Disappearing oil?

[JG1966]

I recently changed oil and filter in my 340. When I stored old oil for recycling, I had gotten a little less than four quarts from engine/filter. Oil level on dipstick read full before change (That's odd. Will check accuracy now I know there's 5 quarts in it). Stock oil pan.
340 was refreshed with new rings, valve stems, seals, bearings, etc., less than 500 miles ago. I am NOT burning oil (no blue smoke at all), and my only oil leak is tiny (at distributor o-ring). I'm going to fix o-ring leak but it's literally less than a thimble of oil -- if that -- every 3-4 months. No other leaks. Nothing on garage floor.
Where is oil going?
My only guess is I'm losing it into my PCV system into the carb and it's burning, which would hurt my octane. Any way to check that? Switch to two breathers and ditch PCV?
Any help/suggestions would be great. Thanks.

 

[Bill Monk]

So you are saying you lost a quart of oil between changes? If so, depending on how many miles between changes, it sounds like a lot to be loosing it through the pcv and I would think you would see some blue smoke, but....Are you running stock valve covers or aftermarket? Some of the aftermarket valve covers don't have baffles in them and others are insufficient so that can make a big difference if you don't have good baffles. Also most of the pcv valves off the shelf are very generic and don't properly do what they are intended to do. I invested in this:
http://mewagner.com/?p=444 and it's an outstanding product although pricey.
By the way a pcv valve should ALWAYS be run on a street engine in my opinion

 

[BeatersRus]

in the year 2019,companies who make the following statement Have to be few and far between.
TY Mr Monk for that Excellent link.

Try it risk free for 30 days: We’re so sure you’ll be impressed by the quality and functionality of our products, we offer a 30 day return policy. Simply pay the return shipping and we’ll issue a full refund – no questions asked. Read our full return policy here.

 

[JG1966]

So you are saying you lost a quart of oil between changes? If so, depending on how many miles between changes, it sounds like a lot to be loosing it through the pcv and I would think you would see some blue smoke, but....Are you running stock valve covers or aftermarket? Some of the aftermarket valve covers don't have baffles in them and others are insufficient so that can make a big difference if you don't have good baffles. Also most of the pcv valves off the shelf are very generic and don't properly do what they are intended to do. I invested in this:
http://mewagner.com/?p=444 and it's an outstanding product although pricey.
By the way a pcv valve should ALWAYS be run on a street engine in my opinion

Thanks Bill. Yes, it certainly appears I lost a quart between changes. Probably 300-500 miles (absolute max). My level on dipstick was never low. I'm definitely not getting blue smoke and engine runs fine. I have Moroso valve covers and installed these baffles to prevent loss through PCV. The fact that my dipstick was always reading full (or close to it) is what had me so alarmed that I only pulled 4 quarts.

 

[Bill Monk]

Thanks Bill. Yes, it certainly appears I lost a quart between changes. Probably 300-500 miles (absolute max). My level on dipstick was never low. I'm definitely not getting blue smoke and engine runs fine. I have Moroso valve covers and installed these baffles to prevent loss through PCV. The fact that my dipstick was always reading full (or close to it) is what had me so alarmed that I only pulled 4 quarts.
View attachment 786586

Dipstick replaced? some are not accurate. Mark the full mark on the stick as soon as you do the oil change and you know you have 5 quarts (with the filter replacement of course)

 

[Bill Monk]

in the year 2019,companies who make the following statement Have to be few and far between.
TY Mr Monk for that Excellent link.

Most welcome, it was worth the cost to me

 

[JG1966]

Dipstick replaced? some are not accurate. Mark the full mark on the stick as soon as you do the oil change and you know you have 5 quarts (with the filter replacement of course)

The dipstick and tube are definitely not stock. I'm marking the stick now.

 

[PurpleBeeper]

Stick & tube not stock is the likely issue. On a related note, I just pulled the pan off my motor after fully draining it (overnight) and it still had almost a quart of oil inside it when I pulled it off.

 

[Frank Mopar]

Put the oil in, mark the stick and drive it. At that point you can monitor the oil on the stick.

 

[JG1966]

Stick & tube not stock is the likely issue. On a related note, I just pulled the pan off my motor after fully draining it (overnight) and it still had almost a quart of oil inside it when I pulled it off.

Thanks Purple. I honestly think that's what happened. I'm going to drain it and see how much I get out. I know there's 5 quarts in it now (minus about 20 miles of driving). My concern is if there was still nearly a quart in it and I added 5 quarts, I'm almost a quart too much. I don't want to mark my stick if that's the case.

 

[Darter6]

The used oil filter will hold allot of oil because of check valve,paper saturation and what purple beeper stated.Takes a long time for oil to run off completely.If you poke a hole in the filter this causes the check valve to become inoperative.Some more oil will drain out. Due to EPA the last place I worked required us to have a oil filter crusher to remove the excess oil and have proper disposal of used oil filters.It is surprising how much comes out.

 

[dvw]

Did you only put 5 quarts in it after the rebuild? 1 quart usually clings to the internal nooks and components after the initial change. I measure the exact pan level in my racecar, not the actual amount of oil in the engine. The pan itself was filed and measured during the build to be accurate. It always takes an extra quart after a refresh to get the pan level correct.
Doug

 

[JG1966]

Did you only put 5 quarts in it after the rebuild? 1 quart usually clings to the internal nooks and components after the initial change. I measure the exact pan level in my racecar, not the actual amount of oil in the engine. The pan itself was filed and measured during the build to be accurate. It always takes an extra quart after a refresh to get the pan level correct.
Doug

I did only put 5 quarts in after the rebuild. I changed oil about 50-75 miles after the break in. And again at about 500 miles. It's very possible I only got out 4 quarts those times and just didn't realize it.

 

[WileERobby]

Missing Oil only goes to one of two places: in the tailpipe or on the ground. ( burned or leaked)

 

[oldkimmer]

Did you only put 5 quarts in it after the rebuild? 1 quart usually clings to the internal nooks and components after the initial change. I measure the exact pan level in my racecar, not the actual amount of oil in the engine. The pan itself was filed and measured during the build to be accurate. It always takes an extra quart after a refresh to get the pan level correct.
Doug

. This is correct. Kim

 

[69L48Z27]

@Darter6 is telling you what the issue is, post 11. If you do an oil and filter change, you pour 5 quarts in the top of the engine you will only get 4 out the bottom assume you ran the engine. Filter holds a quart. If your stick isn’t showing a loss then you didn’t lose anything.

Maybe I’m missing something in the thread but I think you may be overthinking this.

 

[JG1966]

@Darter6 is telling you what the issue is, post 11. If you do an oil and filter change, you pour 5 quarts in the top of the engine you will only get 4 out the bottom assume you ran the engine. Filter holds a quart. If your stick isn’t showing a loss then you didn’t lose anything.

Maybe I’m missing something in the thread but I think you may be overthinking this.

I emptied the filter into the drain pan and still only got 4 quarts. But I see what you are saying. Between what stays in the filter, oil still in pan, etc., I think that's my missing quart.

 

[69L48Z27]

Compare how heavy the ‘drained’ filter is compared to a new one. Lots of oil is still in there especially if your using one of the big Wix 1515 filters.

But if your dipstick is showing the same level the chances are you’re not losing any.

Try this... Next oil change check the dipstick then drain about a quart and replace the drain plug, check the dipstick and see how far down it is. That should give you the peace of mind you’re looking for.

 

[fratzog lover]

Think of how square inches of surface area a rebuilt engine has after it has been hot tanked, and had new, dry, out of the box parts installed. Thats a good bit of oil that clings and never drains no matter how long you leave the plug out.

 

[dvw]

Now that its had its initial full. Change the oil. Warm it up. Let it set overnight, check the stick. Then check the stick before draining at the next oil change. Either its low, or not.
Doug