Merc Mechanics & Big HP Guys!!! Oil Consumption Issue...
 

I have a pair 99' Carb'd 500HP blocks that were stroked 4.25" and all new equipment from crank to top end replaced. Eng. hours = 20. Dyno HP @ 650. The port motor is using about 2 quarts of oil every 1.5-2 hours. Oil: Valv VRI 20-50. Engine starts and runs great no smoke, no power loss. There is considerable "black exhuast" film that builds under the swim platform and ladder area. (Not oily, but dry) Pulled plugs and there was considerable black build-up on all plugs, and oil at base of plug and threads.
Starboard motor is perfect has not used any oil and the plugs are running a little rich, but no build-up and are clean. Plugs: NGK V Pwr 8. Any help or suggestions would be appreciated...
[email protected] - email :(

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Ouch!........ who built the motors? Someone may have put in a few rings upside down. If a couple of second compression rings were put in upside down the oil consumption would be horrendous. The only other explanation would be the cylinder walls are glazed and the rings never seated.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

You might check intake gaskets. If anything was machined you may have a problem angle of head to manifold being off a bit and trouble with gaskets sealing and sucking oil. Just a thought,

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Thanks Reed & Paradigm, I was getting nervous no one wanted to reply back to me!!! A&W Performance built the motors out East, but I am in WI. Still waiting on spec sheets on the motors. Motors are in a 388 Slingshot. I am hoping it is either the Power Valve/Float Levels in Carb. I heard this may push a ton of fuel and wash the oil down past rings??? I have a strong feeling although that it will turn out to be the Intake like Paradigm suggested. Just sucks because I only have 10 hours on the boat.
I just had the oil pan exchanged and the cylinder walls looked perfect, not glazed... The motor ran great for about 10 hours, and has just started to get worse and steadily using more oil. Any other thoughts or suggestions are EXTREMELY APPRECIATED :D

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Matty,
Start the engine and let it idle. Take off one of the valve cover breathers and spray about a ten second shot of carb cleaner into the valve cover. If the idle speeds up or changes a few seconds later, you can almost bet its the intake gaskets.

If it ran ok for the first ten hours, I doubt that it would be a ring problem.

Bill Koustenis
Advanced AUtomotive Machine
Waldorf Md

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Start with a leakdown test.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Had the same problem with my motors when they were freshend last year,,, turned out the PCV valves were not strong enough to close after the new cams were put in,,,, and the carbs/blowers were sucking the oil out of the pan !!! simple fix , once we found it ,,,, Good luck!

RHC

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

You might have gotten a bad set of valve seals on that one motor . It could cause the same condition your talking about. Brian

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Awesome ideas from all - thanks - keep them coming!!!

RHC - I know the carbs & cams were built up pretty heavy to go with the rebuilds. What did you do for the PCV Valve replacement? Did you go with new stock PCV Valves or Heavier Duty PCV Valves? Would my Merc 500HP's have PCV Valves?

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Check'd the devil :evilb: motor today. THe line from back of carb to top of intake was indeed loose and the grommet was worn out. I ordered a new PCV Valve and Intake Grommet will be in tomorrow. My hopes is this will cure thristy motor, but I still think its intake related!??!
Question: Will a stock 500HP PCV Valve be strong enough to open/close on a storker 540?????

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

I came from a 540 ci blower motor with an 871.. Never burned any oil. Now I have a pair of stock carb HP500's and just happened to check my oil after a few hours. The oil wasn't even on the stick!!! so I asked my mechanics who are Mercury trained and they told me stock HP500's could burn up to 1 qt for 3 hours of hard running. I've found you can burn a quart in 5 hours. This is without smoke and any black residue on the transom, so just check your oil all the time. I was glad to hear that as I was not having a problem out of the ordinary.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

check to see if the trays were installed under the intakes. if you leave it out it will consume oil like crazy and foul the plugs. all you have to do is pull the hose out in the middle of the intake and look down, or stick something in there. you should hit tin.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Was the lifter valley tray/shield re-installed? Hopefully with this PVC system.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Also, the rocker arm studs go into the intake ports. I've seen some people forget to use thread sealer on these and pull oil down into the intake port.

Just a heads up and throwing this against the wall to see if it sticks.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

SB is correct. When we put the intake back on, we forgot to put in the windage tray and the pvc was sucking the oil out of the intake. Just for kicks, try blocking off the pvc and go out and see if you have the same oil consumption. After finding this out I ran the rest of the season with mine blocked off and no more oil consumption.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Ditto on the lifter valley pan !!! :D

John S.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Everyone - thanks so much for all the excellent info=:) Installed the new pcv valve and grommet today with new plugs. Started great, but then loaded up under idle... Pulled air cleaner and the Holley Carb was dumping fuel "Like Mad" into the carb and intake. We believe it is the needle/set, possibly the float bowls... Ordered a "Carb Rebuild" kit today will install tomorrow and test... I will check for the windage tray through the pcv valve port??? I will give you all an update tomorrow after the water test. :D

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

How did you correct this ? Different PVC valve or did you eliminate it all together ?

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Matty 439 how are you making out in correcting this problem ? May have a similiar deal going with one of my engines now as well. Thanks in advance.

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

when mine was eating oil it turned out to be the oil cooler the
oil was going out with the water easy fix.and i would not use
20-50 oil i use straight 40

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Installed the new PVC Valve and rebuilt the Carb as it was dumping an enormous amount of fuel at idle. Do not know if the carb was original problem, more than likely washing the oil past rings into the bottom end where it was burning it. I ran the boat for about 2 hours on Saturday and put it back on the trailer to fully cool. Out of town on business today, but will check the motor tomorrow. I will give you all an update!!!

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

Why would you suggest Straight 40?? What Brand?

Re: Stroked 540cid - 650HP Eating Oil???? HELP!!
 

UPDATE - Problem Solved :D Pulled PCV Valve from base of intake and removed. Sealed intake port and carb line. Ran the boat 2 hours on Saturday, with W/O Throttle for a good run at 90++mph. Cooled motors and checked oil - OIL LEVEL WAS PERFECT & LITTLE TO NO EXHAUST BUILD UP ON SWIM PLATFORM!!!! My guess is this motor has no windage tray or it is pulling so hard with the big cam that the stock PCV Valve does not function correctly. I did switch to Mobile 15/50 Synthetic. Thanks for all the help from the OSO members!!!!!!

I have the same issue on my new 500 efi clone. Any idea if this could be my issue aswell. I know it does not have a liftervalley trap installed was told by the builder that it was not needed

you are having the same problem.... i ran across that last year on a friends 500's. the windage tray was left off the intake and it was eating oil like crazy. bad enough to foul the plugs every time we went out and ran hard. we left the pcv valve in the back of the intake but blocked the intake port and removed hose. not a drop lost since. try that and see if it solves your problem. that tray IS necessary.

If you have a PCV pr crankcase vent in the intake, then the baffle is 100% needed to keep the oil from entering it. If the PCV is not in the intake, the baffle isn't totally needed but still prefferred in the sense of keeping hot oil from heating the intake.

Can anyone point me in the right direction for this baffle plate I can't find one . Part # anything. I understood that merc didn't use them so I didn't put one in


QUOTE=SB;3736544]If you have a PCV pr crankcase vent in the intake, then the baffle is 100% needed to keep the oil from entering it. If the PCV is not in the intake, the baffle isn't totally needed but still prefferred in the sense of keeping hot oil from heating the intake.[/QUOTE]

Mercury did install them in most all of their BB engines. As mentioned, you need one. I replied to your email saying that I may have one at the shop. I'll look tomorrow.
Eddie

Any GM Performance Parts place can get it for you. Probably Summit Racing too,
http://www.gmpartsdirect.com/perform...CATID=611.html
Part#12555320 - Manifold Oil Shield

Pic
http://www.gmpartsdirect.com/perform...ecache/199.gif

Yep thanks guys that seems to have fixed my issue

if you have a carb that has the float level set to high it will polute the oil with gasoline and that will make it burn oil.

I am having exact issue on both of our 500efi. Going thru 1 qt per hour. Plugs are all fouled. Intake feels extremely hot. Talked to the builder they said windage trays were put back in correctly. Haven't tried pulling pcv valves but would both valves go bad at the same time? What else should we check?

check leakdown, 502s used metric ring's and are famous for having ring seal/oil consumption problems

Didnt have an issue last year before valve job. Would go 20 hours without having to add any oil. 15-50 M1. Not to mention all plugs being black. Doubt all rings are shot at the same time. Not to mention both motors are showing signs of same symptoms. Won't throw out the idea of a leak check tho.

Years ago I did a valve job on an older engine. Engine didn't burn any measurable oil before valve job. A bit after valve job i was going through a quart of oil a week. Did some research and it was a common problem. Sealed up valves and worn rings.

both motors only have 340 hours...I'll make sure to do a comp test tho.

Windage trays and valley trays are two different animals. I would double check that the lifter valley tray (subject of this thread) was re-installed.

Chevrolet Performance Lifter Valley Baffle # 12555320


https://static.summitracing.com/glob....jpg?rep=False

Who needs 125$ a hour mechanics when we have OSO !!!
:coolcowboy:

thanks for the clarification SB. Looking in the intake, there was oil in there. What are the other mechanisms to get oil in there?

All 16 plugs look like this after 1.5 hours run time...these were brand new plugs.

https://i.imgur.com/t8ZEl7r.jpg

looks excessive for rings...idk