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#16
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No, the OM602/603 engine manuals also specify a dial indicator method. However the cam tower marks are fine for a ballpark measurement. You need to do it about 4-5 times and average the results. I did it both ways - dial gauge and cam marks - and the numbers were within 0.5 degrees (my chain is stretched 4 degrees, have new chain, waiting for crimp tool to arrive!). I'd say that if the cam is worn, it should be replaced - not adjusted for - as the valve lift will be too low. So far I've never heard of an OM60x camshaft wearing the lobes, they are built pretty beefy!
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#17
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Thanks, Dave.
I'll update the slide on my DIY pictorial. |
#18
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"If that is a valid procedure for the OM60x motors, why does it not apply to the earlier OM616/7 which, I keep reading on this forum, require the use of a dial indicator?
Could it be that the dial indicator approach, which I understand allows for cam/follower wear, is obsolete, mistaking precision for accuracy?"--Thomaspin Here is what I would describe as the reason to use the dial indicator method... It specifies a Performance objective the engineers decided was important... it takes the movement of the intake valve a certain distance as something which should happen in a certain relationship to the rotation of the crankshaft. All sorts of things wear in this equation... some may offset the wear in others, some aggravate them... this takes the bottom line and checks to see if the items are getting the primary jobs done at the right time..... |
#19
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hotskillet
These guys are right about about the dial indicator being the most accurate method to check chain stretch and for sure you want check for a woodruff key. the mark on the cam method is a quick and dirty check to be done when you adjust valves. It will give you a good idea where you are. Steve |
#20
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For some reason it seems people have the impression that dial indicator test = hard job...
It is a ten minute job once you have done it once... and considering just how important it is to have the valves and timing correct that seems very reasonable.... |
#21
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Greg
It may be an easy job if you have a dial indicator and the holder gizmo but if you come up with, say 2 or 3 degrees of stretch via the cam notch method what would be the point of getting any closer than that. The dial indicator is not going to show ALLOT more or less or am I missing something. Steve |
#22
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Gentlemen,
After reading all of your responses, I picked up a dial indicator at Harbor Freight ($14). The only problem is that this intrument reads in inches! Does anyone have the specs in inches or a conversion table I can use?
Thanks for the great info. |
#23
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Steve, I think you are assuming something that may not be true.... I believe that the dial indicator measures things in addition to the chain elongation.. therefor is the proper way to see if your valves are acting at the proper time in relation to the crank....
It puts ALL the criteria which are necessary to get the valves open at the right time under Cumulative Test.... which the cam mark/crank mark check does not. Anyway, the Mercedes Benz Factory Shop Manual says to use the dial indicator test if ANY PERFORMANCE Complaint is extant. |
#24
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Hotskillet, You will enjoy your new tool on many projects, not just checking your chain elongation. If you do another search on this site try using ' elongation' with ' chain'.....
These days it is very easy to get answers by just trying a Google.com search.... For instance , I just typed in " inches to metric convert" and got this list... take your choice... http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=inches+to+metric+convert&btnG=Google+Search |
#25
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Greg....Ya that makes sense, with the dial indicator you are seeing what is actually going on. I remember a thread not to long ago explaining the way to set things up. I need to get one of those good "holders" with the magnetic base and the segmented "neck" for my dial indicator, Maybe Harbor freight.
hotskillet...What kind of holder did you get? Steve Last edited by Stevo; 07-29-2003 at 09:39 AM. |
#26
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Steve, That locking adjustable neck for holding the Dial Indicator is the cat's meow... that is what TCane had when he showed TxBill and I how to do it.
However, it is not absolutely necessary to do the job. If one builds a small bridge over the cam then it is possible to just use the normal magnetic base and the indicator. It is also very helpful to buy an extension for the indicator shaft. I bought a 2 inch one in order to get the indicator as much in line with the valve and above the cam. |
#27
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"That locking adjustable neck for holding the Dial Indicator is the cat's meow... "
Greg.....glad you know what I was talking about as I was,nt sure I had described it right. I borrowed one from Aley too check end play in the crank and It did work slick, gota find where to get one. he said it wasn't very expensive. Steve |
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