Distributor Advice needed

[anwat]

Lets start with what I'm working with: Gen 6 454 block with cast iron GM heads. I have an Edelbock 2162 cam, which I think is a cast cam. MSD 85501 pro billet distributor, which came with a bronze distributor gear. After about two years, it failed. I had trouble with timing for about six months prior to the failure, now I understand why. The wear on the gear was very uneven. I posted photos, and got mixed advice, but most folks said to just run an iron gear and I'd be fine. To me, it seemed the gears weren't meshing properly, because the wear was uneven.
The cam gear looked pretty much unharmed when I stuck a camera down there, so I adjusted the height of the distributor about 1/8 of an inch, put another bronze gear on and started over. About 3000 miles later, I pulled the distributor again, and the gear was beginning to wear in a similar fashion. If you look closely, you can see the wear starting in the photo. Not knowing what else to do without tearing the whole engine apart, I switched to an iron gear. It's been about 3000 miles, and I'm getting ready to pull it and take a look. I'd rather not chew up my cam gear if I can avoid it.

It looks like the distributor isn't in deep enough...the wear seems to be on the bottom portion of the gear, as if the top isn't contacting anything. Should I try to drop the the distributor? What is the correct way to determine how far in it goes? I pulled off the gasket at the bottom of the dist, inserted it until it bottomed out on the oil pump drive, tightened the collar and then replaced the gasket. I don't think I can get it in any deeper, without some modifications to the oil pump drive on the distributor. I don't know if the block has been decked. I know the engine was rebuilt at one point, but don't really know the history for sure. I don't have a high pressure oil pump, and I run synthetic oil which is pretty thin, so I don't think this is drag from the oil pump. If the iron gear isn't meshing properly, will I even seen anything before it's too late? It didn't take long to start to chew up the second bronze gear, it seems to me something isn't lined up right. What else could be wrong...If the cam wasn't bolted down right, I'd have other issues, correct? Everything seems to be running good right now. I'm just worried about some kind of wear that's going to cause something to fail at the worst possible time. Advice? Does the wear on the gear seem to match with it not being in far enough, or am i oversimplifying things? There's a lot of discussion about gear material. but I can't find much about getting the distributor and cam gears to mesh...it seems like there aren't too many things that can be adjusted between the two.

Here's the photos of the two bronze gears:

 

[dyeager535]

First thing I'd do is call the cam manufacturer and ask them what drive gear material is needed with that cam. There is so much info out there about which material to run, depending on cam type, it can be confusing.

It sure looks to me like the gear is just getting chewed up by the cam based on the less-worn one, which to me goes towards too soft material given the other info you mention.

Do you maybe have a stock distributor you can compare the critical measurements on, just to ensure what you have isn't made improperly? Unlikely I'd hope, but easy to eliminate as a factor if so.

 

[Wes Harden]

yeah i wouldn't even think twice running a normal iron gear on that cam. Edelbrock doesn't spec it, and that cam can run stock springs, I bet they expect people might still run stock hei with it.

 

[ktmoutfront]

I just read through the instructions for that cam. Does not say to swap the factory gear to bronze. So you should be running the factory gear.

The wear you are seeing is what I would expect with the soft gear.

 

[anwat]

That helps....when you say the wear is what you would expect, does that include the way the top of the gear is more worn than the bottom?

Edelbrock says they recommend whatever the OEM distributor gear is. and GM sells both steel and melonized gears for their distributors. If I'm understanding the materials, the steel and melonized gears will be harder than the iron gear I have on there now, correct? So I should see some wear, but not as quickly as with the bronze gear?

I do have the distributor that was in it when I bought it, but it's not OEM. It's still a good start, though.

I was thinking about sticking a dowel in the hole until it touches the top of the cam gear an using that measurement. Problem is touching the "top" of the round gear thats offset is going to be impossible to judge by feel. I'll see if I can find some specs on the distributor that comes in the long block from that year...The engine came from a Workhorse chassis, so of course it will be a little more difficult, but nothing is easy.

 

[tarussell]

That helps....when you say the wear is what you would expect, does that include the way the top of the gear is more worn than the bottom?

Edelbrock says they recommend whatever the OEM distributor gear is. and GM sells both steel and melonized gears for their distributors. If I'm understanding the materials, the steel and melonized gears will be harder than the iron gear I have on there now, correct? So I should see some wear, but not as quickly as with the bronze gear?

I do have the distributor that was in it when I bought it, but it's not OEM. It's still a good start, though.

I was thinking about sticking a dowel in the hole until it touches the top of the cam gear a using that measurement. Problem is touching the "top" of the round gear thats offset is going to be impossible to judge by feel. I'll see if I can find some specs on the distributor that comes in the long block from that year...The engine came from a Workhorse chassis, so of course it will be a little more difficult, but nothing is easy.

Shims for the distributor base to manifold are available and will enable you to dial in the height of the gear contact.

 

[dyeager535]

Also, how much play do you have at the end of the distributor? I don't feel like endplay is the correct terminology, but how much play does the gear have if you push/pull it into the housing? I've only seen a significant amount on high mileage distributors.

Minimal experience with the gear mesh/wear though, I've never had any issues. I did get a shim set for one older distributor that had a bunch of play, clearly more than another distributor I had so I just tried to make the two match.

 

[anwat]

This distributor has an adjustable collar, so I think that would take the place of the shims. Unless you're talking about something that just raises one side which sounds like a bad idea. With the new gear on, there's very little movement but with the first bronze gear there was quite a bit. So much that I asked a buddy of mine about it, and he said it was OK since the gear always turned in the same direction, it would always be tight, which made sense until I saw the wear. Yeah, it was tight against the gear, but it was way off and eventually started slipping teeth.
I'm going to double check the manifold, and from there, it would seem that as long as I'm fully engaging the oil pump drive shaft, I should be in the right distance to mesh the cam gear and distributor gear
Didn't get to pull the dist yet, I had some help this afternoon and took advantage of it to bleed the brakes, so hopefully I'll get it pulled and see if I can see any wear pattern starting.

 

[tarussell]

This distributor has an adjustable collar, so I think that would take the place of the shims. Unless you're talking about something that just raises one side which sounds like a bad idea. With the new gear on, there's very little movement but with the first bronze gear there was quite a bit. So much that I asked a buddy of mine about it, and he said it was OK since the gear always turned in the same direction, it would always be tight, which made sense until I saw the wear. Yeah, it was tight against the gear, but it was way off and eventually started slipping teeth.
I'm going to double check the manifold, and from there, it would seem that as long as I'm fully engaging the oil pump drive shaft, I should be in the right distance to mesh the cam gear and distributor gear
Didn't get to pull the dist yet, I had some help this afternoon and took advantage of it to bleed the brakes, so hopefully I'll get it pulled and see if I can see any wear pattern starting.

Adjustable collar should give you what ya need - just use the proper gear material.

 

[folkenheath]

It looks like it's a little high, but not way too much.

Bronze gears won't last that long, maybe as little as a few thousand miles or maybe 30K, depending on lubrication, the finish on the cam gear, the load on the oil pump, etc. They are made for steel cam cores and are a consumable item.

You don't want to bottom the gear out on the pump drive shaft, you want some clearance there so when it heats up it doesn't preload the oil pump and make it fail.

I would make a mark with a sharpie where the collar is now on the bottom of the collar on the distributor housing, and then put the distributor in with no gasket, and the collar slightly loose, and push it all the way down to bottom out on the oil pump drive. Then see how much room is there between your mark and the new collar position, once you put the gasket on you should have enough clearance, but that may move it too low, so adjust the collar according to the gear mesh. Don't move it too high either, or you won't have enough oil pump drive engagement.

There have been instances where I make a tiny groove or oil hole in the side of the distributor housing to squirt oil right on the gear, but it's usually not necessary if everything is right, especially with modern hydraulic cam cores and melonite distributor gears.

 

[anwat]

That's exactly how I installed it. And I have a groove for oil, you can see it in the photos. So it sounds like all is well for the time being. I will run it for another few thousand miles and recheck for wear. I just need to play with the timing curves a little to get it dialed in, but with the fitech it's easy to adjust. Thanks for the help everyone....