Per,
Thanks for the reference, I read through those posts. Walt Mordenti says you can drive fast without OD as long as you warm up the engine right. You have suggested greater caution. Cassady drove his 49 Commodore real fast cross country, but the book never identifies the motor or if he had OD. When my 48 is sorted out, I'm going road-tripping, so I'd like to cruise at 65. How hard is it to retrofit OD?

On the topic of the flashing oil light, the regularity of the flash suggests that it is not a short in the wire, and that instead, the valve spring is returning with each pulse of the oil pump when under load at high revs. Could it be oil viscosity? Or is the car sending me a message?

Josh,

Thanks for your quick response! As I mentioned in one of my comments, my desire is that my engines outlast me. I guess I'm just getting old. A 1946 six cylinder Pontiac owner's manual I once saw said that, "if you typically drive your car more than 45 miles per hour, you will eventually need expensive motor work". (The marketing people removed that statement from more recent manuals!) It was not easy to convince people, when the average car had 3 gears, that there was a limitation like this. Now I can point to my daughter's six cylinder Honda Pilot and Honda Odyssey, where the automatic shift keeps the engine at about 1500 revolutions per minute when going 60 miles per hour on level ground.

The removable floor panel above the transmission in Hudsons makes it fairly easy to take the transmission in and out of the car without needing a lift. The three-speed transmission can come out from above. The transmission with overdrive is about 8 inches longer. It is necessary to lift it up into position. It is handy to have a suitable jack when doing this, since the transmission has to be carefully aligned to the engine when it is being moved forward into the clutch.

There are some topics where people with a lot of experience doing this have tips. I have only done it a few times, the most recent one being when the engine was out of the car, so I put the transmission on the engine before putting the whole thing in the car.

The front driveshaft needs to be about 8 inches shorter. It can be shortened. Also Al Saffrahn, who has many used driveshafts can be contacted, to see if he has one from an overdrive car.

Several times when I have installed overdrive transmissions in cars which didn't have overdrive, I did not install the control wiring. I just put a switch on the dashboard that turned the overdrive on or off. People also have comments about the details of doing this on Hudsons.

However a couple of years ago, when preparing the '49 Commodore sedan (using a '51 Pacemaker engine and overdrive transmission) that has taken a couple of trips across the country recently, I wired everything properly, using the relay and foot switch from the Pacemaker.

Per

Josh,

I'm trying to visualize what is happening that would produce regular blinking at high rpm. However in your original comment you mention intermittent blinking, so I am not sure what is occurring.

I have heard that at high speed with rather thick oil, there might be a problem with the oil getting back to the suction pipe consistently. The recommendation being to keep the oil closer to the full mark than to the low mark on the dipstick. However I have never had this problem with my '35 Hudson 8.

As was commented, if the oil light is working correctly, it should always turn on when the ignition is on but the engine is not running. If the light is hesitant about coming on when the key is first turned, it might be a good idea to investigate.

A friend was driving his '36 Hudson at night. He saw one brief flash from his oil light. Fortunately he stopped right away to check. When he opened the hood, he saw oil gushing out of the pressure switch! The fiber insulator had popped out. His engine would have been messed up if he had kept driving. When the wire had swung away from the engine, the end of it touched the exhaust pipe, giving that one flash. It is worth checking the condition of this insulator.

Per

Josh,
You've gotten my attention again. So.....which is it? 50-60 flashes per minute at idle? high speed? Steady? intermittent? All are important to figuring this out, but I'm now wondering what you know about the history of this engine. The low mileage is great, but if it has not had its pan removed and thoroughly cleaned in recent history, you may be seeing the result of sludge/crud restricting the oil pick-up screen, thus starving the pump for oil. In spite of what some will say, if it hasn't been regularly cleaned back in the olden times (did anyone really drop the pan and clean it every 5000 miles?) and you are now using a modern detergent oil, it may have had some crud released that is now partially plugging the screen. It will get progressively worse as the debris accumulates. I have seen it happen.
If you are, in fact, seeing the light at high speeds (or any speed for that matter) then deadline it until you know for sure. That's an engine you don't want to smoke (read "very expensive to rebuild").
Frank

For Per and Frank, here are some clarifications. First, the flashes happen at high speed in 3rd gear, but I can also get the flashes at high RPM in 2nd going uphill. It never flashes at idle, low rpm or low speed.

Just to confuse matters, I noticed a few intermittent flashes at high speed that seemed to correspond with bumps in the road. Still, most of the flashes are on a regular interval, and are regularly timed and predictable, which is why I don't think its a short in the wire.

As it relates to the history of the engine, that might be the answer. The car had been in storage for about 18 years. The previous owner woke the car up not long before I bought it, and I can't be sure if he removed the pan and cleaned things out in the recommended manner. So I should do this right away; it could solve the problem, and there's no downside.

Also, I'm using 10W40 oil. Should I be using 30 weight?

Yes, cleaning out the pan is one of those, "It can't possibly hurt and very well might help"-type of propositions. For a car that sat that long un-used, I think finding out what is or isn't in the pan is a must.

Josh,
My prediction is that you'll see the answer when you remove the pan. If it had been sitting for 18 years before being "awakened", it's almost certain that there is a substantial accumulation of sludge restricting the inlet screen. If the previous owner doesn't remember removal of that pan, he didn't do it......it's a memorable experience with a stepdown eight.
"Awakening" of a splasher [i]must[/i] include preparatory procedures before any attempt to actually start it. These are a different breed of engine......not a bad one, just very different.
Frank

As the guys say... drop the pan. I bought a '50 Caddy with 70k miles, but it sat for 17 years. I drained the oil first thing. The dip stick showed about full, but only 3 1/2 quarts emptied into the container. I pushed my finger into the drain hole and the finger came out with this gray brain like matter over it. I dropped the pan and was horrified to find a quart of sludge caked in the base of the pan. I cleaned the pan and pump screen etc., reassembled the pan & ran some engine cleaner( probably a kerosene base) and fresh oil through the engine for about 50 miles. Drained and refilled 5 quarts of new fresh oil a second time. BTW, have a good time removing the oil pan on a stepdown 8. "It's good training", as we told recruits in the Army.

Josh,

Removal of the pan can be made easier by lowering the front crossmember of the frame. I took one bolt out to match the threads. I then got six long bolts (I can't remember if they were 6 inches long or 8 inches long) with the correct threads. These bolts should only be threaded near the end, most of their length should be smooth.

I detached the center steering arm from the crossmember. Next I supported the center of the crossmember.

I then took out each regular bolt and put in a long bolt. After this I raised the car slowly. The crossmember was hanging, supported by the long bolts, and I had a nice amount of clearance to get at the front part of the oil pan.

I don't remember whether there are any other things that have to be detached.

Per