I checked my timing chain stretch yesterday by using the cam mark method. I had about five degrees of stretch. Well, I did some more reading and noticed people saying its not really an accurate method. I figured it was probably close enough but I thought, what the heck, I'll pick up a dial indicator at Harbor Freight and do it the right way. So I did. I've got 14 degrees of stretch!!!! I performed the test multiple times to make sure I was doing it right and came up with the same result each time. With 2mm of lift my crankshaft reads 25ATDC. I've got a 616 with a #10 cam code which should be 9 degrees ATDC with a new chain or 11 degrees ATDC with a used chain. 25 - 11 gives you 14 degrees of stretch. Yikes!


LET THIS BE A LESSON TO EVERYONE WHO USES THE CAM MARK METHOD. It is NOT always "close enough."

I'd be curious to know if other people have done it by both methods and had the same discrepancy I found.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

What is the part number? I should get around to doing this...

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Andrew

1989 Volvo 745- 202K

You can buy the tool at Harbor Freight - nothing special about it:

Dial indicator:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=33675

Magnetic base:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5646

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

The two methods cannot differ by 14 degrees.

There is an error of some type in the procedure that you are using for the valve lift method.

The chances of the chain having an elongation of 14 degrees are just about zero.

I concure. Your measurement is flawed in some way.
Possibilities are =
Taking reading from follower finger instead of valve spring retainer.....Worn valve gear...Worn cam....worn follower...or balance pulley position migrated.

Please explain the method you used.




.

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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

I would be curious if someone rolled a new chain in sometime and got the cam one tooth off. The degrees off sound about right. Also there is another way to get chain stretch but you will have to hunt the archives for it. You physically measure the link pin distance over a specified distance and calculate the findings. Probably have to borrow a micrometer to do it. New chain distance is a known refference. Just my two cents worth and perhaps wrong but worth checking perhaps.

This is the method I used:

http://www.peachparts.com/Wikka/OM617TimingChainStretch

Look here for pics I posted using the cam tower method. You'll see the indicator on the 4-5 degree mark:
Scuff marks on timing chain rollers

Like I said, I did the valve lift method about 5 times to make sure I was getting an accurate reading to include removing the tool and reinstalling it to make sure it was on right. I removed the valve lash, put the tool on top of the flat part that sits on top of the spring (valve keeper, I think its called) and then rotated the cam until I got 2mm of lift.

I don't know what I could have done wrong???

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Removing it means tightening it up so there is no lash (space for the feeler gauge). Perhaps that's the problem you are experiencing Scott.
Steve

Bingo. I loosened it. Aargh!!!!!!!!!!!!! I will check it again later this morning and post the results.

Thanks for everyone's help.

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

The new results are in. I checked it about 15 different times from various angles. It really is a challenge getting the indicator as straight as possible. The more of an angle its on, the more your reading will indicate "less" stretch. It looks like my previous error was most definitely the valve lash. I thought it meant to loosen it, not tighten it. I loosened up the retaining nut and then screwed the other nut up by hand until it was snug.

My new reading was 15 degrees ATDC. My 616 with #10 cam code should read 11 degrees ATDC with a used chain or 9 degrees ATDC with a new chain. I assume I should use the used chain measurement as my bench mark. Doing that, 15 - 11 = 4 degrees of chain stretch. Is that right, using the used chain figure? Or should I use the new chain figure which would give me 6 degrees (15 - 9) of stretch? Also, if I only have 4 degrees of stretch, then I probably don't need a new timing chain, or do I?

Anyway, I'm glad to report I don't have 14 degrees of chain stretch . I'm not very mechanically inclined so sometimes I make mistakes like that (valve lash). Thanks for all of the help from this forum. I would never be able to work on my car without this website.

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

That's more like it. The valve lift method results in a chain elongation of 4 degrees. The cam marks also confirmed a chain elongation of 4 degrees.

No need for a new chain. If the numbers bother you, you can purchase a 4 degree Woodruff key for the camshaft which will return the cam to spot on.

Just out of curiosity, where does the woodruff key go? Is it difficult to install?

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)