Distributor Shaft End Play/Dimple

[Joe C.]

The end play on my distributor shaft was .009 (1965 069 distributor). I don't remember the end play specs, so I set it to 001. Can someone confirm the range--I think it is .002-.007, but not sure.

There is a dimple on the dist. driven gear, but is it supposed to coincide with the rotor contact? My driven gear has 2 dimples: 1 is more like a centerpunched mark between the teeth of the gear itself, on the bottom of the cog, near the oil pump drive. ; 2 is a much more pronounced depression, about 3/4" above the top of the gear, on the flat area just above the gear, but on the gear "assembly". The funny thing is this: I HAD THE ROTOR CONTACT ALIGNED WITH THE DIMPLE ON THE GEAR TOOTH (although it did not align perfectly with the rotor),AND WAS ABLE TO TIME THE ENGINE. TODAY I PULLED THE DISTRIBUTOR, SEE THE LARGE DIMPLE, TURN THE COG ABOUT 165 DEGREES, AND BINGO, PERFECT ALIGNMENT WITH THE ROTOR CONTACT. So, which dimple should I be looking at, and how should it be aligned with the rotor contact.

Thank you.

[Patrick H.]

Re: Distributor Shaft End Play/Dimple

See John Hinckley's article with the pictures in this month's "Corvette Enthusiast" magazine (formerly Cars & Parts Corvette). It shows the dimple nicely.

I think it's a case where the picture will equal 1000 words.

Your end play specs are correct. Actually, many Corvette distibutors were built with up to .060 end play, so your previous number will work just fine.

Patrick

[Duke W.]

Re: Distributor Shaft End Play/Dimple

The end play spec is two to seven thou and GM shims are .030" and .006", so if you had nine thou to begin and took out one six thou shim you should be at three thou,which is in spec. One thou is NOT in spec. If you can't get at least two thou, leave it at nine.

Your dimple descriptions confuse me, but the dimple that should be aligned with the tip of the rotor is below the gear teeth (distributor orientation as installed in the engine) on the cylindrical section of the part. It is a machined concave dimple about 1/8" OD. It is NOT a centerpunch mark.

Duke

[Joe C.]

Re: Distributor Shaft End Play/Dimple

Duke:

Yes, the dimple is about 1/8" diameter, and is on the cylindrical section, which is below the driven gear. The dimple is below the roll pin, and about 3/8" from the bottom end of the shaft. Is this supposed to be in line with the rotor tip? That is how I put the shaft back together, and it now aligns perfectly with the rotor tip.

I had previously assembled the dist. by aligning the rotor with another "dimple" located between the teeth of the driven gear. This other "dimple" is about 160* around from the correct(?) dimple, and did not precisely line up with the rotor tip (off by about 20*). STRANGELY ENOUGH, I was able to time the engine w/o any problems. What other trouble might this have caused me?

As far as the end play is concerned, as it is now assembled, I cannot insert a .005" feeler gauge between the gear and the shims. The .005" is the thinnest feeler gauge that I have. The shaft spins freely, with no binding, but no discernable end play if I yank it axially.

Joe

[Duke W.]

Re: Distributor Shaft End Play/Dimple

I still have the Craftsman feeler gage set that I bought countless years ago that has gages begining with .0015", .002" and most sizes in one thou incresments up to about .032". My suggestion is to buy or borrow a gage set that will allow you to positively confirm that the end play is in spec.

Duke

[Lonnie Johnson]

Re: Distributor Shaft End Play/Dimple

A lot has been discussed on this board pertaining to this "dimple". Mine is rather strange in that it does not line up with the rotor contact no matter which way you turn it. If you line it up exactly with the contact, the pin will not go throught the hole. If you get it close, I'd estimate off about 1 tooth, it will. Is this typical for the rest or you guys with experience on these distrubutors?

Thanks

[Craig S.]

Re: Distributor Shaft End Play/Dimple

Lonnie - that's fine, it's just to ensure you are not off 180 degrees...Craig