View Full Version : Metallic cam gear-bind?

02-17-2007, 06:07 PM
Today, we are assembling a 259. Everything is going together smoothly; Crane cam with new bearings turns well, new crank with new Federal Mogal standards turns well; new metallic crank/cam gears installed and it's a bear to turn. This is the first time I've not used the fiber cam gear. Have I missed something? Is this normal?

I thought, maybe the aluminum gear is close tolerance and will wear in. Then I thought, others have used these and I should ask before proceeding. I don't want it to wear out on the first revolution but I doubt a starter will be able to turn this over.

Your experience and feedback is appreciated.

rusty nut garage
02-17-2007, 06:10 PM
Was this block align bored or align-honed??

Russ Shop Foreman "Rusty Nut Garage"
57 SH (project)
60 Lark VIII 2dr sd (driver)

02-17-2007, 06:21 PM
Neither. Block was hot-tanked and new bearings were installed. When we re-installed the old fiber gear everything turns smoothly.

rusty nut garage
02-17-2007, 06:23 PM
I just rebuilt a 289 using a aluminum cam gear. Not sure what vendor it came from since the customer supplied the parts. Myers I think.
I noticed no bind whatsoever with the one we installed. Sounds like a out of tolerance gear if the fiber gear turns ok.
Good Luck

Russ Shop Foreman "Rusty Nut Garage"
57 SH (project)
60 Lark VIII 2dr sd (driver)

02-17-2007, 06:23 PM
Greetings, All,

Your instincts were right - NEVER try to run in a binding short block. Something is seriously wrong somewhere.

As previously mentioned, if the block was align bored or honed, the gears may be bottoming out. This can be corrected by a skim cut on the top of each gear on a lathe.

Find the bind by removing the gears and turning the cam and the crank separately. Sometimes incorrectly installed or sized cam bearings can cause a bind.

Occasionally, incorrectly sized main or rod bearings can make an engine turn hard. If it is the crank, Plastigage all the bearings and check the end play.

Did you check piston ring end gap? An oversized ring can be pounded in, but it will cause serious drag before it seizes up.

Don't forget to set the timing marks when reinstalling the cam and crank gears.

thnx, jv.


02-17-2007, 06:42 PM
If it's the repro gear, I'd take a hard look at it. I know some were keyed about 2 degrees retarded, who knows what else may have been screwed up.

64 Commander 2 dr.
64 Daytona HT
63 R2 4 speed GT Hawk (Black) #2
63 Avanti R1
63 Daytona convert
63 Lark 2 door
63 Lark 2 door #2
62 Daytona HT/ 4 speed
62 Lark 2 door
62 GT Hawk 4 speed
60 Lark HT
60 Hawk
59 3E truck
52 Starliner
51 Commander

Dwain G.
02-17-2007, 08:00 PM
Check for specified backlash (.001"-.003") between the aluminium cam gear and the crank gear teeth. Sounds like there may be none!

Dwain G.

02-17-2007, 08:22 PM
Based on how tight these went together, I would say there is negative backlash.[:0] Definitely immeasurable. We managed to move it through a third of a revolution and the aluminum teeth are already scored.

02-18-2007, 07:28 PM
I just went thru this as well. However, in my case the block had been line bored thus making the new billet cam gear too tight. We sent it back to the maker who got with the machine shop and figured out the clearence needed and it was taken care of.