points rub block lubrication

Moderators: 330GT, abrent

Post Reply
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

points rub block lubrication

Post by Jumprun »

I had an interesting failure on the way back from Concorso in Monterey. Cylinders 7,8 and 9 took a vacation, so the best explanation was the set of points that fire those cylinders bought the ticket, I was correct.

The failure of these essentially brand new points in the left distributor was the rub blocks of both sets of points prematurely wore down enough after only 1,000 miles to close up the points. I initially lubricated the cam and felt wick pad with a somewhat thick, special Bosch distributor grease I've used for many years. The owners manual says to use "olio vasalina"

Another mystery is the right distributor shows no debris or powder from wear like the left side, despite being lubed the same way.

Does anyone have any thoughts? should I use vasaline? I wonder if the rub blocks are defective?

Best Regards from SoCal---Tom M.
John Vardanian
Posts: 1906
Joined: Wed Sep 04, 2002 12:13 am
Location: San Francisco Area

Re: points rub block lubrication

Post by John Vardanian »

Even if you had used no lubrication the rub block should not wear away like that. It cannot be substandard material because the others did not wear the same way. I am thinking the pivot pin hole was too tight and the block rubbed against the lobe under excessive friction.

Sometimes an early sign of this upcoming failure my show at the flywheel. If your timing mark jumps around at hi rev that might mean that the points are sticking or floating.

john
PF Coupe
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: points rub block lubrication

Post by Jumprun »

John, thanks for the reply, that is a good point (pun intended) I can't thing of anything else. I just removed the other distributor and confirmed that everything looks good, gap ok and no abnormal wear with the cam and wick retaining a light film of grease.

I'll assume the fit between the pivot pin and rub block hole should a close slip fit. I measured it and it is 6mm. I have a complete set of points on the way so I can start from scratch.

On a tangent to my problem I learned something valuable, which is probably common knowledge, I discovered its far easier and quicker to remove the distributor to work on the points than to do it in-situ (dope slap to the head)
I initially spent much time and spewed many bad words at Enzo's ghost trying to set the points in the car.
Any other comments are still welcome.

Regards from SoCal.--Tom M.
John Vardanian
Posts: 1906
Joined: Wed Sep 04, 2002 12:13 am
Location: San Francisco Area

Re: points rub block lubrication

Post by John Vardanian »

Hi Tom, yes it is much easier to work on it out of the car and less chance of dropping a wrench, chipping paint, etc. You'll also see if your lip seal are leaking.

john
PF Coupe
enio45
Posts: 826
Joined: Wed Jul 02, 2003 6:56 pm
Location: Gilbert, AZ

Re: points rub block lubrication

Post by enio45 »

in the past yr or so, i have heard that there has been a number of failures to the points rubbing blocks failing at @1000 miles. Exactly as you have described....so obviously there is some issue with defective ones out there. I talked to GT Car parts and they have confirmed this issue they have also experienced. Their solution - go the the electronic pickups in the dist....

We did go this route with a recent 330GTC car and am very happy with the results.
Ed Montini
330 GT 2+2 Series II - 8289
58 Ellena - 0855GT - orig drivetrain
87 El Camino SS
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: points rub block lubrication

Post by Jumprun »

Ed thanks for the reply, I bought another set of points from GT to try again, I should mention the failure to them.

I have had good experience with electronic pick-ups such as Pertronix on other cars so I'd be interested in converting. What brand or part number is working for you?

Tom in SoCal
User avatar
michaelbalk330
Posts: 130
Joined: Fri Feb 06, 2015 8:28 am

Re: points rub block lubrication

Post by michaelbalk330 »

pertronix has a few models- Pertronix MR-1121A Ignitor Ignition Module for a 6 lobed cam, and a different model ( I think its 1122 ) for 3 lobed cam. the issue is you need to change the resistance if you go pertronix- too much current and they burn out apparently (I spoke with the engineers after reading about it in the manual ) and there are plenty of stories on the web about pertronix dying----- likely they didn't add a resistor as specified.
I am running a lobe sense ( not powered, no magnet reluctor) pick up from the 70s- it senses the cam lobe as it goes by and sends signal to an electronic box like MSD.
Pertronix makes a LS model ( lobe sense) 1181 LS for Delco distributors, and it works in the same way as my motorola. I have no other info, but it too would be an interesting, simple,"no moving parts, nothing to burn out" approach to reliability. Nothing touches anything, and metal going past a magnet induces field change so its a law pf physics. As long as the lobe sense pick up remains in place, it will work.
In the pic you can see where there use to be points and at about 5 pm there is the magnet lobe sense pic up..
330 Gt distributor - 01.jpg
330 Gt distributor - 01.jpg (180.89 KiB) Viewed 6125 times
Michael
1967 330GT #9693
1960 190SL
1967 Ducati 350 Sebring #04783
1959 Moto Guzzi Galletto #GNR93
1973 450SL
1988 Mercedes 300CE 5 spd
Jumprun
Posts: 276
Joined: Wed Aug 01, 2012 6:28 pm
Contact:

Re: points rub block lubrication

Post by Jumprun »

Thanks for all the replies. I might have found the problem that prematurely wore down the rub blocks in that one distributor. When I went to replace the points, I made sure the 6mm hole fit the pivot shaft freely with no binding. I then added the small metal washer and the phenolic washers to the stack, of course followed by the E-clip. I now noticed a bind to the action and quickly discovered that the phenolic washers were too thick, causing an axial bind so I sanded a few thou' off the washer to free things up. The bad part is I think I knew to check this before the failure but I guess I neglected that aspect of the assembly.

--Tom in Socal
Post Reply