Flathead 6 - Chrysler

['38 Dodge Mel]

I have two old flathead 6 motors that were sitting outside for at least a couple decades.  Needless to say they are pretty rough shape, but I have a flathead 6 in my 1938 Dodge Business Coupe.  Therefore I am looking to see if I can get one running engine out of these two.  I have a number of parts etc, and am somewhat hopeful that I have a 50:50 chance of success.  

 

What can people tell me about this motor?  There is a number stamped on the side of the block C22C2765

 

thanks

[keiser31]

C22 is the designation for a 1939 Chrysler. That second "C" may be a shallow stamped "0".

Edited February 23, 2020 by keiser31 (see edit history)

[Rusty_OToole]

C22 is a 1939 Chrysler Royal six cylinder. 241 cu in, 3 3/8 bore X 4 1/2 stroke, 100HP. Part of a series of engines made from 1937 or 38 up to the early seventies, used in Chrysler and DeSoto cars until 1954, in Dodge trucks until 1968 and in Dodge Power Wagon military vehicles until 1972 also Chrysler industrial and marine engines possibly as late as 1972.

 

A version of this engine was used in Canadian made Plymouth, Dodge, DeSoto and Chrysler cars and Dodge trucks 1938 - 1959 (Cars) and possibly later in trucks.

 

They made millions of these engines and there are still plenty in service. They are a simple engine and parts are available. A company called Vintage Power Wagons has a lot of NOS parts, but you can get practically anything you need from your local auto parts store ( it may take them a couple of days).

 

You could take the head off and see if the cylinders are rusted up. If not, a rebuild should be a cinch. If they are it will be more difficult but they have very thick cylinder walls and you should be able to rebore and fit new pistons if the block is not cracked.

 

Last I looked VPN was offering NOS pistons for $65 a set of 6. How good do you want it?

 

Incidentally you can easily bore this block to 3 7/16 which was standard bore size on later versions and use stock, standard size pistons. This gives you a 250 cu in engine like postwar Chrysler and DeSoto and many Dodge trucks.

Edited February 25, 2020 by Rusty_OToole (see edit history)

[Rusty_OToole]

This engine will bolt up to your 38 Dodge transmission. You may have to relocate the front motor mounts 2" forward and move the radiator a similar amount.  Some frames are even drilled for the different mount location. The Chrysler engine is 2" longer than the Dodge ( 25" vs 23"). This makes a good swap if you want a little more oomph. They used this same block in Canadian Dodges.

['38 Dodge Mel]

Awesome info - Thanks!

 

I want to do a good job, but the motor in my ‘38 Business Coupe runs perfectly fine, so this is a project to keep me busy (and out of my wife’s  hair) until the snow melts.  Once completed I have no idea what to do with it afterwards.  But one step at a time. Your tips are very helpful as the last time I rebuild an engine was 40 years ago.

[Rusty_OToole]

Since the same engine will fit Plymouth, Dodge, DeSoto and Chrysler cars and Dodge trucks, if you rebuild the motor it shouldn't be too hard to find a car to put it in. It is also possible to do a mild hop up without spending a lot of money if you are handy. You can modify the intake for dual carbs, split the exhaust manifold for dual exhaust,  mill the head for more compression, buy a reground cam for $165, shave the flywheel for whippier acceleration. As I already pointed out you can bore the cylinders 1/16 and use stock later model pistons for larger displacement. The advantage of this is, stock size pistons are the cheapest. Your block could be bored up to 3 9/16 if it is in good shape but the pistons would be more expensive. You could have a lot of fun with such an engine in a Plymouth or Dodge coupe. Or you might find a chassis and build up a speedster or raceabout.

Largest version of this engine was a 3 7/16 X 4 3/4, 265 cu in job used in Chrysler and DeSoto 1952 - 54 and some Dodge trucks and industrial and marine engines. The long stroke crank and rods will fit your block. But, these engines are somewhat rare being only made for a short time more than 50 years ago.

Edited February 23, 2020 by Rusty_OToole (see edit history)

[Rusty_OToole]

If you want to know what one of those engines is capable of, see this report on nearly 200,000 miles in a 1951 DeSoto Suburban 8 passenger sedan by the original owner. Same engine but the postwar version with 1/16 larger bore for 251 cu in. If it can make it in this 6000 pound whale your car will be child's play. My favorite part "at 70 MPH it smooths out like a perfectly balanced turbine".  This long stroke engine in a car with 4:11 gears towing a trailer.

 

https://www.allpar.com/cars/desoto/suburban-1951.html

Edited February 24, 2020 by Rusty_OToole (see edit history)

[1937hd45]

Watched this one back in the 1960's, wonder it it had the same engine? Bob 

[keithb7]

If you are only looking to keep yourself occupied, are you not in any real need of a newly rebuilt flathead 6 engine? The cost of an engine rebuild is considerable. Even if you all the assembly the labor yourself. Parts prices are getting considerably higher in my opinion. Machine shop costs too.
 

If you are looking to learn, tear one of your engines apart. Then measure the cylinders and crank for wear. If all is half decent you might get by with a cylinder hone and new piston rings. Could install all main and rod bearings if cranks shows and measures well. Perform a valve grind. Replace any worn valve guides and weak springs. All new gaskets and seals. Rebuild the carb. Check timing chain, replace if needed.  New rotor, cap, points, condensor, coil, sparkplugs and lead wires. You might get away with a half decent, lower priced engine refresh. Bonus if you learn lots!

Edited February 24, 2020 by keithb7 (see edit history)

[Rusty_OToole]

The flathead Chrysler is easy and cheap to rebuild as such things go.  I can see spending $1000 - $2000 or maybe more if you indulge in some speed equipment. Then looking around for a cheap Plymouth or Dodge with a sour engine. Maybe something like a 53 Plymouth hardtop or even a prewar coupe, whatever turns up. It seems if I watch the for sale ads a deal turns up every month or 2. You could put together a fun little car for not too much money. Those old flathead sixes are foolers, on paper 100 - 150 HP isn't very impressive but the long stroke and accompanying broad powerband makes driving so easy and gives them a lot of punch especially at low to medium RPM where you appreciate it in normal driving.

['38 Dodge Mel]

Thanks, that is my plan - the learning part.   I am in the midst of an off the frame resto on the ‘38 keeping it as stock as I can keep it.  The engine it currently has in it doesn’t seem to be giving me any issues whatsoever, however since I was given these two motors and I have some down time, I thought ‘what the heck’, let’s see how far I can take it, and who knows what I may end up with.  After taking the head off there was a lot of rust in the cooling system, the pistons are shot, but the cylinder walls seem smooth and not pitted, so hopefully a polish should suffice.  Given that this is not an engine I am relying on to get the car up and running, the engines are being used to fill time while I wait for the body man to finish the work he has to do before it goes on the rotisserie.   I don’t do body work, but the mechanical is more my interest, so I have a bit of down time before I get the chassis and I can start to do my thing.  I really appreciate all the comments, and history on this motor as I like telling people stories about the car and how it runs when it is at the various local shows.

 

[Rusty_OToole]

If the cylinders and crankshaft don't need to be trued up you should be able to do the job for $1000 or so with new pistons, bearings, etc. Check prices at Vintage Power Wagons they seem to have a lot of NOS parts at good prices. Or regular outlets like NAPA and Rock Auto.

['38 Dodge Mel]

In looking at the engine that I currently have in the vehicle it is stamped AP-071.  I was previously told that the motor is not original, but I would like to get some indication of what it is.  Therefore from doing some research trying to get some info about this model of the flathead the computer keeps directing me to a Ford website.  Any insights??

 

Thanks

[keiser31]

16 minutes ago, '38 Dodge Mel said:

In looking at the engine that I currently have in the vehicle it is stamped AP-071.  I was previously told that the motor is not original, but I would like to get some indication of what it is.  Therefore from doing some research trying to get some info about this model of the flathead the computer keeps directing me to a Ford website.  Any insights??

 

Thanks

Got a photo or two of the engine?

['38 Dodge Mel]

['38 Dodge Mel]

['38 Dodge Mel]

['38 Dodge Mel]

Just now, '38 Dodge Mel said:

Here is what the girl looked like before I started in on it.

[keiser31]

Definitely a Chrysler Corporation engine. It may have a factory replacement block number on it. Is that "AP-071" number stamped on the boss under the cylinder head?

['38 Dodge Mel]

It's apparently stamped on the upper left hand side of the block under the head.  I haven't seen it personally, but asked the body man to tell me what was stamped in that location.  This is what he told me, however I may need to take a run out to validate what he is looking at.

[barry22]

21 hours ago, Rusty_OToole said:

If you want to know what one of those engines is capable of, see this report on nearly 200,000 miles in a 1951 DeSoto Suburban 8 passenger sedan by the original owner. Same engine but the postwar version with 1/16 larger bore for 251 cu in. If it can make it in this 6000 pound whale your car will be child's play. My favorite part "at 70 MPH it smooths out like a perfectly balanced turbine".  This long stroke engine in a car with 4:11 gears towing a trailer.

 

https://www.allpar.com/cars/desoto/suburban-1951.html

 

 

Very interesting article. Chrysler products are well-Engineered vehicles, but are not given sufficient credit for their simplicity and reliability.

[Guest]

1 hour ago, Tim in NC said:

  22 hours ago, Rusty_OToole said:

If you want to know what one of those engines is capable of, see this report on nearly 200,000 miles in a 1951 DeSoto Suburban 8 passenger sedan by the original owner. Same engine but the postwar version with 1/16 larger bore for 251 cu in. If it can make it in this 6000 pound whale your car will be child's play. My favorite part "at 70 MPH it smooths out like a perfectly balanced turbine".  This long stroke engine in a car with 4:11 gears towing a trailer.

 

https://www.allpar.com/cars/desoto/suburban-1951.html

A great article about a fantastic car.  Thank you  Rusty_OToole.

[Rusty_OToole]

5 hours ago, '38 Dodge Mel said:

In looking at the engine that I currently have in the vehicle it is stamped AP-071.  I was previously told that the motor is not original, but I would like to get some indication of what it is.  Therefore from doing some research trying to get some info about this model of the flathead the computer keeps directing me to a Ford website.  Any insights??

 

Thanks

AP-071 isn't a Chrysler serial number. It may be a casting number or some such. The system they used was a letter, and a 2 digit number, to identify the model, then the serial number. P =  Plymouth engine, D = Dodge, C = Chrysler, S = DeSoto, T = truck, IND = industrial.

 

They did deviate from this system for 1958 - 1968 Dodge truck engines but none used an AP prefix so far as I can tell.

 

I have heard of industrial engines and replacement engines that were sold blank so the end user could stamp their own number, to match the registration in the case of a replacement engine or according to some system of their own when used in a new app like a Bombardier snowmobile, tow motor  or some kind of boat or industrial machine.

Edited February 25, 2020 by Rusty_OToole (see edit history)

['38 Dodge Mel]

That makes sense.  I think the body man read something wrong or was looking in the wrong spot. 

[60FlatTop]

That extra 2 inches of engine length doesn't sound like much until you start compensating for it after it is in the car. I swapped a Chrysler 6 into a '36 Plymouth waaaay back when I was 15 or 15 years old and still remember what a bad idea it turned out to be. I don't think there was room in the front sheet metal to move the radiator forward without a lot of cutting and fabrication and some other issues, enough so it never got finished. It taught me a lot about making assumptions and has been a recurring memory.

 

Better to rebuild your existing engine that is running with nice shiny bores, not pitted from lying out in the weather. When I think of engines lying outside I think about pits that won't come out and the chance of a "smoker".

Bernie

[Rusty_OToole]

Funny thing about rust pitted cylinders. An old time mechanic told me how he overhauled an International truck during WW2 that had been left outside with the head off. The cylinders were pitted with rust but he had no choice but to hone them and put the engine together with new rings and the old pistons. During the war there were no new trucks to be had, and even parts were in short supply.

 

The engine burned oil for the first thousand miles then settled down and ran like new. Several years later he had it apart for a valve job and noticed the pits were filled level with hard carbon and polished smooth.

 

Saw a similar situation in the late 80s. A 1971 GMC six cylinder pickup truck that had been out of commission for several years. The engine was stuck but we freed it up for a customer and got it running. It ran well but burned oil. After a year or so we tore the engine down and found the rings stuck in their grooves and a ring of rust on each cylinder where the rings came to rest and rusted up while it was sitting. We honed it with a bottle brush hone and put in new rings and it ran fine and burned no oil.

Edited February 25, 2020 by Rusty_OToole (see edit history)

['38 Dodge Mel]

I agree 60FlatTop - the engine that is currently in the vehicle runs perfectly fine and doesn’t burn a drop of oil.  There is no point in messing up a good thing.   The motor I am working on will ultimately be a ‘spare’  if all the stars align.  I took the head off, and popped the pistons out, and found the head and valves to be a bit of a mess, but the pistons and cylinder walls were in amazingly good shape.  The crank also seems to be in fine condition, but time will tell.  

[60FlatTop]

Funny thing about old mechanics....... most of them repeated the stories they had heard so many times they thought they had actually done the work themselves. And they love an audience.

 

I'd say depression and WWII era were about the worst of them. There is a shelf right above my computer with a set of McGraw Hill mechanics textbooks I bought in 1959. Guess what inspired me to buy them.

 

That 2" longer engine will bite you right when you need it most. The correct core shouldn't be more than $500.

 

Oh, this picture is concurrent with the time I owned that Plymouth. The Plymouth was parked behind.

Edited February 25, 2020 by 60FlatTop (see edit history)

[Rusty_OToole]

You have to use your judgement. Big deep pitted areas that can snag the rings, no good, you have to bore the cylinders. A few pin head size pits scattered around, nothing to worry about if you are putting an engine together for casual street use.

['38 Dodge Mel]

Thanks, IF the motor gets used (still a big if at this point) for my ‘38, the only running it gets is in sunny days in the summer going to the local car shows, so there isn’t a lot of strain, but as we all know the intermittent use has its own draw backs. 

 

Running my hands around the inside of the cylinder walls reveals no pits, scratches, or not even any wear marks. They walls feel smooth as smooth can be. There is a bit of rust at the top of each cylinder wall where where the top of the piston was sitting, but even that feels like it can get honed out. I may be still be missing something and will get a much better look at it when it’s all cleaned up.  So far I am pleased, but it’s still too early to be certain. 

[Rusty_OToole]

If the cylinders are good and the crankshaft is good it should not cost much to put together a real nice motor.

['38 Dodge Mel]

The car that I am doing a full, body off frame, restoration is a 1938 Dodge Business Coupe D10 (Cdn built in Windsor Ontario), which is similar to the USA D8 with some minor differences which I have yet to identify what they are (other than the Cdn models had a slightly different body colour pallet).  In doing a bit more research on the engine that I am rebuilding, (not the one in the car itself) I found this on Wikipedia:

 

"There were essentially two lines of flathead inline-sixes made by the Chrysler Corporation. Chrysler and DeSoto used a longer 25 in (640 mm) block with greater cylinder spacing, while Dodge and Plymouth shared a 23 in (580 mm) block. There is one exception to this: when Chrysler established an engine foundry in Windsor, Canada in 1938, it was decided to only use the long block for all Canadian-built engines. These engines received a trailing "C" in their designation, becoming P8C for example."

 

Therefore the S/N number on the block being rebuilt, C22C2765, tells me that this is a C22 engine, that was actually made in Windsor Ontario given that it has the trailing 'C'.  I realize that only I would find this fascinating, but the trailing 'C' in the number is starting to make sense, and maybe by some fortuitous stroke of blind luck, they might actually fit together when push comes to shove and I decide to put it into the vehicle while I rebuild the existing motor.

[Rusty_OToole]

If your Dodge was made in Canada it has the Chrysler based engine. Same block as Chrysler but different bore and stroke. The 4 1/2" stroke Chrysler crankshaft will fit your Dodge block if you use the matching connecting rods and you could bore the block out to Chrysler size and have a 250 cu in Dodge.

['38 Dodge Mel]

The engine that is currently in the vehicle is definitely the 23” block, it also has a 2” spacer between the fan and the pulley in order to keep the blade closer to the radiator.  The S/N that is stamped on the block is NAP 071 with the numbers being half the size as the letters.  I have attached a couple photos.  Any insights on what motor is currently in the vehicle?   I have done some preliminary research and coming up blank, but still looking.......

Edited February 28, 2020 by '38 Dodge Mel
Added a picture (see edit history)

[Rusty_OToole]

That is not the original engine. Someone put in a US Plymouth or Dodge type engine. The number is hand stamped and does not match any known Chrysler product. The engine may have come from some kind of industrial application. If you want to know what size it is, you can measure the stroke thru a small pipe plug on the head, over the #6 piston. This was made so you could find top dead center at tuneup time but can also be used to measure the stroke of the engine. Unscrew the plug, drop a screwdriver down the hole, slowly turn the engine by hand and you can measure the difference between top and bottom piston position. Be careful of using a plain wire and don't drop it down inside the engine, best to bend a loop in the end so it can't fall down the hole. Standard stroke on this type engine 4 3/8 for 217 cu in  or 4 5/8 for 230 cu in, both with 3 1/4 bore.

 

Original engine would have been the long, 25" Chrysler block with 3 3/8 bore X 4 1/16 stroke for 218 cu in.

Edited February 28, 2020 by Rusty_OToole (see edit history)

[JACK M]

Is it just me or does that alternator look like it needs another bracket to align it better?

[Australian dodge truck]

Hello all. Greetings from Australia.  I came across your forum and have learnt a lot from this thread I have  a flathead six 25” 251 in my Australian dodge truck that I have just bought. I want to upgrade exhaust to a duel and Change intake to a twin carb set up. Can anyone tell me where best place to buy from that will ship to Australia?