changing motors from flat 6 to 283 small block fr 49 plymouth

[vickij37]

i am looking for information on any kit that would help to adapt a 283 small block chevy into a 49 plymouth special deluxe p15 this is just in the event we cant get the flathead running

 

Edited March 4, 2021 by vickij37

[plymouthcranbrook]

I would suggest checking here as it is more a site for modified cars than here.

https://www.jalopyjournal.com/forum/

[Plymouthy Adams]

or maybe even a chevy forum.....I have no heartache with you using brand x but in truth your questions would be best answered on their forum...

[vickij37]

i want to switch out the flat 6 to a 283 chevy smallblock any help or suggestions? this is my 1st 49 plymouth special deluxe 2door p15/// we may keep the flathead 6 if we can get it to run... going over and replacing alot of things so far it turns over but doesnt start... we did plugs/wires/ going to rebuild the starter, 

 

Edited March 4, 2021 by vickij37

[knuckleharley]

8 hours ago, vickij37 said:

i am looking for information on any kit that would help to adapt a 283 small block chevy into a 49 plymouth special deluxe p15 this is just in the event we cant get the flathead running

 

MY serious suggestion is "don't",for a couple of reasons. Number 1 is a stock 283 doesn't produce enough HP or torque to make the expense and the work worth the effort. Not even if you already have it.

 

The second reason is I am one of the crazy people that like flatheads and semi-original or orignal cars,and since you obviously have no intention of making a street racer out of it,why not spend the same or less money to fix the flat 6 you already have? After all,all you are going to do is drive the car,and people had no problem driving them cross country back in the 40's and 50's. Just make sure you rebuild the brakes with NEW parts (NOT NOS parts that have been sitting on a  shelf for 40 years),and fix anything suspiscious in the steering/handling.

 

Finally,since this is a Mopar board and you now have a Mopar,why not put a 318 or a 360 in it if you decide to go with a V-8? Or even a 340 if you have deep pockets? It ain't like it would cost you a pile of money compared to the Chevy swap,providing you stay away from 340 hi-po engines. Chances are you could even find a good 318 a LOT cheaper than a good 283-350. 

[58prostreet]

Butchs Cool Stuff has tome kits for puttiong V8s in older mopars.

[vickij37]

Thank you so much!  i do appreciate the information and we too would prefer to be original, we are just struggling with the flat 6/since we've never dealt with them or the 6volt system... we get it to turn over but doesnt start/run. we've change point/condensr, plugs/wires and may rebuild starter but not sure what to look at next to get it running

[Frank Elder]

..........I said something mean @vickij37 and so I erased it, the truth is I simply don’t believe in putting chevrolet products in a chrysler product. You could sell that motor and probably buy 3 318 motors the tri five guys love 283 motors.......

Edited March 6, 2021 by Frank Elder

[vickij37]

It looks like we're going to continue working with the flat 6 but it's a struggle as we don't knw anything about those motors or the 6volt system,  we are now trying to get as much info as we can to learn more and make her run and be original, so any thoughts or ideas would be greatly appreciated..   We are chevy people to start with(71 nova and 64 c10), but this car is so classy and still a beautiful car, we thought we'd give'er a go. 

Edited March 5, 2021 by vickij37

[Merle Coggins]

There's nothing exotic with these engines. Basic breaker points ignition system troubleshooting would apply. One thing that will cause problems with a 6 volt system are undersized battery cables. If the cables are "off the shelf" modern battery cables they are likely way too small and don't carry enough current to satisfy the needs of the starter motor. This can cause enough of a voltage drop to your ignition system to reduce it's function. Be sure you have 0 gauge, or larger, cables and a fully charged battery. Then recheck the ignition system for proper function and timing. Then, if you have spark at the spark plugs you also need compression and fuel. 

Have you done a compression test on the engine? These engines have a tendency to get sticky valves after long periods of inactivity. If the valves are hanging open you can't get compression. And finally, what is the condition of the carburetor? Getting gas spray from the accelerator pump when you move the throttle linkage? Have you tried opening the throttle a bit when trying to start it? Sometimes the idle circuit gets plugged up and won't supply enough fuel for proper idle. 

[vickij37]

we haven't done a compression test yet. We have made it through the plugs/wires, points and condensor, and have just gotten the starter off to get it rebuilt., we are also going to replace the battery cables as one looks frayed. Then we are planning on purchasing a new 6volt battery and see where this gets us. We've also talked about sending the motor up the road to a guy who rebuilds and just have the whole thing rebuilt, we just want to try ourselves first before taking on that cost.

[Sniper]

Basic troubleshooting is the same for any make.  You haven't even told us if you checked for spark or fuel.  So who knows where to start looking for issues.  Before you jump into rebuilding things, if the engine spins why is the starter being sent out for rebuild, I suggest we figure out if it needs that major a job done.

 

Does it have spark?

 

Is fuel in the carb? 

 

Both are yes/no answers.  Once we know these things we can make some cogent decisions as to where to go next.

 

 

[Frank Elder]

Be a troubleshooter, not a parts changer.......

[vickij37]

so i got more info, sd it turns over slow will test /and is using starter fluid first as we have to get gas tank cleaned or new one not sure yet

[vickij37]

any suggestions also for body mount kits, and complete floor plans

[Los_Control]

I am a total noob at these old trucks. I am really happy I was smart enough to run a compression test before starting. Had a couple cylinders that were low.

After getting it running I can monitor the progress as the rings start to seat and valves free up.

I had one cylinder @ 60 pounds before I fired it  up, think it is between 80-90 now ... While  it is still unacceptable, I can see it making progress and hoping to actually drive it and see if it improves.

Just having the information helps make future decisions on what work will be doing in the future to the motor.

 

Nothing wrong with rebuilding the starter, you crossed one more item off your to do list.

One common problem with a 6 volt system is to find 12 volt battery cables installed ... 6 volt you need 00 or 01 welding cables to carry the current. All the wires are twice the size on a six volt vrs 12 volt .... and wrong cables will cause slow turn over issues, grounds are critical and cause slow turn over.

If you decide to convert to 12 volt in the future, your 6 volt starter will hold up just fine.

 

Also the valves on flatheads are notorious for sticking open, the rings get stuck to the pistons. Do not spin in the ring landings or expanded and rubbing on the cylinders .... 50/50 mix of atf + acetone probably the cheapest. just fill the cylinders and let the rings soak and will lube up the valves at same time. Let it soak a few days or a week, run a compression check, if needed soak it again. Change the engine oil before you try to start it.

When you do start it, it will remove every mosquito in your neighborhood. All the oil will be gathered in your muffler, may have to drive it for 3 hours to burn it all out ... you will have a happy oiled engine.

[knuckleharley]

3 hours ago, vickij37 said:

so i got more info, sd it turns over slow will test /and is using starter fluid first as we have to get gas tank cleaned or new one not sure yet

ALL 6 volt engines turn over slow. You would swear your battery is going bad if you didn't know better.

[knuckleharley]

3 hours ago, Los_Control said:

I am a total noob at these old trucks. I am really happy I was smart enough to run a compression test before starting. Had a couple cylinders that were low.

After getting it running I can monitor the progress as the rings start to seat and valves free up.

I had one cylinder @ 60 pounds before I fired it  up, think it is between 80-90 now ... While  it is still unacceptable, I can see it making progress and hoping to actually drive it and see if it improves. i

  

You might be surprised at how often pouring a little Marvel Mystery Oil down the carb ast is running at fast idle will clear that sort of thing right up.

 

Seriously. It's almost like magic. I make it a standard practice to pull the plugs on any old engine I get that has been sitting,and pouring a little Marvel Mystery Oil in each cylinder,letting it sit overnight with the plugs still out so it can work it's way past the rings. Go out there the next day and turn the engine over with the starter or a breaker bar if it is stuck,and let the slickness work it's magic. Hell of a lot cheaper than broken rings when trying to unstick one,not to mention all the labor and parts money it MIGHT cost you if you didn't.

 

Be aware that if you do this,you need to push or pull the car out of your garage before trying to start it. It might smoke a bit once it starts.

Edited March 9, 2021 by knuckleharley

[knuckleharley]

4 hours ago, vickij37 said:

so i got more info, sd it turns over slow will test /and is using starter fluid first as we have to get gas tank cleaned or new one not sure yet

DO NOT USE STARTER FLUID ON AN ENGINE THAT HAS BEEN SITTING FOR MONTHS OR YEARS!

 

Pull all the plugs first,fill the cylinder with Marvel Mystery Oil,and let them soak overnight with the sparkplugs out. Then spin it over by hand the next morning to get it broken free if it is stuck,and then spin it over with the plugs still out until you can see the engine has built oil pressure on the gauge.

 

THEN you can use the starter fluid.

[vickij37]

thanks fellas! This helps

Edited March 9, 2021 by vickij37

[knuckleharley]

1 hour ago, vickij37 said:

thanks fella! This helps

 

 

 

Don't forget to sping the engine with the starter while the plugs are still out until you see oil pressure on the dash gauge before trying to start it.

 

Also,don't forget to pull or push the car out of your garage before you do start it. You will be glad you did when you see the cloud of blue smoke.

Edited March 9, 2021 by knuckleharley

[Plymouthy Adams]

have your cat positioned behind the car so they can catch the mice you blow out.......

[vickij37]

ok so while he tinkers with the motor he gave me a list of replacement items to look up/buy...  i have been doing research online and found what i thought would be someone for the floor pan, but we are looking to also not sink every penny into it... may only need partial floor pan sections and inner/outer rockers, but checking for, complete partial floor pan, master cyclinder and body mounts, any thought on leads? i found items on ebay, but we've been burned there so i really hesitate with ebay.................................. also  he did the compression check and we're good there, it even almost, started so he is getting excited now!!!

Edited March 10, 2021 by vickij37

[Sniper]

The Plymouth Doctor sells what you need, but I have no idea as to the prices.

[vickij37]