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About PT81PlymouthPickup

  • Rank
    Advanced Member

Profile Information

  • Gender
  • Location
    Yardley, PA 19067
  • Interests
    Machinery, Travel, Fishing
  • My Project Cars
    1939 Plymouth PT81 Pickup Truck

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  • Biography
    Yardley,PA resident working for Princeton University
  • Occupation
    Tool & Die Instructor


  • Location
    Yardley, Pennsylvania
  • Interests
    Retro Rodding

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  1. Jerry, Yes, just about everyone tells me split master cylinder with Prop. valve in order to be safe with disc / drum brakes. Does your truck stop well? Can you lock up the brakes? (Please don't go and test on the highway) I would think with the original master cylinder (1-3/8" dia. bore) you would have to stand on your brake pedal? Steve
  2. Mark, could you tell me what year and model jeep your dual MC and prop. valve came from? Am I correct, that you do not have a booster? Are you happy with your braking? Can you lock them up if needed? Steve 🙂
  3. Thanks Campton 1941 and thanks Jerry Roberts Are either of you guys using combination, proportioning, residual or metering valves of any kind to address bias? Also, were you able to mount your original 16 inch wheels without interference? Question for Campton: Would you know the piston diameter of your Corvette master cylinder? Very much appreciated your responses. Steve
  4. I'm wondering if anyone out there is driving a 1939 - 47 Dodge or Plymouth pickup with upgraded (front discs / rear drums) brakes? A couple years ago I installed a Borg Warner S10 T5 trans behind my Flathead and a 1986 Jeep Cherokee 3.55 differential along with it's drum brakes and that all went OK. I also installed a Master Cylinder from the same 86 Cherokee in my original bell housing location. It sorta worked, but too much pedal travel which I believe is due to the smaller (.9375) M.C. bore? The original M.C. had 1.375 bore. I'm now considering converting the front drum brakes to disc. The Rusty Hope setup has my attention, but I'm hoping to talk to someone that may have done this before. The more I read about brake engineering and about the myriad of issues others have had modifying brake systems, I'm hesitant to start buying any parts. Not wanting to offend any purists, I have gone to great pains to keep my truck visually original and have all the parts to go back if I wanted to. I'm hoping to make it a bit safer stopping now that it goes a bit faster at lower rpm. I want to keep my original wheels as well. I've been reading for days on several sites trying to find trucks similar to mine with the brake modifications and how they perform. No luck so far. Perhaps I'm not searching correctly but haven't found much regarding 39-47 dodge / Plymouth pickups. Any advice would be much appreciated!
  5. That's interesting Ed! I have been told that my rims are too narrow and also because the rims are riveted to the center part of the wheels they probably would not hold air without tubes? Are you using tubes? Did you find your vehicle drove much better after installing?
  6. Greetings! Anyone know if there are any 16 inch wheels (either new or used) that would go on these trucks and are a bit wider to accept modern radials? I'm also hoping that I could use the original hub caps and trim rings. I think bolt pattern is 5 X 4.5. Also it's difficult to measure the offset and backspacing without removing the tires. Anyone have this info? I'm hoping to install a set of Michelins 215/85/R16. Anyone drive one of these trucks with radial tires? Any advice would be much appreciated! Regards, Steve Lowe
  7. Thanks Reg! I couldn't find anything refering to the SR-4488? Do you have any idea what SR stands for? I'm fairly certain this engine will bolt right into my 1939 PT81 pickup? Just slightly larger cubic inches. My original engine was 218 cu. in.
  8. Hello, Need help identifying an engine I've come across with engine number T214 SR-4488 still in a crate. Crate is marked as Army surplus. Anyone know how to identify this number? It is a 23" long block. I'm considering purchasing for my PT81 1939 Plymouth pickup as a spare. Any information would be most appreciated. Year? Cubic inches? Regards, Steve
  9. Now that's funny Jerry! I remember that phrase too. Has the engine in your Dodge ever been bored for oversized pistons? I just read where that could contribute to harmonics? I can't remember exactly how much, but I know my engine is at least .030 over. Thanks for the compliment! I tend to over do things, and it's bugging me I can't get a handle on this.
  10. Thanks Jerry for the information! It reads just like what my engine is doing. I have read other articles that led me to believe a damper might solve my issue. What is confusing me, is that if undesireable harmonics was an issue, why didn't Chrysler Corp. install them on all the inline flatheads? It sounds like there were more L6 flatheads without them than with them? Engine balancing and harmonics are evedently two separate issues. An engine could be balanced to perfection and still produce undesireable harmonics. It's more of a Physics anomoly of the engine designs. Some engine designs are more prone than others. I was thinking I could possibly adapt a smaller diameter damper which would allow me to get a belt off and on, but I also have read that these dampers are specifically designed to counteract known harmonics of different engine designs. So, not being an automotive engineer, it might be a waste of time? The high frequency vibration I have is minimal and only occurs shortly on acceleration. I think a lot of people might not even notice it? Overall, my truck runs really well. There is also a possiblity that something else in my driveline could be causing or exasberating this vibration. Perhaps, as one responder to my posting indicated I'm just being too fussy? Using anecdotal evidence only, I surmise that all of the mopar L6's may have had this issue. Chrysler Corp. may have installed the dampers on the higher end Chryslers and Plymouths? I'm thinking my best course of action is to reinstall the original crank pulley and get back on the road. I'll pay closer attention to details of how and when the vibration occurs which might lead to solving this mystery? Does this sound logical?
  11. Jerry, I was afraid someone would ask that question. Lols! At this point, I'm not sure of anything! It's been 37 years (1979) since I rebuilt this engine. I think you're correct that orignally it would have come with a 201? I'm completely sure it was not the original engine that came with the truck when I got it. There was a engine replacement tag on the firewall and there were / are no numbers on the block where they should be? I'm fairly certain at the time we rebuilt the engine we were able to deterimine it was a 218. I cannot remember how. Perhaps casting numbers? Anyhow, Yes, this engine could have come from a later model car that had a harmonic balancer? I've heard by some that it would make a difference and others say not? Some say they were added only for extra smooth running on the higher end cars? I really don't know what the facts are?
  12. Hey Jeff! You must be older than I am if you remember linked belts on old cars. Lols! Your comment got me to thinking. I just read that the reason they used the wide belts on early vehicles was to dampen vibrations. Not sure if that's a fact or how that works? I have been using a cogged belt on my truck. I'm wondering if perhaps a solid belt would be a better choice? You're definitely right Jerry! I'm just too lazy to make the pulley if I can't keep it on there.
  13. Yes, but I have to adapt an old, or make a new pulley first. The balancer would be spinning too close for comfort to the cross member and when a belt change was needed it would be a royal pain. Not a practical solution, but you are correct, it could be done.
  14. At the full diameter there is only about 1/32 inch clearance. Even with a flat positioned downward the belt will not fit. Wow! Don, you really did some serious work there. I had to modify one cross member to get the T5 to fit, but at this point, I'm not willing to modify the front cross member for a harmonic balancer that might not fix my vibration problem anyhow. I'm disappointed there was not enough clearance. It would have been a simple job for me to adapt or turn a pulley. I'm surprised that you were able to weld a flange to your balancer without melting the rubber or throwing it out of balance? Did you have it re vulcanized after welding?
  15. Yeah, It's the angle of photo. The rubber is amazingly perfect. I bought this NOS balancer and other than some light surface rust it looks like it was made yesterday. Too bad I can't use it.
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