problem installing cam

TwoToneThunder

Registered User
we just installed a coy miller cam in my sc and once we tighten the spring tensioner down to the spec the engine becomes hard to turn over
with it un tourqed the motor turns over like butter but once it is tourqed it becomes harder to turn

i want to know from people who have put these motors back together how hard is it to turn over once its all together?
i can still turn it over with a 1/2" drive ratchet but its difficult
 
There is a spacer on the front of your stock cam that you need to take off and install on the new cam. Everything should turn smooth with no binds at any point, though it is not going to be especially easy. Make sure when you tighten down the rockers, tighten them down while the valve that pertains is closed so you don't have any discrepancies on torque specs. Torque the rockers to 25 ft/lbs.

Without heads on the engine, it should turn over like butter. With heads on it and rockers installed it will feel much more firm but still smooth as butter
 
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Once you install the rockers, your fighting against the compression in each cylinder. Will be much easier to turn with all the spark plugs removed.

David
 
The spring tensioner had nothing to do with the tightness, Jim. It was the cam bolt, after the little spacer, the big spacer, the cam gear and chain, then the synchronizer gear went on, when we tightened down the bolt and washer on the cam synch gear, thats when it got really tight.

Now if you crack that bolt loose that goes into the front of the cam, the motor will turn over EASY. But torque it down to 29.5 lbs, it gets pretty tight, not so tight were you cant turn it by hand though.

Also, ALL spark plugs are out of this motor as well, I think its alright, but wont hurt to listen to others opinions.

Mike
 
I went through a similar issue on my engine rebuild as the spacer on the cam was stuck on there really good so I didn't notice it was separate.

How it goes together is:

Cam + Machined Spacer + Thrust Plate (screwed to block, use blue thread loc-tite on screws) + Spacer + Timing Gear + Distributor gear + Washer + Bolt (more blue thread loc-tite).

The machined spacer is on the old cam.

Don't forget the assembly lube on the thrust washer and spacer, and basically all the metal surfaces that rub on each other.

I've been documenting most of my rebuild and lots of questions and answers were in the member forum.

Note the downside to that machined spacer is it needs to go onto the cam before you put the key in the keyway.

Here are pictures. First one is the spacer on the old cam after I got it loose as well as the assembly minus the distributor gear and bolt + washer.

Now if that is all right and it's still tough, did you lube all the surfaces? When I was missing that small spacer, it was very...very hard to turn the engine over with the cam bolt torqued. (using about a 12" lever on the crank bolt.. if yours is longer, it'll make it easier)
 

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Mike, as a note to what you said. That was the FIRST thing I checked, as when I did my top end rebuild last winter I did the same EXACT thing you did. That little spacer was stuck to my old cam, and didnt even know it was a seperate piece. :D :D

It was moderately hard to turn with a normal size Craftsman half inch driver, but was still able to rotate it by hand, just took a lot of effort. Were just not sure how tight is too tight.

Mike
 
I just checked on my motor which is in the garage. Heads are on, valves adjusted, front cover on. But otherwise should be similar to you.

Took 46lb/ft with a click torque wrench to turn the motor with the crank bolt. I started at 35lb/ft and just increased the torque until the wrench didn't click and moved the motor.

I'd say if you're much more than that you could have an issue.

Did you check the crank before. should have been about 20 lb/feet before you put the pistons in.

Note that I used a dry lube in the cylinders, and total seal ring lube on the rings. The types of rings and lube could effect the torque. I'd think mine should be a little high.
 
There should be NO increase in force necessary to turn over the motor with the cam installed. Something is wrong. A complete rotating assembly with spark plugs out and rockers off should take only a few pounds of force to turn over.
 
Well, Whenever I get a chance to head back over to Jims Ill take a look at it again.

The old cam came out and the new one went in, NOTHING else was changed.

Without the cam bolt tightened down, the assembly is VERY EASY to turn over, and once that bolt was torqued down, it tightened up pretty tight.

Jim, why dont you go pull the lifters out of there, and take that cam out, and check everything again. Let me know what you find.
 
You might want to take a look at supersixmotorsports.com. They have a thrust bearing and spacer kit that replaces the stock thrust plate and spacer with a bearing.
 
I wiped out a fresh HI-PO $3K bottom end, because of that damn washer. The car turned over and ran for about a minute. Then it locked up. That was one of my worse days of sc ownership. Second worse day was when I blew up the stock block. Lets see if this time around I got it right. This weekend is the big day.
 
I have not even set valve lash yet, the pushrods are just sitting on the lifters.

Im going to head over there sometime in the future and triple check everything, its not like I dont know what Im doing. Im sure we will figure it out.
 
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