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+--- Thread: 617 Cams (/showthread.php?tid=556)
617 Cams - Motorhead - 07-26-2009
I have been busy at work but have spent some time looking at the valve train of the 617, we can regrind the cam and shim the rockers to make the geometry correct. My next move is to pull the adjusters off and see how much adjustment we could get out of them, I can't see any other reason why a regrind on the cam won't work. I will pull the stock cam off my spare engine and take it over to my friends cam shop and put it on the Cam Doctor, that will tell me everything about the valve events.
As I have been looking into performance cams for diesels I have noticed that they respond very close to a gas engine, we just need to find the sweet spot for the 617.
RE: 617 Cams - ForcedInduction - 07-26-2009
I have been wanting to try a Miller-Cycle grind to get more air pushed into the cylinders by the turbo.
RE: 617 Cams - GREASY_BEAST - 07-27-2009
You could also make new adjusters that are the appropriate height if the existing ones don't work.. They are fairly simple parts to cut from hex stock or whatever.
RE: 617 Cams - Motorhead - 07-27-2009
I remember talking to Bruce Crower about his engine that runs a second stroke on steam created by the exhaust heat, I think the Miller-Cycle concept is cool and I do agree with the need of a supercharger for bottom end responce. Right now I will focus on getting the valve events characterized from the OEM spec to the responce of changes done on the dyno, I have a Vortec V-1 supercharger as a spare but I need a small (1.3-1.8L) roots or screw type for my testing. I would like to compound the boost from the supercharger to the turbo, I just may end up with alot of good looking junk.
RE: 617 Cams - GREASY_BEAST - 07-27-2009
Wow that must have been awesome to talk with him. His 6-stroke engine looks really cool, but I wonder about the problem of water in the lube oil. Closed crank case steam engines employ a centrifuge or similar mechanical method of extracting water from their lube oil, as well as lube oil from their steam (but that's not a problem for the 6-stroke unless you plan on re-condensing, which would probably be a bad idea) Also, I wonder how the power pulses vary between steam and gas (or diesel)... does the thing vibrate like crazy?
Anyway... Could you just use a VNT with a Miller Cycle valve train or do you need boost even at idle?
RE: 617 Cams - Motorhead - 07-27-2009
Now that I am thinking cam's I could not wait to take the cam to the cam shop so I just put a set of calipers to the cam and the valves and came up with the following, remember this is an average so not exact but it will give me #'s to dwell on.
Lobe lift .320" E / .310" I the rocker/follower ratio is 1.2:1 so valve lift is .384" E / .372" I , the cam base circle is 1.250" .
Does anyone have specs on a stock turbo cam and see how far of the junkyard measurement is, I would like to mount the engine to a stand and put a degree wheel on it to see where they parked the cam. This way I could use dial indicators on it and see all the valve events, I could even pull off a valve spring and install a low tension test spring to check piston to valve clearance. Then we will know how much cam we can use on stock pistons or if we need to fly-cut valve relieves, if Mercedes made 230 H.P. over 30 years ago then we should be able to match it today.
RE: 617 Cams - Motorhead - 07-28-2009
What I found out so far is that a slight increase in exhaust duration will lower the point the power comes on by a couple hundred RPM, an increase in intake duration will raise the power curve but add to total power. This sure shows me the importance of cylinder head porting and the long runner intake manifold (FINA), with a little cam work and all of the above we should be able to make some noticeable gains in the 617.
I also found out that with bigger diesel cams the practice of fly-cutting the pistons is alive and well, I would not want to take too much out of the piston and decrease C/R but looking at the specs of the C-111 at 17:1 I won't be concerned with a half point.
I can see I will be spending alot of time on the dyno at Westech swapping cams to find the sweet spot, hey who has any '81-'85 used cams?
Colt Cams - DeliveryValve - 02-10-2010
I got in contact with Geoff Bardal at Colt Cams in Aldergrove, British Columbia Canada. I was led to his company through the VW TDI circle in which I priced out a profile for my own TDI. He has done thousands of profiles on various applications and has also done extensive work on the Cummins 5.9L diesel.
While I got him 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 90’s in which his customer was happy. He has not done one recently, but is experienced in the OM61x since he has reground or repaired several to factory specs in the past.
After a little discussion of varying applications the 617 is being used in our circle, he thinks there is a lot of capability 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 my engine is still in a stock setup. It would be a while before I will install a VNT and do some manifold modifications. I think it would be waste of time and money if I profile the cam for the stock setup, so I think I will hold off.
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 and get this project going. The more profiles available, the better for all of us.
Just throwing it out there. If you do contact Geoff, tell him Richard from Bakersfield gave you the info. Hopefully I can get a discount off of this.
http://www.coltcams.com/
Colt Cams Inc.
2325 264th street
Aldergrove BC V4W 2L5
Canada
Phone: 604-856-3571
Fax: 604-856-3572
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RE: 617 Cams - btrapr - 02-10-2010
I am by NO MEANS an expert in this area! I found this on another website! it was posted by Doktor Bert who always very informative posts...but he has not been on the site in a long time! He said that always used the 05' cams from the 125hp 617 because of the longer valve openings--IF you can find the specs for it, it might be a good starting point...[b]Doktor Bert said-I prefer the lengthened valve timing of the later (617.951/952 125 HP) camshaft marked '05' and use it in all 617 engines I work with.[/b]
link to post
http://www.peachparts.com/shopforum/showthread.php?t=250069&page=6
**I would also recommend searching for cam information on thedieselplace they had several very knowledgeable DIESEL camshaft threads...and several formulas were mentioned...I remember there was a question about the MILLER design and they talked against it, but I can not remember why, I think something to do with 2 stroke vs. 4 stroke diesel engine I think!
Delta Camshafts in Washington do custom regrinding, etc...NOT sure about Mercedes though...They do cut cam tooling for people as well, if you access to a cam grinder...THEY did the 6.2/6.5 diesel cam studies for the military and have two grinds one N/A and one Turbo! The 6.2 camshaft which is a regrind is about $200 shipped or you cans end them yours...MAYBE they will work up a Mercedes if they do not already do it.
http://www.deltacam.com/
just my 2cents___________
RE: 617 Cams - DeliveryValve - 02-10-2010
(02-10-2010, 02:08 PM)btrapr .... He said that always used the 05' cams from the 125hp 617 because of the longer valve openings--IF you can find the specs for it, it might be a good starting point...[b]Doktor Bert said-I prefer the lengthened valve timing of the later (617.951/952 125 HP) camshaft marked '05' and use it in all 617 engines I work with.[/b] ....
According to the information dug up from the OM615, 616, 6177.91 FSM and OM617.95 FSM. Older 615/6 motors Camshaft code(s) 02 & 06 and all 617 N/A and 617.950 Camshaft code(s) 00 & 08 up to 1979 had a cam timing of- Intake opens 11.5* ATDC and closes 13.5* ABDC, exhaust opens 21* BBDC and closes 19* BTDC.
The later 616 Camshaft code 10 and turbo 617.951 and 952 Camshaft code 05 . Intake opens 9* ATDC and closes 15* ABDC, exhaust opens 27* BBDC and closes 16* BTDC.
My conversation with Geoff at Colt Cams is he will be playing with the lobe separation, lift and duration. I too am not an expert, but because of regrinding, it could be possible the earlier designed cam with wider lobe separation might be a better starting point.
This is where he is allowing me to send back the cam if it doesn’t work out and regrind it to where it works or I get my money back provided I send him back the cam. If I do proceed, I'll have more conversations with him as to what cam I should send over for a regrind.
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RE: 617 Cams - btrapr - 02-11-2010
DV
sounds great! Nice to know that you will be able to send it back, and make it right.
From what you posted here it sounds like the 616 already has a profile like the 125hp 617 cam________
The later 616 Camshaft code 10 and turbo 617.951 and 952 Camshaft code 05 . Intake opens 9* ATDC and closes 15* ABDC, exhaust opens 27* BBDC and closes 16* BTDC.
6.2L diesel
Delta dyno'd 6.2' N/A and turbo and they developed a 202 and 206 profile for that motor...The only difference between them is 4 degree of duration! Crane also did a re-grind but I do not remember the numbers...Basically Delta said that the turbo'd 6.2 preferred 4 degrees more on the dyno and the N/A peaked with 4 degrees less! they just have not released the dyno numbers to my knowledge...
I am very interested in seeing how it works out for you. My projects are going to take quite awhile! I would really like to try and build a solid motor with a little more hp/tq!