cam gear wear

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cam gear wear

Post  68galaxie on May 21st 2014, 1:35 pm



Distributor gear has wear and so does the camshaft gear. (looks less on the picture, but the wear is probably 0.010" deep.
I had used the old Crane steel gear that was said to work with steel solid roller cams.
I was going to switch to an AMPCO 45 distributor gear. However, with the cam gear showing wear is this a bad idea?

I am thinking a camshaft replacement is probably required.
One good note, the cast camshaft trust shows no wear, other than being polished.
I was using a rollmaster billet timing set and chain was still tight.
Boss bulkhead?


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Re: cam gear wear

Post  IDT-572 on May 21st 2014, 2:26 pm

Have you done the oil mod to squirt oil the distributor gear?
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Re: cam gear wear

Post  kim on May 21st 2014, 2:39 pm

Looks like gear on distributor is riding low, might be a bind issue within the block. Look at the thrust surface under the gear. The wear all on the top 2/3 of distributor teeth, gear is low on shaft.

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Re: cam gear wear

Post  68galaxie on May 21st 2014, 2:43 pm

Hello Blake,

I have not done any oil mod to squirt oil on gear.
I have seen the oil gallery plug drilled on other forums. Not even sure what size one would use to drill it? 0.040" dia?
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Re: cam gear wear

Post  68galaxie on May 21st 2014, 2:45 pm

kim wrote:Looks like gear on distributor is riding low, might be a bind issue within the block.  Look at the thrust surface under the gear.  The wear all on the top 2/3 of distributor teeth, gear is low on shaft.  

Hello Kim,

The trust surface of the distributor gear has a very slight wear pattern indicating it is riding on the block thrust surface (as I assumed the distributor gear was supposed to rest on the block thrust surface - if it did not the drive pin would shear) I could be wrong of course.

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Re: cam gear wear

Post  IDT-572 on May 21st 2014, 2:53 pm

68galaxie wrote:Hello Blake,

I have not done any oil mod to squirt oil on gear.
I have seen the oil gallery plug drilled on other forums. Not even sure what size one would use to drill it? 0.040" dia?

.040-.060 would be fine.............
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Re: cam gear wear

Post  kim on May 21st 2014, 3:44 pm

Nope, mie has about .050 air gap cold and about .020 or so hot. The only time I've sheared a pin is when I did a new MSD distributor, oil pump drive, and a Titan oil pump, and dumb assed the install and didn't ensure air gap In the assembly. Jamed the distributor against the upper thrust surface and sheared the pin. MSD did a whole shaft rebuild and lock out for free... so it was just some down dyno time as I threw a second distributor in after cutting the oil pump drive shaft.

With the gear pulling down on the lower thrust surface, your adding a not needed friction point. That alone is what most likely cost you cam and distributor gear, distributor and oil pump, even a Titan pump at 120 psi, aren't that hard to turn, so steel to steel shouldn't wear.

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Re: cam gear wear

Post  68galaxie on May 21st 2014, 6:34 pm

Hello Kim,

I had set up the distributor gear at 4.00" and end play of 0.030" (per MSD sheet)
I assumed this was to get the distributor gear riding on the block thrust surface without binding.
Does this mean that one must have the engine apart to set up any distributor?


I am trying to get my head around this one.
One should ignore the MSD set up distance?

help!!!!please
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Re: cam gear wear

Post  Lem Evans on May 21st 2014, 6:37 pm

The only steel roller cam that I ever saw with gears so sharp that one could have shaved with them had a Crane steel diz. gear applied to it.
 
I'd guess the 1st question would be...was it because the diz. gear was steel? Maybe but it could be:
 
The alloy of the steel, the heat treat or lack of, the way the gear was machined or all of these.


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Re: cam gear wear

Post  Lem Evans on May 21st 2014, 6:42 pm

68galaxie wrote:Hello Kim,

I had set up the distributor gear at 4.00" and end play of 0.030" (per MSD sheet)
I assumed this was to get the distributor gear riding on the block thrust surface without binding.
Does this mean that one must have the engine apart to set up any distributor?


I am trying to get my head around this one.
One should ignore the MSD set up distance?

help!!!!please
 
4" with the end play out works great.
 

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Re: cam gear wear

Post  68galaxie on May 21st 2014, 9:11 pm

Thank you Lem,

4.00" is what it will be set up as.
Should I expect a gap between the dist gear bottom and the block thrust?

Cheers

Perry



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Re: cam gear wear

Post  Lem Evans on May 21st 2014, 9:53 pm

68galaxie wrote:Thank you Lem,

4.00" is what it will be set up as.
Should I expect a gap between the dist gear bottom and the block thrust?

Cheers

Perry




At rest the gear will be touching the block....when you fire that mofo up it'll start using that .030" end play.

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