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Keith Black Hypereutectic's

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Keith Black recomends Polishing the combustion chambers and pistions! I have also sent them an e-mail asking this but they also recomend cutting a small "discontinuity" :? close to the intake valve seat to turbulate wet flow. They say forcing the wet flow over the sharp edge, fuel will re-enter the air stream and give the same effect as dimpling without losing the benefit of polishing. "BLP's OIL SPRAY SYSTEM" to cool the underside of the pistons also also looks interesting, 8) any of you ever try it and what are your thoughts? I'm sure some of you guys have built quench engines. 8) Thanks!
 
Polishing the combustion chamber is a great idea. Anything that is smooth with no sharp edges will reduce the chance of detonation. Carving a fuel throwing bump in an advantageous place won't hurt unless it disrupts intended air\fuel path. They get these ideas (and that's what they are) from engineers who develop EFI fuel injection , where the fuel doesn't get to take advantage of the long drop down the intake runner like a conventional carb fuel supply does. Keep in mind that every engine's airspeed will try to be around .62 of MACH at peak power. Every engine searches for this, unless goverened like a Briggs. It still searches for the 420 mph air, but obviously will never see it. Even a slower speeds, once the fuel leaves the plenumn on it way down the tube, it haulin ass. Even in a long runner situation, most charges are in the chamber by 3rd pulse max. The air/fuel never really stops, the sonic wave does. It just slows a bit and speeds back up. If I look like an illiterate, I may be, but my keyboard is junk and misses alot of letters when I mash em. I try to go back but sometimes miss.
 
The Winston Cup boy's copied that from the Cummings and various other diesels. I wouldn't recommend piston oiling for an airboat unless you are willing to spend thousands on a dry sump system because the volume of oil required to do piston cooling correctly can't be achieved with a stock oil pump design and still maintain enough volume for the rest of the motor. I use KB pistons allot I have been using them in airboat motors for 10 years now by far the biggest advantage they offer is how much you can tighten up the piston to head or quench tolerances because they run a tighter piston to wall clearance. This has happened in the past if you take one of my motors that was clearanced for an airboat and run it in a car and you miss a gear or over rev it all the pistons will hit the heads. You should run differant piston to head clearances in an airboat then you do in a race car. I push this clearnce to the max because the tighter you get that quench the more compression you can run without going into detonation and the more torque and horsepower you will make.
 
Thanks guys! The piston oiler drilling jigs are $475.00 US with jets anyways. Thanks for the info, I was wondering about the oil pump capabilities as far as keeping up! :? So with constant load I can run less than 0.040" quench? I was planning to run 0.0025" cyl to wall clearance and Zero deck with the 0.039" Felpro. Should I run a little Positive deck? I assume the Bump is just a shallow groove cut next to the valve seat? Thanks again guys! :lol:
 
I ran + .0035" on my Engine Masters Challenge engine with a .043" gasket and they just kept it all clean at 6500. I mean shiny clean. To be safe, we zero deck each engine and advise customers who buy parts to do the same. As long as you stay under .055 to .060" , you avoid the "dead zone" as we call it. You don't get out of it until around .120" piston to deck. I had looked at piston cooling, but we didn't have any room with a 180 degree screen that I managed to work in under the main bearing girdle.
 
Anyone here ever try the 1996 BBC Vortec heads on thier MkIV? Almost sounds to good. It would leave me with 10/1 with my flat tops. 8)
 
Edelbrock offers a 100 cc head that looks pretty good. I think that is how I will go when I build my 496
 
Reason I'm asking is one source said thy won't work, will leak antifreese into the lifter valey. Another couple said they work great and just need Fel Pro gasket #1017-1. Another thing was wondering if 10/1 is to much for a direct drive? everything would be polished with .030-040 deck clearance. Also have a set of "049's" on the line so just trying to make up my mind! :?
 
ALL I KNOW KB ! IS THE MAN ! HE MAKES THEM FOR ALL OF US ! HIM AND POTTER HELP DESIGN OUR CAD PISTONS REALLY WORKS WELL ! :shock:
 
OK, The L29's have a nice heart shaped combustion chamber with a good exhaust port and a fair intake from what I read. The valves are VERY shrouded and small but from what I read they should work pretty good for a DD. The 049's have bigger valves, better ports and the combustion chamber being 14 cc's bigger doesn't really bother me. The difference in C/R is 10/1 vs. 9/1. I have given up on the peanuts. :lol:
In your opinion what is the better choice for a direct drive? If Waterthunder is correct and I eventually end up with a gear drive, the 049's are a better bet. I would feel safer at 9/1 but I'm just asking your advise guys! :wink:
 
Man1 :evil: The guy said those 049's were 113 cc but mortec lists 121cc. That won't work! :cry:
 
My personal guide lines on a motor with a tight quench as in .040 or tighter. On a 14ft or smaller boat with iron heads I run 10.25:1 compression!! and with aluminum heads 11.25:1 compression!! However with a 15 or larger with iron heads run up to 9.5:1 and with aluminum heads run up to 10.5:1. Also if you run a belt drive or a ratio lower then 2.38 or a heavy boat I would run around another 1/4 point of compression less.
 
Do the guidelines change as far as Reduction/Direct Drive? I was planning 15' DD. Thanks a lot for the input! 8)
 
I had better not make a suggestion on a DD. If there is anything that needs cylinder pressure it's a DD and if there is anything that would burn a piston is a DD with cylinder pressure. I haven't built a DD motor in over 10 years so I had better not make any suggestions besides Buy a gearbox if you can because pushing a 15' with a DD is to much to ask unless you only run water!
 
I'm just recommending things I by no means am trying to insult anyone. It is just so much easier and more reliable and better performing to run a gearbox over a DD. The cost is more then worth it I have yet to meet somebody who said I wish I never switched to a gearbox.
 
It could still happen, I'm just concerned about some fuel consumption posts I have seen on the Alaska site. I think they quoted 5 to 18 GPH for a big block. Nebraska's boats performance would be OK with me. I don't think he quoted his fuel burn though. I do realise that properly set up you could probably cruise at the same rpm with a reduction with less throttle opening than a DD . Burning a piston would sure would be a kick in the hindsight but it seems there's enough successful direct drives out there, I'm thinking blower pistons would be a good bet for a DD, TOO LATE. Seems nobody wants to talk about fuel consumption.
What ratio are you recomending for a big block? 2.36/1 ?
REASONABLE Fuel consumption at cruise is what it would take to win me over. Everything else is WIN WIN with a reduction and I do realise you are going to pay for the performance benifits in fuel if you use them. I am just looking for some reasurance that If it is DD it will stay together with the build choices I make or I can cruise along with reasonable economy with a reduction. :?
 
I believe right now I’m putting more effort into improving fuel consumption then most anybody else. Ask Sniper or JL or other people I have convinced to run the 2.68 ratio with a wide blade. Sniper stated his fuel consumption was cut in half with an LS1 with a 2.68 gearbox. With a 2.68 you can swing more prop with less engine RPM’s think about it have you ever seen a three blade wide blade let alone a four blade or a ultra wide blade on a DD. A properly matched drive system on a gearbox combo will produce more thrust at the same RPM as a DD. A DD @1,500 RPM will not move across dry ground at 1,500 my boat will run across ground. I know people will say it’s hull but a DD on my boat will not move @ 1,500 RPM it could only swing 1/2 the prop at best!
 
Waterthunder":1u3z36lb said:
I'm just recommending things I by no means am trying to insult anyone. It is just so much easier and more reliable and better performing to run a gearbox over a DD. The cost is more then worth it I have yet to meet somebody who said I wish I never switched to a gearbox.
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I agree 100%

I wish I had the funds to have started with a gear box. For now I'll have to make my direct work, but rest assured, I will get a gear box in the future. Anyone who has the money, should start with a gear box.

For now, I am having a blast with my direct. One thing I can definitely say, I wish I would have built a boat years ago!
 
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