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Moe
Dodge Dakota
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3/10/2006
21:53:34
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 Subject: Cracked heads
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Message:
Is it a really bad problem when the heads crack between the valve seats? I've seen the cracks and they look almost like a scratch. What happens to the performance? I dont suppose you can still use a head that is only slightly cracked.
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ScojoDak
Dodge Dakota
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3/11/2006
00:17:54
| RE: Cracked heads
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Many of us have been running our Magnum motors with cracked seats and not even know it. It's just we dont find out about the cracks till we pull the heads off. The cracks are micro in size and dont hinder performance enough that you can measure and/or feel in the butt. Can they be fixed? Yes. By a good head shop. Would I put the heads back on knowing about the cracked seats? Not me! I'd have them fixed or replaced. But that's just me. There's an ebay seller that has HD heads that have a new seat mfg process that wont crack. The heads are like $450/$500 a pair or something like that. Anyway, there's lots of info out there on this issue.
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rnaz
GenIII
 
3/11/2006
08:50:05
| RE: Cracked heads
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Message:
It sounds to me like it's a good time to get those R/T heads! I had the same problem last year when I was building my 5.2L. I was bummed out until my wife ENCOURAGED me to get the R/T heads!! (She said "Won't it be better if you just get brand new ones?")
M1, CAI, Flowmaster 40 true duals, no cats
KRC 210x cam, headers, Mopar PCM, R/T heads, MSaine 2800 stall converter
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ScojoDak
Dodge Dakota
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3/11/2006
11:29:41
| RE: Cracked heads
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Message:
rnaz, *lol*
My response would be... "well, yes honey. Maybe I should replace those cracked, worn out, rusty, valve seat leakin, freeze plugs are rusted out, valve guides loose, wont flow worth a sh!t ports, gasket leakin, old cylinder heads."
You gotta love it when the wife says things like that.
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OBIO3
Dodge Dakota
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3/11/2006
14:44:59
| RE: Cracked heads
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Message:
He never said the valve seats were cracked. He said the crack is BETWEEN THE VALVES. Seats are replacable. Heads cracked between the valves as stated need replacing.
So many problems .... So little time
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ScojoDak
Dodge Dakota
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3/11/2006
16:03:27
| RE: Cracked heads
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Message:
ummm... ok
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ScojoDak
Dodge Dakota
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3/11/2006
16:10:23
| RE: Cracked heads
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Message:
Revised version
Many of us have been running our Magnum motors with cracks between the valve seats and not even know it. It's just we dont find out about the cracks till we pull the heads off. The cracks are micro in size and dont hinder performance enough that you can measure and/or feel in the butt. Can they be fixed? Yes. By a good head shop that has someone who knows how to weld cast iron. Would I put the heads back on knowing about the cracks between the seats? Not me! I'd have them fixed or replaced. But that's just me. There's an ebay seller that has HD heads that have a new mfg process that wont crack between the seats. The heads are like $450/$500 a pair or something like that. Anyway, there's lots of info out there on this issue.
Anyway............
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Moe
Dodge Dakota
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3/11/2006
16:43:46
| RE: Cracked heads
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Message:
I'm lookin at Hughes iron heads - assembled $990.00 (pair)- or the upgraded head with 2.02/1.62 and narrow stem racing valve - assembled 1195.00. Out flows the R/T head.
http://hughesengines.com/heads/hd_magnum_heads.asp
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OBIO3
Dodge Dakota
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3/11/2006
17:10:05
| RE: Cracked heads
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Message:
One more thing . You don't run all that long on cracked seats. The crack gets wider ever so slightly and first thing you know the seat pops out and WALLA.... There goes a bent valve plus a great chance of losing the piston. If your lucky enough, the engine will develope a miss at idle or rough idle and the owner is smart enough to get on it checking out what the problem is.
So many problems .... So little time
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.boB
Dodge Dakota
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3/11/2006
23:31:13
| RE: Cracked heads
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Message:
$1200 for worked iron heads. Not bad I guess. Add a good valve train and you're about $1600.
But how much is a set of alum Edelbrock hads and associated valve train stuff? I think the math comes out to about $2K, give or take. But according to Huges, "They are significantly better than any other Mopar head available."
Alum heads weigh less (but not enough to really matter in a truck). But you can run more compression and more ignition with alum than iron. Heat transfer is better.
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rnaz
GenIII
3/12/2006
08:59:00
| RE: Cracked heads
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Message:
LOL! Too funny ScojoDak!! I should've told her that I NEED a 408 shortblock to go with those new heads.
M1, CAI, Flowmaster 40 true duals, no cats
KRC 210x cam, headers, Mopar PCM, R/T heads, MSaine 2800 stall converter
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ScojoDak
Dodge Dakota
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3/12/2006
14:34:01
| RE: Cracked heads
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Message:
rnaz, shoulda, coulda, woulda. BTW, does your girl have a sister? j/k
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Moe
Dodge Dakota
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3/12/2006
19:30:03
| RE: Cracked heads
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Message:
Heads will be from hughes $1195.00 a pair assembled with the 2.02 race valves - I was going to get the roller rockers from summit ($195.00). And a head stud kit (117.00) from summit so I can put the new heads on and keep the gasket lined up easier. While I'm at it I'll get a cam from hughes too. $197.00 reground - not sure of the grind yet, I'll be talking to hughes about that. My wife saw the cracks and agreed I needed parts for the truck and ok'd $2500.00.
:o)
oh by the way - I just ported my intake manifold and I already have a supercharger and 4.10 gears. She ok'd that too.
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Shatto
Dodge Dakota
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3/17/2006
02:05:17
| RE: Cracked heads
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Message:
I replaced the heads on my 3.9 at 350,000 miles. because they were cracked.
Got factory heads. MOPAR quality control was so poor that my machine shop had to replane and re-seat all the valve guides.
The V6 valve seats are simply heat treated. No seat inserts.
My machinist also said it was common for new Cummins heads to have cracks. Fell within their specs. Go figure.
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