Thoughts on MoPar Flatheads - 2

[grey beard]

Thermostats

It is impossible to operate an internal combustion engine without generating condensation in the crankcase. It is just a fact of life. If the moisture is removed, it presents no problem. If it is not removed, the result is an eventual buildup of sludge.

The only way by which the moisture of condensation can be removed from a crankcase is evaporation. This evaporation can only take place in the presence of heat and air movement. If the crankcase and engine block heat is not high enough for evaporation to occur, the condensation moisture will remain inside the block. Since this is water, which is heavier than oil, it will go to the bottom of the crankcase or valve chamber. It is for this reason that these are the areas where sludge is typically found in greatest quantity on tear-down. This writer has disassembled many of these engines were more than one pint of sludge was present in the valve chambers alone.

The best remedy for condensation removal is a high temperature thermostat. Vehicles built in the forties and fifties (and before) were designed to use alcohol based antifreeze. This required the use of low temp thermostats. Today we use glycol based antifreezes with much higher boiling points. Actually, the use of a 50/50 mixture of permanent antifreeze and water RAISES the boiling point of the coolant. All this is in aid of explaining why higher, rather than lower temperature thermostats are beneficial to longer engine life. The use of a 160 or 170 degree thermostat today with permanent antifreeze is an invitation for sludge to form in the crankcase. You are doing your engine no favor at all by keeping it running cool, in spite of how it may seem to your own sensitivities.

Not only do higher temp stats cause higher engine operating temperatures which aid in condensation removal, but they also help to raise the temperature more quickly, resulting in less cold engine operating time. Once stat temperature is reached, normal cooling will take place, but at a little higher temperature. Yet another reason why these flatheads need more heat than some engines is that they are heavy castings. A flathead six cylinder 218 cid engine weighs several hundred pounds more than a small block Chevy 350. This casting mass takes TIME to heat up and get up to operating temperature.

Many owners believe that when their dash gauge shows normal temperature, the engine is truly warmed up. Nothing could be further from the truth. Remember this one idea: an engine may warm up and the thermostat open to full circulation long before the block casting around the valve chambers has come up to full operating temperatures. It is this writer’s estimate that it takes nearly thirty minutes of engine operation for a typical flathead block to reach normal operating temperature in cool weather.

Please remember, I’m not talking about the thermostat or the top radiator tank, but the block casting, itself. This is where the condensation occurs and must evaporate from. In order to keep these block casting spots free of sludge, they must get up to full operating temperature. Proof that many of these engines have spent much of their lives running too cold is the sludge found inside the blocks. Granted, engine oils and filtration were of poor quality by comparison to today’s technology, but those engines that are run warmer are always cleaner. An example of this is the fact that larger truck engines are usually found to have less sludge than small trucks and automobiles. Check it out.

Consider a newly restored vehicle with a completely new and clean engine assembly. To keep this engine clean, it should not be started and driven short distances, again because the block will not have an opportunity to achieve operating temperatures. When I use my old stuff, I start it, let it run at idle for a while, then drive it, hopefully at least thirty minutes. I will jack up a car and push it in or of a stall to avoid starting a cold engine for only a few minutes, for this very reason.

It goes without saying that all this talk about getting engines up to temperature is doubly true for the exhaust systems. Exhausts live linger in an atmosphere where they warm up completely each time they are used. Why do you think tail pipes rot off three or four times before head pipes and mufflers? They are always cooler and warm up slower, since they are farther from the source of heat.

Cooling Systems

Cooling systems seem to be one of the more misunderstood components of older engines. In order to understand them, it is necessary to understand the combustion process. A typical gasoline engine running at 2000 rpm under no load will generate a certain amount of heat, but this will soon be realized and stabilized.

Add to this engine now an increased load on the crankshaft, and many things happen at once. First, in order to maintain rpm, the throttle plates must be opened further. This is done automatically if the engine is governed, or manually in an automotive application. The amount of fuel entering the engine increases, the result of which is an immediate increase in combustion chamber pressures and temperatures. It is this sort of use that cooling systems must handle in order to protect an engine. Normal driving under light load barely works the cooling system at all. It is at higher engine loads that the cooling system must be able to function well.

From the engine’s perspective and from a combustion standpoint, the hotter an engine temperature, the better and more efficiently the engine will. Fuel atomizes more freely and the combustion process thrives in an atmosphere of heat. This is difficult for many older vehicle owners to comprehend, yet it is fundamentally true . . . . . . Up TO THE POINT where the engine will begin to suffer metallurgical from the heat. Therefore, the job of the cooling system is to allow the engine to run as hot as safely possible in order to aid the combustion process, yet keep it cool enough to protect it.

Engines are designed to withstand lots of heat safely. Unfortunately, the margin for safety between “hot enough to run well” and “too hot for engine safety” is not a very wide one. When metal parts are heated, they expand. When they cool again, they contract. This cycle can happen over and over with complete safety, as long as the extremes of the heat range are not reached. If metal parts are heated so much that they do not contract to their normal tolerance after cool-down, the metal is said to have warped. This action is most often noticed on cylinder heads and manifold castings that have been subjected to hundreds of heat/cool cycles.. Typically, the remedy for a warped casting is resurfacing.

An example of this action is the typical small block Chevy cylinder head, where the valve arrangement is such that two exhaust valves sit adjacently in the middle of the cylinder head. This is nearly always the point of failure with these castings, for this is the hottest spot on the component.

How does this all relate to MoPar flatheads? The design of these engines is such that a water distribution tube is used in the cooling system to aid in dispersing coolant to the bottom of the exhaust valve seat castings. In this sense, these engines are truly overbuilt, for this is a feature not used by very many other manufacturers of the time. An analogy to this feature would be oil nozzles directed to piston crowns in modern diesel engines – a feature that goes far to extend engine life. Flathead radiators are also overbuilt from a size standpoint, and are truly impressive in their ability to transfer heat from the engine and transfer it to the air. When these engines are warmed up to 180 – 200 degrees F, they run happily all day, run more efficiently and stay cleaner. They live linger, as well.

Having said all this, the water distribution tube is a critical link in the cooling system. Never pull a water pump without at least pulling and checking the distribution tube. It goes without saying that no engine overhaul should ever be contemplated without inspection of this part as well. The tubes are reproduced by several vendors and are available.

Bottom Line

If you truly want to do the best you can for your MoPar flathead, here’s my recipe:

• Modern high detergent motor oil in a clean engine

• Full-flow oil filtration system in place of the part time bypass system

• PCV system instead of the primitive road draft tube

• High temperature (180 or higher) thermostat

• Good quality paper air filter instead of an oil bath system

[Guest bizzycoupe]

Thank you, this is very good info, I printed it.

[central52]

Good advice. I'm new to this game. How do you change the oil filtration system from the old part-time bypass to a full-flow system? Ed

[Don Coatney]

Dave;

Good, well written, informative posting. Thanks for sharing your thoughts.

[Norm's Coupe]

Bottom Line

If you truly want to do the best you can for your MoPar flathead, here’s my recipe:

• Modern high detergent motor oil in a clean engine

• Full-flow oil filtration system in place of the part time bypass system

• PCV system instead of the primitive road draft tube

• High temperature (180 or higher) thermostat

• Good quality paper air filter instead of an oil bath system

I only have one question. What difference does it make having a PCV system instead of the draft tube? The only real purpose I see for the PCV system is to control air pollution, not helping the engine last longer.

[Don Coatney]

I only have one question. What difference does it make having a PCV system instead of the draft tube? The only real purpose I see for the PCV system is to control air pollution' date=' not helping the engine last longer.[/quote']

Norm;

A positive crankcase ventilation system will use negative pressure (intake manifold vacuum) to purge the moisture laden foul air from the crankcase. The draft tube relies on the engine moving at road speed to create a slight negative pressure in the crankcase and it is not nearly as effective at removing moisture and other contaminates as a PCV system.

[Norm's Coupe]

Norm;

A positive crankcase ventilation system will use negative pressure (intake manifold vacuum) to purge the moisture laden foul air from the crankcase. The draft tube relies on the engine moving at road speed to create a slight negative pressure in the crankcase and it is not nearly as effective at removing moisture and other contaminates as a PCV system.

Don,

I'm not sure I fully agree with that. The draft tube may not be fully functional while idling, but it does dump moisture while idling. I use to see a lot of steam and water coming out when the head gasket was blown before the rebuild, just idling. If the crankcase had been closed with a PCV system, that moisture would have been directed back into the engine, before being sent out the tailpipe.

In my view (and keep in mind, it's just my view), it's best to dump something bad from the engine directly, such as the draft tube, than recirculate it. Think of the old fashioned "Out House" instead of a toilet in the house. You never had to worry about plugging up the outhouse because it was direct to the ground. Move the toilet in the house into a plumbing pipe, and you can stop up the system. So.........not saying I want to go back to the Out Houses, but that a direct opening to dump the unwanted is usually a better faster option, than recirculating the unwanted.

[TodFitch]

I only have one question. What difference does it make having a PCV system instead of the draft tube? The only real purpose I see for the PCV system is to control air pollution' date=' not helping the engine last longer.[/quote']

Positive Crankcase Ventilation does make for a cleaner crankcase. If I recall correctly the first car fitted with one was a 1928 (or so) luxury car (Pierce or Peerless). And they were not thinking about air pollution when they used it. It was intended to make the oil stay cleaner and thus have the engine last longer. The only reason that Detroit used a draft tube for so long was cost.

Most of the pollution on a "uncontrolled" engine is unburned fuel/air mixture from crankcase blowby. Since a PCV valve happens to work by sucking the blowby into the manifold and burning it, it does have the side effect of working as a anti-smog device. So PCV values became the first pollution control device but they were invented to make your engine oil stay cleaner and your engine to last longer.

I vary between being amused and dumbfounded when people remove PCV systems from their old cars because they think they are only for "pollution control" and therefore must be bad.

[Rodger S-11]

Hola There

The early fifties Military 230's had an in-closed system on the Dodge Truck's. Or I had one that had this system.

Rodger & Gabby

S-11

[47dodgepu211]

I am willing to try the pvc system. Where do I buy a simple one today. Is the old type smog pump needed? I hated those smog pumps, they were noisy and failed after about 15K miles.

John

[woodscavenger]

Great write up Dave. Thanks. That one goes in my clipboard for later.

How do you make a PCV system for this engine?

How do you make a full flow oil filter system and is there a way to get to a twist on style with minimial difficulty?

[Tom Skinner]

Good information Dave, however, what about keeping 'em stock?

That is to say now you have changed all these things, Oil Filter Housing, Breather Tube, Airfilter, and why can't you

see that you have damaged the original Motor of the car?

To me the same go's for an Electronic Ignition/Distributor.

To a purist it is perposterous, to think that I, or anybody else would buy

a car that had been butchered in such a way.

Tom Skinner

PS. If you have to re-engineer things to make yourself happy, find another

brand of cars (Read Not Mopar) to Jimmy up to suite yourself. My Grandfather used to say some people are so smart, their stupid. I have to agree he was right.

[PatS....]

Good information Dave, however, what about keeping 'em stock?

That is to say now you have changed all these things, Oil Filter Housing, Breather Tube, Airfilter, and why can't you

see that you have damaged the original Motor of the car?

To me the same go's for an Electronic Ignition/Distributor.

To a purist it is perposterous, to think that I, or anybody else would buy

a car that had been butchered in such a way.

Tom Skinner

PS. If you have to re-engineer things to make yourself happy, find another

brand of cars (Read Not Mopar) to Jimmy up to suite yourself. My Grandfather used to say some people are so smart, their stupid. I have to agree he was right.

I have changed alot on my car, a Mopar. I intend to change a little more on my Mopar.

I take great exeption to being called a stupid butcher.

This board is VERY tolerant of everyones take on modifying or not, but we DO NOT flame or insult each other because we choose to modify a Mopar. Or any other car/truck.

[Tom Skinner]

Dear Dave, PatS, and all Modifiers,

My apology to you and all Mopar Modifiers for name calling, I wasn't thinking when I started on about describing how I feel about bringing Chrysler Products back to original.

I will refrain from name calling in the future. Once again I am sorry for

my insensitive wording towards other Mopar Mechanics.

Tom Skinner

[greg g]

Why are you so frightened by newer technology? Most of what has been sugested is bolt are bolt on external upgrades, Easily removable if any purist wants to revert to 1930's stuff. I'll bet if I looked at some of your stuff, you are using some of those new fangled batteries in your old flashlight. Should't you stick to the old cardboard tube lead acid based Ray o Vacs?????? Wouldn't a purist cringe they found the energizer bunny lurking there?

If you are loooking for purist dogma and factory original mantra, there is a source for that. How is butchering another brand any different from butchering a MOPAR??? Wouldn't the Chevy, Buick, Ford Borgward guys be just as incensed if you start modifying their DNA?

I see you have apologized for your sentiments, so this rant is probably a day late and a dollar short, for which I apologize.

My grandfather used to say " A closed mind and a closed parachute function with about the same result." I believed him.

[55 Fargo]

This is why I lurk here, instead of a Website that is exclusive for my car. I have a 47 Chrysler Club Coupe, it has a flathead from a Canadian Dodge,a dry clutch and 3 spd trans. At some point I want to convert it to a dual carb, dual exhaust, electronic igntion, pcv system, front disc brakes, however I want to leave the body and interior looking stock. Now some purist might cringe on this car, but I don't really giving a flying rip, if you know what I mean, I gotta live with it and drive her. Just my thoughts.......Fred

[Norm's Coupe]

I think everyone here knows I'm not against updating or modifying an old car. After all, I'm guilty of doing that myself with a few things on my coupe. Most of my modifying though is either for safety reasons (like the disc brakes) or cosmetic reasons to suit my own taste.

When it comes to adding things like the PCV systems, electronic ignition etc. is where I draw the line though. About the only thing I would consider modifying things under the hood is possibly the addition of AC, but even that is unlikely.

Why? It comes down to one thing. Simplicity. Raise a hood on a modern car and it's difficult to even see a spark plug in some newer cars. That means to just change a spark plug you have to remove several things just to get to that plug. In fact, on my van you must loosen the motor mounts and rotate the engine forward just to change the 3 plugs in the rear of the engine. What makes the older cars (of all makes) interesting is the fact that when you open the hood, you can get at just about anything under it, without removing something else because you don't have all those add ons under the hood. The electrical is a lot easier to work on in the older cars too and you don't have to worry about the electronic computer killing the car. If our cars die due to electrical, it's usually a simple and fast fix that you can do without a lot of tracking with special equipment.

With all the pollution add ons such as PCV systems, you are compounding trouble shooting. For example, back in the early 80's I had a friend who owned a Rambler that was only about 3 years old. He tuned it up and the car still ran rough. He couldn't figure out why and ask me what I thought. When I looked at it I determined his PCV hose was bad. He replaced it and that solved the problem. Yes, it was an easy and cheap fix. However, it did complicate his trouble shooting.

So, the key here is. These cars were built with simple engines and electrical systems. Why do we want to make them hard to work on by adding all the modern stuff that makes them more difficult?

I know many of you have said about the same thing over the years. You like the old cars because they are simple. So why not keep them that way?

NOTE: Yes, I've said I may put a V8 in my coupe a few times. However, even if I do it, it will be using the old 50's/60's set ups, just using a more modern engine. No pollution or electronic garbage.

[62rebelP23]

i recently re-read a good book by Belton Cooper about the Armored Divisions in WW2 and he had a lot of references to how often the maintenance battalions had to change engines in various vehicles, one being the ubiquitous deuce-and-a-half GMC. they were lucky to get 15 thousand miles out of brand new engines, and racked up these miles fairly quickly! and these guys weren't slouches, they did regular maintenance on everything with an engine in it. but only 15k before replacement? man that's not good.

he was very critical of the high command's policy regarding the M4 Sherman tank, too; seems that it was the least efficient tank ever made, and only survived due to the extremely high number of units built!

[5.9diesel]

a sherman tank saved my grandpa in the invasion of Sicily in WWII, so anyone who argues against the can kiss my A$$.

I have to say im a purist at heart. what other people do to their cars is fine with me, but it breaks my heart to see at least half the cars at a car show running the same bland chevy 350 or ford 351. I plan on buying a 1950 B-2-C, and the only modernification it will see is a paper air filter (most likely housed in a stock style housing) Im only going to do this because its easier to maintain, and it filters the air better, so my engine will stay protected.

these trucks survived due to their simplicity, and simple it shall remain.

each to his own, of course!

[Don Coatney]

I plan on buying a 1950 B-2-C, and the only modernification it will see is a paper air filter (most likely housed in a stock style housing) Im only going to do this because its easier to maintain, and it filters the air better, so my engine will stay protected.

I have no intent of starting world war 3 here but in my opinion a well maintained oil bath air filter does a much better job of filtering the air than a paper filter. All air going to the engine is pulled through an oil mist and any dirt particles are washed out. If I could find a sutable pair of oil bath air cleaners I would be using them on my dual carburetors as opposed to the paper filters I am currently using.

[55 Fargo]

I have no intent of starting world war 3 here but in my opinion a well maintained oil bath air filter does a much better job of filtering the air than a paper filter. All air going to the engine is pulled through an oil mist and any dirt particles are washed out. If I could find a sutable pair of oil bath air cleaners I would be using them on my dual carburetors as opposed to the paper filters I am currently using.

Hi Don, I have also heard that the Oil Breathers are superior.

I have one on my 47 Chrashler, it is in great shape.

I had cleaned it very thoroughly last year and filled it with fresh oil, my question is, with my limited driving, how often should it be cleaned and re-olied?

Fred

[Don Coatney]

Hi Don, I have also heard that the Oil Breathers are superior.

I have one on my 47 Chrashler, it is in great shape.

I had cleaned it very thoroughly last year and filled it with fresh oil, my question is, with my limited driving, how often should it be cleaned and re-olied?

Fred

Fred;

With limited driving you should be able to go until the oil gets dirty or 5 years whatever comes first.

[55 Fargo]

Thanx Don

[old woolie]

I dipped a spoonfull out of mine just to see what it looked like,been in there for 4 years,couldn't tell it from new oil.

[Bodacious]

Good advice. I'm new to this game. How do you change the oil filtration system from the old part-time bypass to a full-flow system? Ed

I too would be very interested in hearing about this.