Distributor gear wearing out
 

I posted a couple weeks ago that I couldn't get the rpm's to get up on plane. After changing the plugs, wiring, coil, and checking the ecm, it ended up being the gear on my distributor was badly worn.

It's a 502 (with a procharger). The previous owner had passed away, so I don't know if the cam is stock or if anything else has been modified in the engine.

Well, I put 5 "easy" hours on the new distributor and the same symptoms are happening again. Today, I pulled the distributor and again it's badly worn......in only 5 hours!

The top of the gear is pretty rough, so my friend who pulled the distributor thinks when the new one was installed it was bottoming out.

From what can be seen the cam looks good. I know that's no guarantee that it is clean, but it looks clean. A harder gear will not fit the stock delco distributor. So, my choice is; buy a new MSD distributor that can accomodate a harder gear, buy another soft gear and hope that the other one was set wrong and this one lasts, or lastly; tear the engine down and check (and possibly replace) the cam.

I would like to buy the MSD distributor and harder gear, but I'm worried if I go that route and I have a stock cam (I think I do) will the harder gear screw up my cam?

This whole thing has been very frustrating. I've only had this boat since May, and what looked like a brand new boat for a great price has turned into a nightmare. I just want my problem fixed and let me enjoy my new toy. Any advice?

understood. the boat project probably killed him straight away.

the metallugy of the gears is pretty specific. steel cams need different gears and if you make the dist gear harder than the cam gear and the problem isn't fixed then you just wear out the cam. you need to identify very specifically what the issue is. there are more than a few things that will wear out distributer gears some as simple as what you mentioned. i am a firm believer in factory equipment first. unless something material has changed ( like the cam that you may or may not know anything about) then the factory gear should last essentially forever. it didn't.

so fix what caused it to fail. not just throw another part at it without understanding what happened the first time.

That's the problem --- identifying what caused it to fail. How can I do that? It seems like the most cost effective way would be to buy another stock gear (about $45), and set it up so it isn't bottoming out. But, if that's not the problem I might not be as lucky as I have been. For example, maybe the next time one goes I may be 5 miles off of shore with my wife on board. Whew.......that wouldn't be a good idle ride home (if I can even idle). So, how can I test it, without actually relying on it?

Or, the next route could be to put a harder gear and aftermarket distributor on. That's not as expensive as tearing down the engine, but it's not cheap either. The key question here, is will the aftermarket hardened gear damage the stock cam?

The right solution would be to tear the engine down and check the cam out. Is it damaged? What type is it, and what's it made of? That's a BIG job. I could end up spending a couple thousand dollars, when all I needed was a $45 gear.

So, back to my question......is there a reasonable way to find out what the problem is? Or, do I have to tear it apart?

Where is all the metal from the previous gears going:eek:

IIRC a stock delco dist does not have a bronze gear. If it is eating up cast gears, there is definitely a problem and changing gears is not going to fix it. Is only the top of the gear eaten?

The oil pump rod that the dist mates too, does not move down at all (or shouldn't). Take a tape measure and measure (as close as possible) from the centerline of the cam gear to the top of the distributor base on the manifold. Then measure the distributor from the base of the pad to the centerline of the gear. If they are pretty close, then it must it isnt the distributor. Could be the gear or even the gear on the cam... maybe a burr on the cam gear?

But like 1Bigjim said, where are the shavings going? That would make me very nervous.

I assume the shavings dropped in the pan (the shavings would be miniscule). I changed the oil after I put the new gear on, and have magnets on the bottom of the pan as a precaution.

From what we can see the cam looks good.

I'm frustrated with this whole thing and am seriously considering pulling the engine and selling the whole thing, 502 with only 70 hours - new ecm, coil, wiring, MI Procharger, A1000 Aerosmith fuel pump, and all of the fittings. Sell the whole lot and go with a stock 502

"aerosmith" my favorite group! How about aeromotive fuel pump

Everyone is just trying to help you, that's is why this site is priceless:drink:

If it where my engine I would pull it out, find out what the problem is and refresh-it. It's a only a matter of time before you spin a bearing or a cam goes flat with all the debris in the engine.

Just my 2cents:grinser010:

Agreed.

You could always put another gear in it and try to keep it alive for the rest of the season.

You have a issue with the cam, if you do not know what it is, replace it and install a new gear, but those miniscule metal shavings is going to be deadly to the bearings and such, so as I've said before..the pin has been pulled....only a matter of time..good luck Rob