Hi there
just a thought being i live in hot australia, would the oil pump work (have enough pressure)ok , if I installed an oil cooler especially being the m20 allready has overheating problems, also would chroming the head and barrel be ok ,or would it add to overheating, im just tying to think of a way off not spraying pot black on head and barrel which dosent last very long
reagds
mark

Hi Mark...Chroming the head and barrel is a non starter..not only would it make cooling worse but the chrome would not deposit well between the fins ....
The M20s oil system will run a cooler ok...if one is used it should be fitted into the return side of the oil system. An added benefit is a slight increase in the overall oil capacity.
Saying that although M20s run hot, if the bike is well set up regarding fuel/air mixture and ignition timing it is not generally at damaging levels.
I guess in a hot climate some cooling of the oil would be beneficial though.
Another thing to consider is fitting an alloy head..I run one of these on my M20 and it definitely runs cooler. Mechanical noise is increased slightly but as the head doesn't rust, when painted black the finish tends to last longer. With the alloy head a spark plug change will also be needed, a Champion N5C replacing the iron head plug. Finally with the alloy head, all 10 cylinder head bolts are the length of the longest ones fitted to the iron head...Ian

One trick you could try is using a frame component as an oil cooler (and adding capacity) On some old Harleys they used to use the crash bars as a cooler, just put a fitting in each end where they bolt to the frame and use the crash bars as a cooler, maybe you could try this on some part of the bike (possibly you could fit a post war fitment Pyrene fire extinguisher and use this as a cooler (these were fitted post war and don't look too out of place on a wartime one) just hide the plumbing on the back.

email (option): davmax@ntlworld.com

Hi Mark and all.

I use a heat-resistant spray or paint the cylinder and head with heat resisting paint with a brush, and it lasts years.
You would just want to make sure that all is completely clean before painting, using a degreaser and / or metal brush.

As to heating:
It did wondered me:
I drive my bike with a quite heavy metal sidecar in town traffic and also on highway,
usually for about continues 10Km / 6.5 miles in a speed of 80 Kph / 50 Mph,
and in summer sometimes in temperatures over 30 degrees centigrade, (86 degrees Fahrenheit)
but whenever I touch the oil tank, it is never seem to be hotter than a body temperature..(?)

I use a 40 mono SF mineral oil and 95 octane fuel, adding potassium as lead substitute in order to protect the valves,
and have a good oil circulation when looking inside the oil tank.
Also, when touching the barrel fins, I can usually keep my hand on it for about 2 seconds or so before forced to take it off due to heat,
So I guess it would not be over 80 – 90 centigrade or so. (180-190 degrees Fahrenheit).

Should oil and barrel get hotter under normal use?..


Noam.

email (option): noam10@gmail.com

Hi Noam.. I use 'ordinary' cylinder paint and it will stay on fine until the bike is used in the rain a few times. It may be that your paint lasts so well because it doesn't get wet so much!
Oil temperature doesn't seem to get that high on an M20, and less so on OHV versions (B31/3).
Most of the heat is concentrated in the head and barrel which is only cooled by the air and oil splashed up by the rotation of the crank (and none of that reaches the head.
I've never got into a competition to see if I could hold my hand against a hot M20 barrel for more than a second and I don't want to! ...Ian

Hi Ian,

Of course..

I only mention the time I can keep may hand on barrel side, In order to give a clue on it's heat rate..

I used to have much modern 2 and 4 stroke bikes,
In which you could not even accidentally touch the barrel for a friction of a second and get away without a "Grill" pattern on you..

Question is- If oil doesn't get hot at all,
is there any logic to install an oil cooler?..

Cheers !

Noam.

email (option): Noam10@gmail.com

I agree Noam..I am not convinced of the benefits of fitting a cooler as oil temperatures don't seem excessive in my experience. Of course, until your posting I didn't have any knowledge of running in a much hotter climate.. We haven't seen the other side of 30 degrees in the UK for some years! .. ...Ian

Hi Ian.

Yes, I can imagine..

It is 31C (87.8 degrees Fahrenheit)
in Tel-Aviv today, with high humidity,
as we are on the shore of the Mediterranean sea.
Shooo! Like a sauna..

Would love to lawn few degrees (Say 10?..)
To whoever feels cold..

Cheers !

Noam.

email (option): noam10@gmail.com

It was over 100F most of last week and in the upper 90's here in Virginia USA. You will surely cook most anything air cooled if you're not careful.

hi guys
remember we are talikng australia in summer it averages 40deg and at traffic lights? temp rising, so would the oil pump cope, I do have flhtcu harley and that has no oil cooler but its 1992 not wm20 vintage

email (option): markbrob1@hotmail.com

Hi Mark..You are probably the best man to consider the situation in your own area...If you live in a built up area and you spend a lot of time in traffic jams or sat at the lights, in those sort of temperatures things will get hot! Don't forget however, that an oil cooler won't help much either without any airflow...though your oil will be a bit cooler when you initially come to a stop.
These are air cooled lumps so with low air flow and/or in high air temperatures they will inevitably run hotter (short of fitting an electric fan or converting to water cooling).
The only thing I can say is that the M20 was exported all over the world and was designed to survive in varied climates. Also, I believe, a fair few M20 engines were pressed into service in Oz as stationary engines and I guess they survived that ok. I think Noams comments are interesting and relevant...he is running in temperatures of 30 degrees plus, with a sidecar and is not experiencing any problems...Ian

yes sound as if the engine might not get that hot,I think I'll ask the local vintage club off which im a member ask ask there opinion as well, thanks for the input

email (option): markbrob1@hotmail.com