I am in the process of installing new guts in the distributor. I put a new lower bushing and main shaft in it so far, and was wondering how tight a fit this should be. It takes a pretty firm pressure to turn the shaft right now. Is this just because it's new, or should the shaft spin freely?

Thanks,
Jeff

 

The shaft should spin freely. If not, it will not get adequate lubrication, and you will score the shaft and the bushing.

In most cases, the cause of a tight bushing after installation is that the upper and lower bushings are not in perfect alignment. Try inserting the shaft upside-down: insert it just into the lower bushing and see if it spins easily. If not, the bushing needs to be reamed. If it spins nicely, but not when you engage the shaft in both the upper and the lower bushings, it's because the bushings are slightly "cocked" in relationship to one another. To correct this, you can insert the shaft down through the upper bushing until it hits the lower bushing. Using a flashlight, look up into the lower bushing to see which "side" of the bushing the shaft is hitting. Then, pull the shaft out of the upper bushing and insert it upside-down into the lower bushing. You can now use a rubber mallet and give the shaft a few swift blows on the side to "straighten" the lower bushing.

After a few hits, you can get the lower bushing in almost perfect alignment with the upper, and the shaft will spin freely. Whatever you do, don't install it with a tight shaft: you'll loose the shaft and the bushg, and you'll pump metal through ytour engine oil system.

 

Thanks Lars, I was afraid it felt too tight. I'll try your suggestion this weekend. I've got a fresh rebuild on the motor, and sure don't need to be pumping metal through it!!!

Jeff

 

Make sure to remove the upper breaker cam from the shaft and "free" it up too. There are grooves in the upper part of the shaft for lubricant to be applied to. Take the centrifigual advance springs off and the two parts shpuld seperate freely. I use a old can of Red Line Oil synthetic moly grease that you cnt buy anymore for lubrication. I used to mix STP with some thicker molly grease to thin it out, you may want to do this. The upper part of the distributor also has a "well" below the upper shaft seal that needs to be filled with the grease type lubricant. STP thinned synthetic grease would be a good substance or Extreme Pressure Moly lube from a machine shop is another alternative. I find 75% of the distributors I check have frozen points cams in them. Frozen cam = no centrifugal advance in your distributor. Put some molly paste between the two plates in the top where the advance springs and weights go onto. Make sure you orient the advance weights in the proper direction, years ago, I "fixed" a guys Z/28 that had the weights installed backwards! I NEVER use the lightweight springs in a "tuning kit" if your swapping advance springs out. I like a set of springs bringing the advance in by about 2500 RPM. Good Luck, I'm glad there are other people out there who do the right thing, I HATE MSD Distributors on Vettes (I have enen seen them on a 68 L-88 Vette in a "Concours Car show" ARGGH!)

 

Thanks for the advice, guys. Now another quick question - I just noticed after looking at an exploded drawing in the parts catalog that it shows a "distributor housing oil seal" and a "distributor housing oil seal washer (felt)" where the shaft comes out of the top of the body. Mine did not have either of these parts when I disassembled it. Are they necessary?

Man, I'm never going to get this car back together - every time I turn around I'm missing parts!

 

Yes, the two parts are neccessary. You need to pack the upper well with wheel bearing grease (after cleaning out the old, custy stuff that's proably in there now), and then the plastic seal washer presses down on top of the grease wad to push it through the upper bushing hole and to keep the grease from polluting the inside of your distributor. The seal is actually available brand new from GM (I buy them in 10-packs). You can also get both the seals from Paragon.

 

Thanks Lars!

Jeff