distributor 70-72

[Wayne M.]

Re: distributor 70-72

....Makes me wonder how they set the point dwell at the factory as you clearly cannot use the window to adjust the points with the RFI shield in place ......

Robert -- Reading the assembly instructions included with the package: " ... 4. After attaching condenser and primary leads to contact set, put rotor and shaft back in housing and re-install gear.
5. Attach shields to plate so contact dwell adjustment screw is exposed."

So, not being a C3 guy, I must assume that one of the shields has this hole that lines up with the distrib cap window and the hex center of the points adjust screw.

Unfortunately, the person I bought this item from must have wanted just the shields.

[Michael H.]

Re: distributor 70-72

Robert -- Reading the assembly instructions included with the package: " ... 4. After attaching condenser and primary leads to contact set, put rotor and shaft back in housing and re-install gear.
5. Attach shields to plate so contact dwell adjustment screw is exposed."

So, not being a C3 guy, I must assume that one of the shields has this hole that lines up with the distrib cap window and the hex center of the points adjust screw.

Unfortunately, the person I bought this item from must have wanted just the shields.

Wayne,

I remember the "plate kit" that you show above. Somewhere around 1971-72, (?) GM started using a new point and condenser unit called uniset, or something like that. The points and condenser were combined into one assembly.

A month or two later, the original inventor of the uniset sued GM as he held the patent for the concept. Many thousands of cars had their original point plate, points and condenser replaced under warranty. Dealers had the kit in stock so there are probably a lot of these kits still sitting in GM parts departments.

About a year later, GM either bought the rights, or won a court case which allowed them to once again use the uniset.

[Ed D.]

Re: distributor 70-72

Depending on which point conversion kit you purchase determines if it can be detected externally. .Some units have 2 wires coming from the conversion set, where as the points only used one wire.
Ed

[Robert S.]

Re: distributor 70-72

The two piece RFI shield has no hole to permit access to the adjustment screw. So the factory would either have had to set the points by mechanical gap or run the engine without the RFI shield and set the dwell and then take the distributor cap off and install the RFI shield. I cannot imagine, in a production environment, GM having someone take the cap off and reach over and install the RFI shield with their two little screws which, if dropped, would likely fall to an inaccessible spot in the distributor. The RFI shield halves have holes for the attachment screws, not slots, so screws cannot be installed in advance. All in all a rather odd concept from both a production and on-going maintenance perspective.

[Robert S.]

Re: Correction to previous post - distributor 70-72

Well after submitting previous post I went to look at the two piece shield which I should have done in the first place. Had not looked at the part in more than a year. The two piece shield does indeed have an access cutout to allow the point adjustment screw to be adjusted through the distributor cap window. My apologies - pls ignore the previous post.

[Joe L.]

Re: distributor 70-72

The two piece RFI shield has no hole to permit access to the adjustment screw. So the factory would either have had to set the points by mechanical gap or run the engine without the RFI shield and set the dwell and then take the distributor cap off and install the RFI shield. I cannot imagine, in a production environment, GM having someone take the cap off and reach over and install the RFI shield with their two little screws which, if dropped, would likely fall to an inaccessible spot in the distributor. The RFI shield halves have holes for the attachment screws, not slots, so screws cannot be installed in advance. All in all a rather odd concept from both a production and on-going maintenance perspective.

Robert-----


The shield assembly definitely DOES have a hole for point adjustment. See the picture below.

The shield can only be installed if the appropriate breaker plate is also used. Not all plates have the 2 extra tappings for the shield. The correct plate was included with the pictured kit, was included with PRODUCTION distributors originally using the shield, and also included with many SERVICE distributors for earlier applications manufactured after about 1971.

Pictures of the GM #1876065 kit [not for sale] are shown below.

[Joe L.]

Re: distributor 70-72

what is the part number for RFI?

Lyndon------


The RFI shield set was once available under GM #1846216. It was discontinued without supercession in October, 1991.

The shield was also available as part of SHIELD AND BREAKER POINT KIT GM #1876065 (as previously pictured by Wayne and I). It was discontinued in May, 1982. Unless one has the proper breaker plate to allow for shield installation, one needs the kit. However, it might be possible to drill a non-conforming breaker plate and use self tapping screws.

[Joe L.]

Re: distributor 70-72

Wayne,

I remember the "plate kit" that you show above. Somewhere around 1971-72, (?) GM started using a new point and condenser unit called uniset, or something like that. The points and condenser were combined into one assembly.

A month or two later, the original inventor of the uniset sued GM as he held the patent for the concept. Many thousands of cars had their original point plate, points and condenser replaced under warranty. Dealers had the kit in stock so there are probably a lot of these kits still sitting in GM parts departments.

About a year later, GM either bought the rights, or won a court case which allowed them to once again use the uniset.

Michael-----


Yes, the combined point and condenser was called Uniset. However, I think it was released sometime after 1974. The first record I have of it is 1976 but it could have been around before that. As far as I know, all 1970-74 Corvette PRODUCTION distributors used the RFI shield with separate point and condenser.

In May, 1982 the GM #1876065 breaker plate and shield kit (previously discussed and pictured here) was discontinued and REPLACED by the GM #1876600 Uniset points.

[Ed D.]

Re: distributor 70-72

Joe, I know for sure the 72 came with the seperate points and condenser set, not sure of the 73 and 74.
Ed

[Michael H.]

Re: distributor 70-72

Michael-----


Yes, the combined point and condenser was called Uniset. However, I think it was released sometime after 1974. The first record I have of it is 1976 but it could have been around before that. As far as I know, all 1970-74 Corvette PRODUCTION distributors used the RFI shield with separate point and condenser.

In May, 1982 the GM #1876065 breaker plate and shield kit (previously discussed and pictured here) was discontinued and REPLACED by the GM #1876600 Uniset points.

Joe,

It's possible that the uniset first became available in service in 1975 or 76 but the first use was for a VERY short period in production in 1973 or 74. As I mentioned, it was a new release but almost immediately canceled because of a patent that was held by someone other than GM. For the 75 model year, points were no longer used in new cars.

I think that was the reason why the kit to replace the plate/points/condenser became available. GM was no longer able to sell replacement Uniset points and had to supply the kit so the conventional points and condenser could be installed in service.

I don't remember exactly how long after that that the Uniset was again available from GM but 1975 or 76 sounds right.

I may still have the TSB that describes this situation.

[Jim T.]

Re: distributor 70-72

Jim,
The 1970's with the 3 piece shielding did not use and RFI shield. I believe that was up until VIN 11,500 or so. All later 70's , 71's and 72's had an RFI shield.
As I recall your 70 is very close to mine (#14803) so it has the 1 piece shielding so you would need one.
If you have a 70 or 71 LT-1 than you have TI and that would not require an RFI shield.

Dave I still have my original RFI shield that I removed many years ago when I started using the uniset Delco points. I was just curious to know how many points would be lost in judging if the RFI was missing.

[Patrick H.]

Re: distributor 70-72

I was just curious to know how many points would be lost in judging if the RFI was missing.

See #8, second page:

https://www.ncrs.org/sinor/68-72%20Score%20Sheets/68-72%20Mchncl.pdf

[Michael H.]

Re: distributor 70-72

Michael-----


Yes, the combined point and condenser was called Uniset. However, I think it was released sometime after 1974. The first record I have of it is 1976 but it could have been around before that. As far as I know, all 1970-74 Corvette PRODUCTION distributors used the RFI shield with separate point and condenser.

In May, 1982 the GM #1876065 breaker plate and shield kit (previously discussed and pictured here) was discontinued and REPLACED by the GM #1876600 Uniset points.

Joe,

I just got off the phone with an old friend from GM. I mentioned the issue with the Uniset points and he said he definitely remembers the issue with the legal dept at GM and the patent infringement. He didn't remember exactly what year but agreed that it was around 1973 or 74 and also that new cars were called in to replace the Uniset and point plate etc.
He still has a LOT of paperwork from late 60's and 70's GM and he will see if he has something on this issue.

I knew my memory wasn't completely gone.