617 timing chain 12* to much? - Page 2 - PeachParts Mercedes-Benz Forum

JonL · #16 04-13-2009, 12:19 PM

Quote:

Originally Posted by leathermang

"But, I don't see why that method would be bad for determining if a timing chain was stretched.."

Are you German ? Have you spent millions of dollars and a century of making automobiles ? It is for mere mortals that the makers of our automobiles wrote INSTRUCTION manuals.... Even with the manuals , since they were not written by a native English speaker , they are not easy to decipher.

I think you are being kind of tough on the guy. If his timing marks are as far out as he says after carefully checking (rotating the engine in the correct direction several times, etc.) then he can be 99.99% sure he needs a new chain. Reading the FSM (as well as any other reference materials) should not preclude reasonable independent thinking and common sense. I doubt anyone would write a FSM that included something like "the proper method for checking timing chain stretch is the following relatively involved procedure using a dial indicator. However, if you do a 'quick and dirty' check by lining up the marks and find you are really far off... don't bother with the dial indicator. Just change the chain, then check it with the dial indicator to see if you need to fine-tune it with offset keys." No, that would leave too much room for interpretation, and the factory doesn't want to take responsibility for someone's independent judgement. The OP, however, has this wonderful resource at Peachparts where he can get more experienced opinions to validate (or repudiate) his common sense thinking.

jt20 · #17 04-13-2009, 03:45 PM

Mr.L,

In support of your wonderful analysis, I believe The Star magazine wrote an article on determining chain wear for the 60x engines using this exact method; although in the engine manuals it clearly outlines the valve lift method as the appropriate means.

jt20 · #18 04-13-2009, 03:47 PM

chain wear check PDF

leathermang · #19 04-13-2009, 06:21 PM

Quote:

Originally Posted by JonL

I think you are being kind of tough on the guy. If his timing marks are as far out as he says after carefully checking (rotating the engine in the correct direction several times, etc.) then he can be 99.99% sure he needs a new chain. Reading the FSM (as well as any other reference materials) should not preclude reasonable independent thinking and common sense. I doubt anyone would write a FSM that included something like "the proper method for checking timing chain stretch is the following relatively involved procedure using a dial indicator. However, if you do a 'quick and dirty' check by lining up the marks and find you are really far off... don't bother with the dial indicator. Just change the chain, then check it with the dial indicator to see if you need to fine-tune it with offset keys." No, that would leave too much room for interpretation, and the factory doesn't want to take responsibility for someone's independent judgement. The OP, however, has this wonderful resource at Peachparts where he can get more experienced opinions to validate (or repudiate) his common sense thinking.

I probably was tough on him...
What is at stake potentially if he does not listen and follow the proper instructions..? Lots of unnecessary money spent fixing his engine...

Already a page was quoted where the wording left the impression that one method was simply more accurate than the other one.. as compared to the situation where MB SPECIFIES the one method be used..

and you are totally correct with your statement about him being able to find that he needs a new chain....that only requires a ' past go' situation....

But if you read closely you will see he was down to considering using the method NOT specified in conjunction with an OFFSET woodruff key. That potentially could cause him some big money.

JonL · #20 04-13-2009, 07:18 PM

Well, I think if he wasn't going to listen to everyone who answered his post telling him he needs a chain and not to try an offset key, he probably wouldn't listen to his dial indicator either!

I think in total he got the information he needs, certainly your post was the most "forceful" in showing him the way.

Doktor Bert · #21 04-13-2009, 07:23 PM

Even with new gears and chain, I have always found it necessary, in almost every case, to use an offset key to get things right where I wanted them to be. As previously mentioned, the marks are just a quick reference point...Robert

leathermang · #22 04-13-2009, 07:25 PM

Quote:

Originally Posted by JonL

Well, I think if he wasn't going to listen to everyone who answered his post telling him he needs a chain and not to try an offset key, he probably wouldn't listen to his dial indicator either!
I think in total he got the information he needs, certainly your post was the most "forceful" in showing him the way.

No matter what HE decides... others viewing this thread in the future will know there is a question to investigate... and potentially dramatic ( valves against the top of the piston ) results if wrong decisions are made...some things are not OK just getting ' pretty close'....

JonL · #23 04-13-2009, 08:21 PM

Quote:

Originally Posted by leathermang

No matter what HE decides... others viewing this thread in the future will know there is a question to investigate... and potentially dramatic ( valves against the top of the piston ) results if wrong decisions are made...some things are not OK just getting ' pretty close'....

Agreed!

BenzDiesel · #24 04-13-2009, 11:13 PM

Quote:

Originally Posted by rummur

Hey ive got this 617 engine but it smokes badly and has a ruff idle. I read some articles on smokey engines and decided to check the timing..

I lined up the marks on the cam sprocket and the cam tower..

Then checked the crank pulley and found it to be at 12*

I read that 2* was good for an engine at 200K Im assuming that 12 is bad.. Is there a way to adjust the timing 12* or do I have to get a timing chain?

And is the 12* from the chain stretching or from the guides wearing?

I would set my crank to 0 (zero) and then get all of the other marks to match from the crank zero.

BenzDiesel

rummur · #25 04-14-2009, 02:13 AM

Hey, I appreciate the concern fellas.. won't use a woodruff key.

Why would it be off a tooth? I dont know the history of this engine. The previous owner could have put one on wrong I guess.. The chain doesn't have a master link, so I would think its the original.

rummur · #26 04-14-2009, 02:17 AM

what is the easiest way to get the IP timed? Is there pin or somthing? Or only with the drip tube?

your saying put the crank on 0, and get the valve to 2mm, then put the chain on.

leathermang · #27 04-14-2009, 08:25 AM

Rummer,
You really need to get some literature to follow for some of these important procedures....
A forum is not a sure enough thing to keep you and your engine safe. I have complained for years that few if any Safety warnings get posted... much less the Warnings about mechanical procedures... they are ALL over the literature... but one reading and doing JUST from the forum instructions often do not get to see very important information...
The literature by itself is not very good for understanding the big picture... thus being able to ask the forum members ( DO a search on the subject first because many of your questions will have been chewed on for years and the best mechanics had a chance to argue the fine points ) for clarification fills in the gap hopefully.
There are HUGE threads and Great Pictures concerning putting on a new chain.. in the archives... but also,Roy Hunter has a DIY section where is has gathered up many of the best according to subject matter.
On setting the IP timing... the only method specified by the FSM if you do not have the expensive electronic tool is the drip method. All of these things are in the archives with great pictures.... all available with a simple search..
IF you are correct that it has no master link then the suggestion it was a tooth off is much less likely.... some of our oldest and best mechanics have wound up a tooth off when rolling in a new chain.. we have tried to figure out why... it puts things 18 degrees off in many instances.... If you follow the FSM instructions you should not have that problem...
I find that having BOTH the Haynes manual and the MB FSM are very helpful .. the pictures and less than great English grammar adds up.... studying them, then asking questions they leave unclear should do a good , safe, money saving job for you.
We have lots and lots of opinions... with enough reading you will get good at seeing the chaff mixed in with the wheat.

81300sd · #28 04-14-2009, 08:37 AM

1 tooth off equals 18 degrees so I doubt its off a tooth.

dannym · #29 04-14-2009, 08:40 AM

Quote:

Originally Posted by JonL

I think you are being kind of tough on the guy. If his timing marks are as far out as he says after carefully checking (rotating the engine in the correct direction several times, etc.) then he can be 99.99% sure he needs a new chain. Reading the FSM (as well as any other reference materials) should not preclude reasonable independent thinking and common sense. I doubt anyone would write a FSM that included something like "the proper method for checking timing chain stretch is the following relatively involved procedure using a dial indicator. However, if you do a 'quick and dirty' check by lining up the marks and find you are really far off... don't bother with the dial indicator. Just change the chain, then check it with the dial indicator to see if you need to fine-tune it with offset keys." No, that would leave too much room for interpretation, and the factory doesn't want to take responsibility for someone's independent judgement. The OP, however, has this wonderful resource at Peachparts where he can get more experienced opinions to validate (or repudiate) his common sense thinking.

Common sense should always prevail!
Beagle said it best:

Quote:

To put this into perspective it should be remembered that these FSM’s were compiled and translated from German (by girls who would struggle to change a wheel ) into about 30 languages in the early 70’s before these cars even hit the road. Ambiguities, contradictions and mis-translations abound and they should never prevail over sound engineering workshop practices and informed common sense. Countless Tech. Bulletins were issued over the years as problems arose but the FSM’s were never updated. They are none-the-less a useful guide for a DIYer.

Maybe if rummur posted better pictures we could make better judgement on the method he used. From what little I can see I think he went too far, which would make his reading higher than it is.

Danny

winmutt · #30 04-14-2009, 11:10 AM

Once again this is a measure of cam timing not absolute chain stretch. I would *not* replace the chain, woodruff key is fairly easy and much less likely to fail. You *must* use the 2mm lift method to get an accurate reading.