617 performance cams
 

Delivery valve posted this in the regular forum:
At the beginning of this year I got in contact with Geoff Bardal at Colt Cams in Aldergrove, British Columbia Canada. I was led to his company through the Volkswagen TDI circle in which he makes a performance TDI profile that people have had good reviews on. He also has done thousands of profiles on various gas and diesel applications and has also done extensive work on the Cummins 5.9L diesel.

I called him to price out a profile for my own TDI. While on the phone, I asked him about a performance profile for the OM617.95x and said he has one that he did back in the 1990’s in which his customer was happy. He has not done one recently, but is experienced in the OM61x since has been to regrind or repaired several to factory specs.

After a little discussion of varying applications the 617 is being used in our circle, he thinks there is a lot of capacity to get more performance out of the 617 cam, even more so then his earlier profile.

He is very interested in the working with 617 folks to create custom grind for each custom use. He offered me for about $340 shipped, a custom grind that he will work with me to get it right, provided that I get him a cam to regrind. I think this a great idea but unfortunately for my engine, I still want to make other mods i.e. different turbo and IP mod.

However, I do think it is important to get some R&D in and if somebody who is further along then I am or is looking to improve on the stock setup, should contact him or even Delta and get a project going. The more profiles available, the better for all of us.


http://www.coltcams.com/


Colt Cams Inc.
2325 264th street
Aldergrove BC V4W 2L5
Canada


Phone: 604-856-3571
Fax: 604-856-3572


And im wondering where could someone get blanks--You gotta have more material for more lift-Not regrinding a used cam-You could only play with the ramps that way

I know in the old days of stroking engines they would use stock cranks and weld extra steel onto one side and then regrind the crank so that the stroke would be longer. I don't see why a custom cam shop could not do the same with a cam lobe.

You better jump on this.

In my opinion, the performance improvement from the camshaft grind alone will be marginal.

I posted this answer here in the original thread also.

http://www.peachparts.com/shopforum/diesel-discussion/290268-om617-non-turbo-cam-profile-specs-piston-height-specs-etc.html


A cam is basically a bump on a circle. When the follower is siding on the circle, it is at zero lift. As the cam rotates, the follower goes over the bump positive lift is created. When you regrind a used cam, you make the circle smaller so the bump would have a higher lift. The valves are then adjusted to take up the slack from making the circle smaller. But there is a cut off point to how much it can be adjusted and custom adjusters may have to be created.

Lift is just one aspect of a few aspects to consider in cam grinding, the art is to find the right amount to make the engine happy. Some other aspects to consider are lob separation, overlap, duration and lobe centerline.

Of course IF your engine calls for a much higher lift, then a blank cam maybe in order. But you have to remember with the higher the lift, it may also entail having a reliefs cut in the pistons from keeping the valves from hitting them.

You might want to talk to Geoff in person, he is very approachable and will talk to you through on what he can do with a used cam that's not worn.

I know they go hand in hand but im intrested in enhancing the torque mainly which is what i thought most everyone went by before i had any experience with the high speed automotive diesels- which is another animal from the norm.

MB got an extra 15hp from increasing the valve lift in 1980. I see no reason to believe adding more lift and/or duration wouldn't increase volumetric efficiency a little further, especially when used with increased injection quantities. Every little bit helps on a uniflow 2valve engine.

The yards here have plenty of used cams. How many do you need and what price are you willing to pay?

I'de rather start with a new --HARDENED blank. I wonder where metric's suppliers gets theirs??

I guess they don't have hardened blanks as that would be
1) more costly to machine
2) most hardening processes are surface processes which means you'd be removing the expensive treatment.

I think you might be better off getting a specification for the steel purity and finding out where they are cast... I know that Febi make cams but I don't know who actually makes them. I guess a custom cam shop would be a good place to start - though I guess they will be CNC boys rather than people who cast.

I thought it was mentioned here that all cams past 80 on US turbo models had hardened cams.

I have no doubt that that is true - all I'm saying is that it is unlikely that the blank is hardened before it is machined to shape. I think it is most likely that the hardening process used on something like a camshaft is a surface hardening process that is applied once the cam has been made to the desired shape / profile.

So asking people for a hardened blank might cause some confusion - that's all.

Hardness
 

Actually the cam is hardened before it is ground. Drop a cam it breaks real easy that is cause it is hardened and never annealed. Finding blanks might be hard to find. :D

Finally someone in the right direction......ok i have a Q for anyone who KNOWS and isnt guessing.

I have reason to believe the cams on late model euro sec NON turbo 617s have a high speed cam.

I was told by my mercedes mentor back before he died that the euros had a high speed cam.

I believe this for one reason only. If you take say a 1984 euro 300d and swap the long block (NOT IP) with a us spec not turbo long block it will not have the same off the line power. I say this because i have seen and felt it with my own eyes and body.

Brand new rebuilt us spec 81' 617 into an 84' euro 300D.....the stock euro motor with 300k+ had WAY more power and speed then the rebuilt perfect compression US spec 81 did even with the same euro M pump.

Engine purrs super smooth and NO blow by. Valves adjusted and all.

Only thing i never checked side by side was the cam numbers and profile.

What do you guys think?

Find out if you would please.