Thoughts on MoPar Flatheads - 2

[james curl]

Answer for Central 52 and Bodacious

Riche Hodge did the car that Loman, (Lou Earle) has now. He bored half way down the bore on the output side of the boss that the oil pump mounts on and installed a welch plug on the bore aginst the sholder he created in the bore. On each side of the plug he drilled and tapped a hole for 1/4" pipe fittings I believe. He installed hose fittings on them and ran them to a remote oil filter. This puts all of the oil that the oil pump puts out into the oil filter. Maybe Loman can post a picture, I thought it was a very clever solution to the problem. It may be that Loman has Riche's brothers car the dual 6/12 volt car with air conditioning, I am not sure now that I have posted this.

[5.9diesel]

well, i wont argue efficancy now, 'cuz i dont care.

the oil bath filter on the truck im looking at only has a screen and the oil. should it have a wire mesh element inside, or was the oil the only filtering media?

[Mustang6147]

I dont know if I agree totaly with the original post. Simply put, I would if the oil was just sitting there stagnant. Oil is constantly being rotated sloshed around, and as it is stirred up by normal operation, the moisture is going to steam off. Simply put, If you run an engine up to operating temp it should be fine ragardless. That is why grandma's car has an oil pan the rusted from the inside out.

Crankcases historically have preassure. In race application, you connect the PCV system to a vacume pump, or like olds did in the 90's. or hook them to the collector of the header. The PCV system simply keeps the crank case from building to much preassure and blowing out gaskets. Oil Pan , valve cover ect...

A cool engine is a happy engine... Todays high temps are because of pollution control, and sensors. These flatheads are not todays engines.

[bearheart]

Aside from the disagreements this kind of info is exactly what a new guy like me needs as I have no mopar experience. I have read many references to the water tube and had no idea what it was or what it did. A recent post asked the "lurkers" to get more involved. These technical presentations are really important to me. The disagreements are really good in a way too as they present different perspectives that actually provide more clarity to issues. I appreciate the polite and diplomatic approach to those different observations and experiences. Keep it up please and THANKS.

[JBNeal]

It's been my understanding that PCV systems were developed to withdraw excess combustion gases from the crankcase. These gases would build during engine operation as not all charged air would be ignited during the power stroke, collecting along the cylinder wall perimeter on the piston rings, and become entrained in the oil, much like air bubbles can form in oil. This oil would re-enter the crankcase, and the gases would separate from the oil, briefly pressurizing the crankcase a few psi. These gases contained enough hydrocarbons that they could still be ignited if combined in small quantities with charged air entering the combustion chamber. If moisture vapor was with these hydrocarbons, it would also be removed from the crankcase & out the tailpipe, minimizing the opportunity for sludge formation.

Exhaust gas recirculation, on the other hand, can be vastly problematic if not monitored regularly. Excess hydrocarbons in exhaust can still be ignited with charged air; however, these hydrocarbons are more than likely particulates rather than vapor. EGR systems on poorly maintained engines build up carbon, forming a restriction that can cause excessive back pressure and all kinds of problems snowball from there. I recall early Magnum 318s that had plastic EGR valve contraptions that would melt when carbon built up in the intake manifold passages, causing the "check engine" light to illuminate as the O2 sensors were generating readings outside of ECM parameters.

During engine diagnosis of the 218 & 230 flatheads, I've noticed a considerable amount of 'smoke' that would exit the draft tube & oil fill tube at engine shutoff. This 'smoke' would have a definite hydrocarbon odor, a mixture of oil & slightly burned gasoline. Redirecting this amount of hydrocarbon through the combustion chambers appears to be a good way to keep the crankcase oil clean by removing contaminated air from the crankcase. If another problem, such as a failing head gasket, were to put coolant into the combustion chamber &/or crankcase, the PCV system would in effect blow any gaseous material out through the tailpipe, which would be a definite indicator of a problem as exhaust gas would change color & density.

From what I've found on the technical archives & Power Wagon websites, Chrysler recognized the added benefit of a cleaner crankcase with the PCV system, as several service bulletins were issued regarding field fixes for different flathead induction setups. First, the draft tubes were converted to an adapter + check valve to the intake manifold. Later fixes added a vapor tube from the oil fill tube to the air cleaner base. These setups suggest that Chrysler had done evaluation of crankcase oil with & without PCV systems and found that a field fix for existing L6 engines was worthwhile preceding new designs that would incorporate the PCV system on Slant 6 & V8 engines.

IMO PCV systems help more than they hurt. Choosing to not use a PCV system is just that, a choice. Updating a flathead with a PCV system can be considered 'original' as Chrysler had issued service bulletings regarding this topic, complete with assembly drawings, part numbers & installation instructions, much like the dealer-installed radios and heaters of that era.

Happy motoring!

[Mustang6147]

This is an intresting discussion... The crankcase has no connection to the exhaust. If it does theres a problem. The egr system simply moves exhaust,(which heats up fast ) to the intake manifold so fuel atomization can take place during warm up. White smoke coming out of oil breathers, valve covers, or and PCV system hoses ect during warm up is slightly normal. After the engine is warm, is a sign of a tired cylinder, reffered to as Ring blowby. Very common when looking at any used car, pop the oil cap off while its running, if there is alot of white smoke, walk away unless you want to rebuild the engine. There is always a level of oil contamination from combustion. Normal oil change intervals take care of that with the use of detergent oil. Air compressors use non detergent for that reason.

I am some what new to these forums, but no stranger to engines.

[grey beard]

I'm puzzled about how an EGR system has gotten confused with this original thread on flatheads living longer by using PCV systems. There is no relationship between the two systems. EGR systems reburn a portion of exhaust gasses as a part of some late-design carburetor engines before EFI was introduced. It has nothing whatsoever to do with a PCV system. Furthermore, EGR systems do nothing whatsoever in any way beneficial to engine health or long life. They are simply a device to reduce tailpipe emissions at the expense of performance.

The reason why PCV systems work so beautifully with old MoPar flathead sixes and eights is that the block is a very heavy casting and in many applications never gets up to operating temperature. As a result of running cooler than smaller block V8 engines, these heavier blocks tend to build sludge. If your own engine application allows for the engine to get completely up to operating temperature - at the oil pan, not at the dash water temperature gague - then you may not benefit from a PCV system. Such is not typically the case with most collector cars today.

Don't take my word for this. Buy a $20 infra red temperature probe from Horrible Freight and check the temp of your oil pan sump after you THINK your engine is warm. Or, conversely, jack the critter up and FEEL the oil pan temperature. You will be amazed how long it takes to get the engine oil up to operating temperature in these older, heavier engines.

Anyone who has ever had a flathead six on an engine stand knows how heavy they are. My flathead 218 and 3 speed transmission drive train weighs nearly 800 pounds. This is simply a whole bunch of casting to get up to operating temperature. I'm gonna' guess - without any scientific data at hand - that it takes a minimum of thirty minutes' running time - not at idle, but pulling down the road - to get the oil in the sump up to a temperature that is high enough to evaporate water from the crankcase. Now be honest with me, how many collector cars are driven this long every time they are fired up? Think about it . . .

This whole thread is about keeping our engines clean. When they are driven for a few miles and shut down, or driven only short bursts, the oil temperature simply does not get high enough to evaporate condensation. This is exactly the thing you do NOT want to happen inside your clean rebuilt engine. So the way to keep it cleaner longer is to get the temperature up quicker - with a 180 or 190 stat, AND by using a PCV system to help scavenge the condensation and blowby gasses away from the crankcase.

I am sure that if two identical engines were put into identical service and given identical maintenance - one with a PCV system and one without, the one that had the benefit of the added ventillation would be much cleaner in the long run. AND this is a modification that destroys nothing in originality - it was even made by the mfr. for some MoPar flathead vehicles - and can be put back to the old, dirty road draft with one bolt and one vacuum plug.

If your engine had a full-flow oil filter, this thead would not be nearly as pertinent. But only a few of the bigger block sixes have this feature. None of the 218/230 engines have it. Which means that we are stuck with inefficient part-time, part-flow filtration of our oil.

No modern engine made today uses such a primitive filtration system. This is one of the many reasons why newer vehicles are more efficient and dependable. The oil in our engines is filtered at about a ten percent flow rate. Just a 1/8-inch steel tube diverts a small amount of oil from the pressure regulator into the bypass filter element. AND this small amount of oil is only filtered some of the time, because the pressure regulator shuts it off at very low and very high pressures. Thus, the oil in our engines gets passed through the filter media only occasionally. By contrast to this, modern engines with full-flow filtration filer every drop of oil that leaves the oil pump, BEFORE it enters the engine.

This all means that the oil in our engines gets dirty more quickly than the same oil will in modern engines. How can we combat this? By changing it more often - always when the oil is hot. We can help keep the oil clean longer by installing a higher temperature thermostat. My own Pilothouse has a 180 stat, but the dash temperature gauge rarely ever gets up to that temp, even in long summer driving on the interstate.

Fortunately for us all, oil technology is vastly improved from that of sixty years ago, when our trucks were built. I change my own oil twice each season. My truck mainly sits idle all winter. When I drop the oil, it is aleady black and dirty, in spite of the fact that the engine is squeaky clean inside, with no sludge. I hope to keep it that way as long as possible, so I am glad to use anything that helps keep things inside cleaner - longer. The PCV system and the higher stat both help . . . JMHO

[HanksB3B]

Greybeard,

Thanks for the well written and thorough information of why I should change from a 160 to 180deg thermostat. I'm interested in what Chrysler offered in the way of documentation on adding a PCV system. Also a diagram and some pictures might help if this is something I have to fabricate on my own.

Thanks,

Hank

[Don Coatney]

Greybeard,

Thanks for the well written and thorough information of why I should change from a 160 to 180deg thermostat. I'm interested in what Chrysler offered in the way of documentation on adding a PCV system. Also a diagram and some pictures might help if this is something I have to fabricate on my own.

Thanks,

Hank

Follow this link.

http://www40.addr.com/~merc583/mopar/framesets/softwareframeset.html

[HanksB3B]

Thank you Don,

Hank