chasing dist gear wear problem...

[powerslide]

This is the first motor i let a machine shop assemble and appears to be the last. Gear only has about 20laps on it and looks like chit. I checked and the dist goes almost all the way down to the intake without a gasket. i could put pressure down on it and it wouldnt let the housing spin anymore. The wear pattern almost looks like it isnt in far enough.

Looked down in dist hole and driveshaft moves side to side atleast 1/8 of an inch. I cant remember for sure but dont think the other two motors i assembled had this much play. They were both a factory production head and this motor has the usra/imca spec head. Does this sound like my problem? If so does it sound like the sleeve that keeps the pump and shaft together sound worn?

[Dirtrunner35]

The gear is getting worn at the bottom of the teeth ?? Solid cam or roller ?? What kind of gear?

driveshaft ????????

If so does it sound like the sleeve that keeps the pump and shaft together sound worn? ????????????

[powerslide]

the wear starts at the bottom and doesnt go all the way to the top. its a just a little off the shaft side of the teeth on the top and as it goes down it works it's way toward the shaft almost like its trying to dig into the shaft more at the bottom.

gear is brass

roller cam

Could i of got the intake on just a little bit at an angle and it be causing this?

Found original build sheets. says heads were flat milled .006 and angle milled .028. cant find deck height anywhere

i called a couple guys and they all say the shaft should move side to side alot so that doesnt sound like my problem. Any other questions let me know.

[parrot69777]

Maybe your distributor is bottomed out against the oil pump shaft and when you tighten it down....it is forcing it to the side.

[BLOWER]

is cam moving

[powerslide]

Maybe your distributor is bottomed out against the oil pump shaft and when you tighten it down....it is forcing it to the side.

i placed the dist in the hole without any gasket's and still had end play. This should mean its not bottomed out. Right?

[powerslide]

is cam moving

I really hope not. I am going to try it again i pulled intake because it was leaking some oil. hoping maybe somehow it was slightly to one side the first time.

[parrot69777]

You said it "almost" goes all the way down with no gasket. If it isn't sitting on the manifold with no gasket...then the oil pump shaft is holding it up.

The only other thing I can think of is either the cam is too far back, too far forward, or it's moving back and forth.

[hogracer3d]

We now set up the distributor height looking through the rear oil galley plug hole, and we notch the rear cam bearing toward the gear for added oiling

[powerslide]

question. i bought the dist used and it doesnt have the orings on the bottom where the two indentions are. i asked one person if they were needed and was told no. Any input on that possibly being the cause?

[ssr1st]

oil pressure to high? takes alot to turn those high pressure pumps.

[wristpin]

i use a dummy dist. when i put the intake on. It just helps aliagn the dist. shaft. when snugging up the intake. I had problems too in the past. I bought a copostite dist. gear. brass, but when i started using the dummy shaft i have no problems over seeing deck height, no gasket.

[powerslide]

oil pressure to high? takes alot to turn those high pressure pumps.

i hadnt noticed it before this past saturday but it had 80psi when i fired it up. still had 60 after the heat. had ignition issues in feature and didnt get to finish

[mbaker76]

Unless you are only turning 6500, I would not say 80 is too high, its plenty but not necessarily too much. Most of the engines we have run 75-80 WOT, and will still idle at 50 or so hot, at fast idle(1800) and a bronze gear will last over a full season.

Did you check the height of your distributor, and when you say the distributor almost goes all the way down without a gasket do you mean it wont sit all the way down on the intake without a gasket? You should always check the distributor height and shim as necessary to keep from bottoming out the drive. Ideally you want the groove in the enlarged shaft of the distributor to line up with the oil galley in the block. You can either look through the rear galley plug, or measure carefully through the dist hole and adjust the slip collar or shim as needed. At the same time you want to make sure you don’t bottom out the drive shaft.

[powerslide]

Unless you are only turning 6500, I would not say 80 is too high, its plenty but not necessarily too much. Most of the engines we have run 75-80 WOT, and will still idle at 50 or so hot, at fast idle(1800) and a bronze gear will last over a full season.

Did you check the height of your distributor, and when you say the distributor almost goes all the way down without a gasket do you mean it wont sit all the way down on the intake without a gasket? You should always check the distributor height and shim as necessary to keep from bottoming out the drive. Ideally you want the groove in the enlarged shaft of the distributor to line up with the oil galley in the block. You can either look through the rear galley plug, or measure carefully through the dist hole and adjust the slip collar or shim as needed. At the same time you want to make sure you don’t bottom out the drive shaft.

When i said it almost goes all the way down i mean you could maybe get a piece of paper under it. and if you put pressure down on it slightly it touched so i think once you get the gasket under it should be ok. Right?

i have ran a couple times since this original post and its still together i am going to pull it out this week when i get it all washed and unloaded and see if it looks any worse or if maybe i just had the intake on at an angle or something. Lost spark on lap 5 so have to figure out if box went bad or coil or a switch. Running fine then coming out of 4 just died

[mbaker76]

Since the cam gear and oil pump shaft position remain unchanged relative to the oil galley and only the deck, heads or intake get surfaced 9 out 10 times lining up the oil galleys will get you where you need to be and then you use whatever shims or slip collar location you need to fit it.

What I usually do anymore on a new or different motor is take a 12” piece of wire straighten it and make a 90* bend about ¼” long in one end. Stick this down in the dist hole and hook the top edge of the oil galley hole then while holding it straight up mark the wire at the top of the intake surface where the dist sits. Now take the wire and transfer it to the distributor and set your slip collar or use shims so that with a gasket the top of the groove around the bottom of the distributor llines up with the marks on your wire. You can also do the same by pulling the rear galley plug and looking in through there to line it up. This way you have the oil galley lined up with the distributor for proper oiling and it should also set your dist gear to drive clearance where it needs to be. I will usually still check to make sure the dist doesn’t bottom out on the drive and that I have good drive engagement just to check if somebody put the right drive shaft in it