? Of Mopar Flathead Reliability

[55 Fargo]

Here is a topic, that no doubt gets "hashed out" very often whether it be a Chrysler Flathead, A Chevy Stovebolt 6, or Ford Flathead V8, Studes, Hudsons, Ramblers could be lumped in.

A lot of people out there, and some most likely on this here forum too, have a mindset, that none of the aforementioned power plants, but specifically Mopar L heads, are reliable or capable of modern day use.

Most of these same folks choose SBCs for all there old car and truck projects, nothing wrong with that, no point of contention from me, use whatever "you choose".

I hear it all the time, oh when you swap in another modern engine, oh that would be cool with a 440 or hemi, etc.

Now some of you know I have a 318/904 combo, that was bought to go into my 55 Fargo, to date no such thing has happened. It may never happen, but I never say, "never will it happen".

Was talking with a relative today, younger guy around 36, has a few projects, Ford stuff, all V8 stuff, has no experience with inline 6s, let alone a Chrysler flathead.

He has a belief that our blessed flatheads are fragile, need to be treated with kid gloves and should only be used for restored antique purposes. Now he wasn't slagging these powerplants, just to him they are such old technology, they can't certainly be reliable for a lot use, including daily driver use, or travel across the country use.

I did stress these engines are very reliable, and can take a lot of abuse, when in good condition, that the 318 is a super reliable powerplant, but the little flathead 6s can certainly hold their own in this department. heck 1 216 Chevy babbit pounder is pretty reliable, if you go easy on them, have had a few of those in my life.

So Lets here your stories, experiences, and opinions on this topic......

 

[Bobacuda]

Prior to going in the Navy back in '71, a couple of friends and I drove my '51 Plymouth (flathead) from the San Antonio area, to Ft. Smith, Arkansas in one day.  After visiting a couple of days, we drove to Hurley, Wisconsin & Ironwood, Michigan for about a week.  Went to see Lake Superior, then gassed up, and drove in shifts straight through back to Texas (about 26 hrs, if I remember right).

 

We were all young and dumb, so we drove my old Plymouth 70-80 mph both ways.  Car never faltered, never overheated, never used any oil.  Always fired right up and was running when I parked it in 1975 when I got out of the Navy.  Then, like a dumbass, I sold it for $100 (college beer money).

 

I think that once you get the "rebuilding bugs" out of them, they are as reliable as any other engine when kept within their designed functions.

[plyroadking]

I don't believe that they are fragile. I bought my 1940 plymouth 10 years ago almost to the date. It had a blown Dodge 6 in it and my grandfather gave me his spare running 49 Plymouth 6. I swapped it out a couple years later for a 50 dodge 230. The 49 block was cracked but didn't leak a lot. I "went through" (tore it down and saw how it worked and reassembled it) and after a fresh paint job dropped it in. I was driving the car 75 miles round trip to Junior college at the time. Apparently I didn't seat a wrist pin retainer fully and a year or two later it had worn through the cylinder wall and halfway into the next cylinder. I swapped it out for a 55 plymouth 230 that had a recent bottom end job. That 6 got me through junior college and I hauled the car out to Iowa in 2009 when I continued my education at Iowa State. 3 or 4 years worth of unsalted season driving and she was smoking a little, I think I'd put around 50k miles on the car since I bought her in '06. I had a summer internship opportunity in Napa Valley and decided I'd pull the 6 apart and see how it was doing. The bottom end was still within spec but the top end was ready for a rebuild a while ago. I had it bored out a little and reassembled it myself with a lot of attention to the wrist pin retainers. Dropped it back in the car and two days later drove her out to CA at 75 mph straight for 2 days, with overdrive and a 3.73 3rd member. I drove her all summer out there and then drove back to Iowa in the fall.

After I finished at ISU I commuted in the car to work 400 miles a week for 6 months until the salted season started. I moved closer to work and still drive her daily the 5 miles to work and wherever else I go during the summer.

I put the car in winter storage a month ago and she just turned over 78k miles since I reset the odometer when I brought her home in 2006.

As for them being "fragile" or "un-reliable" I'd disagree, especially after having them survive the flogging I gave them in my teenage driving years.

[40plyrod]

I have about 10 billion miles on my 51 Chevy pickup 235 inline six with barely any problems. I had it since I was 16 (I'm 41 now) and the worst problem I had was a blown head gasket between  #5 and #6 and I still managed to drive it home... new head gasket and we're good to go. Teenagers never use kid gloves! 

Edited December 2, 2015 by 40plyrod

[55 Fargo]

I have about 10 billion miles on my 51 Chevy pickup 235 inline six with barely any problems. I had it since I was 16 (I'm 41 now) and the worst problem I had was a blown head gasket between  #5 and #6 and I still managed to drive it home... new head gasket and we're good to go. Teenagers never use kid gloves!  100_1418.jpg

Still runnin a closed driveline or did you upgrade to open and more highway friendly gears.

I love stovebolt 6s too, they have there own unique sound too....

[55 Fargo]

I don't believe that they are fragile. I bought my 1940 plymouth 10 years ago almost to the date. It had a blown Dodge 6 in it and my grandfather gave me his spare running 49 Plymouth 6. I swapped it out a couple years later for a 50 dodge 230. The 49 block was cracked but didn't leak a lot. I "went through" (tore it down and saw how it worked and reassembled it) and after a fresh paint job dropped it in. I was driving the car 75 miles round trip to Junior college at the time. Apparently I didn't seat a wrist pin retainer fully and a year or two later it had worn through the cylinder wall and halfway into the next cylinder. I swapped it out for a 55 plymouth 230 that had a recent bottom end job. That 6 got me through junior college and I hauled the car out to Iowa in 2009 when I continued my education at Iowa State. 3 or 4 years worth of unsalted season driving and she was smoking a little, I think I'd put around 50k miles on the car since I bought her in '06. I had a summer internship opportunity in Napa Valley and decided I'd pull the 6 apart and see how it was doing. The bottom end was still within spec but the top end was ready for a rebuild a while ago. I had it bored out a little and reassembled it myself with a lot of attention to the wrist pin retainers. Dropped it back in the car and two days later drove her out to CA at 75 mph straight for 2 days, with overdrive and a 3.73 3rd member. I drove her all summer out there and then drove back to Iowa in the fall.

After I finished at ISU I commuted in the car to work 400 miles a week for 6 months until the salted season started. I moved closer to work and still drive her daily the 5 miles to work and wherever else I go during the summer.

I put the car in winter storage a month ago and she just turned over 78k miles since I reset the odometer when I brought her home in 2006.

As for them being "fragile" or "un-reliable" I'd disagree, especially after having them survive the flogging I gave them in my teenage driving years.

Sounds like you have a got a whole lot of good reliable use out of your flattie powered machine.

I enjoyed your post, and hope to see more like it. This doesn't have to be limited to reliability stories from years ago, but could be in the present day too....

[dpollo]

I put 123000 miles on my first 50 Dodge (D36) over and above the original 56000 and it was driven up to 20 000 miles each year.

I put new rings in it at 70 000,  rebored at 98 000 after a high speed run tore up the top rings.  At 150 000 I rebored again and put a new crankshaft in it and ran the car up to 179 000 when the inevitable rust caught up to us.  I still have the engine which was running perfectly at the time I scrapped the car.  This car was driven very fast and hard.  Over the years I have seen these engines totally worn out at 50 000 miles and others running well at 100 000.  I knew a man who bought his D24 limousine new in 1948 and drove it

650 000 miles . (Commercially) Three engines, one overhaul on each. No crankshaft troubles at all.  His secret,  Clean oil. In all that time, and he was nearly 90 when he died, there was no collision damage to the car so we can assume he was a good driver but he never hesitated to take his car on long highway trips. Even today I do not hesitate to drive my cars . Anywhere.

These engines were not fragile but failures certainly could occur through mistreatment.  Ford V-8s and Chev sixes were no better.

Each had (has) its limitations but all will give good service even today if treated with the respect they deserve.  I have said before It was the duty of every young man of my generation to find the limitations in the cars his parents drove and we worked hard at it.

Chev owners got pretty good at changing transmissions as I recall.   Me, I preferred to keep driving in my Dodge.  I put a 283 Chev in a 50 Plymouth and a slant six in another but neither car appealed to me as much as  ones with an original drivetrain.

[greg g]

Look at the current evidence, most of the old Fords you see today have Chevy engines in them.  Most of the Chevys you see have new Chevy engines in them.  Most of the old mopars I see these days still have mopar engines in them, Most of the Mopars that came with flathead 6 engines in them when they were new, still have some sort of Mopar Flathead 6 moving them down the road.

[55 Fargo]

Very good posts, thanx for sharing.

Question for those who have rebuilt a flathead once or even multiple times.

Did you notice a significant power loss, just before rebuilding, and a power gain with a fresh rebuild?

[Mark Haymond]

^{I had the 217 flathead rebuilt when I restored my 1950 Plymouth in 1998. I have driven it as a hobby car mostly around town, but with some occasional 200 or 300 mile round trips. I even drove it every day to work for a year. Over the past 16,000 miles I have done some maintenance and garage repairs like most owners, but it always brought me home on its own power and I never needed a tow. I feel this engine would take me anywhere.}

^{It is in stock condition, with generator, four blade fan, distributor, mechanical fuel pump, partial flow oil filter and other stock stuff. Reliable, not fragile.}

[55 Fargo]

Just got back from own "reliability cruise", however today is about 25, very dense fog, some ice on the highway too.

Drove 3 miles down my road to the highway, visibility is about 50 ft, trees and any vegetation insight is covered in hoarfrost.

Got on the highway, didn't go too far, cruising at 55 mph, very easily with 3.23 gears, usually cruise at 60 or so, but fog was super thick.

Got home in 1 piece, now wasn't that fun..........LOL

[JBNeal]

the engines I have rebuilt were done because fluid loss/consumption had increased to the point where the engine could not be run safely for extended periods (oil pouring out of crank seals, coolant blowing out exhaust pipe, etc.)  The engines still had power, but overheating and mechanical damage was a concern so that I would not put a full load or hard throttle on them.  As far as flathead reliability, it might be important to note that these engines have been out of production for decades, yet there are quite a few still around, which may speak to their reliability.  From my experience, Chrysler engines can hold up if properly maintained; it's what else is on the vehicle that usually poops out first.  For example, some folks try to convert to 12V to make the vehicle more reliable, but the underlying problem with their 6V system was their degraded wiring.  Another example is upgrading a rear axle to a modern unit (with more readily available brake parts and a highway friendly axle ratio) to make the vehicle more usable, even if the original axle only needed some refurbishing to make it reliable albeit a little slow.  So reliability may be more of a function of personal usage and original system degradation (or replacement quality) than of the engine itself

[46Ply]

I have about 10 billion miles on my 51 Chevy pickup 235 inline six with barely any problems. I had it since I was 16 (I'm 41 now) and the worst problem I had was a blown head gasket between  #5 and #6 and I still managed to drive it home... new head gasket and we're good to go. Teenagers never use kid gloves!  100_1418.jpg

10 billion?  Just goes to show you can't trust anyone driving a Chevy!       But the truck looks goooood!

Edited December 2, 2015 by 46Ply

[Bobacuda]

Fargos -

The more I read this topic, the more I am convinced you need to have your friend read the Bamford Garage tour to the Artic Circle.  Pretty much answers his questions on reliability and dependability.

[55 Fargo]

Fargos -

The more I read this topic, the more I am convinced you need to have your friend read the Bamford Garage tour to the Artic Circle.  Pretty much answers his questions on reliability and dependability.

Hey Brother I agree, but then he would mention that break down in the north, and the engine going kinda south after a 5000 mile trip.

Hey I know the entire journey, Bamford was in my Kitchen a year or so back showing us a pictorial presentation....truly amazing, young V8 heads won't understand. I don't even try to change there minds, my 13 YO Son wants me to get rid of the flathead like yesterday, unless I can get a super George Asche 265 Hi-perf.....

Edited December 2, 2015 by Fargos-Go-Far

[55 Fargo]

Actually just got back from drive #2, much less fog, cruising down the highway at 60 or 100km/h like nothing, no wind, a fine mist in the air.

Engine just purring along, heater box blowing, was bored so this helps....

[William Davey]

Ask your "friend", if Chrysler flatheads are so unreliable, why were they used in: farm machinery, stationary generators, airport tugs, welders and countless other hard use applications?

[55 Fargo]

Ask your "friend", if Chrysler flatheads are so unreliable, why were they used in: farm machinery, stationary generators, airport tugs, welders and countless other hard use applications?

Hold on He is young has no idea about such things. He of course is not putting down our beloved flatheads, just misinformed on how friggin really tough they are.......I don't care what anybody thinks to be honest, talked with a guy today while at the filling station with my Hemi Ram, talked a minute about my flathead, he was under the impression it needed lead fuel additive, and special oil, i just smiled and said nope.....

[Jeff Balazs]

It had better be reliable.........it is all I got.

 

Jeff

[Bobacuda]

Every time we watch a WWII documentary, I point out the Dodge, Stude and Willis warhorses to my wife and kids.  They all understand that those engines went through hell and back, in the desert, in the freezing cold, in rain and mud and every other lousy condition without preventative maintenance, and they still chugged on.  That is how my brood came to recognize that the engine and its technology are old, but extremely functional and durable.

 

My kids (and my wife) would disown me if I pulled the flathead out of my truck for a V8.

[40plyrod]

Still runnin a closed driveline or did you upgrade to open and more highway friendly gears.

I love stovebolt 6s too, they have there own unique sound too....

 

No I upgraded to a saginaw 4-speed (a direct bolt on) and a open gm diff with 323's, it turns about 2000 rpm @ 90 kmh. Some can get pretty "rappy" sounding but mine isn't, it's fairly mellow with just a split exhaust manifold and a pair of turbo mufflers.

[55 Fargo]

Looks great Plyrod, zat a 216?

[Oldguy48]

I've owned several Mopar flat head powered vehicles over the years, and my experience has been that if you can get them started, they are rock solid reliable. But beginning with a 48 Plymouth that was our family car, this thing was a problem in cold weather.  My Dad used a dipstick heater, a 150 watt floodlamp laying on the head pointed at the carburetor, and a can of ether when winter was upon us.  Sometimes, maybe it would start. And this was a vehicle that was well maintained.  And I've owned a few other Mopar flatheads that had the same behavior.  I had a 57 Dodge Pilothouse that even though it was 12V, and even though I installed a second battery, it was a bear to start in cold weather.  Get it rolling, and start it in gear, and it would fire right up.  But using the starter, was an exercise in futility. I have a lot of respect for Mopar flatheads as far as reliability goes, but getting them started in cold weather was a crapshoot.  Others may disagree, but I speak from experience...a lot of experience.  And a lot of frustration.

[40plyrod]

Looks great Plyrod, zat a 216?

 

235.

[40plyrod]

I've owned several Mopar flat head powered vehicles over the years, and my experience has been that if you can get them started, they are rock solid reliable. But beginning with a 48 Plymouth that was our family car, this thing was a problem in cold weather.  My Dad used a dipstick heater, a 150 watt floodlamp laying on the head pointed at the carburetor, and a can of ether when winter was upon us.  Sometimes, maybe it would start. And this was a vehicle that was well maintained.  And I've owned a few other Mopar flatheads that had the same behavior.  I had a 57 Dodge Pilothouse that even though it was 12V, and even though I installed a second battery, it was a bear to start in cold weather.  Get it rolling, and start it in gear, and it would fire right up.  But using the starter, was an exercise in futility. I have a lot of respect for Mopar flatheads as far as reliability goes, but getting them started in cold weather was a crapshoot.  Others may disagree, but I speak from experience...a lot of experience.  And a lot of frustration.

 

Funny but, my dad had a friend that would say a dodge flathead would start fine as long as there wasn't a cloud in the sky.   

I always thought is was just a prejudice against dodge but may some truth to it?