Red-Line "RPM" Confusion

[SasquatchSanta]

In my 15-year, 4-truck experience with M37s I've always been told not to run the engine over 2,500 RPM. I've been told that the Chrysler Industriel 230 engine isn't balanced and at anything over 2,500 RPM they will shake themselves apart.

In a stock M37 2,500 RPM produces approximately 45 MPH therefore I've always considered the M37 to be a 45 MPH vehicle.

I've got a tach my M37 and the engine seems to run best between 2,000 and 2.400 RPM. I've never ran it above 2,500.

Wellll ..... I'm going along dumb and happy, believing the the 2,500 RPM rule was gospel until I spoke with Tom Langdon, owner of the Stovebolt website about purchasing a Holly/Weber 2-barrel progressive linkage carburetor.

Mr Langdon's position is that the 230 is good for 3,600 RPM, that it doesn't produce it's rated power until 3,600 and at 2,500 I'm only running at half throttle. His advice was to put my foot into it.

I wasn't successful in convincing him that because the 230 isn't balanced it is dangerous to exceed 2,500 RPM for an extended period of time. On the balance issue, he said that in-line engines are naturally balanced and unless someone has changed component parts OR the clutch or flywheel assembly is out-of-balance there shouldn't be a problem. His then said to check the book on the rated RPM.

I've checked the book in the past and it does indeed say 3,600 RPM. This has always been a confusing area.

Given that Mr. Langdon comes highly recommended I don't want to automatically dismiss his comments. Having said this, I also don't want to blow an engine.

Are there any flathead fanatics out there that can shed some wisdom on the subject.

 

[citizensoldier]

Not a pro Sas but I think a fresh well built engine can handle it.. Its the old worn down engine that cant take it for a sustained period of time.. My opinion anyway.

 

[M-37Bruce]

RPM's

Hey Ernie,
My 230 is almost 10 years older than my M, it was rebuilt in France (of all places) in 1967. She, the od godess will rumble along @ 45-50 most all day, if I could stand it that long.

 

[NDT]

Back when I was young and stupid I would drive the local civil defense M-37 against the governor at 52 mph all day, that is until it would vapor lock and leave me on the side of the road for 10 minutes.

 

[Bill W]

The M-37 has a internally balanced crank., When I rebuilt my 230 I brought all the appropriate parts ( including clutch pack) to a performance machine shop to have them balanced. When I went to pick them up the owners son came out and told me that he barelly had to mill the crank as it was so close to being dead on balanced.
TM9-1840A ( 230 engine rebuild manual) has the max ( governed) rpm of 3400, grosss brake horse power ( 94) is reached at 3200rpm. I liked to keep mine at around 45-50mph max

Foot note: ( Externally balanced cranks have harmonic balancers)

 

[SasquatchSanta]

Bill W. write:

Foot note: ( Externally balanced cranks have harmonic balancers)

Are you saying to add a harmonic balancer that it has to be balanced with the engine it is being installed on?

I've wondered in the past if the reason we've been told to keep the RPM down to 2,500 was because the engine doesn't have a harmonic balancer?

If they don't have to be balanced (matched) to the engine AND they help in smoothing out an engine a harmonic balancer wouldn't be difficult to add.

Also --- that's good to know where the engine develops it's max power (3,200 RPM). I've never seen a torque and horsepower graph on the T245 engine. Do you know where the max torque curve is?

Thks

 

[bulldog_mack13]

So what stops them from vapor locking all the time and shutting off for 10 , 15 min? Electric fuel pump ? Thanks - Jay

 

[Bill W]

"Are you saying to add a harmonic balancer "

No not at all!
All I pointed out was the difference between "Internally" and "Externally balanced engine's. The 230's crank is balanced "Internally" it doesn't have or NEED a harmonic balancer!
The M-37's gross max torque is 188ft/lbs @ 1200rpms

 

[M-37Bruce]

Thanks Bill,
Are they rubber or metal ft/lbs?

 

[Bill W]

Thanks Bill,
Are they rubber or metal ft/lbs?

Why "Douglas" of course

 

[SasquatchSanta]

Thanks for the torque info Bill W.

I spoke with my old Buddy Bob Stahl at Veterans Vehicles as well as Vintage Power Wagons today to get their opinion on the max RPM for a T245, 230 CID Dodge. Bob Stahl concurred with not going over 2,500 RPM and Vintage Power Wagons said if you try to drive 55 MPH they will not last long before the crankcase gets ventilated with a rod. I haven't done the math but I doubt if 55 MPH with a stock M37 reguires the engine to turn anywhere close to the 3,600 RPM that Tom Langdon at Stovebolt is saying it will run.

I called Langdon back today to get an email address to send a linkage picture for the new carb kit to but during the conversation I sensed that he still isn't buying into the 2,500 RPM max requirement. I think I'm going to stay away from the 2 barrel carb project simply because of fears that he won't work with me in good spirit on the project. The sizing requirement are different for an engine that runs 3,600 versus 2,500. I fear it will end up getting sized wrong.

 

[M-37Bruce]

Are you sure they aren't Packard?

 

[JasonS]

The M-37 has a internally balanced crank., When I rebuilt my 230 I brought all the appropriate parts ( including clutch pack) to a performance machine shop to have them balanced. When I went to pick them up the owners son came out and told me that he barelly had to mill the crank as it was so close to being dead on balanced.
TM9-1840A ( 230 engine rebuild manual) has the max ( governed) rpm of 3400, grosss brake horse power ( 94) is reached at 3200rpm. I liked to keep mine at around 45-50mph max

Foot note: ( Externally balanced cranks have harmonic balancers)

Externally balanced cranks (ie. sbc 400) have a balance weight in the balancer. Internally balanced cranks still have harmonic balancers.

 

[Tanner]

So what stops them from vapor locking all the time and shutting off for 10 , 15 min? Electric fuel pump ? Thanks - Jay

Typically, to prevent the vapor lock issues, you should insulate or otherwise route the fuel lines away from high heat sources -

Tanner

 

[JasonS]

Thanks for the torque info Bill W.

I spoke with my old Buddy Bob Stahl at Veterans Vehicles as well as Vintage Power Wagons today to get their opinion on the max RPM for a T245, 230 CID Dodge. Bob Stahl concurred with not going over 2,500 RPM and Vintage Power Wagons said if you try to drive 55 MPH they will not last long before the crankcase gets ventilated with a rod. I haven't done the math but I doubt if 55 MPH with a stock M37 reguires the engine to turn anywhere close to the 3,600 RPM that Tom Langdon at Stovebolt is saying it will run.

I called Langdon back today to get an email address to send a linkage picture for the new carb kit to but during the conversation I sensed that he still isn't buying into the 2,500 RPM max requirement. I think I'm going to stay away from the 2 barrel carb project simply because of fears that he won't work with me in good spirit on the project. The sizing requirement are different for an engine that runs 3,600 versus 2,500. I fear it will end up getting sized wrong.

My brother purchased the holley weber from Langdon. Landon wouldn't sell him the linkage kit; insisting that it wasn't necessary. Took a lot of work to get Langdon to sell it. In the end, it was exactly what was required.

It seems common to rate engine horsepower at an RPM not intended for constant service. Recommended maximum rpm for continuous service is often a bit nebulous. The 400 Reo in my M35 has it's maximum horsepower rated at 3400 rpm but the engineering document indicates 2800 to 3000 maximum at cruising speed. It clearly states to NOT run against the governor at all times. I try to avoid much over 2500 and this is in a better built engine than the 230. I have talked to Langdon a few times and respect that fact that he is a retired GM powertrain engineer but I think that 3600 for long periods of time is poor practice.

 

[SasquatchSanta]

JasonS wrote:

My brother purchased the holley weber from Langdon. Landon wouldn't sell him the linkage kit; insisting that it wasn't necessary. Took a lot of work to get Langdon to sell it. In the end, it was exactly what was required.

It seems common to rate engine horsepower at an RPM not intended for constant service. Recommended maximum rpm for continuous service is often a bit nebulous. The 400 Reo in my M35 has it's maximum horsepower rated at 3400 rpm but the engineering document indicates 2800 to 3000 maximum at cruising speed. It clearly states to NOT run against the governor at all times. I try to avoid much over 2500 and this is in a better built engine than the 230. I have talked to Langdon a few times and respect that fact that he is a retired GM powertrain engineer but I think that 3600 for long periods of time is poor practice.

Thanks for the comments on the RPM.

Being a retired GM engineer I'm sure he brings a lot to the knowledge table. My apprehension comes from the way I interpreted his response to being challenged about running the engine at 3,600 RPM. I'm not looking for performance guarantees but I do want someone that will work with me (at my expense) with an open mind in trying to improve the performance of a 2,500 RPM 230 CID flathead. Given the weight of the truck and the fact that I refuse to run the engine at 3,600 RPM it's probably going to require experimenting with jet sized to optimize the performance. It may even require a different carb than he originally intended to supply. I've dealt with vendors before that have formed a hardening on the attitudes when they feel their ego is being challenged. Sometimes people let their expert status get in the way of solving a problem. Perhaps I'm geing over critical but in areas like this I spook easy.

I realize that this is a departure from the stock military carburetor but it can be make to work --- to give better fuel economy (screw the 3,600 PRMs) --- it could represent a nice market for someone.

 

[Bill W]

I wanted to change out the oil bath filter on mine for a paper filter, figured it would breath better to make for a better burn., Also VPW use to sell a performance/econo cam for the 230 ($$).
I think egge machine sold them also http://www.egge.com/