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  #1  
Old 11-15-2008, 04:55 PM
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cam gear woodruff key replacement questions

How do I loosen the cam sprocket bolt without cranking the engine backwards? I am afraid to proceed because it seems like a ccw turn on that bolt will turn the whole engine.

Also, there was no spring in my tensioner
The bolt/cap came off with nothing behind it. I have been noticing a trickle of thick black oil on my short coolant connector hose (actually degraded the one that came from PO, so I replaced it). Seems to be coming from the tensioner.

Would this (no spring) affect my measurement of chain stretch?

Should I just get a new spring or get the whole tensioner - I expect to have to replace the timing chain and all the other fun stuff in the next 1-3 years as I am using the 5* key to correct what I thought was 8* of stretch (but see previous question).

Thanks everyone

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Current Mercedes
1979 maple yellow 240D 4-speed


Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
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  #2  
Old 11-16-2008, 10:03 AM
ForcedInduction
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Originally Posted by zeke View Post
How do I loosen the cam sprocket bolt without cranking the engine backwards? I am afraid to proceed because it seems like a ccw turn on that bolt will turn the whole engine.
Brace it with a long screwdriver or bar.
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  #3  
Old 11-16-2008, 11:57 AM
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if you do not have a ratcheting tensioner it is very important that you replace the spring. If you do have one it isn't such an issue, but provides an essential 'initial setting'. The spring is cheap and serves a function in both cases - replace it! You will not need a new tensioner unless the piston does alot of wiggling in its housing.

You will need to remove the entire tensioner for this project, replace the gasket behind the tensioner.

You should read a few threads on chain life expectancy.

http://www.peachparts.com/shopforum/showthread.php3?t=75180
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  #4  
Old 11-22-2008, 05:02 PM
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How do I remove the woodruff key???

Ok, I have the tensioner out, and the cam gear forward enough to reveal the front of the woodruff key, but I can't get the key out.

I tried using needlenosed pliers, but they slipped off. Also, there is a washer behind the cam gear that seems to also have a slot for the woodruff key. Do I need to get the cam gear forward enough to get the washer in front of it too?


Thanks!!!!
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cam gear woodruff key replacement questions-img_0606.jpg  
__________________

Current Mercedes
1979 maple yellow 240D 4-speed


Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT
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  #5  
Old 11-22-2008, 05:06 PM
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try pushing one end down so that the other end is forced up (think fulcrum) the hidden edge is a semicircle.
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  #6  
Old 11-22-2008, 05:18 PM
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also, Does the cam sprocket washer conceal part of the key? You may have to remove the cam and washer completely to ensure that you put the new key in properly.
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  #7  
Old 11-22-2008, 05:22 PM
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Stuff some clean Rags around the openings below to keep things like the Woodruff Key from falling down into Timing Chain Tunnel. Remember to remove the Rags when finished.
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  #8  
Old 11-22-2008, 08:10 PM
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Thanks everyone! jt20 that did the trick, and I got the new one in by making sure the washer was turned so that the key fit in the solt then leveraged it back in the opposite direction.

There are a couple of places in the cycle where the chain kind of "jumps" as i turn it by hand. I can see the new tensioner working well, so I am not sure if this is due to looseness on the PS belt, or something else, but it is predictable - right before the hash mark is aligned with the mark on the tower to determine stretch.
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Current Mercedes
1979 maple yellow 240D 4-speed


Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT
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  #9  
Old 11-23-2008, 05:02 AM
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Quote:
Originally Posted by zeke View Post
There are a couple of places in the cycle where the chain kind of "jumps" as i turn it by hand. I can see the new tensioner working well, so I am not sure if this is due to looseness on the PS belt, or something else, but it is predictable - right before the hash mark is aligned with the mark on the tower to determine stretch.

What is the issue?

the chain is 'jumping' in relation to what?

are you turning the engine by the PS nut?

is there any slack in the chain?
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  #10  
Old 11-23-2008, 12:47 PM
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I am turning the engine by the PS bolt. There may be some slack in the chain, I can kind of wiggle the chain on the sprocket but I can't deflect the chain by pressing on it like I could a bicycle chain.

I was thinking that I might have installed the offset key upside down? Would that be really bad? I have only turned the engine over about a dozen time by hand since installing the new key - it's all still apat so I could go back in and turn it around pretty easily.

What I am trying to describe is that as I turn the engine. the chain will move smoothly with my strok except in a couple of places where I will turn the engine, and the chain won't move for a split second, then it will jup forwad and catch back up with the stroke.
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Current Mercedes
1979 maple yellow 240D 4-speed


Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT
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  #11  
Old 11-23-2008, 12:51 PM
ForcedInduction
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I am turning the engine by the PS bolt.
Get a deep 27mm socket on the crank and turn it right.
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  #12  
Old 11-23-2008, 02:33 PM
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I am with Forced on that issue. ^^


there should not be any play in that system. Make certain your tensioner is doing what it needs to do.

The semicircular side of the key should have went into the groove on the camshaft nose.
It may be possible to have put it in uspide dow, but highly unlikely, the profile is too great, and we both know how tightly that sprocket fits over it.

Which side of the chain is it that you can not deflect?
the camshaft and the vac pump both put forces on the chain. It is deceiving, make sure your tensioner is truly tensioning before turning that engine!
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  #13  
Old 11-23-2008, 03:40 PM
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Are you sure the chain is jumping? Maybe you're sensing an overcenter bump as a piston crests on the compression stroke. Such would be the case right at TDC and you'd feel it every 90 cam degrees in a 616 or every 72 cam degrees in a 617.

Sixto
87 300D
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  #14  
Old 11-23-2008, 04:35 PM
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Ok, I got a 27mm deep socket. I'll go out and try that straight away.

The attached file is what I mean about upside down. The view is of the cam tower from the front of the engine. The semicircle is down in the groove, and there is an offset on the outside that fits into the notch on the cam gear. The key has an offset and it could force the gear to go either cw or ccw. I am afraid I forced the gear the wrong way.

How do I know if it is tensioning properly? I see the rail pop into place as I spin the engine.

sixto - point taken - I will look into that.
Attached Files
File Type: pdf woodfruff.pdf (10.3 KB, 482 views)
__________________

Current Mercedes
1979 maple yellow 240D 4-speed


Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT
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  #15  
Old 11-23-2008, 04:43 PM
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Location: Eastern TN
Posts: 20,834
The offset key is bi-directional - it offsets the cam sprocket plus or minus n-degrees. The key, pun intended, is to get it right. If you're compensating for chain stretch, you'll want to use configuration B in your diagram so the cam isn't waiting for the chain, as it were.

Sixto
87 300D

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