Composite Distributor Gear Wear
 

Is this too much wear? Gear has about 12.5 k miles on it after 13+ years running on a Comp hyd roller cam. On one of teeth lower in the picture, you can see a slight ridge, maybe a thou or two deep.

Is it just me or does it look like the gear isn't engaged completely? More wear at the bottom?

I've never had a composite gear wear like that in such short mileage.

13years??

Looks waaay better than mine did after one month and a few hundred miles.

If the cam gear is not dressed perfectly, they wear.

its normal . Especially if you run a 80lbs oil pump..

Somewhat related........

Articles from MSD will point out the effort that goes into a ring-and-pinion installation. Yet many don't think twice about the distributor gear/cam gear relationship unless performance starts to suffer. How the dist gear and cam gear mesh is just as important as the quality of the metals involved. MSD states the excessive clearance between the gear teeth shouldn't be fixed by shoving the distributor farther into the hole; this screws up the proper wear pattern.


.

I think the wear pattern looks reasonable. It has heavy contact in the middle tapering evenly off at the ends. I appreciate everyone's input and will keep running it.

The first time I ran a solid roller Cam custom ground by Crane in 81 it ate up the bronze gear in less then 300 miles of street driving with never going over 5000 rpm, and this was with a oil spurt oil in the galley plug lubing it!

I pulled the Cam, polish up the gear like a baby's Butt and then ran a stock gear for 8 years until some ware started to show up.

This was with a 60 lb pump that due to my duel 2 QT filter set up always had 60 psi above 2600 rpm.

One reason I pulled the distributor was because of a problem I'm having with it. If I switch out distributors, would it make sense to run a steel or bronze gear for a while to "polish up" the cam gear?

Since it's already assembled the bronze gear for a while and then switching over is usually the accepted practice among many here. I never do that myself and prefer to dress the cam gear during assembly, then go straight for the composite gear. I use 80 lbs. pumps in everything and the gear always looks good after 10's of thousands of miles.

I'm having trouble telling in the picture but if you say it appears normal after 13k miles then I'd stab it back in and run with it.

For interest.....

Bronze Distributor Gear Durability

https://forums.maxperformanceinc.com...ght=MSD+bronze


.

Experience tells me I would never run a bronze gear on the street. Your composite gear is fine. Run it.

Did you encounter poor life from the bronze gear?

I am experiencing the opposite as my plastic gear got chewed up fast, but my bronze seems to have no wear so far.

Time will tell....

Yes. On a race car with only about 150 passes on it. It would not have made it another 50 passes. I put a composite gear in it and checked it after 250 passes and it didn't show any wear.

Below is a picture of the bronze gear on my distributor after 10 years of use. The engine has a LOT of time on it including hundreds of drag strip runs and quite a few street miles.

The key to long life with these steel roller camshafts is to spend some time with the gear to remove any sharp edges, tool marks, etc before placing it in service.

I've seen others chew up polymer gears in less than 20 miles when they didn't take time to clean up the distributor drive gear on the cam.....FWIW.....

Yep... I think that’s what got my polymer gear. The cam gear was rough.

The bronze gear that I am currently running seems to be incurring no wear.

In retrospect, I should have paid much closer attention to the cam gear surface and possibly ran a steel or bronze gear prior to using a poly gear.

I also have the plug drilled for direct oiling to the cam gear.

Another lesson learned.....

Curious as to the some of the actual methods to dressing the gears before assembly. What's your procedure?

Good question. I'm similarly curious why the cam manufacturers deliver finishes on the gears that cause high wear rates? They grind the lobes... can't they debur or peen the gears? Seems like they assume a break-in period that doesn't go well with composite distributor gears?

It's not just the gear on the cam to worry about these days, that's the easy part to address. Anymore they deliver camshafts with pretty rough finishes around the edges of the lobes that need to be addressed, and a lot of the cams are also bent. I know Paul has had some that were so bad it's amazing how those things got through any kind of QC check. I've bought recent cams through Paul and pay Paul to go through and check them over. Every one that has come in has been bent and Paul had to straighten them.

It really pays to order a camshaft from a reputable machine shop anymore, and pay them to inspect it, polish it, and straighten it. They will also dress up the gear too. Order one straight from a catalog and there is not telling what you'll get these days.

If you want to dress the gear yourself, doing what Cliff suggested above works very well.

Ugh

Noted, thanks!