higher compression pistons
09-17-2010, 01:19 PM
#4
My 8.8:1 supertechs will end up being around 9.8:1 with all the head and block shaving that will be done. If you want higher than 11:1 just let your engine builder know that and they can adjust with deck height and head gasket thickness along with a few other things. Just because the pistons "says" it will be X compression dosen't mean your engine will be that compression when it's fully assembled.
You can also use the 10.6:1 an have some head work done to smooth out the combustion chamber and run a thicker head gasket like 1.2mm instead of the standard 1mm to make it around 10:1.
You can also use the 10.6:1 an have some head work done to smooth out the combustion chamber and run a thicker head gasket like 1.2mm instead of the standard 1mm to make it around 10:1.
Reply
0
0
09-17-2010, 01:28 PM
#5
I'm Miserable!
Thread Starter
Join Date: Jun 2009
Location: albany, ga
Posts: 1,866
Total Cats: 0
just figuring out what higher compression pistons are out there for the motor. Orginally was looking at dropping compression, now I may just try to find forged pistons at the same compression as stock or higher.
Reply
0
0
09-20-2010, 11:09 AM
#10
When we needed custom pistons for the vintage two-stroke SAAB rally car, Weisco had one set in stock from a previous run and sent them right out. Next time we needed some, it took about six weeks and I think they made around six sets (18 pistons).
Reply
0
0
09-20-2010, 11:15 AM
#11
Y8s knows not of what he speaks. There is no tool and die, just a forged billet of aluminum and a 5-6 axis cnc machine. You tell them what CR you want, and they make it. A week or two later you get it. Most of the manufacturers don't even carry stock, they just make large batches that other places stock, thus the illusion of a shelf piston.
Reply
0
0
09-20-2010, 11:17 AM
#12
I'm Miserable!
Thread Starter
Join Date: Jun 2009
Location: albany, ga
Posts: 1,866
Total Cats: 0
oh Im very much aware of this, I was just wondering if anyone knoew off the top of their head if there was some around 10:1. I have looked around but I hadn't seen any yet, still looking.
Reply
0
0
09-20-2010, 12:23 PM
#15
2 Props,3 Dildos,& 1 Cat
iTrader: (8)
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
Y8s knows not of what he speaks. There is no tool and die, just a forged billet of aluminum and a 5-6 axis cnc machine. You tell them what CR you want, and they make it. A week or two later you get it. Most of the manufacturers don't even carry stock, they just make large batches that other places stock, thus the illusion of a shelf piston.
They can vary the shape and size a little bit, but the bulk shape from which they start machining is pretty piston-like already. I've watched "how stuff works", I have seen the bideoz.
the goodness starts at about 1:20.
Reply
0
0
09-20-2010, 01:03 PM
#17
I had JE make my pistons in the CR I requested. Pretty close to the same price as an off the shelf. For my latest motor, they requested a mold of the combustion chamber. That will cost a little more, but it is not out of reach for Joe Shmo that wants something special.
Good piston manufacturers can make any bore, any pin location, any ring grove, and any combustion shape you desire.
And by the way, do not get to hung up on CR specs. Those numbers are estimates, and are affected by many variables like stroke, bore size, and valve timing.
The actual cylinder preasure I have when the engine is assembled, is what I would base on how I would force fed it.
Good piston manufacturers can make any bore, any pin location, any ring grove, and any combustion shape you desire.
And by the way, do not get to hung up on CR specs. Those numbers are estimates, and are affected by many variables like stroke, bore size, and valve timing.
The actual cylinder preasure I have when the engine is assembled, is what I would base on how I would force fed it.
Reply
0
0
