How-To: Studebaker Delco Distributor Rebuild

If you've been following the past few posts, you've read of the self-destruction of Barney's Prestolite distributor, and my being gifted with a Delco distributor core (see A Drive To Perris). At first I thought maybe I'd send it off for a professional rebuild, but decided on doing it myself, mostly because I got antsy and didn't want to wait, but also because I was told what an easy job it was.

Amazingly, my searches of the Web turned up absolutely NO tutorials on how to go through a Delco distributor, so hopefully this will help others seeking this information. It's actually pretty simple. And here's a plug for the necessity of having the Studebaker shop manuals: the disassembly and reassembly instructions Studebaker provided are better documented and photographed than the procedure I found in my '67 Pontiac shop manual! If you are embarking on a Studebaker project, I strongly urge getting a set of Shop, Chassis and Body manuals for your car - they are absolutely invaulable.

Many folk associate Prestolite distributors with Studebakers, but in fact Delco spark-slingers were used on Stude V-8s through most of the 1950s and into the 60s. The advantage of the Delco is that parts are easier to come by; additionally, two model years (1960 and 1961) used the common Delco "window-type" unit that any GM fan is intimately familiar with. It's called a "window type" because the cap has a small metal "window" that can be slid up to facilitate setting the point dwell while the engine is running - a massively convenient perk. Another perk of running the Delco is that you don't have to get "the look" from the counter guy at your FLAPS* when you ask for Studebaker parts; you just tell 'em you need distributor parts for a '61 Impala and you're golden.

Bob Johnstone, the keeper of all Stude technical knowledge (check his tech site at www.studebaker-info.org, if you haven't already) posted the following numbers for Delco-Remy distributors with Studebaker applications. This number can be found on a stamped aluminum collar in a machined groove just below the distributor head:

• 1110839 - All 1953, '54 and '55 V8
• 1110864 - All 1958 & '59 V8, 1960 289 cu. in. V8 only
• 1110869 - 1960 259 cu. in. V8 only
• 1110969 - all 1960 cars w/V8 (except Hawk) & all 1960-61 trucks
• 1110969 - 1961 259 cu. in. V8 only
• 1110864 - 1961 289 cu. in. V8 only
• 1110981- 1960 & '61 V-8 Larks, all (this is the "window-type" unit)
  

My Delco is a 1110981 - the desirable "window" unit. Although this is only correct for the two model years shown above, it will fit any 259 or 289 Studebaker engine. So, off we go!

My first step was to clean the sucker off. As you can see, the sucker had acquired a nice suntan of surface rust; Warren showed me a junk V8 engine he'd pulled it from. It looked like it had been outside without a cap for a while. But mechanically it was fine; the rotor shaft had no side play and runout between the drive gear and adjacent brass bushing was within the spec called for in the Studebaker shop manual (.036" - .068").

I pulled off the old points, condenser and vacuum advance, as well as the homebrew primary lead. With a little exercise and the application of some trombone slide oil, the breaker plate began to move freely, so I elected not to fully disassemble the unit by driving out the pins that hold the drive gear and oil pump drive shaft to the rotor shaft. The advance weights were hard to get off due to the light rust on their pins, but the trombone oil freed those up as well, and I stowed all the removed parts in Ziploc bags.

Since I'm the kind of guy that likes to make things look good as well as work well, I set to work with a Nyalox abrasive wheel. This is a "wire" wheel that's made of impregnated Nylon - it strips paint and rust quickly without harming the metal underneath or leaving that telltale "brushed" look on metal surfaces. I think I got mine at Home Depot, but you can buy them direct from the manufacturer, Divine Brothers.

I carefully unlocked the irreplaceable aluminum Delco tag from the machined channel and proceeded to buff off the surface rust. The Nylox wheels work with amazingly little effort, and in no time the distributor head casting was nice and shiny. The next step was to shine up the advance weight mounts, breaker plate and breaker cam.

On the advice of Jeff Rice, I used my Dremel tool with a small steel brush to clean the rust from the interior parts. The breaker plate appears to be chrome plated, so it was rust-free; the breaker cam and advance cam were another story. I cleaned up the advance parts first, getting all the rust off the surfaces that the centrifugal advance weights slide on. The advance pins had a little bit of wear on them. but not enough to render the distributor shaft useless.

I didn't want to touch the breaker cam with the Dremel wire wheel, so I used some 2,000-grit emery film to polish the rust off of it. Then, my favorite non-abrasive metal polish, Nevr-Dull, was used to further polish the cam and breaker plate. I love this stuff; it's basically a chemically-impregnated cotton wadding that removes rust and other staining from metal parts, depositing a thin layer of lubricant protectant as it works. Soon, the delicate bits were spic 'n span.

After that, I took the Nyalox brush to the two advance weights. They had sustained some pitting, but cleaned up well. Mr. Gasket and other speed-parts suppliers make replacement weights for these distributors, but I'd rather re-use than replace when possible :) With the upper bits clean, I put a small brass cup brush in the Dremel and cleaned the light rust out of the interior of the base casting using the large access hole in the breaker plate.

At this point, with everything cleaned up, it was time for paint. Using painter's tape, I masked off the moving parts and the section of the shaft housing that must remain plain metal. Note that there is a large hole in the bottom of the casting that allows the distributor primary lead to exit; you'll need to cover this from the inside to keep paint from getting into the mechanicals.

I like Rustoleum red primer because it's specifically formulated for rusty metal, and even though I'd cleaned all the rust off, there's no sense taking chances! After a couple of coats of primer, I shot it with black engine paint and let it dry overnight, followed by a second coat of engine black the next morning. By midday, the paint was hard and the tape came off. Things looked great!

I used a little dielectric grease to lubricate the advance weight pins and re-installed the weights. Note that the mounting holes in the weights are tapered; if you turn them over you can discern that the hole diameter is slightly larger on one side than the other. Slide them onto the pins with the large side down, toward the advance cam baseplate. Note that there is a small, button-like raised area in the baseplate that the weighs rest directly over and must slide upon; a little grease in this area is a good idea as well to keep them moving smoothly.

You can get replacement advance springs from a number of manufacturers; just ask for the kit for a '61 Chevy. I chose Mr. Gasket, although Moroso, Accel and others make them. I suppose your friendly GM dealer might have springs too (if he's still in business). The Mr. Gasket kit includes three different spring weights to customize your advance curve; on the advice of SDC member and distributor guru Harry "Bud" Alenik, I installed the gold OEM-weight set. Harry explains:

"Most of the aftermarket springs have more tension than the springs originally installed in stock Studebaker Delco distributors. Studebaker engineers specified full advance at 2400 rpm where most other manufacturers specified full advance somewhere above 4000 rpm. I've found that the guys at Studebaker had the advance set at an optimum point for good engine operation without detonation. I've found that by using the stock advance and setting the base timing around 8 deg. BTDC, that a stock V8 will make plenty of power without detonating. The R series engines still use the 2400 rpm full advance, but limit the amount of centrifugal and vacuum advance to keep the high compression engines from detonating."

Should you choose to play with your advance curve, I've documented the spring weights and the timing advance each set provides on this post.

 The next thing I did was to install the new vacuum advance unit (or "spark modifier", as the shop manual refers to it). I got this from NAPA, it's Echlin part #VC680. Wrong! The correct advance part is VC1765 - see this post for more. It's held on with two screws, one at the edge of the base and the other just under the edge of the breaker plate. To install it, you must rotate the breaker plate so that you can get the vacuum can's actuator rod into the hole in the plate. It takes a little maneuvering to get it in there, but once you get the rod at the right angle, it slides into the hole easily. I put in the screw that holds the unit to the rim to hold the unit in.

There is a black wire crimped to the breaker plate; this is what supplies ground to the points. I slid it under the head of the second vacuum advance attaching screw as shown in the pic to the right. If your ground wire has gone missing, you can get a replacement from NAPA; it's Echlin # LW42. It comes with two spade-lug ends; you can attach the other end under the nearby pointset hold-down screw instead of trying to crimp it to the breaker plate.

I installed a rubber grommet in the hole for the primary wire; this is just a standard 3/8" wire grommet that you can get from the bins at any hardware store.

With the advance unit in place, I installed the pointset. I opted for a "Uniset" combo unit; this is an all-in-one part that combines the breaker points and the condenser into one unit and eliminates fiddling with a separate condenser and lead. You'd think this would be an inexpensive part, but I found that as the use of points has decreased, the cost of pointsets has increased. NAPA wanted $35.00 (!) for the Uniset points; I opted instead to order them for half that price from Studebaker vendor Chuck Collins. They are Borg-Warner #A2120, although I'm sure other manufacturers have them as well. Chuck, as always, got the goods to me immediately; I ordered on Thursday and they arrived on Saturday. I also ordered two new distributor mounting gaskets.

Now that the points are installed, you've got to lube the breaker cam. This is also known as the "rubbing block", for obvious reasons: the points rub on the octagonal cam as it rotates; each time it rubs over one of the cam's corners, the electrical connection between the points is broken. Even though the bit of the pointset that contacts the rubbing block is plastic, without lubrication the block will wear. If you've never had a car with points before, you may not realize that there is a specific kind of lube for this, a silicone grease that is smeared onto the cam to protect it. This has to be renewed periodically, too, so it's good to have a tube around. My old tube of Lubricam has seen duty since the mid-'80s and still has plenty left. Bosch still makes it, as well as some other manufacturers, but you may have to go to a real speed shop to get it - the NAPA and Pep Boys near me have none in stock.

With lubrication taken care of, it was time to put on the rotor. Again, NAPA had the part, Echlin #RR1670. I opted for the Heavy Duty part, since the contact is constructed from heavier brass than the standard-duty part. In Delco distributors, the rotor fits right over the advance weights, covering them completely, and screws to the advance cam. On the bottom of the rotor are two lugs; one round, one square. They fit into corresponding holes in the cam so you can't install it 180º reversed. Once the rotor is screwed down, hold the shaft and twist the rotor counter-clockwise; you should feel some spring resistance as it rotates; release it and it should snap back. This verifies that the molded webbing on the bottom of the rotor is not interfering with the operation of the advance weights and springs.

The last bit inside the distributor is the primary lead. I threaded this through the newly-installed grommet in the base and attached the spade lug to the screw provided on the front of the pointset.If you're missing the lead or yours is boogered up, go to NAPA and get Echlin part #LW67.

After that, it's time to install the cap. Unlike the Prestolite cap, which attaches with a pair of spring clips mounted to the base, the Delco cap has a spring-loaded hold-down on each side. A notch machined in the base of the distributor body accepts the tab molded into the bottom of the cap, which positively locates it and keeps it from rotating; simply place the cap on the base and use a flat-blade screwdriver to depress the hold-down, then rotate it so its ear is beneath the locating notch underneath the cap and release it; it will clamp the cap to the base. Repeat on the other side. The cap, by the way, was also gotten at NAPA: Echlin #RR1650. This is the matching heavy-duty cap for the rotor, with brass terminals instead of aluminum.

That's it! She's assembled and ready to be dropped into Barney's engine. I'm hoping I get the chance to do this tomorrow - stay tuned for further developments.

Thanks to Warren Webb, Jeff Rice, Bob Johnstone, Bud Alenik and all the guys at the SDC Forum for their help information.

*FLAPS -- Friendly Local Auto Parts Store.