A couple P15 questions.

[sketchy5.0]

New to old Plymouths, but not to cars. GM mechanic by trade. I picked up a 1948 P15 that was on its way to the junk yard. It's a little too far gone to restore, but its still there enough to make a cool rat rod.. and at least its not getting crushed. But, anyway my questions..

 

What is the shift pattern on for the manual transmission on the column?  Not a fluid drive, just a standard transmission. I've honestly never even driven a column shift before.

 

Where are the timing marks? Balancer? Belt pulley? I installed a Pertronix ignition kit and I'm trying to set the timing.

 

How much can I shave the head to bump compression? I can't find a solid answer. The best I found is 0.050. I really wanna keep the flathead, just hot rod it a little. Not looking to buy an aftermarket head.

 

Also I haven't been able to find a wiring diagram anywhere. Anyone have a PDF of it? Also looking to buy a service manual for it, which one should I buy?

 

Thank you.

[knuckleharley]

The shift pattern for all column shift standard 3 speed transmissions is a "H" pattern. Imagine looking directly at the column from the passenger side. You pull the shift lever towards you,and then pull down towards the bottom left "leg" on the "H". Reverse is directly above 1st gear,at the top of the "H" leg. To shift to second gear,you just move the lever to the middle section that connects the two "legs" on the "H",and it will automatically "fall" towards the dash/right side of the "H". Once it has done that you push it directly towards the top right side of the "H" leg. Shift directly down to the bottom right leg of the "H" for high gear.

 

the timing marks are on the balancer.

 

People used to routinely take up to .125 off of heads. Sometimes even more,but that was back when you could buy steel shims and special thick gaskets. I had .125 taken off the head on my 39 IHC PU because I had to take that much off to correct the warp on the head. Generally speaking,it's best to just take off the minimum amount you need to take off to correct any warp. You aren't going to gain much power by bumping up the compression on a stock flat 6 engine. Add a hot cam,headers,and a couple of carbs and it could make a difference,but not with a basically stock engine

Since you have never owned a car this old before and want to try to keep it close to mechanically original,in MY opinion your best bet is to go to ebay and buy a Motors Manual that covers 1946 to 1949 cars of all makes. It will give you all the specs you need,tell you how to repair it and shift gears,tell you how to polarize generators and regulators,rebuilt parts,etc,etc,etc. Lots of good illustrations and clear photos,too.

 

BTW,in case you don't know,these cars like the Fords of that era have a positive ground.

[Don Coatney]

Suggest you go to the reference section of this webpage and read everything there. Before you shave the head you best measure your valve to head clearance.

 

 

[sketchy5.0]

 

 

Thank you! I do want to tear in to the motor a little bit more to hop it up, but after I know its a healthy motor. I will be looking for a manual shortly. I've been googling as much as I can so far.

 

Thank you for the pictures!

 

After I get it running, driving and stopping reliably, my future plans would be dual carbs, split header and cam. Still keeping it 6V positive ground for now. It still charges and I like the gauges. Fount disk brakes and maybe even a T5 transmission. Long term, I think a 4BT diesel would be pretty sweet! Hopefully I wont get too much trouble from the purest guys, but I see it better to be running as a rat rod, then crushed and not on the road at all! Thanks a ton gentleman!

[dpollo]

Keep in mind your transmission is the Post and selector type  so the lever drops back after selecting first or reverse.  Makes for

very easy shifting and there is no danger of getting hung up on the 1-2 shifts which was a problem with many cars.

 

There is no particular reason to change to 12 volts but all your dash instruments will work.  A voltage limiter is needed for the gas gauge.

[J-GMan]

Thanks for the shift picture. I am taking delivery of a 1947 Plymouth with a 3 sod column shift and I don't want to look like a complete newbie  I've had many old cars and many manual shifts but no column shifts!