Oil leaking through breather into air filter

[ecodan]

Just completed long trip (11,000km) in 1976 fj55 with 2f motor.
To my dismay on return we found some oil in the air cleaner housing above the carb. Have since noticed two of my sparkplugs are fouled (white and crusty). Have given the beast a full service including a new manifold gasket as the new headers where leaking from a blown gasket. Is running beautifully not blowing smoke and not using much oil that i have observed. Oil pressure gauge reads high (off the scale) and have a reasonable leak below the pcv valve which i renewed recently -also i found the exhast tappets had become tight over the trip, i run 98octane premium unleaded with upper cylinder lubricant, I had hoped this would keep everything running free.

Any thoughts, is it blow by? burnt valve? I have no cylinder pressure tester, but i guess that would tell me whats going on.

I am thinking of putting some kind of canister on the top breather hose off the rocker cover, to collect the oil. Have allready tried retro fitting the old pcv valve (which still rattles) into the top hose, but the pressure build up blew off my oil filler cap...! which im still looking for

Cheers for any help you can give.

 

[Mr. Toad]

My oil pressure gauge used to peg the scale too. It wasn't because of high oil pressure -- it was a bad oil pressure sensor. I wonder how much oil pressure you really have?

 

[Hugh Heifer]

Although I am no authority, I would say it is a bad/clogged PCV system. Let me explain - If the engine does not smoke, then you may not have blowby which will tax a PCV system (like my 1F that blows oil out the exhaust and into the air filter). With a closed PCV system, like the F/2F, the PCV is, of course, connected to the air cleaner. Excess vapors can enter the air cleaner resulting in an oily filter. Worse, crankcase pressures build up to the point that vapors and oil are forced out the front or rear seals and other gaskets that would otherwise seal the crankcase.

If the engine smokes, there will be carbon deposits in the combustion chambers. The valves, spark plugs, piston tops, and piston ring lands will aslo be coated. THe inside of the intake manifold and exhaust system will have oily deposits too.

So before placing blame on the engine rings, check the PCV system once again - particularly the valve. If you shake it, the valve should rattle. Also, remove the breaker and place your hand over the opening with the engine running; you shold feel suction. If that is OK check for restrictions in the PCV lines. Any restrictions in the system can causee high crank case pressures (indicated by you oil pressure gauge if it is right) resulting in the oil where it does not belong and a miriad of problems to follow.

I have rplaced PCV valves in the past and had them go bad right away. This is often due to crud in the lines from the previous problem.

Hope this helps. The knowledge is something I learned in a engine rebuilding class (self taught) so use it as you like - I am a shade tree mechanic not a pro

 

[Hugh Heifer]

I also noticed this - which I see you were looking at I think.
https://forum.ih8mud.com/showthread.php?t=110380

 

[ecodan]

Funnily enough, I just discovered my PCV valve was fitted upside down! I have also replaced all the hoses with genuine vacuum hose (previously heater hose). Seems to be running different so hopefully that’s the end of the oil in the air cleaner.

My exhaust has always been a sooty black colour, but my plugs have always been a tan colour. I fixed a blown manifold gasket last week and now my plugs are oily, but I’m hoping fixing the PCV system might go some way to fixing that, I guess its all part of the problem.

Since fixing the PCV system last night my idle keeps drifting very low once the vehicle has been up to speed. Solenoid operates when I turn on the ignition and turns off when I unplug the cable, and I have adjusted the idle mixture, and turned the idle speed up to 900rpm. Today I’ll check the timing in case the vacuum change has somehow changed the timing advance or something…

 

[grant5127]

If all else fails? here ya go--- http://cgi.ebay.com/ebaymotors/ws/e...90036102301&rd=1&sspagename=STRK:MEWA:IT&rd=1 or http://www.timskelton.com/lightning/race_prep/reliability/oil_separator.htm

I think you get the idea...

 

[ecodan]

Wow, those links really helped! One question, where should I put them, on the top hose off the valve cover And off the PVC valve up to the inlet manifold? Or just on the top hose?

 

[ecodan]

Anyone tried using a fuel fillter as a catchcan? Im wondering about putting a catch can on the valve cover hose, and a fuel fillter on the crankcase hose above the pcv valve.

 

[grant5127]

If you have adequate vacuum through the pcv valve?? I would check the back side of the side cover for blockage there... If all is working like it's supposed to ?? with the engine running you feel a suck at the valve cover air inlet...I've never cared for the vent system on these early engines... pulling the vapors from down low has proven not to be the best.. here is a pic of one mod. that I run... the pcv is in the filler cap & air enters at the back of the v.c. .... the reason i did this was moisture bubbles on the bottom side of the v.c. .. this cured the bubble problem.... there are many variations to this also.......

 

[ecodan]

No suck on the back valve cover hose, just blows a little. Vacuum seems strong above pcv, and prior to re-fitting on the weekend I shook the pcv and blew through it in both directions, it seemed to operate correctly, but i did not check it while the engine was operating.

So you blocked off the original lower crankcase pcv hookup point, and rely totally on the new Oil filler pcv?

 

[grant5127]

No suck on the back valve cover hose, just blows a little. Vacuum seems strong above pcv, and prior to re-fitting on the weekend I shook the pcv and blew through it in both directions, it seemed to operate correctly, but i did not check it while the engine was operating.

So you blocked off the original lower crankcase pcv hookup point, and rely totally on the new Oil filler pcv?

Yes.. side cover pluged.. air enters at the rear. flows forward pulling the vapors with it...