This is a general comment to EVERYONE with regards to purchasing a cam.

There is out there what they call an EVERWEAR gear that cam manufacturers use that will allow you to use a standard distributer gear in lieu of the bronze or other "softer" distributer bushing that DO NOT LAST.

They will need to use a different cam core, but they have them, and it will cost you a little more 25-50 dollars more, but its well worth the money.

I have gotten on on every cam I have ever gotten and they look like new when you pull out the cam, and they are more than compatible with the stock distributer gear.

-------

Usually a sign of pre-mature wear on a dist. gear is caused by the oil pump. It you shim the oil bypass, or pressure relief on the oil pump to hold too much pressure, you will cause more wear on the distributer gear.

 

Can the distributor shaft lift up in the distributor from worn bushings? This would allow plenty of slack.

 

I try to reply to all.
Yes the engine is a new 383. When the builder gave me the car he said that the dist gear was a bit worn. Hom much? I asked.
He replied that if I change it in a thousand miles I'm Ok.
I made about 1500 miles so I decided to change it.
The previous engine (a 355) was with original Dist gear and the original camshaft. When I upgraded to 383 I installed an Accel 219 cam without buying a new dist gear. (my fault).
When I looked to buy a dist gear I see many posts here in the forum and thatnks to CFI EFI, Jake TJWong and many others I bought the melonized one. (The one is referring Jake in this thread). Why?
Bronze gear are for aftermarket cam ...but my 219 is with a cast pressed cam gear....so I don't need a soft one (bronze) I need a stock one. The melonized one is the right replacement.
When i removed the dist (sunday) I was a bit disapointed about the dist gear condition ... I was thinking to see a dist gear tapered (as I saw on many pics of worn dist gears in this forum). Looking at it closely I see how it is worn. Follow me.
Every tooth is long and tall as the new one.
One side of every single tooth is shine (milled, worn..)
now if you see it from the top and dividing it in 4 parts I can say that a 0 degrees the thickness of the teeth is of 90% left (If the thickness of an original one is 2mm the worn one is 1,8..not so much..).
at 90 is at 70 %... at 180 deg is near 50% (half of the thickness of the tooth is worn) and at 270 is again 70%.
I haven't pics of the gear removed but I think I described in a decent manner
I have no idea how the 15 year old camshaft looks...(i'ts on another car now...not mine...)
I have to say that I have an hi pressure oil pump...
What I don't understand is this diffferent wear pattern in the teeth.
-Beppe-

 

Adding spacer reduces back lash between distributor and cam drive gears, i.e. it forces distributor and cam gears closer together. Backlash causes distributor gear to lift away from cam gear under power and to drop back closer to cam gear on off throttle situation. As distributor shaft lifts or drops, it rotates and causes a timing error. When building an engine I always shim the distributor so that there is no more than .030" of vertical travel on the distributor shaft. I hope this explains reason for shimming.

Larry

 

I understand the results... what I don't understand is WHERE these spacers should be added. I was thinking between the manifold and the distributor ...but probably I do'nt understand WHere?? :o

 

My boat has twin 350s, chasing down a miss I noticed the dist. rotor was eating away at half the cap contacts, I took them both to a guy who speicializes on carbs and dist. he replaced the bushings on both and ran them on his machine-end of problem-but I'd say most of the wear you'll find in the dist. is more than likely due to bad bushings.

 

When you remove the gear, shims will be placed between the gear on the shaft between the shaft stop and the gear. Test fit it w/gear on look for play between the gear/shims and the stop to be between .005 -.010 w/a feeler gauge. moroso sells shim packs make sure they are the steel ones.

 

I don't remember if in this location there was som play when I removed the gear... I notice that there is a series of Stepped-Indented whashers... these are able to roatate up to the poit they reaches their built in stops (the stepped-indents) What are these strange washers??
Sorry for all these questions but I like to understand..

 

Those strange washers are for the gear to wear against. They are thrust washers to prevent wear of the distributor housing when the gear moves upward and makes contact. If the washer were to spin relative to the distributor housing, the housing would wear. The tabs or tangs keep the washer from turning relative to the housing. If they will fit, the shims should go between the funny washer and the distributor housing, if not between the gear and the washer.

RACE ON!!!

 

Thanks
I have to bookmark this thread!!

 

Kinda off the main topic, but interesting.

My company makes the bushing that are used in ALL these distributers. Its a pretty amazing process developed by a guy back in the eary 60's. Its a bi-metal bushing, copper on the id, and iron on the od. Compacted and formed together under several tons. Its a spin-off of the many powdered metal components we make. The process is one of only a handful in the world that compact two different powders at the same time to make 1 part.

 

Jesse, do you guys call it an oilite bearing?

 

I believe it's CompCams that just came out with a tool to check for the proper alignment/depth of the distributor in the engine.

If I recall correctly, it's pretty pricey though.

Jake

 

No, but we sell them to many different outfits that assemble the actual distributer housings. We make on the order of about 200,000 per month of these things. Its pretty much been a non-stop line since the 60's on these things! Its amazing how many we make, but most of the parts we make are that way. Make over 20MILLION parts per month! Hard to phathom the amount of components needed out in the world.

Last guy we had in on them , he was building disributers for race boats and was using our bushings for them. If you pull your distributer apart, there should be on in the top and one in the bottom of the housing.

 

I found these pics on the net:
the first is with too much end play...
and the second is with the correct endplay.
In the pic where the shim is used to correct the endplay the shims are between the gear and the "funny" washers.

 

That is correct, don't forget when you pull the gear to allign the dot (drill mark) on the gear, to the the rotor (position)

 

Why?? what's the purpose? I have 50% of possibilities that the concave dot is in the right side...(or the wrong side..)
-Beppe-

 

That is the way the gear is suppossed to be alligned, the dot matching the rotor position. I belive it would be possible to have incorrect timing without this method (distr. to cam).

 

...mmmm the gear is symmetrical.. so the position of the dot should have nothing to do with a correct timing...unless ...this dot provide some mechanical-magnetic ation..

 

Well I look at it like this, if it was totally symetrical and the teeth lined up exactly the same on both sides, why would they bother to put an allignment dot on it.