Technical > Matt Shaff's Engine Shop
Teardown surprise
janjon:
To be clear, the motor has punched the car down the track a bunch of times before I removed it from the car, so I'm not worried about p-v clearance at all, just sort of perplexed that someone would take the flat-top and-whack-the-xxxx-out-of-the-head-deck approach to build compression. Possible theories about combustion propagation impeded by large domes? Possibly the engine builder giving the customer the desired compression ratio with the parts supplied? Not that I know what the compression ratio is either. Not that I don't know how to determine it either. But I'm too lazy to do that.
JrFuel Hayden:
JanJon, your heads may not have "been-whacked-to xxxx" to get compression. My JF SBC heads have not been milled, and my intake valve stick out from the edge of the deck surface of the heads.
When I have time, I'm getting our dragster ready for the March Meet, I'll take some pictures of my current heads and post them here.
In the meantime, here is a picture of one on my busted heads, when the trans shifted into neutral instead of high gear and the motor went to 12,500 rpm. Just look at the good combustion camber , not the busted one. If someone milled the xxxx off you heads you would have alignment issues, with head bolts, intake manifold etc. Bottom line no matter how much energy you have, a good race motor has higher compression than your "back-n-forth " work car. And even higher compression if you are burning alky. You'll be surprised how much higher compression will "wake up your motor !" 10 Custom made [ with mold] Pistons , rings, pins cost me $1200, I think off- the- shelf high compression pistons will be allot less. Our current pistons are from CP.
I hope this helps,
Jon
Pipe Dreams:
--- Quote from: JrFuel Hayden on February 26, 2015, 11:09:34 PM ---JanJon, your heads may not have "been-whacked-to xxxx" to get compression. My JF SBC heads have not been milled, and my intake valve stick out from the edge of the deck surface of the heads.
When I have time, I'm getting our dragster ready for the March Meet, I'll take some pictures of my current heads and post them here.
In the meantime, here is a picture of one on my busted heads, when the trans shifted into neutral instead of high gear and the motor went to 12,500 rpm. Just look at the good combustion camber , not the busted one. If someone milled the xxxx off you heads you would have alignment issues, with head bolts, intake manifold etc. Bottom line no matter how much energy you have, a good race motor has higher compression than your "back-n-forth " work car. And even higher compression if you are burning alky. You'll be surprised how much higher compression will "wake up your motor !" 10 Custom made [ with mold] Pistons , rings, pins cost me $1200, I think off- the- shelf high compression pistons will be allot less. Our current pistons are from CP.
I hope this helps,
Jon
--- End quote ---
OUCH!!!!
GlennLever:
X2^
JrFuel Hayden:
That's right, it's not fixable, but my head guy can weld-up and fix damaged iron heads, but not that bad !
Bob McKray Performance, the engine builder & tuner on the JrFuel car Don Enriquez has driven for the last 20 ? years, including the last 3 years of NHRA Heritage JrFuel Championships, 949-458-7087 [ SoCal]. If you send him your SBC iron heads he can port them just like his for $1500 pr.
Included is our 2014 March Meet winner's circle picture, BTW we won the 2013 MM too.
Jon
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