[DDBCretin]

I was re-torquing the cylinder head bolts on my truck yesterday and it started me wondering about shifting the cam timing. I've never fooled with cam timing in anything so I have no experience with this. I did some reading on the internet and the rule of thumb seems to be that retarding the valve timing by a small amount will shift the torque curve forward a bit and improve high end performance. This is at the cost of low end performance. Advancing it does the opposite. The torque shift is small in either case. Most of the stuff I read was for 350 sbc's, so I don't know how much of this applies to the M180.

I did a search of the forum, but didn't find anything. The closest was some speculation about grinding the cam shaft.

At the moment my plate is full in regards to tinkering with my engine. EFI tuning is going well. Engine starts and idles very well, but time constraints (as always) limit my progress. But I digress... I don't have any immediate plans to fool with the cam timing thing; I was just curious.

Has anyone tried this? Is there any risk of hitting a valve with a piston by retarding the cam by one tooth?

Thoughts on this?

 

[expeditionimports]

MB obviously thought cam timing was crucial as they have the offset keys for the timing chain sprocket based upon how much the cylinder head has been machined. The increments available are 2 degrees, 3, 4, and 5 degrees.

It is funny as we here from many people that have machined their heads and never correct for the cam timing....obviously based upon that it is not a huge issue, but it still sticks in the back of my mind that it was obviously important enough for MB to correct for it.

Cheers,

Scott

 

[ACAD_Cowboy]

But that also speaks to MB's fetishistic attention to application specific components. They offer the keys to correct the cam back to specification, specification for the unimog specific cam in the unimog specific M180, applicable after machining the head the specific allowable amounts.

With stand alone EFI it sounds to me like cam timing and a stand alone ignition would get you the most effective bang for the buck and allow you to run in nearly any condition.

Dyno software is not always the best indicator of real world performance but for modeling it may be beneficial. Cam specs I have, bore and stroke as well as value sizes I have but does anyone have any specifics on the combustion chamber CC?