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Mopar flathead 6 motors- whats to be expected

Discussion in 'The Hokey Ass Message Board' started by Modeljunkie, Dec 8, 2011.

  1. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,583

    Rusty O'Toole
    Member

    My guess from 1800 miles away is condenser or coil heating up and quitting. When it cools down it starts working.

    Easy way to tell, next time it quits, look down the carb and work the throttle. See if the accelerator pump squirts gas. if it does you are not out of gas. Pull a plug wire, stick a spare plug on it, turn the motor over and see if you have spark. If no spark, try replacing the condenser.

    If you have gas and spark and compression and it still quits it must be a voodoo curse.
     
  2. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

    I want to keep it original as possible. That's why I want to make it a turbo flattie. I have .060 military flathead pistons. Can I use this for a turbo build?
     
  3. 73RR
    Joined: Jan 29, 2007
    Posts: 6,584

    73RR
    Member

    Flat Six Fix, You have done well in considering all of the 'needs' for a v-8 swap and no doubt, at least around my shop, there are plenty other items that we forget about until they pop-up.
    As said, the 251 is a good engine but if tired then it will not perform to its potential. Keeping a 4-spd manual trans with the L6 is a good idea as it allows you to keep the rpm where you need it. Yes, you can manually shift the TF up/down but eventually we get lazy and keep it in D. The biggest drawback to the TF (or any other automatic) is the parasitic HP loss that is not found in a manual trans. The L6 doesn't have a lot of extra to give up.
    The single biggest problem with a truck trans is the granny gear so most folks skip 1st and we are back to a 3-spd.....
    Later 5spd and 6spd truck trans can be adapted, you might even get lucky and find one that will adapt to your bellhousing rather than needing an adapter for the newer 'one-piece' design units.

    Gene made comparisons with the L6 and an 85 -318 so let me remind you that starting with the 1972 model year the HP and torque numbers were changed from gross to net. The actual post-71 engines had minor changes but nothing that would cut the 318 HP from a high of 230 down to 140.
    The 318 will still make more HP and Tq than the 251 if for no other reason than it being a v-8 and 70 additional inches. Recall that the late 70's had the Cordoba/Fury sized cars with the 318 as base engine and they ran down the road fairly well with the TF and lock-up converters. My 79 Cordoba with the 360 was a nice driver (2.45 rear gear) and my 79-300 with the L-58 version was surprising with a 3.23. This is/was a 4000 lb car.

    Gary
     
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  4. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,583

    Rusty O'Toole
    Member

    Minicad get your engine running properly and do a compression test. Also how many miles on it?

    If the engine has over 30000 miles, oil pressure below 45 PSI @ 30 MPH or compression less than 110 on all cylinders you will need to overhaul or rebuild before you do any hop ups. And, if you do the overhaul, you probably won't need to hop it up.

    I suggest you get it running as well as possible first. Then drive it around and figure out what you want to do. That is not a high performance vehicle. It may turn out it will do everything you want it to do, with the stock engine.

    If the pistons are the ones I think they are, you got them from Red buffalo gal on Ebay and they are military surplus, ex Canadian army stock made about 1959? If so they are OEM quality and will work great IF you have the big motor, the one with the 25" long head.

    Recommend you buy new rings because the rings today are way better than the ones they had in 59. The pistons and pins are fine.
     
  5. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

    Awesome info I appreciate it...
    I just found a 6.1 Hemi and tranny low miles just might go with that.
     
  6. James Curl
    Joined: Mar 28, 2006
    Posts: 370

    James Curl
    Member

    I was told that 80 % of rated horse power RPM was max sustainable RPMs without damaging the engine by Tom Langdon, having said that I run mine at 3300 to 3600 RPM on the highway. Have gone as high as 4000RPM while passing without any damaged so far. I did everything to mine when I rebuilt it except have it balanced which I wish now that I had done. I have close to 30,000 miles on it now since the rebuild. Be prepared to spend so money, with parts, machine work, having the harmonic damper rebuilt and clutch and pressure plate rebuilt and flywheel surfaced without the intake manifold and carburetors I have over $3600.00 in this engine with out the dual exhaust system.
     
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  7. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

    Wow my 230 is automatic it's a right hand drive truck
     
  8. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,583

    Rusty O'Toole
    Member

    I'm looking at your avatar and thinking I wouldn't want to go over 50 in that. Which the stock engine should do even with automatic. Didn't know it was RHD that makes it even scarier.
     
  9. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    To be honest that route van was not meant to go much over 50-55, they just weren't designed for it.
    But hey upgraded front clip, or stock in preemo shape, disc brake upgrade, 3.55 gears in the back, and 60-65 mph. I do not see this as an 75 mph cruiser.
    Now having said this, either is my truck in stock form, meant to drive 50-55-60, not 75-80 mph, but who am I to say. Here in Manitoba, I can get away with slower speeds, lighter traffic etc, not in most urban areas in the USA or in around the greater Toronto Ontario area either.
    I would try it over 50 mph though, thats me, heck i drove a 1952 Chevy a couple of years ago down my gravel road over 50 mph with no brakes, just a working ebrake......LOL
     
  10. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Hi Gary, yes there are always those hidden, unknown unexpected expenses that appear, much like major home renos.
    I am very partial to mopar flatties, so this is not an easy decision, if I had a 50s bolt in ploy V8, it would be a no brainer, just a little bit hesitant on more modern engines, not because they are not good, just because it is taking me away from the old 50s type power-plant, not a big deal.
    I have driven all those cars mentioned, and many others some with slant 6s, some with 340s some with 383s and even the old mans 440 Chrysler. The 70s 318 is plenty enough power for my use in my light old truck.
    For the l head, the ranger truck trans looks interesting, but do not like the shifter location for my application, and again with 3.23 gears, do not think I need overdrive, possibly a T4 trans
     
  11. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

    Lol I did the same with my 47 cadillac, I just installed a rearend of a 88 Dakota I just finished now to see how it rides Lol....
     
  12. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

    I have everybody here wanting to see a hemi in the mail truck lol
     
  13. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Just got back from a nice drive, it is cold here 45f, 25-30 mph northwest wind. I had fun drove both town and country, and drove her like I stole her, pedal to the metal a lot.

    I did find though on the last leg of the drive on the highway, a super strong cold wind, had to really push her to get up to 65 mph, once there no problem, she is a bit sluggish with 3.23 gears and a strong head wind. I would equate going against a very strong wind is like hill climbing a lot of load on the crank.

    I had a blast driving tonight.....PS Winnipeg Jets are going Duck hunting tonight at the MTS center....yeehaww
     

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  14. Minicadi98
    Joined: Sep 6, 2013
    Posts: 15

    Minicadi98
    Member

  15. 73RR
    Joined: Jan 29, 2007
    Posts: 6,584

    73RR
    Member

    ....if you were a little bit closer we could do some business...
     
  16. jamesd1502
    Joined: Jul 8, 2013
    Posts: 283

    jamesd1502
    Member
    from san diego

    I just scored this 39 and deciding what drive train to use. I don't know the history of the engine currently installed. There is a rebuilt Plymouth flat 6 (25in) for decent price that I may consider picking up for it. ImageUploadedByH.A.M.B.1429807970.438298.jpg also, any suggestions for parts are much appreciated. Thank you
     
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  17. 73RR
    Joined: Jan 29, 2007
    Posts: 6,584

    73RR
    Member

    How sure are you about that rebuilt Plymouth engine being a 25"...all 25" Plymouths are Canadian.....
    Yes, the rebuilt could easily be a Chrysler or DeSoto. The 25" may be a bit more troublesome to install in a 39 that in a late 40's/50's something.
     
  18. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Hi Gary, here is another thing happening with my flathead engine.
    With a fully warmed up engine, and driving, no issues on acceleration, no popping sputtering , runs smooth. However, she will not idle smooth, just a bit rough,causing a little vibration in the cab, what is with that/
    Compression is around 100, 1 cyl is about 90, vacuum is about 18, but needle quivers. I have not found any vacuum leaks at all.
    The exhaust has a puff puff sound intermittently too, burnt or hanging valve(s)?
    Also last night adjusting the carb, when engine was good and warm, went for a short drive, and idle is slightly higher on return, not sure what is causing this, have idle set around 600 rpm, any slower she gts rougher...thanx for any ideas, gotta use this engine for a while before swapping in 318 or fixing this one.
     
  19. 73RR
    Joined: Jan 29, 2007
    Posts: 6,584

    73RR
    Member

  20. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Thanx anyways gary.
    Yes i am a member over there too.
    Most likely I am dealing with a well worn engine, so I either rebuild it, or another I have, or go with the 318 transplant. Either way is going to cost money....LOL
    Around here is cost about 2500-3000 for a rebuild on the flathead 6s, now if I get my own parts and assemble it myself, it would be cheaper.
    Interesting, my vacuum reading indicate a hot cam or a bad sparkplug, but I figure slightly leaking valve(s).
    I made this video with vacuum test late this winter,
     
  21. EarlsWorkShop
    Joined: Mar 12, 2013
    Posts: 2

    EarlsWorkShop
    Member

    This has been an interesting and informative thread! Its certainly an old one, but I see that it still lives!
    I picked up this '36 4 door 2 years ago.
    It had been sitting as pictured on my avatar since 1973. In Yuma, Az. In the Sun. I first saw the Dodge in '73 because it was a high school buddy's grandfather's car. His grandfather bought it new in Phoenix in 1936, and drove it until he passed away. It ran when parked but the family wasn't going to do anything with it and let it sit. After 40 years of begging, they finally sold it to me.
    Being around Street Rodders since High School, I was going to put in a '73 340 V8 with a 4" stroke and .060 over bore, Magnum High performance heads, FI from a '98 Ram 5.9 and a A500 from a 91 Ram Charger.
    But after getting the Dodge, learning the family history of it, and talking to my Dad about his racing experiences with the old Flat head Six, I decided to save the V8 for another project and just hop up the old 218.
    In the early '50's my Dad dirt track raced with a L6. With a lightened balanced crankshaft & flywheel, home built dual side draft carb setup and he could out-torque the flat head V8's coming out of the turns on a 3/8 mile clay oval.
    This engine had been rebuilt. It has the tag riveted to the head. Its cool that Mr Daniels bought it new in Phoenix in 1936, had the engine rebuilt in Phoenix in 1947, and I live just east of Phoenix.
    I'm thinking that the block is the original, but I'm guessing. Chrysler doesn't really have any info on matching up body serial numbers and block serial numbers. But looking at production numbers of the D2 sedans and the D2 engine blocks, the numbers are close enough that its probably the same block. The production sequence between the engine and the body is only 1,677 apart. (the body number is the 91,319th D2, and the engine is the 92,996th off the production line).
    Even though the block is probably original, I'm sure that the head was replaced in 1947.
    The "rebuild tag" from Phoenix Motor Supply Engine shows work done in Dec 1947 with 42,417 miles. .030" Over Pistons .030" Under Mains .030" Under Con Rod
    Notice the missing heater port on the head?
    The upper heater hose was tied up to the radiator support with baling wire, most likely when that head was replaced. I'm guessing that Mr Daniels didn't really care about a heater. It was in Arizona after all.
    So, I'm going to go with EDGY head, intake , and valve adjuster covers (for appearance).
    I picked up a pair of freshly rebuilt Stromberg 97's.
    I grabbed this 230 Dodge crank (and the rods) from Ebay.
    It needs to be cleaned up and maybe turned. I think that it has already been turned about .020" under on all journals.
    But, I did learn from this forum that I also need to get the correct flywheel so that I can use the original starter.
    The other thing that I plan to do is adapt a T5 transmission. I got the adapter kit already and a '94 Mustang T5. The Mustang T5 tail housing puts the shifter WAY back where it would come up through the bench seat, and I got the S10 T5 tail housing to relocate the shifter farther forward. But, I also located a T5 from a Jeep that has the very short tail housing for the transfer case. I'm going to try doing some internal gear and shaft swaps so that I can still have the Mustang gear ratios but have the short tail housing. I've got some ideas, and if I can get all of it to work, I'll post some pictures and info on it.
     
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  22. 64 DODGE 440
    Joined: Sep 2, 2006
    Posts: 4,283

    64 DODGE 440
    ALLIANCE MEMBER
    from so cal

    Looking forward to following your progress on the car. Our HA/GR build is using a '34 Dodge 218 flathead. Love the old Dodge flatties.
     
  23. Finmad
    Joined: Aug 9, 2015
    Posts: 11

    Finmad

    Hey guys, I have been reading through this thread and am digging it so much. I just bought a 1947 Dodge WD-15, it has a 1950 Plymouth flathead. The guy says it will start and that it just need the carb cleaned out and the fuel tank drained and refilled. Anyone know if you can buy a complete tune up kit for these? points, cap, wires, plugs, carb rebuild kit, etc????
    [​IMG]
     
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  24. plym_46
    Joined: Sep 8, 2005
    Posts: 4,018

    plym_46
    Member
    from central NY

    ^^^^^ You need to take the number off the tag on the distirbutor to make sure you are ordering the correct tune up pieces. There were three of four different distributors used over the years and they interchange between years and applications. Some have tall bodies and short caps some have short bodies and tall caps, some points go on at the top of the body some on the bottom.

    Easiest way to deal with it is to pull the distributor and work it on the bench. Mark the vacuum advance location, to the block and the rotor to the dist body, and pull it. The tag have a number and letter sequence on it like IAT, IAP. IGS followed by numbers. This will guide your parts house toward the correct parts. You May want to rotate the engine so that #1 is at TDC compression. In this position the rotor should be positioned at 7oclock. The drive is a tang so the dist will only go in right or 180 degrees out, but if you mark the positions before you pull it you should have no problem. Once it is out you will appreciate why it is so much easier to deal with on the bench rather than on the vehicle.
     
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  25. Finmad
    Joined: Aug 9, 2015
    Posts: 11

    Finmad

    will do, any more advice like this is hugely appreciated.

    Can you still buy parts through the big box stores or will I have to source them off the net?
     
  26. whtbaron
    Joined: Sep 12, 2012
    Posts: 573

    whtbaron
    Member
    from manitoba

     
  27. Finmad
    Joined: Aug 9, 2015
    Posts: 11

    Finmad

    I was able to get my camera under the distributer, can you tell anything from these crappy pictures? :)
    [​IMG]
    [​IMG]
     
  28. whtbaron
    Joined: Sep 12, 2012
    Posts: 573

    whtbaron
    Member
    from manitoba

    Try a couple more shots directly below the tag... the numbers are what you'll need. Might have to lay on the ground under the vehicle and zoom upwards if you can't get it from above. You might try wiping the tag off with a damp cloth as well. From here it's looking a lot like the dizzy in my 52 Plymouth with the 218.
     
  29. Frankie47
    Joined: Dec 20, 2008
    Posts: 1,877

    Frankie47
    Member
    from omaha ne.

    NAPA Rock Auto
     
  30. plym_46
    Joined: Sep 8, 2005
    Posts: 4,018

    plym_46
    Member
    from central NY

    Dist is tall body short cap. Number is on the red tag but you didn't capture it at that angle. Napa has most tune up parts but most currently available points sets are garbage. No lube wick, poor quality and easily worn down cam follower, weak springs etc. All made in Mexico and China. Last set I got was from a local jobber and they were made in USA. If you can't source good ones locally, check out Vintage Power Wagons site.
     

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