 JimKshortstep4x4
Chevytalk Moderator & "9th Year" Silver Supporting Member
Posts: 4163
Loc: Muskegon, MI, USA
Reg: 03-28-02
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04-28-12 04:13 PM - Post#2220032
My son is building a 350 for his 70 4x4 and we ran into two intake manifolds that were cracked on the bottom under the the carburetor where the exhaust circulates through. They were both cracked in the radius in the corner of the "buldge". The cracks are hairline and when we had the first manifold brazed to insure that there were no leaks the crack spread badly to the point where the maniflod may not be salvageable.
The manifolds that were cracked came from a 69 engine and a 72 engine so they are both older. The replacement manifold that we picked up has three ribs cast into it at the crack area so it appears that there must have been a fix. The replacement manifold is from a 73 truck but does not have the EGR location cast into it.
Since this is the first experience in seeing cracks in the manifolds I was wanting to know if anyone else has run into this problem. Having rebuilt dozens of engines the cracks were a first for me.
If you had a cracked manifold, how did you fix it?
Jim
Member 65-66 Full Size Chevrolet Club
65 Impala SS, 400sbc, Muncie M-22
66 Impala SS, 396, TH 400
69 El Camino, 350, TH 350
71 Short bed stepside 4x4, 350/350
71 Snow plow, 4x4, 350, TH 350
Current project, 72 GMC Shortbed, stepside, 427 |
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C10 Sleeper
Valued Contributor
Posts: 3426
Loc: Redding Ca
Reg: 03-17-09
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04-28-12 06:05 PM - Post#2220063
In response to JimKshortstep4x4
I had one that was cracked in what sounds like the same location. Being that I a stock intake manifold is far from fitting my usual game plans I tossed it in the scrap pile. I have never had good luck brazing much of anything. Working with cast iron is generally in my opinion best left to the professionals equipped with a n oven for pre heating and a good way to control the cool down.
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JimKshortstep4x4
Chevytalk Moderator & "9th Year" Silver Supporting Member
Posts: 4163
Loc: Muskegon, MI, USA
Reg: 03-28-02
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04-29-12 06:02 AM - Post#2220159
In response to C10 Sleeper
You are right about cast iron. The guy that brazed it for me is very experienced and did preheat it. He was very surprised about how it cracked more when he tried to braze it.
The sad apart about having to scrap the manifold is that it was a 72 Corvette only casting.
Jim
Member 65-66 Full Size Chevrolet Club
65 Impala SS, 400sbc, Muncie M-22
66 Impala SS, 396, TH 400
69 El Camino, 350, TH 350
71 Short bed stepside 4x4, 350/350
71 Snow plow, 4x4, 350, TH 350
Current project, 72 GMC Shortbed, stepside, 427 |
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C10 Sleeper
Valued Contributor
Posts: 3426
Loc: Redding Ca
Reg: 03-17-09
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04-29-12 01:33 PM - Post#2220293
In response to JimKshortstep4x4
Its definitely sad that it was a one year only manifold rather than some multi use piece that was used for years. My 70 c10 that I sold had a later cast iron intake on it when I got it. Pulling it off required some work and helped me remember exactly how much heavier the iron is over the aluminum. I still have a couple of production iron intakes from when i was racing hobby stock cars with claimer motors and really restrictive rules. There are actually a few castings that work pretty well and with some work are capable making some decent power and torque figures.
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JimKshortstep4x4
Chevytalk Moderator & "9th Year" Silver Supporting Member
Posts: 4163
Loc: Muskegon, MI, USA
Reg: 03-28-02
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04-30-12 05:17 AM - Post#2220550
In response to JimKshortstep4x4
It is getting difficult to find parts like the older manifolds as yards are scrapping everything.
Smaller yards are almost nonexistant because of the high price of scrap.
Jim
Member 65-66 Full Size Chevrolet Club
65 Impala SS, 400sbc, Muncie M-22
66 Impala SS, 396, TH 400
69 El Camino, 350, TH 350
71 Short bed stepside 4x4, 350/350
71 Snow plow, 4x4, 350, TH 350
Current project, 72 GMC Shortbed, stepside, 427 |
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C10 Sleeper
Valued Contributor
Posts: 3426
Loc: Redding Ca
Reg: 03-17-09
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04-30-12 08:05 AM - Post#2220621
In response to JimKshortstep4x4
In the last couple of years there have been several local yards where I used to find a lot of older hard to find parts getting bought out by the big corporate businesses. One yard that sponsored my car was an old ma and pop shop that specialized in mainly old Chevy stuff. If you needed some odd ball trim piece for a 63 impala he probably had two of what you needed when no one else had one. Then he would probably say you could have it because he wanted to see people taking care of older cars and trucks that are dissapearing. The guy and his one eyed dog were getting pretty old and one day I was headed there for something and the place was closed down. The neighboring big name scrap dealer expanded and crushed everything. The only other game in town is a place I avoid. The guy has the local monopoly and if he has what you need and knows it he will drive the price up and pretty much rob you on the spot.
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Old_Longboarder
Ultra Senior Member
Posts: 12224
Age: 63
Loc: Long Beach Ca, near Vet's...
Reg: 03-28-02
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05-13-12 03:26 PM - Post#2225525
In response to C10 Sleeper
When I had a cracked intake manifold on my 88 454 V8, I fixed it by buying a new one from the local Chevy dealership.
"The most precious jewels you'll ever have around your neck are the arms of your children."
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