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quickv6
10-08-2007, 04:17
Ok guys I am getting down to the final work here. I have cut .030 off these pistons. I am trying to figure the final CR. I am aSSuming the factory CR of 21.3. an .030 cut should put me at 18.6cr. another .010 should put me at 17.9cr. I do not want to cut it off the pistons unless I have no choice. I do not want to alter the Ricardo bowl anymore. What is the factory gasket thickness? What gaskets are available?
Robyn
10-08-2007, 06:32
Felpro makes a +.010 gasket thats used when the block is decked.
I have used these and they should be readily available at any parts house that sells or can get Felpro gaskets.

Good luck

Robyn
More Power
10-08-2007, 10:00
I'd recoat the piston crowns once you're finished. GM spec'ed them to be anodized, but ceramic would likely also work. A member did a crude test a few years ago with a blow torch on a factory 6.5TD piston and on a 6.2L piston, and found the 6.5 piston is quite a lot more heat tolerant. The 6.2 piston holed....

Jim
quickv6
10-08-2007, 20:19
Does anyone know what the factory CR of this engine is?
I read 21.3 or 22.1 19.5 now 20.2/18.0 WTF.

http://en.wikipedia.org/wiki/Detroit_Diesel_V8_engine#Specifications_2
quickv6
10-09-2007, 06:25
I guess I will need to cc this thing out. Where I might be now 21.3-18.6 20.3-17.6 19.5-16.9
Nobby
10-09-2007, 07:03
Try calling Heath Diesel they are very helpfull, Ian who works there increased the CR on his engine.

cheers
Nobby
More Power
10-09-2007, 08:46
Try calling Heath Diesel they are very helpfull, Ian who works there increased the CR on his engine.

cheers
Nobby

Let's see.... Peninsular Diesel pioneered efforts in lowering 6.5L CR to improve durability and allow for an increase in power. Raising CR would then do what? The GM factory 6.5L turbodiesel originally had 21.3:1 CR, which was lowered to 20.2:1 in 1999. Lowering CR allowed GM/AMG to uprate the engine power/tq rating. Raising CR would then do what?

Jim
Nobby
10-09-2007, 10:29
Let's see.... Peninsular Diesel pioneered efforts in lowering 6.5L CR to improve durability and allow for an increase in power. Raising CR would then do what? The GM factory 6.5L turbodiesel originally had 21.3:1 CR, which was lowered to 20.2:1 in 1999. Lowering CR allowed GM/AMG to uprate the engine power/tq rating. Raising CR would then do what?

Jim

You'd have to ask him that.
As I understand it he is running 22.5:1 on a fully built engine with Nitrous. I think he commented over on the Place that he did it to see what happens. He has a garage page on the Place with his complete buildup listed.

cheers
Nobby
More Power
10-09-2007, 12:29
He would have been challenged here... The laws of thermodynamics are immutable. Nitrous, you say.... :D

Jim
Nobby
10-09-2007, 12:42
http://www.dieselplace.com/forum/showthread.php?t=170483

If you are interested here is the thread where he discusses his higher CR and the Nitrous.

cheers
Nobby
quickv6
10-09-2007, 15:59
Let's see.... Peninsular Diesel pioneered efforts in lowering 6.5L CR to improve durability and allow for an increase in power. Raising CR would then do what? The GM factory 6.5L turbodiesel originally had 21.3:1 CR, which was lowered to 20.2:1 in 1999. Lowering CR allowed GM/AMG to uprate the engine power/tq rating. Raising CR would then do what?

Jim

My engine is a c159 in 1999 and is the enhanced. Would this be a 20.2cr engine?
More Power
10-09-2007, 19:58
My engine is a c159 in 1999 and is the enhanced. Would this be a 20.2cr engine?

Possibly.... GM produced a range of modifications for its 1999 model year 6.5 in anticipation of using it in the new (at the time) 1999 Silverado body style GMT-800 trucks. New for 1999 was the screw-on hub fan-clutch, relocated driver's side motor mount bosses on the block, metric transmission bellhousing bolts, 20.2:1 CR, 9-blade 21" composite cooling fan, uprated to 195 horsepower & 440 lb-ft torque (there was talk of going to 215 horsepower), as well as some programming changes. Now, where it gets murky is when GM pulled the plug on the 6.5 equipped GMT-800. Some of the engine mods were scrapped (i.e. 21" fan and power rating). AMGeneral's web site lists the 20.2:1 CR for the 6.5, so they continued with at least some of what GM had developed. What I'm not sure about is whether the 6.5 equipped 1999 & 2000 Classic Style GMT-400 body style trucks and Suburbans produced by GM got the full range of upgrades.

Some of the parts we built into our 6.5 Project engine were a part of the 1999 development. The fan, water pump, turbocharger, and a few other parts were a part of the prototype buildups GM used. I still have a low time DS4 that came off one of those '99 prototype engines.....

Jim