Im a Zero..... well sorta (chain stretch) - PeachParts Mercedes-Benz Forum

coachgeo · #1 04-07-2004, 11:54 AM

Doing a quck view of my timing chain stretch via the line up the marks method.

The knife blade is on zero. NO not the mark prior to zero but dead center on the actual "0" stamped on the pully.

There appears to be a line mark that is just to one side of the zero and before the pin. I'm guessing this is the actual zero mark. If Im understanding that correct, then I have approx. 1 degree of chain stretch?

here is what I have the "i" is line stamped into the pully. The "v" is where my knife blade sits, and the "p" is where the pin is. "10" and "0" are also stamped into the pully

.......v........
1i0 i 0i p

ok.... lets see if this word pic gets chopped up by this forum

Again...... is this about 1 degree of chain stretch?

Rick Miley · #2 04-07-2004, 03:33 PM

Please see the post by stevebfl at the end of this thread: click

My interpretation of Steve's post is that the marks at the cam are not precision marks. So you cannot use them to judge chain wear.

coachgeo · #3 04-07-2004, 05:54 PM

Quote:

Originally posted by Rick Miley
Please see the post by stevebfl at the end of this thread: click

My interpretation of Steve's post is that the marks at the cam are not precision marks. So you cannot use them to judge chain wear.

I read it before posting my question. I should word my question better.

Does the marks as they show in my case dictate that further investigation w/dial indicator etc. is neccissary? Orrrr does it seem to show that the estimation I got; using the Mark Method, is in a range that says no further digging into it is really neccissary?

#4 04-07-2004, 07:17 PM

I would repeat the steps at least 4 times to get a good range of what it can be. I got 2-3-1-2 when I aligned the marks after installing the offset woodruff key in the cam.

coachgeo · #5 04-07-2004, 09:43 PM

Quote:

Originally posted by 82-300td
I would repeat the steps at least 4 times to get a good range of what it can be. I got 2-3-1-2 when I aligned the marks after installing the offset woodruff key in the cam.

hmmmmm... but does even that range of numbers tell you that a more true measure should be taken. I'm thinking no? If the avg. was 3 then Yeah.

Rick Miley · #6 04-08-2004, 09:16 AM

Quote:

Originally posted by coachgeo
Does the marks as they show in my case dictate that further investigation w/dial indicator etc. is neccissary?

Leathermang and I had a discussion about this offline, as he in favor of doing it the factory manual (dial indicator) way only. I initially took your position, that if your marks are close enough then you're fine. But if the marks are more then a couple degrees, you should investigate further.

The manual says to use the dial indicator method, and makes no mention of the "line up the marks" method, so we don't have a concrete reason of why lining up the marks doesn't work. So no positive proof against it leads us to believe that lining up the marks works fine. However, I have a different opinion after reading Steve's comments in the thread linked above. As I said above, the marks at the cam are apparently not precision marks, so you really can't make any judgement, either good or bad, from them.

I think Marshall Booth and gsxr have both written about this in the past, so it should would be nice if they would weigh in here.

stevebfl · #7 04-08-2004, 12:45 PM

This thread was pointed out to me and I am sitting for the moment digging info for two shop problems.

I didn't go to the link so I don't know exactly what I said, but in this context I will give my impression. I will usually at this stage of my experience not worry about cam timing unless the chain has over 100k on it. In my position now I am more likely to put in a new chain than to measure. I believe the mark at the camstand is sufficient to decide how to place the gear on the chain and that is all.

Dial indication would be the only means of effectively measuring stretch. Since a large part of the loss of timing also comes from the gears which are likely to not to be changed, the only way to deal with it is to measure and correct with offset keys or replace the chain and ignor the last few degrees. It has been a long time but I am under the impression that a motor with miles and a new chain will be anywhere from 4-7 degrees retarded due to other worn parts (gears and tentioning rails)