grb

Evidently there are very few who can do it right or even at all. I though Katech could do it. They can't. Schwartz, who built the C5R heads and block suggests someone in Michigan.
Why is it so difficult to prep these combustion chambers? Are the small ones, 30-38cc, the big problem?

Anybody got a good picture of a C5R chamber before and after?

raymond mckinney

iTrader: (4)

Try HKE.

grb

Are they a sponsor?

grb

Who is HKE?

SmokedOutZ28

iTrader: (35)

Send this guy 99blancoss a pm He deals directly with HKE

Robin L

Here is our develoment head.

Right was by hand and the left was CNC from the digitized develoment chamber.

This was the design used on our first 454 LSX that mad 930.

Robin

grb

The right CC appears to be much smoother. What effect on performance would leaving the CC a little rougher, as in the left picture, have had. A lot, a little or none?

grb

Anybody got a clue here? The right side looks rough.

ringram

Yeah cnc will do that. Im sure you can hand finish it if you wanted.

Robin L

Damn I forgot about this thread LOL

Maybe I wasn't clear in my earlier post. The hand finished chamber is the development chamber. It as well as the port are hand ported. After a final version is complete it is digitized. That is what starts out as the program for the 5 Axis CNC.

There is sometimes work done by hand after the CNC. It depends on the design. Most of the CNC heads on the market are not hand finished or tweaked. They are good to go out of the box.

I wanted to make another point, if there is anyone that knows the C5R chamber it would be Katech. Remember they are working on 347 cubic inch Road Race engines. That is a long way from a 454 Cubic inch Nitrous Drag race engine.

Robin

grb

I have some 090 heads and talked to Katech. They don't do any finishing. My combustion chambers are at 48cc now and from what I'm reading they need to be opened up and polished, at least to some degree. Right now the chambers are rough. I have gotten a PM from a guy who I think can do the work. I either want them to perform to the max or sell them. Why have an expensive head that doesn't make HP?

Robin L

What are you using the heads for? What type of engine. Don't believe 90% of what you read LOL.

If you have a large swept volume and you don't intend to run 18:1 compression ratio then you either need a larger chamber or a large dish in the piston. That dish will reduce the clerance at the small end if the rod.

If the cam has a ton of lift at the valve then the ring package will be tight with a large dish. If it has much stroke (4") then the rod length and compression height wil have to change.

All in all the C5R has limitations on large cubic inch engines due to its small chamber. The benifits of the cubic inches starts to diminish when you can have a reliable package.

I would have to have Don West look at our old cut up devlopment heads to see if there is enough to open them up a bunch.
The GMPP LSX Heads should be out any day now. Might want to look at those.

Robin

grb

Looking for 11:1 NA or around 8.5 SC. GM says they have a lot of extra material in the CC to accommodate serious porting. Probably end up going SC 427.