do you take it out from the top or bottom?

__________________
1985 300D - 599,xxxk - blue interior #265 Monark Nozzle, AL129X, 15" Ronals, Gen II Big Brakes hunting
1985 300D - 491,xxxk - in prog-{A-A IC, 3" exhaust, psi\pyro, 28*BTDC, Hella Euros, IP Limiter removal
1985 300TD - 783,xxxk - parts car,used new engine with ALDA cap inplace
1987 Kenworth T-600 8LL 425 CAT Mech. - 6,000,000+k - DEI exhaust wrap, punched through resonators, 1 recent rebuild,

... tensioner rail?
on what? the Timing chain? book shows it going out the top. I would hate to think the pan had to be dropped to change it.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
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My drivers:
1987 190D 2.5Turbo
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1987 300TD
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im putting in a new chain, and a new rail, just looks like a PIA to get it out from the top

the upper oil pan wont come off unless u pull the engine right?

__________________
1985 300D - 599,xxxk - blue interior #265 Monark Nozzle, AL129X, 15" Ronals, Gen II Big Brakes hunting
1985 300D - 491,xxxk - in prog-{A-A IC, 3" exhaust, psi\pyro, 28*BTDC, Hella Euros, IP Limiter removal
1985 300TD - 783,xxxk - parts car,used new engine with ALDA cap inplace
1987 Kenworth T-600 8LL 425 CAT Mech. - 6,000,000+k - DEI exhaust wrap, punched through resonators, 1 recent rebuild,

LOL...
it will have to come off if you drop the chain ....LOL

Really, you need to get hold of some good books before you do this... there are many warnings and specific instructions in the manual which are necessary for you to have a good experience with this job....
Did you know that you need to keep CONSTANT pressure on the chain during this whole process ?
Do you have a replacement chain in there already or are you going to have to grind off some rivets ?
Have you removed your tensioner ?
Greg

Greg, I always thought this to be the situation, as well. But, several folks simply drop the chain into the abyss and fish it back out. It won't fall off the crankshaft or the IP timer. Surprising.........but true. All the efforts to keep the chain taut are largely superfluos. This is with the 617 engine.

LOL, But if they do that then you know they have failed to follow the instructions about keeping both tension on the chain and it in contact with all the available TEETH.... to keep everything in Synch....

It seem a bit risky to me as well, but, both Jim Ellington and Tim Freeh have done it without issues.

Ok,,, aside from the Factory Shop Manual telling people to do this... I am going to argue it on physics and design alone...

And remember that we have had some fine mechanics come up with their injection pump 18 degrees off after this procedure... ( or some exact one tooth misalignment)..

If you look at the route the chain takes..... it is in fact Serpentine.... goes over and under important stuff on the side that counts.... the drivers side... so if you let the tension go enough for the slack in the chain to allow movement away ( gravity does this part ) from the teeth.... then you have the potential for misalignment when you do pull it tight..

A couple of people getting lucky with it still being in alignment does not for me suggest that others on the forum should be advised to IGNORE the Factory Shop Manual instructions.. particularly when they coincide with MY expert experience with GRAVITY....LOL

What you are doing in keeping it tight...is replacing the function of the tensioner on the passenger side of the engine while you have to have it not functioning so you can replace the chain...
Greg

i have haynes but its dodnt say too much,

so leave the rail in when u roll the new chain in,

then keep tension on the chain, fish out the rail and put the new 1 in from the top

__________________
1985 300D - 599,xxxk - blue interior #265 Monark Nozzle, AL129X, 15" Ronals, Gen II Big Brakes hunting
1985 300D - 491,xxxk - in prog-{A-A IC, 3" exhaust, psi\pyro, 28*BTDC, Hella Euros, IP Limiter removal
1985 300TD - 783,xxxk - parts car,used new engine with ALDA cap inplace
1987 Kenworth T-600 8LL 425 CAT Mech. - 6,000,000+k - DEI exhaust wrap, punched through resonators, 1 recent rebuild,

It's rather interesting.

The FSM makes absolutely no mention of a requirement to maintain tension on the chain when the camshaft sprocket is removed. Section 05/330, step 11 simply states "Remove camshaft sprocket".

This is the 617.95 manual.

YMMV

Absolutely leave the rail in while rolling in a new chain but take the tensioner out. You may have to move the tensioner rail around a little because it can grab the chain at the cranks shaft end and prevent it from rolling in.

I've got alot of stuff going on so my memory is not what it could right now and I am trying to picture exactly what it is in my mind but there is something at the crank pulley that keeps the chain from being able to jump a tooth at the crank sprocket. You will see what I am talking about if you ever rebuild one of these engines. It is like a tab that is on the front crank bearing cap. Keeping this in mind there are guide rails between the ip sprocket and the crank sprocket that really won't let much chain settle down in that area (if you drop it down on that side). The spring loading on the vacuum pump can cause the ip to move a little to the low spot on the pump lobe as you roll the chain in but you can pull this back up towards the camshaft if it does this. I have put one together 1 tooth off at the camshaft but I feel pretty certain that I let the cam move a little. With this said I try my best to keep tension on BOTH sides of the chain - the one going in and coming out. I ALWAYS keep the chain securely tie-wrapped to the cam sprocket whenever I do one nowadays though. I do not remove the cam sprocket when rolling in a new chain. This is all talking about the 616 or 617 engines. I would follow the FSM if this is the first time you have done one.

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Jim

Now Brian, in the past you have taken exception to me repeatedly quoting the Factory Shop Manual... now you want to discuss the lack of that instruction in the manual instead of arguing the physics and design logic ?

Keep in mind that there is not just 'one' Factory Shop Manual... those messed up numbers instead of page numbers and repeats of entire sections show they were just compiling and adding changes and updates...

I can find in mine what you note is missing in yours.... but since you did not accept in the past my references to the manual.... can you see from looking at the design of the gears, the function of the tensioner...and its location... and claim that tension is not needed to maintain the specific number of chain links between the important items on the driver's side of the engine...given the potential effects of gravity at a time that tension is not maintained ? No shop manual... just the logic or lack of it with regards to the design of the engine....yea or nay... ?
LOL

Amen....
Jim, you were one of the people I had in mind when I mentioned this...

There is a tool shown in the manual which can be bolted to the head to keep the chain in contact with the cam sprocket... for the same purpose as your tie-wrapping...

Since when did I not accept past references to the manual?

While it's preferable to maintain tension on those sprockets to be absolutely safe that the chain won't loosen and jamb, others have simply dropped the chain without maintaining tension and survived the ordeal just fine.

Apparently, it's difficult to lose the chain off the crankshaft or IP sprockets.

The reason to discuss it is the fact that maintaining upward tension for the entire procedure is not the easiest task in the world. I did it when the head was replaced and it certainly created some interesting moments.

It's good to know that the chain will probably survive the ordeal just fine if upward tension is not maintained 100% of the time. However, you won't find me dropping the chain down the gallery any time soon to test the theory.

.........and, this was what I had in mind when I noted that the chain will survive just fine on the crankshaft and IP sprockets without tension.

Losing a tooth on the camshaft is easy to do without a painted mark or tie wraps.

The manual shows a painted white line across the chain and the sprocket. If this procedure is properly followed, there is no possibility of losing one tooth on the camshaft.