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Oil consumption

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bushwood

Contributing Member
"Chrysler M440s...Heads done l

"Chrysler M440s...Heads done last year and engine looked good. Just back from vacation and during our outing, I had to add oil to port engine every 10 hrs. Plugs looked good (mocha color)and no oil in bilge. Where did it go?

Also, we did have an issue with valve cover gaskets leaking after heads put on (addressed two different times). I am still having some leakage but I don't think it's the amount that I wrote about in the above as it seems to be coming from near front of engine. Is it burning on block before it hits bilge? There isn't a blue smoke plum when I pull hatch."
 
"Oil consumption past the ring

"Oil consumption past the rings might be it, despite the "mocha" plug color.

Is there a leak at the oil pressure sender unit? Mine had one of them. Never saw oil in ht ebilge, but it was using some.

Jeff"
 
"Can't recall being a leak

"Can't recall being a leak at the sending unit as it was never replaced. Will check again. What valve cover gaskets are recommended and is a silicone sealer recommended? I've changed them on cars and never had a problem. I know cork is out, but what/why is there oil leaking from the gasket themselves: bolts are tight, without bending tin."
 
"On some Chrysler marine engin

"On some Chrysler marine engines, a hose is used to send oil pressure to a manifold holding several different sensors. Had two of those leak on me, so check yours.

Silicone on hate valve cover gaskets shouldn't be needed. I turn the covers over and tap the bolt hole distortions the other way with a ball peen (one of the reasons it's there). That seems to help sealing.

Jeff"
 
"Thanks Fastjeff. As I ponder

"Thanks Fastjeff. As I ponder this, I should also add, my oil psi at cruise (1850rpm) is 70. It's at 40 on stbd engine. If I bump it up to 2500, oil psi also goes to 80psi (Rotella 15w40).

It seems there are coincidences here. High oil psi, and oil loss. No blue smoke from exhaust."
 
"The gage may be lying to you.

"The gage may be lying to you. Hope so, for that's way too much oil pressure (rough on the oil pump/ distributor gears).

Jeff"
 
Do I pull the oil pump (mi

Do I pull the oil pump (mine are external) and rebuild it? I did this on the stbd engine pump for an unrelated reason. Where is the pressure relief valve? Is it in the pump itself? I'm not sure the gauge is lying as it stayed fixed at 70 then rose with the additional RPMs and back down when RPMs slowed.

What do I do about the oil pressure?

Thanks
 
"If you can get your hands on

"If you can get your hands on an external/mechanical oil pressure gauge, it may be the best first step in making sure that, as Jeff said, your gauge isn't out-of-whack. If nothing else, it's quick confirmation before you dive into rebuilding the pump, etc.

Re: your question about types of valve cover gaskets, Fel-Pro makes a "high performance/heavy duty" gasket. They're high-temp rubber fiber and much stronger than cork or standard rubber gaskets. Mopar Performance also makes a good gasket (more money than Fel-Pro). As Jeff said, if they're leaking, make sure the covers themselves aren't part of the problem."
 
"A quart every 10 hours is not

"A quart every 10 hours is nothing, I cruise with people who have old 440s and 427s that use a quart every 2 hours at cruise. Oil is cheaper than a rebuild if they still run good.

dan"
 
"Agreed, even though oil is ab

"Agreed, even though oil is about 3 times more expensive than a few years ago. Just keep checking it!

Jeff"
 
"This is the latest thus far..

"This is the latest thus far....I saw some oil around my PCV which drew my attention. It was plugged. Then saw some oil around breather vent/filter on opposing valve cover. Flame arrestor looked fairly clean. Some oil around oil add cap. Replaced it and saw its spring had no spring left.

Next is to check relief spring. I'm not sure if these two items are related (high oil pressure, crankcase pressure) or not. Just an update...

Thanks"
 
"Thinking out loud, regarding

"Thinking out loud, regarding the oil loss/consumption, could my oil cooler be suspect? That is one thing that has not been off and boiled out/inspected.

Thanks"
 
Fastjeff's Law of Oil SPil

Fastjeff's Law of Oil SPills: A tiny bit of oil makes a very big mess!

I suspect that plugged PCV caused oil to blow out and (see above).

Jeff
 
"I'm drawn back to the val

"I'm drawn back to the valve cover gaskets that you'd originally mentioned.

You can loose a decent amount of oil through a good valve cover leak and, if it's over an exhaust port, it could definitely be burning off on a manifold.

If you were, in fact, running high oil pressure on one or both motors, that only exacerbate a leak. You may not see the plume of smoke you're expecting from oil burnoff. You would, however, smell it.

The oil is either going the way of blowby (doesn't sound like it based on plugs...but still possible) or coming out someplace you'd be able to see it. If the valve cover gaskets are the only such place, I think I'd start by fixing them once and for all. Grab a Fel-Pro high perf./heavy duty or Mopar Performance gasket and see if that helps. The covers themsleves may also be bent.

If the motors are running well (temps good, etc.) I wouldn't kill yourself diving too deep into the big stuff."
 
"Again, thinking out loud, the

"Again, thinking out loud, the breather on one side valve cover has a hose to flame arrestor. PCV also has hose to flame arrestor (other valve cover). Is breather allowed to pull air in if carb is overpowering the sucking of air? So crankcase may not be circulating air thus the pressure build up?

Thanks again to all!"
 
"Are you sure your PCV hose is

"Are you sure your PCV hose is running into the flame arrestor?

I’m not as familiar with the big block marine set-ups but that’s not sounding right to me. A PCV hose should run into the base of a carb or the intake manifold (on new automotive engines). It’s operation is dependent on the carb/intake vacuum. A hose that’s simply running up to the edge of the flame arrestor, with the assumed theory of relying on the carb’s intake suction for “vacuum”, won’t work…….there’s not enough seal nor suction to create the vacuum required to open and close the PCV.

Your problem could be the opposite of your theory about the breather. It’s the PCV that’s not allowing pressure to be relieved."
 
"A quick follow up to my last

"A quick follow up to my last post. If you don't, in fact, have a PCV port on the base of your carb, it may be easier for you to remove the PCV valve and switch to a double-breather set up like the attached pic. Without proper vacuum connection to operate the PCV, it's little more than a plug in the venting system.
292380.jpg
360 no PCV
 
And you would be correct. My

And you would be correct. My error. The PCV does go into the base of carb. I'm losing it....
 
"Yeah Jeff, for some reason, i

"Yeah Jeff, for some reason, it's only loud on one side!! That motor actaully belongs to a fellow Buehler jet boat owner so I can't take credit for it's nice fit and finish.

Attached is the 318 that I rebuilt and dropped in last month....thanks, in part, to some good advice from you/the forum along the way.

292394.jpg
Buehler Bolero 318
 
"Update; Oil pressure on manua

"Update; Oil pressure on manual gauge was right on with dash gauge-too high. Changed out relief spring and now at good psi. My mechanic suspects possibly a stuck ring which 'may' cause the blow by. He thinks this because when heads off getting worked, cylinder walls did not show/feel scoring. His recommendation before breakdown and rebuild, is to add a quart of ATF to crankcase and let engine idle for 30 minutes to maybe free up the problem ring and or clear out some of the carbon, then change oil. He's not guaranteeing this, only ruling out.

Stand by..."
 
"my 440 was burning 1qt per 10

"my 440 was burning 1qt per 10 hours last summer. Long story short, I had to replace the head gasket, and I had the valves, guides, and valve seals replaced in the process. This summer it has not used any oil in 100 hrs. So apparently it was using oil via valve guides and seals. Any chance you did not get new guids & seals when your heads were redone?"
 
"Also, its not likely that it&

"Also, its not likely that it's leaking and burning off on a hot block or manifold. Touch your block and manifold. If they are so hot they can burn off oil, then you have some other problem."
 
"With confirmation that you we

"With confirmation that you were running high pressure, I'd put the hunt for blow-by on standby until you've had time to monitor the consumption post-spring-replacement.

The high pressure could have resulted in cumulative consumption culprits (a little blow-by here, leaky gasket there, etc, etc). Check the ft lbs on those valve covers, throw in a good weight oil and see how it does.

Good to hear that you're getting there."
 
"Am I overly paranoid or just

"Am I overly paranoid or just drive it into the ground and enjoy....?

Oil change and short cruise to monitor my lower oil pressure and I notice some steam from dipstick tube-at top. Oil looked OK, fresh and clean, as I would expect after oil change. Other engine does not have steam from dipstick."
 
"Here is the latest...My oil l

"Here is the latest...My oil looks good and my coolant level is good. I am taking that as a small victory.

I ran the engine up to temp and hooked my cheapy vacuum gauge up to the pcv intake at base of carb. It held steady at 18 (I've read 17-22 is normal). At 1500 rpm, it held steady at 21. However, when I accelerate it and drop it, the gauge drops to 0 then back to 21+. In reading online, I see that optimum range would be 0-25. Again, being a complete novice, I may have to take these vacuum readings as a small victory. Not great but....

I put my hand over the hole where pcv goes in on valve cover, and it has a choo-choo feel to it. Not much visible, white or colored smoke or steam that I could see.

I may feel good about today, but my small concern may be from the steam coming from dipstick tube. When performing the above, I did not witness any steam. However, the steam was observed when engines were hot and under load."
 
""Even if you're not p

""Even if you're not paranoid, there could still be somebody following you."

No one's following you, but... Relax and go boating before thew season is over (unless you're one of those year 'round stinkers!)

Jeff"
 
"Excellent response Jeff. I’ve

"Excellent response Jeff. I’ve been known to be a bit paranoid AND a “year ‘round stinker” so, even though this isn’t my thread, I just got some good advice!

Burshwood – of all the things that have been kicked around throughout this thread, the steam from the dipstick tube has me leaning back to Jeff’s first post to the original response (and, subsequently, your mechanic’s suggestion) which is blow-by. The steam is a classic blow-by symptom as some of the air/fuel mixture sneaks past the ring(s) into the crankcase.

Assuming that you rebuilt the heads to freshen up a tired engine, it’s worth noting that engine parts wear together……and when fresh/strong parts are added, it can often exacerbate, or at least call attention to, other areas of wear. This is true with new/rebuilt heads on an older/tired bottom end. You’re restoring a vital part of the motor’s performance to original/optimum condition. Tired rings, etc. may have been okay operating in harmony with a tired valvetrain……but the restored level of combustion efficiency, may simply pointing out the weakest link(s).

Seems like the rest of engine's vitals are good so I'm with Jeff......just enjoy it."
 
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