M37 Started Burning Oil Only Once Warm

[LegionPiper]

Hi folks,

While I haven't started the task of pulling things apart to see what's going on.
Is this a common issue seen on the T245 ?

I run her every two weeks or so for 20 to 30 minutes, sometimes taking her out for a spin.
She starts up very easily and idles smoothly.
Lately, She'll run clean for 15 minutes and then start blowing a bluish smoke.
** Note I changed the Oil when I purchased her in Sept of last year. New Napa Filter, and Non Detergent Oil from CND Tire. ( SAE 10 W )

I have not checked Oil Pressure yet, nor compression either.
I was just looking for some feedback before I start doing a deeper dive.

[just me]

The only place for oil to get in to burn in the cylinders is the rings.

[Carter]

Non Detergent Oil from CND Tire. ( SAE 10 W )

Should be 30W, I use 10W30 in mine. Could be thin oil is getting past the piston rings.

[w30bob]

Hi Legion,

Well, the answer would normally be the valve seals are shot...........but flatheads don't use valve seals.........so that's not it. There are only a couple other ways to get oil in the combustion chamber to burn and make blue smoke. Bad rings are one. The others are excessive crankcase pressure forcing oil thru the PCV into the intake, and..............a blown seal in your stock fuel pump. If that seal goes bad on the vacuum supply to the wiper motors the pump can suck oil from the crankcase and send it up to the carb. I guess if you eliminate the last two you're only left with the first.....and vice versa.

regards,
bob

[LegionPiper]

Hi ya Bob,
now that's interesting !
I'll have a quick look at the vaccum lines for traces of oil.
Hmmmm, what if the connection between fuel pump and Wiper Motors was leaking ?
would that also do it ?

Thanks

[w30bob]

Hi Legion,

If the line to the wipers was leaking I don't think it would cause the pump to suck oil. That would just make the pump work less hard, as it would be sucking outside air when it was trying to make vacuum. It would have to be a malfunction inside the pump that would cause the seal between the pump body and the crankcase to fail. I'll have to take a closer look at a pump to see what needs to fail for that to happen........I just remember talking to a guy once about a problem like yours and he ended up needing a new fuel pump. If I get some time I'll do some more digging.

regards,
bob

[LegionPiper]

Hey there Bob !

I've looked a lot deeper into the Engine components.

Over the years it looks like the Truck has gone through many customization's, so it's been a little difficult to figure out what's going on.

I noticed that there's a copper pipe running from the Oil Filler Tube over to the Carburetor. There is a value on the Carb side as well I assume this is for Fording. ( Whether this is on or off makes no difference to the Oil Consumption )
One thing I have not yet found is a PCV valve. ??
The Engine and Clutch manual does not mention vacuum nor fuel systems specifically.
Do you guys know where these are best documented ?
Thanks

[just me]

Pcv is from the curb side, side of block by the back tappet cover to the center hole on the intake under the carb base. Should have a 1/4 turn valve for fording also. It is inside the bracket that supports it all And is rebuildable. Some one may have removed it over the years and just put a draft tube back on like the civilian engines. That is a oddly shaped piece of approx 1" pipe coming down from the block to under the engine.

[just me]

I studied Tm9-8031-2 and TM9-8030 pictures to find the routings and locations. If you have a part manual, there are excellent breakdowns and photos. Fig 25 of 46 of TM9-8031-2 shows the pcv assy.

[LegionPiper]

Ahhh, I did not have the Power Train manual.
Great call.

Thanks

[j mccormick]

Why are you using 10W oil? Change it to 10W30 or 40 and I think your problem will be over.

Joe

[MSeriesRebuild]

Why are you using 10W oil? Change it to 10W30 or 40 and I think your problem will be over.

Joe

Neither do you need to be running non-detergent oil. Bad call in almost any internal combustion engine, ESPECIALLY with the quality of fuel we are forced to use these days. After initial break-in period, you should run a ZINC rich 10W30 or 40 engine oil such as AMSOIL Z-ROD, or equivalent, especially blended for use in flat tappet engines. If you have not done a compression test, it is time.

[LegionPiper]

Now that's interesting !

Most folks I have spoken to would swear upon their very lives that these trucks must have Non-Detergent Oil.
I'm guessing that Non Detergent Oil was necessary back in the days of Leaded Gasoline ?

I'll hunt for ZInc rich Oil, don't think I've ever seen that kind of oil specifically called out.

Just discovered that I have an Industrial Engine, which was a cool surprise.
Compression test is on my list.

[MSeriesRebuild]

Now that's interesting !

Most folks I have spoken to would swear upon their very lives that these trucks must have Non-Detergent Oil.
I'm guessing that Non Detergent Oil was necessary back in the days of Leaded Gasoline ?

I'll hunt for ZInc rich Oil, don't think I've ever seen that kind of oil specifically called out.

Just discovered that I have an Industrial Engine, which was a cool surprise.
Compression test is on my list.

I can only guess that whom ever is saying use non-detergent oil has not gotten into the latest century yet on checking oil specs. My how things have changed with oils and lubricants in the past 60 years. The old lube order is practically worthless except for an outline of the actual lube point locations and capacities. Almost all oils used to have a proper zinc content, that is until EPA started strong arming about it a few years back. Now there is only a few specialty oils that actually have it blended in sufficient quantities. For a while there was some zinc additive products that were available to add to your oil, have not seen any of that lately, not sure how available it is anymore. We always use Amsoil break-in oil in our new rebuilds, and Amsoil Z ROD in engines that have past the break-in period, both these products are already Zinc enriched.