'46-98

I'm sending off my starter, from my 1946 straight 8, for a rebuild. There does not seem to be much out there in original starters.

Has anyone converted this engine to a modern 12 volt starter?

Tedd Thompson

Unless you are running some kind of hi compression engine there is really no reason to go to 12 volt. The main reason for bad starts is generally poor grounds a weak battery and to small of battery cables. They started for 70 years with 6 volts they will for another 70 if cleaned up and the correct parts are used ....Tedd

47 Convertible

My Hollanders Interchange manual shows no interchange for your starter. Getting it rebuilt per Tedds suggestion is probably your best option if you can find an old fashioned auto electric shop that might be able to source parts such brushes and bearings/bushings plus do labor such as turn the commutator if necessary.

If no shop like this in your area check with other vintage car people or check shops that advertise in Hemmings Magazine. Always a good idea to ask for references.
Jerry

'46-98

When I bought the car and it had already been converted to 12 volts. She has an air ride system a nice Ron Francis wiring system and modern gauges. I have 3 other vintage vehicles with 6 volt systems and have no issues with using a 6 volt system.

I had the starter over to a local rebuilder and he says the starter is engaging too fast with the 12 volts, causing the odd grind. He will check to see if he can order a field coil to convert my present starter to 12 volts, if he can't he said he could adapt my internals to 12 volt. I'm still not sure about the solenoid as it is ment for 6 volts.

Tedd Thompson

That is a little different. I at one time put a step down resistor on a 46 chevy truck that was boosted to 12 volts then dropped to 8 volts to keep the lights and gauges working. Kinda a half *** way of accomplishing the same-thing. I don't remember it being a problem. Doubtful I would do it again though.... Tedd

'46-98

Tedd
Can you point me towards information about your previous step down resistor? Was it just for the gauges or did it step down the starter as well?
I have talked with the rebuilder looking at my starter, he said it is engaging too fast with the 12 volts. He said the field coil in the starter could be modifited to 12 volts. But I would still have the issue with the solinoid on the starter as it has an internal 6 volt relay and these solinoids are no longer available.

I'm thinking of possibly putting in an 6 volt battery just for the starter if that would work. Running a converter off the 12 volts with a trickle charger to charge the 6volt battery seems convoluted.

Tedd Thompson

This was back in my high school days but as I remember the starter still took a full 12 volts . There was a relay coming off the battery and it had a step down off of it for the gauges and the lights. If I remember correctly it read about 7-8 volts and it wasn't a problem for the head lights which were still 6 volts or at least I don't remember changing them or blowing any out. The step down was a roundish 3 inch affair like a huge ballast resistor. I have no idea what make it was but it worked till I sold the truck.... Tedd

Andreas.Johansson

This is how I did it on a old Hudson I had, use a old style battery with open plates between the cells and connect to the plate that has 8V. You need to have a separate cable that supplies the starter only and the rest of the car need to be connected direct to the battery +. Worked out fine for years even if I was a little skeptical in the beginning.

'46-98

I found a thread that has the same issue as my starter. It was in regards to an 1940 with a peddle engaged starter than was grinding when it had been converted to 12 volts. Their solution was to place a spacer in behind the clutch to shorten the engaging distance to compensate for the faster starter motor spin under 12 volts. I will see if I can achieve similar results first by changing the solinoid engaging arm length to see if I can change the timing of the pinion engagement. (going to be a few days it's extremely cold out)

On another note I received email notice of a reply to this thread and I does not show up for me.
Anyway it was in regards to converting the starters 6 volt relay style soliniod to the later model 1953 Oldsmobile 12 volt solinoid. I was suprised to find that Rock Auto list soliniods for these cars, but I am not sure of the accuracy. Was 1953 the year for Oldsmobile converting their line to 12 volts, or just some of their cars? Rock only lists soliniods for the Super 88 in '53 and according to my Motors Manual the cross reference for the offered parts would test out at 6 volt units, also Rock lists all models in 1953 as 12 volts regulators.
On Rock Auto 1954 -56 Oldsmobile solinoids show as testing at 12 volts on Motors Manual.

I have found a supposed 1953 NOS 12 volt soliniod and was wondering if anyone could check out the part number for me to confirm 1119966.

Tedd Thompson

I can't help you on numbers but 53 was the first year for 12 volt and I believe it was through out the whole line not just super 88"s.... Tedd

'46-98

So I found a company online, Vintage Auto Garage, that sells kits to convert vintage vehicles to 12 volt systems. They offer a GM1202 solenoid as part of their conversion kit for 1940- 54 Oldsmobiles, and sell it as a separate unit. The company was very helpful in answering my fitment question and I will probably order one.

I am a bit confused though.
The part looks exactly like an AC Delco U943, and lists as a replacement on the Rock Auto site as 49-53 Oldsmobile. But the strange part is that it also replaces from the late 40's (6 volt) into the 60 and 70's (12v) on many GM applications No specifications list the voltage of this solenoid works for both?

Andreas.Johansson

I have a 1953 Olds S88 and can confirm that it was the first year for 12V on all models.
If it helps, I believe Caddy went for 12V the same year.

'46-98

Thank you for all your suggestions.

I think I have found a solution to my starter grinding, both the starter and soleniod had already been rebuit by the previous owner. I had the starter checked out by a rebuilder and the only thing he found was that they had used brushes for a 12 volt starter. I think my issue was the starter would spin faster with the 12 volt application. The solenoid plunger/engaging arm was set to the proper 6 volt lash. During bench testing the starter bendix would deploye quicker when more of the plunger was inside the soleniod. I thought I would do trial and error by adjusting the arm length that screws into the plunger. I starter off by screwing the arm adjustment bolt all the way in, which is about a quarter inch shorter than the recommended setting for the 6 volt lash. My starter at this setting is working strong with no grinding.

I did find and order an 12 volt soleniod that is supposed to bolt on my original starter at Vintage Auto Garage.
If anyone has or knows of a starter for these cars, I have an ad it the parts wanted section.

47 Convertible

Hi Nick, Glad you found a fix for that starter problem. The only other thing I could have suggested would have been the dual 6V batteries someone else sugge4ed with some kind of isolater to restrict starter circuit to 6V and let other circuits run on 12V. Sounds like you are well on your way to becoming a resident expert on Straight 8 Oldsmobiles and soon others who have them will be turning to you for advice.
Jerry

'46-98

So I have found a modern gear reduction starter for 1951 Oldsmobile V8.
ttps://www.ebay.com/itm/1951-1953-OLDSMOBILE-6-Volt-to-12-Volt-HIGH-TORQUE-MINI-STARTER/273017198748?fits=Year%3A1951%7CMake%3AOldsmobile& hash=item3f9117d89c:g:hm0AAMXQCgpRs9Jz

Seller (not the best rating) states that it should work for my straight 8. I have asked for diamensions as I have throttle controls and gear shift linkage in the area of the starter location, but it also has a 3 position nose plate for clearance adjustments.

Any options whether this starter would work in my application?