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 __________________ posted via La-Z-Boy -Mark 1972 C-10 Fleetside 350/TH350 PS PB A/C Cab Sadly....Sold 1968 Short Fleet 350/TH400 PS PB Delivered by Fine69 Also sadly Sold! It may be that your whole purpose in life is simply to serve as a warning to others. A man is not complete until he is married -- then he is finished. Last edited by Piece of Work; 07-14-2007 at 08:29 PM.

07-14-2007, 09:15 PM	#23
72swbcamo Active Member Join Date: Dec 2003 Location: Waterbury, CT Posts: 591	Re: Unbelievable....broke an exhaust manifold 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.

07-14-2007, 10:13 PM	#24
tx71smallblock Registered User Join Date: Jun 2007 Location: Georgetown , TX Posts: 166	Re: Unbelievable....broke an exhaust manifold 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 __________________ 70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb

07-14-2007, 11:10 PM	#25
mfarmer Registered User Join Date: Sep 2006 Location: Georgetown, Texas Posts: 97	Re: Unbelievable....broke an exhaust manifold 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.

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