Oil Burning

[meadowbrook]

My original 230 engine with 76,000 miles seems to lose 1 quart of oil every 150 miles or so.

However I don't ever see any smoke from the tailpipe.

It does leak oil, from I think the front seal and timing cover and perhaps the rear main seal (despite my replacement of it.).

It does not seem to leak huge amounts, though. Any thoughts?

On changing the front seal, do I need to remove the radiator?

[Don Coatney]

Where in south east Michigan are you located? If you drive 300 miles straight do you have to add 2 quarts? If so your engine is burning some oil. If not then your engine is leaking oil when parked. If you remove the oil fill cap with the engine running do you see a lot of smoke coming from the oil fill tube? And/or do you see any puffing as in oil/air being pushed out or sucked into the oil fill tube? If it puffs then you may have a bad cylinder. Have you done a compression test? From another thread I see you are not using detergent oil. Why?

[meadowbrook]

Hi.

I live Belleville, near Ann Arbor.

Yes, if I drive 300 miles I suppose I would need 2 quarts. It leaks some when parked just after driving but then stops, so it must be leaking out more than being burnt. Should a the engine smoke, if I actually do burn a quart per 150 miles? I never see any smoke.

I replaced the rear main seal but I think it may still leak from there and the front of the engine.

When I shut off the engine after it's been running a while, there is some smoke that comes off the fill cap/breather. I will try to see how it feels when I remove the cap with the engine running.

I will also do a compression test, but I can tell you the engine runs smoothly and starts very easily, I would think if I had low compression it would be hard to start.

On the oil, I have heard both sides of the story:

1. you should not use detergent oil on old, never rebuilt engines because it loosens up decades of sludge, potentially clogging oil passages and also, that detergent oils keep dirt in suspension for the filter to capture, but the old 230has no full flow filter so the dirt would just floats around and scores bearings, etc.

2. you should use detergent oils because they are so much more advanced and lubricate better.

I guess I chose to be conservative and use the non detergent oil the car was designed to use. Also, there is the lack of zinc on new oils, which I believe older flat tappet engines need. Finally, my boss at Chrysler had a 40's Chevy that started smoking as soon as he changed over to a detergent oil.

I am open to re-education, though any thoughts?

[oldodge41]

When I got my car over 20 years ago my Dad told me to not be afraid to run it a quart low on oil. He told me he had several of these flatheads in the day and if he filled them to full on the dipstick they would use a quart very quickly but then use sparingly after that. Both my original 218 and current 230 hold true to that. I keep them just above the add mark and check it every time I drive it. It burns a little (gives a puff of blue when accelerating after coasting down hill), leaks a little too, but if I fill it to the full mark it uses it up quicker than if I keep it a quart low. Has worked for me all these years. If you try it you have to monitor your oil level closely because you won't have as much of a buffer before it goes low.

[Don Coatney]

I am open to re-education, though any thoughts?

I suggest you use the forum search function to look for answers to all the questions you have. The answers are there and you need to form your own opinions on what to believe.

[Young Ed]

When I got my car over 20 years ago my Dad told me to not be afraid to run it a quart low on oil. He told me he had several of these flatheads in the day and if he filled them to full on the dipstick they would use a quart very quickly but then use sparingly after that. Both my original 218 and current 230 hold true to that. I keep them just above the add mark and check it every time I drive it. It burns a little (gives a puff of blue when accelerating after coasting down hill), leaks a little too, but if I fill it to the full mark it uses it up quicker than if I keep it a quart low. Has worked for me all these years. If you try it you have to monitor your oil level closely because you won't have as much of a buffer before it goes low.

I've heard of this from others in the plymouth club too. I doubt I could ever bring myself to run low on oil intentionally. Thankfully both my flatheads are recently enough rebuilt that they don't use oil.

[Don Coatney]

My 71 340CI Duster would suck out the top quart of oil in short order. So I almost always ran it a quart low with no damage. A few years back I had an interesting conversation with a short track racer. He found that running a quart low increased his track times. Seems the extra quart splashed, swirled, and knotted around the crankshaft dropping the available horse power. The track officials finally caught up on his trick and made him add the 5th quart.

[oldodge41]

I've heard of this from others in the plymouth club too. I doubt I could ever bring myself to run low on oil intentionally. Thankfully both my flatheads are recently enough rebuilt that they don't use oil.

I don't even think of it as running low anymore. It is just normal to pull the stick and see the level at that mark. Someday when and if I ever completely rebuild one of these things I will have to retrain myself to keep it full.

[greg g]

My father also espoused the run at the add mark program. It seems obviouse that the engine designers used that mark to tell you when the oil was at or below the level at which damage could occur. And engineers being a conservative bunch were placing that mark with a positive margin of error.

The engine certainly can not have five quarts of oil circulating at one time, if that was so the oil pickup would not be in the middle of the oil pan, it would be at the bottom. Now there is something to be said for the fact that extra oil quantity provides a measure of comfort, and also may have an effect on keeping the temperature down a bit, but is it necessary? Apparently not. I do run mine between the add and full mark.

I have noticed that when it get low, my oil pressure will momentarily drop about 5 lbs on acceleration or when turning sharp corners. Then you know its time to add half a quart.

Edited August 3, 2011 by greg g

[oldodge41]

Greg, I agree on the 5lb. fluctuation. If it fluctuates it is too low. By the way, I think your signature line says it all and I have taken to quoting it quite a bit lately.

[meadowbrook]

Interesting on the 'running at the add mark' oil level discussion.

I will monitor my oil level to see if it actually get below the add mark. Having worked at GM and now at Chrysler, I can tell you that when validating engine and transmission oil levels (at least today, can't say about the 30's when the Chrysler flathead 6 series of engines was being developed) they are tested 1 and sometimes even 2 quarts above the full mark and below the add mark.

Another tidbit of trivia, as I was visiting the Walter P Chrysler museum, they had a section where they discussed the Chrysler flathead inline 6 in the 30's and apparently, the combustion chamber design was developed by Harry Ricardo (a pioneer in combustion chamber design) and the engine did very well in Indy race cars.

[meadowbrook]

Where in south east Michigan are you located? If you drive 300 miles straight do you have to add 2 quarts? If so your engine is burning some oil. If not then your engine is leaking oil when parked. If you remove the oil fill cap with the engine running do you see a lot of smoke coming from the oil fill tube? And/or do you see any puffing as in oil/air being pushed out or sucked into the oil fill tube? If it puffs then you may have a bad cylinder. Have you done a compression test? From another thread I see you are not using detergent oil. Why?

Hi.

Well, I ran a compression test on my engine and these are the results, in PSI, from the rearmost cylinder to the front. Engine was warm and throttle was kept at wide open position:

105

105

105

105

85

100

There was no oil on the plugs and the procelains in all of them were brown in color.

I also took a 5 hour round trip (Belleville, MI to Grand Rapids, MI) and kept an eye on the oil level and it looks like it does not drop much once it is slightly above the 'add' mark so the folks who mentioned that it likes to burn oil when topped off to the full mark may have a point.

So I guess the engine is in reasonable health. Sure, it could benefit from a refresh since the shop manual spec is 120-150 psi, and the one 85 psi cylinder is a concern, but for an original, unrebuilt engine, it seems to be ok. Runs fine and I even averaged 20 MPG on a trip since installing the overdrive.

If I ever decide to rebuild, I will likely try to match the specs of the later 50's 230's which I think had 135 HP. I think I would need a later cam and an increase in compression ratio to the lofty heights of 8:1;)

Any thoughts on what I should advance the ignition to? I currently have it at 0 BTDC at idle, maybe I can advance it since today's gas is likely better in octane than what was around in 1950?

[greg g]

I did my timing with a vacuum gauge, setting it for the highest steady vacuum reading at idle, then backed off a bit. The timing light shows 4 degrees before TDC. This setting works well for my car, but I have a shaved head, and dual carbs on my 56 230 engine.

Its not the octane you need to be concerned about, today's gas has a slower flame front than old gasoline ( whoomph instead of bang) so it does well with slightly advanced firing, lighting it off a bit before it reaches full compression, so the push on the piston starts sooner and lasts longer.

[meadowbrook]

From what I understand, flame speed is one of the items that octane governs. Higher octane means the fuel is more stable and can take more compression before autoigniting, so you can run higher compression and get better efficient combustion (more power). It also means a higher octane fuel will burn slower.

A lower octane fuel will auto ignite earlier and also burn faster. So maybe from what you said, today's fuels are of higher octane than fuels up to the early 50's.

Is there a fuels engineer in the house to tell me if I'm all wet here?

Oh and tomorrow there is an employee car show @ the Walter P. Chrysler Museum. Is anyone in this forum from the Auburn Hills, MI area? I will be there.

[Don Coatney]

Oh and tomorrow there is an employee car show @ the Walter P. Chrysler Museum. Is anyone in this forum from the Auburn Hills, MI area? I will be there.

The WPC Museum is a fun place to go. Follow this link for lots of pictures.

http://smg.photobucket.com/albums/v65/DonCoatney/Museum%20cars/Crashler%20museum/?start=all

Last time I was there I tried to drag this old flathead engine home but they would not let me get it out the door.