timing chain tension

Ronald Wendt

Registered User
When the cam and crank were put in my rebuild both would turn easily.

Now when we put the new timing chain set with the tensioner on, its a bear to turn them

Is this nomal? Could we have done something wrong?

thanks

hope everyone survives Thanksgiving with the family

Ron
 
Are you talking about when the engine was first rebuilt compared to after running and putting a few miles on it? Are the plugs in now and not the first time? Need more info as to what your comparing it to.
 
from what i gather he's got a block with just a cam and crank

he's saying it spins fine without the chain but it hard to spin with the chain?+

sounds like the chain might be too tight
 
When the cam and crank were put in my rebuild both would turn easily.

Now when we put the new timing chain set with the tensioner on, its a bear to turn them

Is this nomal? Could we have done something wrong?

thanks

hope everyone survives Thanksgiving with the family

Ron

Yes, something is definitely wrong! Most likely you are missing the spacer that goes up against the cheek on the cam, behind the woodruff key. Either that or maybe the thrust plate is galled or something. Is it an aftermarket cam grind? Take it apart and check everything, Unless you also have rocker arms installed, everything should take about 20ftlbs (but generally less) to rotate.
 
thanks as always, will check it out tomorrow. I sent the cam out to Comp for a regrind, sure thought we had everything but this project has gone on way too long so misplacing a part is a real possibility

take care

Ron
 
Could also be a cam bearing that's cocked in the bore. Sounds like something is binding to me. If everything is right it will turn over smooth as glass.
 
Here is a pic of the spacer that is on the cam. When pulling your cam you may think it is a machined surface of the cam as it can be stuck on there pretty good from age. You need to remove it and place it on any new cam.

The other picture is of the spacer that is between the cam gear and the thrust plate of the cam.

If you forget the first one, the cam will turn just fine with the thrust plate stuck on but will suddenly get very tight to turn when you tighten down the cam gear retaining bolt as the larger spacer presses onto the thrust plate too much.

I can vaguely recall a similar issue when I first put my motor together as I didn't notice it would come off the old cam.
 

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Here is a pic of the spacer that is on the cam. When pulling your cam you may think it is a machined surface of the cam as it can be stuck on there pretty good from age. You need to remove it and place it on any new cam.

The other picture is of the spacer that is between the cam gear and the thrust plate of the cam.

If you forget the first one, the cam will turn just fine with the thrust plate stuck on but will suddenly get very tight to turn when you tighten down the cam gear retaining bolt as the larger spacer presses onto the thrust plate too much.

I can vaguely recall a similar issue when I first put my motor together as I didn't notice it would come off the old cam.

When I missed mine, set the cam to Coy he sent it out and it came back without the key and spacer (my fault not his) It caused almost total destruction of the engine I built. I was able to salvage the everything but the crank. I had to clean up the face of the cam where the thrust plate would be and I reused it in my 92 SC.
 
ok so we checked to be sure the washer on the cam was there, it was, and there was no galling on the thrust plate. the cam and crank moved easily and smoothly with no timing chain on it.

For giggles when we put the chain set back on, we did not put the chain tensioner back on and now its fine. Is this normal?

To put the tensioner on it had to be bent back until the spring was bottomed out, man was it hard to get it over the chain.

This is a new Cloyes timing gear and chain set

Do I have to use the tensioner?

thanks

Ron
 
Yes, the tensioner will bottom out. But if you had problems with it binding then something was wrong. Did you oil the tensioner?
 
no we did not oil the tensioner.

With it on, its kind of hard to get the crank moving from a stop by grabbing a throw but once over that initial resistance it will move.

Without it it moves allot easier
 
no we did not oil the tensioner.

With it on, its kind of hard to get the crank moving from a stop by grabbing a throw but once over that initial resistance it will move.

Without it it moves allot easier

Oil would have helped. I would not run without the tensioner but you can if you want to.
 
Dave

so oil the tensioner, the chain or both? Does it sound normal that with the tensioner you need a little oomph to start the crank rotating?

The tensioner sure seems to put allot of pressure on the chain, it would seem that is allot of HP robbing friction. How necessary is it? My buddy who is helping me has built allot of small and big block Chevys and he says none of them use a tensioner. I could be wrong but I don't think there was a tensioner in the 460 I had built for my Galaxie.

Just curious, don't want to do anything wrong at this point
 
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