Upgraded Camshaft

[ThePIGSmith]

I was search this topic on this site and cam across this elderly posting:
http://www.thedieselpageforums.com/tdpforum/showthread.php?t=7349

This posting is locked, so nothing new can be posted.

I would like to know if anyone had this cam ground and if they tested it.
Does anyone know anything more about this?

[Robyn]

In looking over the valve to piston clearance on these engines, as Dr Lee Mentioned in that other thread, the Valve to piston clearance is very critical.

As the piston approaches TDC on the exhaust the valves have got to be scurrying to get the hell outta Dodge or get smacked by the piston.

The common place grinds for Gassers that holds the exhausts open a little longer to allow scavenging wont work here.

A little longer open on the intake might be helpful on these though.

The big issue is the clearance at TDC which is .035"-.040" between piston and the head.

On most gassers there is a fair amount of room in the chamber even when the piston is at TDC.

I am going to venture a guess that this is why there is a decided shortage of info on performance cams for these engines.

With the turbo the cam grind is not a real big issue. Just get the valve open and let the Huffer cram the air into the hole.

Probably a moot point with a Turboed engine. The N/A engines could benefit a little though from porting, pollishing and maybe some headers.

GM tried larger valves but as the heads started to crack between the valves they dropped the sizes back some.


Just some thoughts.

Missy

[EWC]

I have a Crane regrind , don't know if it's the same one as Dr Lee mentioned . I was only the second person to get it , the first person could not be located to even find out how the cam worked . They did say that this was going to be used in a boat . My engine is togeter , had the heads ported , gear drive , 4911 pump , banks turbo , etc . Not running yet so I can't give you any feedback .

[convert2diesel]

Jamie of Diesel Depot mentioned this cam once. Apparently the guy with the boat was getting 210HP at 2,800 RPMS running it NA. Interesting but as Robyn said, it's a none issue with a puffer.

Bill

[john8662]

They've had a camshaft on the books for the last 15 years that I've seen. Although the story is the same, no one's running one.

I've got a cam grind that I don't know who designed, but the Diesel Depot was reselling.

The story on the cam is that it was supposed to help on the top end. The trouble with it was that it made the engine hard to start, especially a low C/R engine. Well, upon running this cam verses a stock cam on Cam Doctor software and measuring tool we found out why. It's a sucky camshaft is all I can say. I never ran it in an engine, we just wanted to see what it could do. I was told to throw it as far away from any potential engine as possible.

Another member here, DieselDummy ran one and his impression was that all it did was make pushrods come out from underneath the rocker arms, too much of the base circle was removed in the "re-grind".

We're working on another camshaft from scratch for the 82 pickup in my signature. But because I'm a lasy ass I haven't pushed hard for this.

I'll get the specs from Crane on this cam we're talking about and relay that back to my speed shop machinist and see what he says. I don't know squat about what it takes to make a camshaft perform above and beyond a stocker, he does. If he likes the Crane one, count on me having one in the truck for next race season to test as the engine is already coming out this winter because it's been in there three years now with only (yeah only haha) three head gasket failures. I want to make some critical changes to it, stuff I should have done three years ago. I just didn't know the darn thing would stay together enough like it has to be worth modifying further.

[EWC]

John , mine is Crane regrind 01112 if that is the one you are talking about .