Hi

I have the 327/365 in my '65 Coupe.
i'm not very knowlegable on distributors and engine repairs so please excuse me if this post seems a bit disjointed or confusing but it's the best I can explain it.

When I bought the car a few months ago I was told the distributor needed to be recurved. I took it to my mechanic - he is the only one who touches my car so far and came highly recommended from a friend who also has a '65.
After replacing the points and trying to recurve and redo the timing my mechanic said he couldn't get the timing set properly because the bushings were worn. As I understand it that means as the timing was changing constantly because of the movement of the shaft because of the worn bushings?
Anyway, since I had the cataloges from the Vette suppliers we went through the Long Island Corvette cat and bought the following:
new shaft (the hi-perf one for the 365hp motor)
springs and weights
baseplate and wire
vacume advance
tach driven gear
lower gear and lower gear pin
upper shaft bushing and lower shaft bushing

Two days ago he rebuilt the distributor with the new parts. Again he said he can't get the timing set correctly. On the first try after setting the dwell (with some meter) and than setting the timing with the timing light we drove the car and it wouldn't get out of it's own way and it sounded really bad. He immediatelly said it seemed as though something on the front of the engine "slipped" (maybe a harmonic balancer - I'm not really sure or can't remember what he said exactly) but that he could probably get the timing set by ear and by driving the car.
After almost another 2 hours of playing with it it's SLIGHTLY better than before we started with all the new parts but barely. Previously, the car would rev to 6000rpm than the engine just wouldn't go any further. Now it will go to about 6300rpm but still no further. Also, low end torgue is not what I think it really should be.
I really don't rev the engine up very hight when i'm driving it but I DO want everything to be right and everything set correctly regardless.
Now he tells me we need to get a new "vibration dampener" and that will allow him to properly get the timing set correctly.
Does this sound correct???

The first time I took the car to him was for the distributor recurve (and a few other things). That was $300 and I still left without proper timing. Than I got the parts which cost me over $200 from LICS and than the labor charge again the other day of $270. I've already spent almost $800 and it's still not right and calling around locally this "vibration dampener" runs about $70 and it will be about 1.5 hours labor to install for another approx $112.50.
Am I wasting my time (and more importantly my money!)? What's going on here?
Please Help!
I'm to the point that I've lost confidence in this mechanic and since I can't do the work myself, does anyone know and can recommend a good shop or mechanic in the Delaware or surrounding areas.

Barry

 

I'm sure others more knowledgeable than me will weigh in but I do not think timing has anything to do with worn shaft bushings. The Dwell will vary and you may miss at high RPM but the actual timing has nothing to do with the shaft wobbling in the housing.

To set the timing, your mechanic should be experimenting with springs and weights. All of this (of course) depends on the ability to read the timing which depends on the mark on the harmonic balancer.

Before condemning your balancer and hitting you up for more $$, he should verify TDC using a piston stop and make sure TDC (measured) matches the notch on the balancer. IF the outer ring of the balancer has slipped, then the timing will be way advanced or way retarded.

Brian

 

Brian
I understandwhat your saying. He did say the worn bushings were affecting the dwell - causing it to change at higher RPM's which is why we changed the bushings. He said as the dwell changed it would affect the timing advance. that is how I remember him saying it but since I didn't understand this stuff completely to begin with I may have understood him wrong.
The worn bushings were the main reason we went thru the entire distributor rebuild.


Barry

 

This isn't rocket science - if your distributor has been properly rebuilt with new bushings, correct clearances and end-play shimmed to less than .010", it should be good to go (assuming that the centrifugal weights and springs are providing the correct advance curve); if you're going to enjoy the upper end of the tach, you should also have high-spring tension points. Stock points have 19-23 oz. tension, and usually will start to float over 5000 rpm; get a set of Accel or Borg-Warner A112HP or Standard DR2270P points - they're all 28-32 oz. tension and will support 6500 with no problem.

Step #1 is to verify the TDC index line position on the balancer to ensure that it hasn't slipped, so you have an accurate TDC reference point from which to set your timing and map your advance curve. This is done with a piston stop tool, takes less than an hour. If your mechanic doesn't know this, you need a new mechanic who understands these old cars.

 

JohnZ

thank you!
Between here and your other response on CAC I have a game plan. I'm trying a new mechanic and I'll also tell him what to look for.

Barry

 

The OE 327/365 ignition map is the best ever produced by Chevrolet, and I recommend it as a baseline for all SHP engines.

Centrifugal curve is very aggressive with all 24 deg. in by 2350 engine revs. On engines with milder cams than the 30-30 this may have to be slowed to avoid detonation.

The vacuum can provides 16 deg @ 8", and the infamous NAPA/Echlin VC1810 has the same specs.

These distributors were indifferently assembled, and few have had anything other than points, condenser, cap and rotor since they were assembled by GM. My experience is that with snug bushings, a snug wobble free breaker plate, the high breaker arm tension points, and end play within the two to seven thou spec they will provide reliable ignition to 6500+.

The best you can do is rework your dist. to "blueprint stock".

John - the number I have for the Standard Blue Streak 28-32 oz. points is DR2371XP. The "2270" is the standard 19-23 oz. tension set.

Duke

 

Yup, you're right - I had a spare used 2371XP set stored in an old (wrong) box.