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Timing gear problems- broken tensioner?


Gavin

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Im in the middle of replacing an N47 head.

 

I have the chain over the gear, but I cant lift it enough to put it over the camshaft. It looks like the chain guides might have moved inwards somehow, since I cant see the crank gear if I look down between the chain and can on my P90 motor.

 

Is this common? Does it sound like a broken tensioner or has the chain maybe jumped a tooth on the bottom and become tangled? Or should I just pull harder?

 

Thanks.

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The chain tensioner will pop out if you let it. If that happens you have to pull the front cover to reset it. If you haven't let the tensioner fall out, then the most likely issue is the curved guide. You can loosen the top bolt on the guide with a long 10mm wrench and move it away to get more clearance for the chain. Regardless even with the guide out of the way it's always a bitch to get the stupid chain on, so you kinda have to fight it on there.

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Did you make a wooden shim and tap it down in there before you removed the cam sprocket? It should be a piece of wood about 5/8" x 1" x 7". When you tap it down in there, it keeps the tensioner from popping out. If you didn't use one, you need to pull the timing cover to be sure that the chain is positioned correctly on the crank sprocket.

 

You will probably have to re-time the engine depending on how it was oriented when you removed the cam sprocket. Remeber, you can bend valves by hand cranking an L6 if the head is on, but the timing chain isn't (I'm raising my right hand), so be careful. Even with flat top pistons. You may think it is just compression, but its not, its valve-piston interference.

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I found that the handle of a big screwdriver is the perfet size, plus can easily by maneuvered past the timing sprocket.

 

Hope I didnt let it pop out... I'll try loostening the top bolt.

 

Damn, was really trying to use the flat-rate approach.

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This is the worse spot to be in ...i was there on my frist motor build...

i pulled the wooden stick out and my friend was holding the cain tight ..well he didnt hold it tight and the tensioner pop out ... i tryed everything to make that thing go back in without any luck pretty much had to remove the front cover... had to payed for gaskets and front seal ..

man what a pain in the ass that was ...i feel your pain

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