The Ford Barn - View Single Post

Zener424 · 01-13-2017, 04:37 PM

Here's an update I received from Dan on December 11, 2016:

"Hi Phil- the cam gear cam today. In checking the teeth, the contact pattern is what is referred to as "cross bearing". This means the mating gear is contacting the cam gear teeth near one face on one side of the tooth and the opposide of the tooth on the opposite face. I blued up a crank gear and check you cam gear tooth contact and it is showing contact across about 80-90% of the face so the cross bearing is not being caused by a mismatch in helix angles on the gears.

My guess is that the cam and crankshaft centerlines in your engine are not parallel and is causing the contact pattern we are seeing as well as the cam wanting to walk back and forth. I took some pictures of the contact pattern with my phone, but they are out of focus, so I'm going to take additional ones tomorrow and I"ll forward them to you so you can see what I'm referring to.

I'm pretty convinced that this is the cause of the noise you were hearing.

Just FYI- when tightening a cam gear, don't use the gear teeth to prevent cam rotation- clamp a bar or block of wood to the side of the cam gear and let that bear on the block. I suspect that many folks who experience a fiber cam gear failure do so because of damaged teeth from tightening the cam nut and letting the gear teeth react the torque.

I'll send you gear back next week- my suggestion is to use it or keep it as a spare. Thanks for going to the trouble of sending it so I could look it over.

Dan"

01-13-2017, 04:37 PM	#71
Zener424 Member Join Date: Nov 2010 Location: Staten Island, NY Posts: 77	Re: Camshaft timing gear rattling noise Here's an update I received from Dan on December 11, 2016: "Hi Phil- the cam gear cam today. In checking the teeth, the contact pattern is what is referred to as "cross bearing". This means the mating gear is contacting the cam gear teeth near one face on one side of the tooth and the opposide of the tooth on the opposite face. I blued up a crank gear and check you cam gear tooth contact and it is showing contact across about 80-90% of the face so the cross bearing is not being caused by a mismatch in helix angles on the gears. My guess is that the cam and crankshaft centerlines in your engine are not parallel and is causing the contact pattern we are seeing as well as the cam wanting to walk back and forth. I took some pictures of the contact pattern with my phone, but they are out of focus, so I'm going to take additional ones tomorrow and I"ll forward them to you so you can see what I'm referring to. I'm pretty convinced that this is the cause of the noise you were hearing. Just FYI- when tightening a cam gear, don't use the gear teeth to prevent cam rotation- clamp a bar or block of wood to the side of the cam gear and let that bear on the block. I suspect that many folks who experience a fiber cam gear failure do so because of damaged teeth from tightening the cam nut and letting the gear teeth react the torque. I'll send you gear back next week- my suggestion is to use it or keep it as a spare. Thanks for going to the trouble of sending it so I could look it over. Dan"