possible dist. problem (long, but pls read.)

[chrisf]

I have a quick question concerning my distributor.

I have a 76 2.7L, which I’ve recently done a pretty thorough tune up. If you’re interested for more on that, click this:

Timing chain link-o-mystery!!!

(thanks for all the advice guys, much appreciated!)

Got the car all put back to together and it started right up. And oh-my-god, what a difference! It was beautiful; the car just pulled so much better, and ran some much smoother.

But….there was some chatter from the valves, which went away after it warmed up. I was a bit on the conservative side with the clearance, and over the course of a week, the chatter seemed more pronounced to me, and didn’t seem to subside as much once warmed up. I decided that I should re-adjust the valve. I also had been reading the posts on stretched chains and wanted to re-inspect.

The decision was also based on the fact that after I changed the cap & rotor out, a “grinding” type of sound was intermittently coming from the distributor area that coincided with the development of surges in the idle. When I changed the rotor, the distributor shaft on which it rides on “pulled” up from the distributor quit a bit, enough for me to notice. I got the new rotor on, the shaft went back down. I also noticed that the rotor has about 20-30 deg. of spring, in the advance direction. I would believe this would be for the vacuum, but I cannot see the mechanism moving as a result of moving the rotor back & forth.

This past weekend, I tore it back down and also inspected the rotor & cap and can tell that it seems to be rubbing. Got it back together, and it had trouble idling and was stumbing around 2 to 3K. Read up some more (101 & post) decided that proper course was to adjust ABV, AFR, and timing. (Temp drop of around 15 deg F between the 2 tune-ups). Got that done yesterday. Set timing first, then stabilized idle with ABV/AFR combination, reset timing. Idled wonderfully, but will not run between 2-3K (stumbles & backfires), but absolutely SCREAMS above that!
(No more of that until I get this worked out, rest assured). I’m rambling, sorry.

Back at the house, I noticed that there is the stumble/grinding from under cap while idling. This is the problem I believe and the effect is max at the RPM described above. So I will pull the distributor this afternoon and inspect.

If anyone has ever experienced similar conditions or have any advice on what to look for during my inspection and what I should do while the distributor is out, please offer advice.

Also, note that I have not yet changed the points out. Is it a good idea to do this with the distributor out & then do a final adjustment of the dwell once back in the car & running?

Sorry to be so long, and thanks for reading!

[Early_S_Man]

Chris,

The noise and vertical play are indicative of excessive play in the shaft due to worn or missing fiber washer and shims/washers below distributor body and above drive gear. The vertical play should not be more than 0.001" - 0.004". The distributor needs to be pulled with engine at TDC #1.

The following thread has pertinent data and diagrams you need. The vacuum retard module and point plate need to be removed to get at the centrifugal advance mechanism -- which needs to be cleaned and lubed while you are in the distributor. You will need to punch/drill out the pin that retains the drive gear ... in order to replace the missing fiber washer that is approx. 0.060" thick.

distributor lube...

Good luck!

[chrisf]

whoa.

O.k. Early_S_man. I'll have to read up on the link you provided.
There was one thin washer above the drive gear/below the body, no where near the 0.060" you've stated.

I'll start reading. thanks for the reply.

[chrisf]

There are no igition issues as it revs. There is still a slight buck at lower speeds around 22 rpm or so, but its not the ignition.

Car also will idle a little high, but sometimes will set to the perfect idle. Something is getting stuck. If adjust the idle down it will surge as it drops, and then it'll stall. I think its that plate thing.
I'll get it figured out.......

but, its running great!