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"oil farts" solved
Topic Started: Nov 1 2013, 08:06 AM (9,905 Views)
sphenicie


THE SHORT STORY

an "oil fart" is a condition characterized by "billowing white smoke from the tailpipe" at intermittent intervals, generally between 1 and 10 seconds in duration.

an o/f is created when the level of oil in the head rises to a point that liquid oil is sucked into the intake, via the breather port.

an o/f is a compound problem.

the root problem is too much oil is entering the head. the secondary part of the problem is, that not enough oil is escaping the head.

all of the oil to the head enters via two pathways; 1) the ports to the lifters, and 2) the ports to the cam journals.
1) the lifters and lifter bores can wear and contribute to the build up of oil in the head, but since the lifter just makes one 1/2" movement per cycle vs.
the cam turning continuously, less likely. not impossible.
2)in my case, and by far the most common case, is that worn cam journals and/or cam journal bores are the point of entry. when I refer to a "the cam"
or "worn cam" I am referring specifically to the journals/bores.

the oil in the head returns to the oil pan by gravity, thru two primary return ports, and two secondary ports. the primary return ports are the two of lower elevation, or the front of the engine, or the exhaust side. the secondary ports are the higher elevation ports, on the rear, or intake side of the engine. under proper conditions the primary return ports will accommodate all the oil that is being delivered to the head. when the vehicle is at an incline (going uphill) of >14 degrees, the rear, or secondary ports are at a lower elevation relative to the forward ports. in this situation, the rear ports take over as the primary return ports. these rear, higher elevation ports are, in general, responsible for the release of crankcase gasses to the breather port in the valve cover.

as previously mentioned, an o/f is a compound problem. this is why it was so hard to pin down.

the root problem is too much oil to the head. most commonly thru worn cam journals/bores.
the other side is, not enough oil retuning to the pan. oil can be restricted from returning to the pan because of physical blockage of the return ports. the blockage can be crud or it could be the type of head gasket. there are h/g's that have full size holes for the rear, or intake side ports, and those with greatly reduced size holes.
generally, you will have to have BOTH conditions to create an o/f.

new cam + large hole head gasket = no o/f

worn cam + large hole head gasket = no o/f

worn cam + small hole head gasket = OIL FARTS

new cam + small hole gasket = no o/f

this is not to say that a vary badly worn cam (and maybe bad lifter/bore) + large hole head gasket can not create an o/f, but the increased return capacity will make it less likely.

for those who would like more specific information to the tests and observations I made over the last three months or so and better than 1500 test miles, please continue to read "the long story."




NOTE: member bbowens has pointed out that there is a Felpro 9651PT with small holes, and Beck-Arnley has has two separate gaskets with separate part
numbers.
I have an email in to Felpro. Beck-Arnley p/n; 035-1874 = standard hole, B/A p/n; 0352106 = large hole.




Edited by sphenicie, Nov 3 2013, 05:30 AM.
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sphenicie


THE LONG STORY

Brief history:
I purchased the car locally. The previous owner purchased the car to restore, he put it a barn, where it sat for 4-5 years, until in Sept 2012 I was able to pry it away. This gave me no p/o history to work with.
when I got the car home I ran a compression test, the numbers were not impressive, but the #3 stood out, so I pulled the head, fully expecting to find a burnt e-valve. all the valves were fine, but, one piston was different. I was scratching at the carbon on the top of one of them, when I noticed that the piston was moving a lot, and vary easily.
enough. engine goes to the builder.
i had to work in N. Dakota till March 2013. when i got home the engine went in and i awaited the departure of the snow to start driving it. had to go to N.D. for work again for 3 weeks. when i got home, the DOT requested more info (pix) for the collector plates. sent them in. in the mean time i only drove the car in the area around the house, average of 1-15 mile trips, one or two may have been 20-25 miles. no farts.

then, with the plates in hand, my wife and i set off on a top down ride in the UP, on a beautiful sunny day. the first one came after about forty miles. my wife wanted out! she'd rather walk. well, from there all the way home, we had an o/f about 15-20 miles.


experimental stage:
Since this engine was built by the same builder who has built 2 other G10's for me, neither had farts, as well as a couple fine chev 350's, i called him. he had little idea. it was obvious that at least heavy oil "mist" was going thru the throttle body.
i have 2 other metros, both with G10's. so i started by running all three side by side, and inspecting the oil in the valve cover. at idle or driveway revs, there was nothing that stood out.
compression test, warm/dry, was 175/170/185. (i have to find those notes, but close) low, but not outrageous.

oil capacity of the head: since it appeared oil was being drawn thru the breather port of the valve cover, i wanted to know just how much oil it would take to fill the head and valve cover. i used an old style valve cover, because the bottom of the baffle in the new style would be the same as the full volume of the old style. i began by plugging the v/c bolt holes with epoxy putty, and cutting some thin sheet metal to match the radius on the ends. they were then silicone in place. next the head. the head has a lot of ways for water to escape, so i decided to use sand. i wadded paper towels into the lifter bores and then installing the lifters flush to the top of their bores. filled with sand, then dumped out the sand.

i found the valve cover to have a volume of 24 fluid oz.
i found the head to have a volume of 32 fl.oz. (min.)

56 fl. oz. of oil. my thought was that 56 oz. of oil in the head plus the oil in the filter and the block, would certainly trip an "oil light".

well, just in the case that there is restriction, i decided to try to flood the head. i used a 2L soda bottle filled to the very top with oil. i tried to squeeze as much oil out of the bottle as i quickly could. after several attempts, the most i could get was to the mid camshaft. this was on a 50 deg. day, cold block, cold oil. hot oil in a hot block should flow away even faster. i could not see the oil delivery system pushing as much oil volume as i did with the 2L bottle which has about a 3/4" opening.

baffled, i got in touch with Snowfish for consultation. he suggested installing a fart collector. i did so. i collected farts from <1 fl. oz. to >22 fl.oz., pictured.

in the vert with the top down, i noticed that i was able to smell the fart before the smoke screen appeared. i tried to jump out at the first scent and run around throw up the hood, pull oil fill cap, and see what was going on under the valve cover. although the splash seemed to be greater, the oil level was down.


what was different between this engine and the last two he built for me? PARTS ! it had to be parts. i called him and there was difficulty with getting some parts, so he had to order a different gasket set, and pistons.

i was out of ideas, so i pulld the head and took it down to his shop. he was working on another engine, so i started stripping out the head. we had checked the lifter bores and the cam bores when he commented, "you never did get that cam you wanted". with the head off i figured i would do an open cylinder leak down, no measureable amount after several hours. i then wrote off the problem being in the bottom.

the old memory got up to speed, and i remembered that he asked me what i wanted to do for the cam. i was in N. Dakota working, and i told him to just put the old one in, and i will deal with it when i get home. i then forgot about it, completely forgot about it. never did send in a cam to be reground. in fact, found the cam, in the shipping tube, never sent out.

i immediately ordered a new Beck-Arnley cam and a Felpro head gasket.

the gasket showed up first. in my haste i decided to install the h/g first. following the same road coarse that predictably produced farts at a reliable 28-30 mile point, i got nothing in the collector.
in order to verify this, i put on better than 500 miles without a fart! BINGO !
well, i could not rest, just because the oil was able to escape the head does not mean that it is not being over flowed to the head.

i went to the local parts house and ordered a few different gaskets, hoping to get a small hole type, and return the rest.

next i pulled the head again, and i installed the small hole gasket, with the new cam. HOT DOG ! no farts! 500+ miles of testing, no farts.

being me, i had to pull the head again, to replace the small hole gasket. just me. 500+ miles, no farts.


other considerations:

oil check valve. it was installed. it is my thought that the lack of the check valve would not contribute to the flow of oil to the head. although the volume of oil 'could' be increased by the check valve not being in place, i believe that the proper gap in the cam journal to journal bore would still control the flow into the head. higher oil pressure may.

the function of the check valve is to keep oil in the head after the engine is shut down. lack of the check valve WILL lead to premature wear of the head components.























Edited by sphenicie, Nov 4 2013, 07:05 AM.
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Vkhelldog
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Interesting. I had new cam and regular sized oil hole head gasket I still oil farted... If a regrind can count as new... it's well within spec anyway.

My cylinder two is within spec but Bailrey and is out of round a g'night and I think that contributes to my oil farts.
Edited by Vkhelldog, Nov 1 2013, 08:22 AM.
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sphenicie


what do you mean by " regular sized " holes?

i used ONLY Felpro 9651 PT, gaskets, as the large hole type.

i did the following combinations:

start; worn cam + unknown mfgr small hole h/g.....BAD farts. farts collected in fart collector range from <1 oz. to > 22 oz.

new Felpro 9651PT gasket......same cam....farts gone for test period of >500 miles. typical first fart at 30 miles.

pull head, new, brand new, cam with 'parts master' small hole h/g......test period >500 miles, no farts.

pull head, brand new cam and brand new Felpro 9651PT, no farts.

this will all be in the long story with the other stuff.
Edited by sphenicie, Nov 1 2013, 08:34 AM.
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snowfish
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Basic GearHead

Mr. Sphenicie has gone though great pains to "CSI" the Oil Fart phenomenon. :news Very Much Appreciated! :rocker

Test oil fart collector installed.

Posted Image

Looks like a "toot" here, eh?

Posted Image

Not sure if we can call this a fart. :hmm

Posted Image

Looks like we have to wipe! :oshit :-/ :P :lol
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truckjohn


Makes sense...

Personally - unless you have mic'ed both the cam journals and the cam journals in the head.... Assume a re-ground cam is ground down too much/undersized....

When our friend Sphencie talks about a "New" cam - he means NEW in box new... Not re-ground...

Thanks
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Yes, sphenicie. Excessive camshaft bearing clearances allow too much oil to to the top of the head. Thank you for posting.

As a clarification, what you are referring to as secondary oil drain holes function primarily as crankcase vents due to the angle of installation of the engine in the car.

Too many people are "overhauling" their engines and heads without any regard to camshaft bearing clearances. As a matter of fact, there is no regard to any dimension, limit, or clearance from what I've seen.

The best way to measure is with a bore gauge and micrometer. Plasti-gauge works also, but is not as reliable or accurate.

None of the engines that I have ever overhauled oil fart. I use head gaskets with the standard size crankcase vent holes.

There are three reasons that I believe the camshaft bearing clearances become excessive.

1. Normal wear. Normal operation in a well serviced and lubricated engine does not wear the camshaft bearing clearances beyond new limits for a very long time. I have seen engines with nearly 200,000 miles that have new clearances on the camshaft bearing clearances.

2. Engines sit for an extended period without operation. This may be a few weeks, or a few years. If the oil that is on the camshaft drains off, and the engine is started without manually lubricating the bearings prior to engine start, the bearing surfaces get significant wear in a very short period. The crankshaft bearings and piston rings are also affected. Think about this the next time that you're tempted to start an engine that's been sitting for several years. The best practice is to remove the engine, remove the valve cover and oil pan, and lubricate the bearing areas with some sort of light weight oil. Never mind that rust that's most likely in the cylinders. Pull the head and remove that, too.

3. Engines that have burned valves most often get a valve job. Why does this cause camshaft bearing surface wear? The person who removes the head gasket makes no effort to keep the little partials of debris from the head gasket from entering the holes in the top of the block that are there for crankcase ventilation and oil return. This debris is picked up in the oil and freely flows through the system. No, the oil filter will not get all off this debris. Changing the oil after a 5 minute run doesn't do the trick, either. I see this every time I go to the Pick-n-Pull to get a camshaft or a cylinder head. Unmolested engines have very nice camshaft bearing surfaces. The engines that have had a valve job done have terribly worn camshaft bearing surfaces. Stuff little rolls of paper towels in every hole on the top of the block prior to cleaning the head gasket mating surface when you replace a head gasket.



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bbowens
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Glenn, looking in the FSM, I'm not finding any camshaft bearings in this engine...
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bbowens
Nov 1 2013, 07:08 PM
Glenn, looking in the FSM, I'm not finding any camshaft bearings in this engine...
No need to look in the FSM. Look at any engine. There are none.

It's a bearing surface that's a part of the head. It's the bearing surface on the camshaft. That's all there is to it. The camshaft in the head. It's a bearing surface. Damage the bearing surface on the head and/or the camshaft, and they're junk.

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sphenicie


@truckjohn, new B/A, new cam.

@bbowens, there are no bearings. the journals are directly fit to the bores.

@Glen, I will be posting "the long story", your questions will be answered there. it will take me a bit to put it together from
my scraps of paper and recognition. John should be able to help me with specifics as we were in touch all thru the
"experiment".
Edited by sphenicie, Nov 1 2013, 07:32 PM.
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sphenicie


Glen, if one of your engines farted I would fall down dead where I was standing.

I agree, nobody pays attention to the journals/bores.

now is the time that more folks will.

it was a miscommunication between my builder and myself (entirely my forgetfulness) which led to the o/f's. see the long story
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Flash
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53 mpg last trip

snowfish
Nov 1 2013, 09:54 AM


Test oil fart collector installed.

Posted Image


Ya know, it looks like you could modify that "tester" for cars that have O/F issues.
Make it able to drain the oil back into the engine.

I had to rebuild my motor (1 qt. oil per fill up ) to stop it from smoking....I'm wondering if ring blow-by adds to the oil fart problem? :hmm
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sphenicie


I have not found any evidence, what so ever, to lead one to believe that "ring blow by" would cause the head to flood with oil.

'ring blow by' should and would be entering the lower crank case, as designed. there is always some amount of "ring blow by", as it can not possibly be eliminated completely. it is the design of the engine to vent the gasses, up thru the head, and ultimately thru the valve cover breather port, to the intake.

an "oil fart" is a condition where the head floods with oil, resulting in liquid oil being sucked thru the intake, being burnt, and emitting a ' billowing cloud of smoke '.

although, I believe that the cam/journals are the primary place to look, this is not the only place that the oil may be coming from.



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sphenicie
Nov 1 2013, 08:07 AM
THE LONG STORY......coming soon, too much typing for this old fart for one day. and i will have to organize my notes and such.
I thought this was the long version.

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bbowens
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The following was posted on yahoo's geometroclub forum in reference to my other issue, oil pan leak (is Ode Coyote also on this site?):

[most recent reponse first]
Quote:
 
The blow by goes upward through the oil return holes in the head, preventing oil from returning.

At some point the teeny weenie PCV then is an oil injector and the overburden gets dumped into the throttle body...while injecting oil, the PCV doesn't vent gasses...pressure builds up in the crank case and is vented though the crank seals and pan gasket etc.

At some point..the dreaded 2 mile smoke screen at 70 MPH.
Check under the air filter for an oil puddle. If it's there, the PCV is being overwelmed.
One cure for the smoke screen is to install an oil separation chamber.

Yank the dip stick to see if the pressure comes out of THAT hole..where there SHOULD be a vent like every other engine has.

A tube and an oil catch can may be in order.

Ode

At 05:30 PM 10/2/2013 -0700, you wrote:
>
>
> is there something that makes the gases in the crankcase separate from the gases in head? if not, then the pressure throughout will equalize and be controlled by the PCV system. If the PCV is not adequate to relieve the pressure from excess blow-by, then that is another matter, but the crankcase is still a ventilated system.
>
>
> ---In thegeometroclub@yahoogroups.com wrote:
>
> Totally inadequate to handle any blow by....and it vents the valve cover, not the "crank case." It's the only engine I've ever seen that didn't have a vent in the block itself.
>
> ...could pull the dip stick.
>
> ode
>
> At 12:07 PM 10/2/2013 -0700, you wrote:
>
> PCV = Positive Crankcase Ventilation
>
> ---In thegeometroclub@yahoogroups.com wrote:
>
> Really? Where?
>
> Ode
>
> At 10:04 AM 10/2/2013 -0700, you wrote:
>
> but the crankcase is ventilated...
>
> ---In thegeometroclub@yahoogroups.com wrote:
Sounds like blow by. Cylinder wear will do this. Air pressure in the pan.
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