Smokin' in the boys' room and a holy filter...

[sparkydave]

Okay, maybe not in the boys' room, but in the valve cover. Went for a spin yesterday, and engine temp is normal (about 180), but I noticed that when I took the oil cap off, I could see some smoke wafting out. Anybody else experiencing this? I guess I haven't seen a car do that before.

On a completely unrelated note, I have a Longflo air filter (eBay surplus that came attached to a spare carb), and I just noticed that there are two holes in the back plate which are inboard of the foam element . They look like they were intended to be there, but what good are they if they bypass the foam?

 

[tosoutherncars]

Smoke, or vapour? If it's water vapour, it could either be the signs of a little bit of condensate from winter storage, or a head gasket going south...

(And yes, the holes sound like they need to be plugged!)

-D

 

[DrEntropy]

The holes are likely for a crankcase breather application, meant to be either routed there or plugged if not used. Usually when new, the plugs are included with the filter..

 

[Morris]

I have seen smoke from worn out engines plenty of times. But, didn't you just rebuild yours?

I have heard that the 1500 Midget can have serious oil cooling problems, and I have experienced it myself... except the issue was primarily caused by mistakes made in my fuel injection experiment. (live and learn) If you are cooking your oil by running too lean or overly advancing your spark, it could make things smoke.

Another thing about the 1500 is the exhaust runs awfully close to the oil pan. If it is an oil cooling issue, some exhaust wrap could help the problem.

 

[sparkydave]

I haven't done a rebuild; the engine only has 30,000 miles. Seems to run fine, oil pressure is good (usually around 25-30 PSI at idle, 60-70 PSI at speed). I hadn't considered an oil cooler, although I see Moss has one that doesn't look like too much of an undertaking to install.

Since you mention too much advance being a source of overheating, would it be cooler at high speeds if I plugged the vacuum advance, or would that cause other problems? The vacuum and centrifugal advance seem to be giving the right amount by the book. Not sure about the lean running; if anything it's running rich. Just ask anybody who comes up behind me ;-).

 

[middleagecrazy]

Sounds like a crank case ventilation issue to me. If the evauation system is not functioning it will cause excess pressure in the crankcase that will generate heat. That would also cause smoke to rise from the filler cap when removed. If the ventilation is right there shouldn't be any smoke with the engine running. It should be pulling it through the intake and out the tail pipe. Any time that the engine is hot and then shut off there will be a slight bit of fumes come out of the filler cap when it is removed. Thats just oil on hot parts. Kind of like oil in a skillet. It will produce smoke.

 

[Billm]

And don't disconnect the vac-advance, then you are at speed there is little vacuum in the manifold and it doesn't really do much, with high vacuum at idle is where it has a lot of effect.
Bill

 

[sparkydave]

Bill, the vacuum advance comes into play at speed, not at idle. Unless my vacuum gauge is lying to me. I would plug the line from the carb if I did, since any vacuum leak is a bad thing.

 

[Morris]

The vacuum advance does not work at idle but kicks in at about 1/8 throttle. However, at speed, engine vacuum is low, so there is little if any vacuum advance.

 

[wolfman]

For a 77 1500, isn't that a vacuum retard unit, not advance?