I'm in the "Run it" camp. Probably, a light buggy and mild driving habits will give many miles of smiles.
Shit at .080 over a SBC is lucky to have .060 wall. so If you have .200 you have more than enough. Worst case scenario just put some hard block filler in the bottom of the block, that is where they typically blow out and break.
Hombre, I have another very reasonably priced option for your pistons, contact Eric Henke @ Rebco Machine in Kansas, he makes a living lightening pistons for racers, and could certainly modify your pistons to lower your compression ratio. He has a website rebcomachine.com, you can see some of his work there. Also he is VERY reasonable on his pricing. I say mow em down to size, and run that motor as is with all of the good stuff! Hope this helps, I have personally had Eric modify at least a dozen sets of pistons for my super stocker and various other projects, his work is impeccable.
If I were in this situation I would take advantage of it. 12:1 ain't no fun, if you have to fill up at the airport, every time. I'd shoot for 10:1, which would also be easier on the cylinder walls.
Hey 55 Man I like that idea a lot. I tried the link you provided with no luck, could you get me any other contact info? Thanks man great idea...
Just be careful about overall piston crown thickness - these are cast pistons and not the strongest to begin with. As another mentioned, a different approach is to use thicker head gaskets - from Cometic. They are not cheap (at least twice what you'd pay for a 'regular' set, but good stuff). You can probably order them from Jegs.
Somebody please explain how "quench area" affects hemi combustion chambers please. I know the score on wedge head engines and that a thicker head gasket can and often does increase detonation because it reduces the quench effect. But I have no idea how or even if this applies on hemis
There is no quench on the older hemi designs. On some more 'modern hemi' designs, they have 'quench pads' on the sides (not a full hemi chamber) - so that is a different deal than these ole' 92 motors.
try the below link, the site seems to be down but this link will give you contact info. http://212.82.99.181/search/srpcach...U&icp=1&.intl=uk&sig=ESJZ6hiGxwGDQRMmE9NW.A--
Hombre, I meant to put the phone number in and forgot, Eric's contact number is 316-440-2828 and the proper site is www.rebco-machine.com I hope this helps. He will let you know if you are getting too thin on the lid of those pistons, he's got all the right tooling to do this.
I would suggest a hand blending after machining to whatever size / compression he can get you to, to eliminate all of the sharp edges. Its one of the things he does, he can also weight match them as well to help out the guy balancing the assembly.
100 Octane aviation fuel has 4 times the lead of super-unleaded. I run super-unleaded with 25% Avgas. I don't think there is an advantage in running 100% Avgas due to potential lead fouling, plus the mixture burns very slowly with all that lead. Aircraft engines rarely run over 2400 RPM.
I don't advocate running any avgas. I there is no safe Human lead exposure level. Also, airports here have 12" fences.
Use the CC's of the new heads and measure the CC's of the dome and find out what your actual static compression ratio is. you will need the cam spec to figure the dynamic compression ratio. Know what you have before you decide what to do. Just my 2 cents
Okay - after all the help you received . . . what did you decide to do? How did your quest turn out? Inquiring minds need to know! LOL
If you have a radical cam it will inhibit cylinder filling at low speeds which will reduce detonation. You may get away with 12:1 compression, if not you could add a water injection system. That kind of motor is not for the little old ladies, you need to know what you are doing which I think you do.
I must say I appreciate all of the recommendations and advice, and I mean that I really do appreciate you guys taking the time to comment and advise. Not hollow words at all. I am a lucky guy in the fact that I have 5 Hemi's. Now don't ask me how I acquired all of the damn things It was just after I bought that first one they just started showing up. I did find a little history on that .120 over motor that inquired about in this post. It was in fact a drag motor, guy ran it in a Gasser corvette of all things. It was injected then and a interesting question was answered by the Old Builder when I found him. There were a couple of things, funny things, when I got this motor apart. One was it does have a solid lifter roller cam, and adjustable Push Rods that is adjustable push rods on 12 of the liters. The other 4 had Adjustable Rockers, "picture above". The old guy I found that was on the pit crew for this gasser and built the motor all those years ago had an explanation for that. He said thy were at a Drag Meet in Texas and during a run tore up four lifters and bent the Push Rods. According to him there was another car there a Willys that had been eliminated and this guy furnished the adjustable rockers and the push rods from his motor so that they could continue. When the meet was over they guy that loaned them the parts had left and they never were able to return them to him. Cool what you find out sometimes. What I have decided to do is to go ahead and build one of the other motors I have ""For Now"" I just got it back from the machine shop and it cleaned up at .040 and I installed a set of Egge 10 to 1 pistons in that motor. The .120 over motor is going to run again, I have it almost built and it is now setting on my test stand. I will keep it for a spare for my Model A or maybe find another car to put it in. It will run again and soon will be going down the road in something. Thanks again guys for the advice and counsel.
Folks, I see that 73RR chimed in here. I want to say to all of you Hemi guys out there That 73RR ( Gary) is one hell of a nice guy and a real source for Hemi parts. He has some parts that if you are building a Hemi you need and that aren't readily known about or available. He has a jig for taping the crankshaft on the early Hemi that just makes that job very easy. He is also a source for Forged Pistons and at a great price. Most of all Gary is just a wealth of information, he has been kind enough to take my phone calls and listen will I just try and pick his brain. Great guy and if you hit a wall, as I did more than once, he is the guy who just may have a few answers for you. Thanks Gary!
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