Composite Distributor Gear Problem.

[Rbace123]

What’s the correct gear to run on a 12-433-8 cam? The composite gear I installed when I built the motor back in the fall is crap. I noticed my timing was bouncing all over the place when trying to set total timing at 3000 RPM. I removed the distributor to see what was up and by accident found the composite gear had a wobble to it when rotated, I thought the shaft was bent so I reinstalled the original steel gear from the Mallory distributor and it looked fine. Reinstalled in car and was able to set total without a problem.

Is this a common thing with the composite gear? I would think for $ 100.00 that plastic gear would be made better. Looks like the hole is not drilled straight. Also is the standard fuel pump rod ok or should I have used one with a bronze tip. Any help is appreciated

Thanks !!!

[amick]

We always recommend using a steel/iron mealonized distributor gear for our Austempered Roller Cores. We only recommend using the Composite gear for billet roller cams. You could use a composite gear on the Aust. cam if you wish but there is no real reason to do so. The composite gear is designed to wear out over time. That is the whole reason behind it. This way you wear out the distributor gear and not the cam gear. Also we only drill one hole in our composite gear so the owner must drill the second hole for the pin to go through. We do this so that the holes in the gear will always be able to line up with your specific distributor. And yes you do need to be using a bronze tip fuel pump push rod. If it has not done so already it is very likely that the standard pushrod will grind the lobe off the camshaft.

[Rbace123]

The motor only has less then 2000 miles. Do you think I may have damaged the cam already by running the standard fuel pump rod or can I just change it now? The cam came with and install booklet which was very good but I did not see anywhere that it mentioned changing the fuel pump rod. I did see the recommended the new cam gear.

Thanks for the help !!!

[amick]

No problem at all. It is possible the cam is already damaged but if the fuel pump is still working fine and you are not seeing any metal in the oil then I would think you're probably safe. I would however check it to be sure. I am not sure off hand if the instructions say to change the fuel pump pushrod. I do know it says it in the catalog. Either way check it and see where we are at. Hopefully we have caught in time before it could do any damage to your cam. Let us know if you need anything else.

[Rbace123]

As far as checking to see if the lobe is worn how much lift does it have when new and what is acceptible wear ? I will check it when I replace the rod to see how bad or if it is worn.

Thanks

[amick]

You don't have to go as far as checking the lift on the lobe. Basically just give it a good visual inspection and insure there is no wear mark through the cneter of the lobe and it is not flaking or pitting.

[Rbace123]

Checked fuel pump lob and it looks like it is ok. I ordered a bronze tip fuel pump pushrod that I should have today. How can I tell if the steel gear is mealonized or are all steel distributor gears mealonized?
I put the one that came with the Mallory distributor back on. Are Mallory gears mealonized ?

Note: In my first post I think you misunderstood when I said the hole was not drilled straight. I did not mean the hole for the pin. I meant the hole that fits the distributor shaft. The gear has a noticeable wobble when spun. Only way I would think that would be possible is if the hole for the distributor shaft is not straight.

Thanks again !!

[amick]

Glad you got that fuel pump push rod taking care of and that the lobe was still ok. On the mealonized gear part the best thing to do would simply be to call Mallory and ask them if their gear is mealonized. Not all steel gears are. You can get one direct from GM also if they don't happen to have one. I did indeed misunderstand you about the hole in the gear. If the gear is less than a year old you can always send it in for warranty consideration. I have not seen that paticular problem with one of our composite gears before but there is a first time for everything. I would recommend checking the shaft itself for straightness also and checking to see that you get a proper wear pattern when you go to install the new gear back in the motor.

[louich]

i just checked my composite gear since im heading out on the 3rd power tour with it in a couple weeks. but im impressed. 20000 kms and its showing hardly any wear.