Metal Camshaft Timing Gear?

[dtgolder]

I see some vendors are selling metal camshaft timing gears instead of the more common fiber cam gears (and at a very competitive price).

I'm wondering what the opinion is of the group? Has anyone used one of the metal timing gears?

And curious on the history - why were fiber gears used in the first place? Cost? Lightness? Noise?

Would welcome opinions as I'm starting to shop for parts for my engine rebuild project.

Thanks!
d

 

[1955cj-5]

I have read that the fiber gears were used to create a "weak link" in the otherwise steel gear driven cam/oil pump/distributor portion of the engine.

Also some suggest that the fiber gear is quieter.

But early L-134 engines had a chain driven cam....no "weak link" there.....

Maybe to avoid heat expansion and excess wear?

I put an alloy cam gear in the Model A, and it ran fine, and I could not hear it. But a Model A four banger is not meant for silent running....lots of other clatter.

 

[JABJEEP]

I was told by the parts guy at the Willys Jeep dealership back in the mid-70s that the reason was noise. Since the fiber one wore out I installed the metal one..... and it was indeed noisey.

 

[1955cj-5]

I was told by the parts guy at the Willys Jeep dealership back in the mid-70s that the reason was noise. Since the fiber one wore out I installed the metal one..... and it was indeed noisey.

For what it's worth, both the CJ-3a and the Model A engines got fiber gears when rebuilt.

The fiber gear was pressed on to the cam before install...

This is the L-134:

 

[dtgolder]

I was told by the parts guy at the Willys Jeep dealership back in the mid-70s that the reason was noise. Since the fiber one wore out I installed the metal one..... and it was indeed noisey.

So @JABJEEP ...knowing it was noisy (but perhaps the metal is more durable) would you do it again? Or would you go back to fiber?

And @1955cj-5 I'm thinking of pressing the gear on before install - did you use a press, or how did you accomplish that? (The last guy I think had trouble getting that on, and ended up with too much lash and a distorted cam washer).

 

[JABJEEP]

I don’t think there’s really anything wrong with the fiber gears as long as you don’t have backfires. The steel gear will definitely wear out the crank gear long before the steel cam gear wears out. Did I read somewhere that some of the metal gears are a special aluminum alloy? That may be better solution. We were so frustrated with the lack of power with the 4-cylinder that we replaced it with a 327 shortly afterwards, so I really don’t know how it fared afterwards.

 

[1955cj-5]

And @1955cj-5 I'm thinking of pressing the gear on before install - did you use a press, or how did you accomplish that? (The last guy I think had trouble getting that on, and ended up with too much lash and a distorted cam washer).

The machinist who did the rebuild had a proper press...he was going to send it out to be pressed on, but it just fit in the press that he had...so having it pressed on was important, rather than using a big mallet!

 

[JABJEEP]

If he will let you, you might want to help hold it during the set up. If the cam falls it could shatter. Wear safety glasses.

 

[motorhead]

The cam gears I have seen to replace the fiber gears were Aluminum. I worked at UPS for 30 years and when I was there, a very popular and very Durable engine we ran was the FORD 300CI, 6 cylinder. UPS ordered all new and rebuilt FORD 6 cyl engines with the Aluminum cam gear. The fiber gears didn't hold up. You could hear the additional noise from the metal gears but they ran until the engines wore out between 200,000 and 400,000 miles.