composite or melonized distributor gear?

I have a steel hydraulic roller cam in my 74 Euro Pantera along with a melonized gear that came with my Progression Ignitions distributor.  The gear has been working correctly for several years.

In my GTS project, it has a steel hydraulic roller cam (Comp Cams) and a Holley Dual Synch distributor that came with a steel gear.  It has been running for several months this way.

I think the bronze gear would only be an issue if you drive the car a lot.

That’s probably true (regarding the bronze gear) Steve, but how do you know for sure?

If you get a bronze gear - you might always be wondering about it’s condition, and then you’ll have to pull the distributor regularly, and you’ll be checking your oil for bronze particles…

It seems that even if the bronze gear doesn’t wear that fast, it gives one some concern…

I did some investigation of the Kevlar (composite) gears, and I saw enough bad reports to know that I want to stay away from those as well.

I guess I am lucky that my camshaft seem to be compatible with a standard cast iron gear, and have had the engine apart often enough feel confident in the gear.

I have done the modification to the oil gallery plug that sprays oil directly onto the gear/cam interface.  Rene - since your motor is apart - I’d recommend that simple modification!

I have never run the melonized gear, but that would be the approach I would consider first.

Rocky

I had a carbon ultra-poly gear from Tri-Tec and had zero trouble with it; however, installation is not trivial. You must set the height of the gear on the distributor shaft, as per Ford’s procedure. Ford says every dist. gear should have its height set. The poly gears come with a hole that may be too large for some distributor shafts. I had to special order one with a smaller hole, then ream it to size. The interference fit of the gear on the distributor shaft must be perfect. “Perfect” for a poly gear is a different spec. than you would use with a steel, iron or bronze gear. Once you go through all of this, the poly gears are stronger than steel but more forgiving than bronze. That’s why ALL of the NASCAR teams use them.

Wilkinson ran bronze gears for a while.  He said the teeth eventually wore down to razor blades.  The symptom was that the engine stopped running because the timing was too far off.  This was a car he was driving daily, back in the glory days.

Below is a photo of a cast iron gear that ran on a steel cam.  This gear came out of my GTS project that you may have seen in other posts.  It is the reason my car became a project.  Fragments from the failed cast iron gear damaged the engine enough to require a rebuild.  The previous owner told the shop to refinish the engine bay and suspension while the engine is out.  Then covid happened and he ran out of money.  I ended up with the car. It was largely disassembled but the engine had already been nicely rebuilt.

If I were you, I would definitely go with the melonite gear.

@rocky posted:

That’s probably true (regarding the bronze gear) Steve, but how do you know for sure?

If you get a bronze gear - you might always be wondering about it’s condition, and then you’ll have to pull the distributor regularly, and you’ll be checking your oil for bronze particles…

It seems that even if the bronze gear doesn’t wear that fast, it gives one some concern…

I did some investigation of the Kevlar (composite) gears, and I saw enough bad reports to know that I want to stay away from those as well.

I guess I am lucky that my camshaft seem to be compatible with a standard cast iron gear, and have had the engine apart often enough feel confident in the gear.

I have done the modification to the oil gallery plug that sprays oil directly onto the gear/cam interface.  Rene - since your motor is apart - I’d recommend that simple modification!

I have never run the melonized gear, but that would be the approach I would consider first.

Rocky

Rocky, I already drilled the 0.5mm hole in the plug to improve the lubrication of this gear

I think I'll go for a melonized coated gear.

Use the gear the cam manufacturer tells you to.

It offers a choice of three materials

Then any of the three WILL work.

There isn't any reason to question the cam manufacturers recommendations. You have chosen to take a different path with this type of cam selection so you need to go with their recommendations as the best solution.

There are unquestionably "pitfalls" out there in some of the details. I think of it as safest to stay with the simplest solution, with the longest known record of dependability.

That doesn't guaranty 100% dependability either. Just likely a better known long term result. Everything else is some kind of a risk and I ask myself, "is that an unnecessary risk?"

I still say, much of the decision is just plain "risk analysis". "You" are now the Doctor and you prescribe the solution.

When you stray away from the original stock then you may have different results and additional risks.

"You pay your money, and you take your chances". Maybe this is just, pick the "Lady or the tiger"?