oil in the driveway - I do not understand

[muldoon]

1974 gmc seirra, 454 engine, in decent shape. 

I have done quite a few things to this truck and overall am happy with the truck.  This series of events has me a bit puzzled, and I want to understand what happened before going forward.  Thoughts or explanations appreciated. 

Last week, went to start the truck after it sitting for 4 or 5 days and had zero battery.  The battery is a yellow top and newish, so I did not question the battery.  I assumed I had left the lights on or something, not worrying about it terrible.  I pulled my other truck around and proceeded to jump it.  Battery was very very weak and the truck did not want to start.  I left it in connected to jumper cables for about half hour with the other truck running.  I cranked and cranked on the ignition, and it felt like it would start to turn over and then be dead battery again within 1 second. 

I disconnected the cables, cleaned all the contacts with steel wool, and reconnected.  After 10 minutes charging, it fired up.  Ran awful, until it just sputtered and died.  Once it died, it would not start again no matter what.  I tried a few times over the course of the day. 

Eventually, I discover that the fuel pump is not running, therefore no fuel is going to the carb.  This explains why when it did start it ran poorly as it used all the gas it had inline and eventually sputtered out.  It explains why it would not start no matter what after that.  However, the next morning, I come out to find a large oil spot under the truck.  Like half a quart or somewhere around there.  I did not recall seeing it the night before and the truck does not leak oil.  (actually a very minor leak at the rear seal), but that was not this. 

I chased the issue with the fuel pump back to the relay from holley.  With key on, I read 12 volts from battery, 12 volts going to ignition, and 9 volts going to fuel pump.  Ok, that's why the puel pump is not working.  Oddly enough, with key off, 12 volts from battery, 0 volts from ignition, 2 volts going to fuel pump.  That's a problem, and it explains my original dead battery. 

So I take the relay and go to oreillys, find a 5 pin 30 amp relay that fits the harness.  matched up 86's and 87's and 30's.  No problem, it looks like a generic relay.  I plug it in and take voltage readings, all good back in business.  I jump start the truck and find it running absolutely terrible.  Fuel pressure is good at 6psi, the electrical problems are sorted, the fuel problem is sorted.  But the oil spillage from the night before now looks like a full on oil leak. 

I usually run oil pressure around 45 or so and when I accelerate or gun it a bit easy see it up around 60.  Not that day.  It had weak oil pressure, and whitish smoke coming from engine and exhaust.  I open the hood and see oil predominantly on the left hand side of the engine (if you were standing at the front bumper looking at the engine.  passenger side).  I checked the oil, it was right at the full mark, might have lost some but no real danger.  I looked at the fuel pump push rod plug thinking it had worked loose, but I could not see any oil coming from it.  Underneath the truck it looked like it was leaking from everywhere.  Oil was plastered all over the entire bottom of the engine and splattered everywhere.  Impossible to determine where the leak was.  I let the truck sit a day or two, and when I started it back up, it was running better.  After driving it for about 30 minutes, I saw oil pressure right back where it used to be, could squeal tires at will.  no smoke, no hesitation. 

The truck is not leaking any oil now.  But what the heck happened?  When I was cranking the engine trying to get it to start (without fuel) does the oil pressure build up?  If so, could it have slipped a seal and then returned to an ok situation after getting back to running condition?  What kind of problem does this indicate for me in the future? 

Any other explanations? 

[zieg85]

If it was an all of a sudden occurrence I've seen oil pressure sending units do this.  Hopefully you can get under it and determine where it came from.

[muldoon]

I just babied it to a car wash close by, let it cool off, soaked it in simple green, and pressure washed everything under the engine and under chassis I could get to.  I visibly do not see any leaks or signs of leakage in the driveway now, or in the last 3 days.  And it is running well.  I moved where I park it so I could be certain.   While it is not doing it now, I do not want to ignore a problem. 

Thoughts on oil pressure during repeated cranking without engine firing? 

[zieg85]

The oil pressure is highest when the engine first fires as the oil is highest in viscosity.  Low oil pressure readings in your initial statement would also point toward the sending unit going bad.

[muldoon]

zieg, thanks for that.  if pressure built up enough from dry cranking without firing, is it possible that it backed up and spilled out from dipstick?  that would be exactly the area where I saw the oil on the headers smoking, and the plugwires in that area were covered.  On the underside, oil was everywhere from me driving and splattering it everywhere. 

is that plausible?

[zieg85]

I had one old Ford the belched through the dipstick and made a mess occasionally.  Never is find a solution and it didn't do it often but when it did it made a big mess.

[muldoon]

I went to look at it again, and see the valve cover breather cap is also right above that area.



I pulled the cover off the filter and there is oil in the filter material. 



There was oil on the valve cover, in the area and pattern that would be consistent with it dripping down the valve cover but I'll be honest and say that I didn't pay attention to it because that spot has had a small oil blob for forever and I just ignored it.  ..and of course I power washed it this morning so now it is clean. 

[zieg85]

Is your PCV operational?  If your crankcase is not vented properly and builds up needless pressure, oil squirts out...

[muldoon]

Yes, PCV is on drivers side valve cover, goes straight into (newish) edelbrock 750cfm.  The rear of the carb goes to brakes.  I have the ported vacuum line going to distributor, and the manifold vacuum port from carb blocked off.  I do not have any reason to believe any of that is acting up. 

I sprayed wd40 around base of carb and vacuum lines not long ago, no idle changes so I do not think I have a vac leak.  For what it is worth, I do feel vacuum "pull" off the carb line to distributor (using my thumb).  As far as I know PCV is perfectly functional. 

[zieg85]

Maybe BD or Vile will chime in with their thoughts

[rich weyand]

To check if the PCV valve is functional, take it out and shake it up and down.  It should rattle, meaning the piston is free to move.  If not, either replace it (like two bucks), or spray it out with WD-40 to loosen it up.

BTW, your vacuum advance is connected incorrectly.  Ported vacuum is for emissions-equipped engines.  If you have no AIR pump on the engine, correct vacuum advance connection is to manifold vacuum.

That it is not leaking now means that the oil seals and gaskets on the bottom are tight.  So it pushed oil out the top somewhere, such as the crankcase breather or the dipstick.  I would keep it clean and watch for repeat occurrence, then try to track it back immediately you see it.  It may be a one-time occurrence associated with the other problems.

[thefarmboy21]

Your fuel pump wasn't left on and pump your crankcase full of gas did it? I've had the relays malfunction/short before and not be able to turn them off until they shorted out.

[muldoon]

Thanks Rich.

I have a redtop HEI distributor and MSD 6a, and I went to read and sure enough it wants the manifold vacuum line.  I moved it tonight and capped off the timed port.  I put that new carburetor on about a month ago and somehow missed that.  It does sort of explain some of what I thought was timing problems.  I guess it would have affected timing, truck seems to sound much mellower and meaner while still having plenty of pep, especially lower rpm bands.  I probably need to re-tune my carb after that. 

I am keeping a closer look on oil pressure from the cab, it's pretty much hovering just under 60 or right around there.  I have no oil in the driveway.  I have taken about half dozen short trips today under various driving conditions.  I'll keep an eye on it, but I think this is behind me now.  If it stays the same for a week or so I'll call it good enough. 

Next up is the sanderson headers...   

[muldoon]

Your fuel pump wasn't left on and pump your crankcase full of gas did it? I've had the relays malfunction/short before and not be able to turn them off until they shorted out.

Nope, the fuel pump was getting 9 volts when the relay was failing and did not pump at all.  Also, I have a hidden kill switch that disables power to the fuel pump when I am not driving it.  I am pretty religious about killing it when I shut it down but admit I forget from time to time.  When the relay was key off, it was pushing 2 volts to the pump.  I think me forgetting to hit the kill switch is what drained the battery that night but did not power up the pump. 

[rich weyand]

Thanks Rich.

I have a redtop HEI distributor and MSD 6a, and I went to read and sure enough it wants the manifold vacuum line.  I moved it tonight and capped off the timed port.  I put that new carburetor on about a month ago and somehow missed that.  It does sort of explain some of what I thought was timing problems.  I guess it would have affected timing, truck seems to sound much mellower and meaner while still having plenty of pep, especially lower rpm bands.  I probably need to re-tune my carb after that. 

I am keeping a closer look on oil pressure from the cab, it's pretty much hovering just under 60 or right around there.  I have no oil in the driveway.  I have taken about half dozen short trips today under various driving conditions.  I'll keep an eye on it, but I think this is behind me now.  If it stays the same for a week or so I'll call it good enough. 

Next up is the sanderson headers...   

Based on my experience with that setup, you don't need to re-tune the carb, but you can now re-time the ignition.  You want about 25* BTDC at idle with the vacuum advance in, and about 37* BTDC with with the centrifugal advance all in (check it at 3000 rpm) and no vacuum advance.  I'm not sure what the mechanical and vacuum advance setup on that distributor is, but if you have standard vacuum and centrifugal advance curves (8* vacuum advance and 20* centrifugal), that would be 17*BTDC at idle with the vacuum advance disconnected.  Try that, and if you get knocking when loading the engine at low rpm (like accelerating from a stop up a hill with your foot in it), back it off a couple degrees and try it again.