More dist gear issues

[oldcarnut]

Not sure if this is the right place to post this. Having dist gear issues and wondering how I should proceed. Engine in restored car, 1969 390 previously rebuilt by a prior owner (2002?) with few miles and I don't know what parts were used other than new Venolia pistons and Comp roller tip rockers. When I pulled msd distributor gear was chewed. Noticed when I cranked engine and tried to pull distributor it would bind at a certain spot and not on the rest. Used dial indicator and found cam gear was out of round. (maybe normal?) Ordered matched set of gears from Bulltear. Used dial indicator and cam gear now seemed to be within specs. Installed those on a NOS AMC distributor and put into the car. Ran 100 miles and same thing. Distributor gear has one tooth that has no wear but lots of wear on the rest. Again distributor would bind very hard on one area but when engine turned more became loose. Timing cover does not have AMC part number. I have access to used AMC parts however am not adverse to buying new to not have this reoccur. I was going to try turning the pump and see if I can see oil moving around through the fuel pump hole and if so take the pump off and see if the distributor now goes in easily. Before I do anything I thought I would get some opinions as it seems many people have had this problem.
I can see two possible avenues to take.
1)Check for oil getting to the dist gears, take the front cover off and replace with either used AMC after checking clearances or Bulltear, check the timing gear to make sure it's either an AMC one or that it has the proper oil passages, check oil pump gears or put new ones, change the cam and dist gears to either new Bulltear again or used AMC, change oil filter and oil and put magnetic drain plug. This should rule out the dist, cam gear, timing gear, front cover and oil pump but will not address any cam oiling issues, if the rear cam plus was inserted to far in or any damage that may have been done. It can all be done with engine in the car which is my preference.
2) Take the engine out, check all the above plus the cam and all the bearings.
Any ideas would be greatly appreciated.

[jeepsr4ever]

Where di you place your indicator? Was it on the shank or turned round part of the cam gear? It sounds like you may have a few issues BUT when a can gear goes it always goes a little more on one side than the other. When you say 'Distributor gear has one tooth that has no wear but lots of wear on the rest' that means something is WAY out of round. I would suspect the actual cam bearing spun or you have something more ominous going on. I wouldn't discount runout on the distributor. Check that, check to see if the distributor hole is oversize. If you have a omix ada, silver seal or preform Tcover then you have a Chinese copy of a faulty Taiwanese cover. They never gave enough tooth depth between the gears.

[oldcarnut]

Thanks for your suggestions. I had the indicator on the cam gear so it was difficult to be 100% accurate as I was basically checking the teeth of the gear. Not sure how valid that is since there was no load on the cam. In your second sentence you mentioned when a cam gear goes the cam moves to one side a bit, are you saying when a cam bearing gets spun? Is there a way to know if a bearing has spun? Would I have to take the cam out and see if the oil holes still line up? I will check the runout on the distributor and the size of the distributor hole. I spun the oil pump, first by hand, no binding, and with a tool I made on a drill and I was surprised at the amount of drag there was. Did not see a lot of oil splashing around so I will try it again and look through the fuel pump hole. After checking those areas I will probably start taking it apart. Just not sure if I should pull the engine. The chances of scratching something are pretty high if I do.

[oldcarnut]

I spoke to someone at Bulltear and they suggested I go with option 1. The only other unknown is why the gear did not wear evenly. He suggested I post pictures. I'm wondering if anyone has come across this before.
558559

[jeepsr4ever]

That is a oil pump loading issue. Something went through your pump....probably a chunk of old gear

[oldcarnut]

Thanks jeepr4ever. I'm not familiar with how the oil pressure flows on the engine and have not been able to locate a schematic. Where would that piece go and where would it have come from? I would think not through the oil pickup. Maybe just kept on spinning in the pump gears? At this point what do you think would be the best route for me to take. Should I continue with doing what was mentioned in 1 above? Seems like you have researched this a lot and obviously know more than I do. I know it's a bit of a guessing game and there are no guarantees, just trying to figure out the best.

[oldcarnut]

I decided to take the second option instead of the first. Ended up that the front main bearing was scorched quite a bit and the other a little. The pistons and cylinder walls were good. So the plan now is new main, rod and cam bearings, use a set of old distributor and cam gears from another engine, get a new BT cover and oil pump gears and possibly a new cam. The timing set is a comp cam 3118 which was new from the rebuild that was done. The pistons are Venolia 425 flat tops with recesses for valves. I have not measured the rings yet but plan on using those again if they measure out. I have a few questions that I was hoping for some assistance on.
1) The timing sprocket seems to have the oil slot in the right place and is new. Should I use this timing set again? Has anyone had problems with these?
2) If I change cam any idea of what to go with? I know there are so many factors that come into play here and it's also a bit of what i want out of the engine but ideas may help. The engine is 69 with newer dog leg heads. Larger CCs. I imagine the one in there is a comp cam but it's at the machine shop so he can check the runout on it.
3) Should I get an anti walk kit for the cam?
4) Anything I am not looking at and should be?
It's obvious someone spent a lot of money on this engine. Unfortunate it fell into the dreaded gear issue. Thanks.
565566

[oldcarnut]

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These problems don't seem to go away. Purchased new cover from Bulltear along with new pump gears and gasket. Took distributor gear and matched cam gear from another engine that I had that worked well. The gears were in good condition. New rod, cam, main bearings, new cam. This is what the cam gear looks like after running one hour on test stand. Distributor gear still looks good. Can anyone tell me what would cause this? Thanks. If you need more information let me know.

[oldcarnut]

These problems don't seem to go away. Purchased new cover from Bulltear along with new pump gears and gasket. Took distributor gear and matched cam gear from another engine that I had that worked well. The gears were in good condition. New rod, cam, main bearings, new cam and lifters. This is what the cam gear looks like after running one hour on test stand. The top of the fins are squared off and the left sides of the fins also seen to be worn. Distributor gear still looks good. Can anyone tell me what would cause this? Thanks. If you need more information let me know.613

[tufcj]

Did you replace/check the oil pressure relief valve in the filter cover? The only gear I've ever destroyed was caused by a stuck plunger causing too high oil pressure, overloading the gear. Mine was pushing over 50 PSI idle, and over 100 PSI at 2000 RPM. Make sure the plunger is in correctly (point away from the spring) and that it slides freely the full length of the bore.

Bob
tufcj

[oldcarnut]

Not sure if I replaced it but I did check it and everything seemed ok. This has been going on since last fall so I've forgotten some things. It was pointing the right way and moved freely in the bore. I went through the 12 steps for distributor and cam gear wear and think they are all covered. I used an AC Delco PF24 filter. Any issues with these? Going to go to a Wix next try. When I took the filter apart everything seemed ok. I also don't have the filter bypass blocked off. I checked a main bearing and there was a slight amount of debris. Hope I don't have to do all that over again. I am using an aftermarket timing gear which has 6 slots to sling oil to the chain area. Someone wrote on another forum that they always braze 5 of those slots closed so less oil goes there and more to the cam and dist gears. Have you ever heard of having to do that? Apparently the factory gears had no slots. I also ran warm oil through the oil sending unit hole while turning the engine with the oil pan off. Oil streamed from the normal places and in normal quantities except from the front which seemed to stream quite a bit. Couldn't tell if it was from the front cam bearing or from the timing sprocket slots. Any way to tell if the front cam bearing is ok without taking everything apart again? Thanks tufcj for your input.

[tufcj]

What brand of timing set are you using? I've never had to braze slots shut. I have had to clearance the oil supply slot, some have casting flash blocking them. One thing I could suggest is to remove the fuel pump and spin the oil pump with a priming tool. Watch the cam gear thru the fuel pump hole and see if you're getting a good oil flow thru the cam gear. If you look closely it has small oil holes in it. They should flow a good supply of oil. Another thought is that if the left lifter galley plug (looking at the engine from the front, it's behind the upper cam gear) is threaded in too far, it can block oil flow to the front cam bearing, which oils the cam gear.

Bob
tufcj