914 w 911 SC motor, Spitting oil Options

[Nick]

I have a 914 with fresh CIS 3.0 6 in it (less than 3k on rebuild). Due to travel etc I'm only driving it every 6 weeks or so. Every time I start it it smokes like crazy and some oil actually flows out of the tail pipe. Oil level is 2/3 of the way up between low and high marks. Took the air filter off to look for oil @ the air intake and did see a little as well as a small trickle of oil @ the top of the breather in the oil spout running back into the tank. Do I just need to keep the tank emptier?

If the car is driven 3 - 4 days in a row the symptoms go away

[rfuerst911sc]

I have a 914 with fresh CIS 3.0 6 in it (less than 3k on rebuild). Due to travel etc I'm only driving it every 6 weeks or so. Every time I start it it smokes like crazy and some oil actually flows out of the tail pipe. Oil level is 2/3 of the way up between low and high marks. Took the air filter off to look for oil @ the air intake and did see a little as well as a small trickle of oil @ the top of the breather in the oil spout running back into the tank. Do I just need to keep the tank emptier?

If the car is driven 3 - 4 days in a row the symptoms go away

My 914 with a 3.0 and my 83 SC both blow smoke if I let them sit for a week or two it is normal. Conventional wisdom say's halfway up the dipstick is the proper oil level. Remember to check with motor warmed up and level with engine idling.

[ConeDodger]

This is pretty basic but sometimes you have to start there... The proper way to check the oil on a 911 and 914 -6 is with the engine warm and running on level ground. You want to have the oil come about halfway between the two marks on the dipstick. If you checked it with the engine off, you will overfill it.

[GeorgeRud]

My six conversion will smoke like a mosquito fogger if it's been sitting for a long time, but runs great and doesn't use too much oil.

Check the oil level when warm and keep track of your consumption. One quart every 600 miles is even considered normal if I remember correctly, so they will use some oil. If you're not leaking oil or fouling plugs, you should be fine.

[Jeffs9146]

How did you fit the CIS in? Did you lower the engine or modify the CIS?

If you modified the CIS do you have a photo you can post? (IMG:style_emoticons/default/beerchug.gif)

[type47]

I think 911SC's smoke on start up due to oil draining back down the oil return tubes. Unless there is a poor leakdown measurement or compression measurement, which I doubt on a rebuild w/3k, I'd just keep an eye on it...... and drive it more (IMG:style_emoticons/default/biggrin.gif)

[eimc]

when you let it sit for a couple of weeks the oil seeps into the bottom of the crankcase (called wet sumping). If you have a drain plug on the engine(not the oil tank) drain the oil from the engine and pour it back in the tank. It should be only about a quart.

[Cap'n Krusty]

I think 911SC's smoke on start up due to oil draining back down the oil return tubes. Unless there is a poor leakdown measurement or compression measurement, which I doubt on a rebuild w/3k, I'd just keep an eye on it...... and drive it more (IMG:style_emoticons/default/biggrin.gif)

Well isn't THAT an interesting theory? However, if all the oil drained down the oil return tubes, there wouldn't be any in the valve train area to cause smoking, would there? The smoke comes from oil leaking past the exhaust guides and into the ports, and maybe a little oil sitting in the cylinders, that burns when the engine fires up. Common to most, if not all, horizontal engines. In fact, if a VW or Porsche air cooled engine DOESN'T emit a bit of smoke on startup, there's cause for concern. The longer they sit, the longer they smoke. Loose valve guides and deteriorated valve stem seals (where present) contribute to the severity of the smoking. To answer the next post in line, the oil drains into the crankcase overnight, making your theory equally questionable

The Cap'n

[type47]

Never said ALL the oil drains back. I've read the explaination about 911 engines smoking at start up in several credible sources. Not claiming to be an expert and defer to your explanation.

[J P Stein]

OK, I'll say it. (IMG:style_emoticons/default/biggrin.gif)
If my 2.7L sits un-used for over 2 weeks, ALL the oil drains back into the sump.....except that in the Aux cooler & lines. At oil change I get nearly 10 qts out of the sump if it has sat.
This brings the oil level in the case above the bottom of the cylinders. If the ring gaps line up just right, a bit of oil leaks into the combustion chamber and it puffs on start up. I'm fairly sure it leaks back thru the oil pump....a reverse scavenge. (IMG:style_emoticons/default/dry.gif)
The motor has done this is with 2 different sets of PCs, new guides, yada over 10 years. Compression is currently over 200psi in all holes using cams with a fair amount of overlap.


A word to the wise. If your engine has sat for a week or 2 (or more) disconnect the coil wire and spin it over for 60 seconds or so to at least partially refill the oil tank.
This is sufficient to give oil pressure at start up.

[sixnotfour]

Back in the day this pickup screen replacement , was an upgrade to help with the oil pickup, they have been NLA for awhile , and are now available agian. If you have just a screen, this venturi style screen will help, and It is just plain a better design.
FYI the picture is the bottom view.
Check your dipstick it maybe short.
http://www.fcpgroton.com/product-exec/prod...Screen+(65-83)+

[Nick]

I'll try and answer all the question above even though this seems like normal behavior

Oiltemp @ time of checking Oil level 180 F engine idleing @ 950 rpms

CIS fit by both lowering the engine using spacers & Cutting a notch in the trunk firewall. Maybe yoyu could weld the whole engine mount lower, but that would put it in a place not specifically recommended by the moung manufacturer so I didn't want to risk it

Oil consumption has been 2 quarts in 3K so no issue there. I'm sure about this as I keep a log of every gallon of gas and every oil addition