Smoke and engines??

Alright, I know I should know this, but I don't so I'm asking for a little bit of advice. I swapped in a supposedly good running engine in my cj the other week to help me limp to when I could machine my original engine to what I want it to be. Now then, the new engine has this nack of creating an awesome greyish cloud behind me when it's under load, and with 3.73's and 34's until I get the cash to regearafter putting in a fresh engine the little engine (225) is always under some sort of load. Add to that a nice little knock because the engine is holding 20 lbs of oil pressure at cruising speed and I've found my temporary engine to be far more temporary than what it was billed to be. Is there any way of getting this thing together fairly quickly and back out on the road without the plume of nastiness following me wherever I go?? It might be a little too much to ask, but I'm only in town for the week and need to get this thing back in some sort of running condition before I head back out.

It's got plenty of power, much more than the previous engine, but with the added bonus of smoke everywhere I'm enclined to say no thanks on running it much longer, if any.

anyone have some timely advice??

 

I'm assuming you've already checked the simple stuff. I had a similar problem once on a 60's SBC. Turned out to be gaskets. My first guess would be intake or heads, depending on exactly what shade of "greyish cloud" you had.

More white - probably heads. Check for water in the oil.
More grey - probably intake.
Could also be carb - usually some black soot and rich fuel smell, though.
Knocking could be spark knock - check your timing to see if it's too far advanced and make sure you're not running hot.

Chances are, though, if you're getting a cloud of smoke there are already vacuum leaks contributing multiple symptoms to your problem. If you've got a whole week to spend, pull the heads to check for cracks, then put a full top end set of gaskets on and roll.

Are you Subs or SWO?

 

grey smoke is usually caused from poor/incomplete combustion. The usual culprits are air filter, plugs, etc.

I'd suggest a full tuneup as a first step, but I'm sure the east coasters will wake up soon and offer better advice

 

Welp, the carb and timing are on my list to look at. When I first put the engine in I had zero oil pressure and found the sump loose from the block (remember, this was a running engine...) Now it cranks up at 60 lbs pressure because i threw the 60 lb melling high volume kit spring in the oil pump and gradually drifts t about 10 to 15 lbs at idle and 20 when loaded at cruising speed. I did put new plugs in it when I swapped engines, and the distributor is an HEI unit with all new internals as of about a year and a half ago so it shouldn't "really" need to be looked at. It could very well be a leak, thank you for mentioning that, I'll get the propane out to check that theory later in the day if I can.

Maybe there's another peice of the story I forgot in there. I appreciate the help guys.

edit -- I forgot to mention, smoke smells like it is a fuel problem, but it's got a little bit of an oil smell in it as well...

 

Usually white smoke is water, blue smoke is oil, and black smoke is excess fuel. An engine with worn rings will smoke all the time. If the valve guides are worn, the engine will smoke more on decelleration. What you describe as gray I would expect is more blue, ie oil. Sounds like a tired engine to me. How much oil does the engine use?

You should have a minimum of 10 psi of oil pressure for each 1000 rpm. Some engines, like the 134 (?), can run very low oil pressure at idle and still be alright, but I don't think that's the case with a V6. The 20 psi at cruise would worry me - I would want at least, say, 15-20 psi at hot idle and 35-40 at any speed above that. If you have low pressure due to worn bearings, there's not much you can do short of an overhaul or rebuild, especially of you already hear bad noises.

 

I guess what's so confusing to me is that this engine has more power, alot more power, than my old one had. Yet it has the smoking problem that the other one didn't have. I've got the port for the automatic choke open on the passenger side, and no smoke is coming out of there, so I am assuming that all of the smoke is coming out of the driver's bank??

I guess what I'm trying to figure out is... can the upper end of this motor be good (giving me more power) while the lower end is bad, while on the first engine the upper end was bad (no compression to really speak of) and the lower end was good (50 lbs pressure running down the road). Does that make any sense?? It baffling me to have more power, yet have soo many problems with this stuff.

 

what do the plugs look like? they should indicate what's going on in your cylinders

 

After driving it back home the other night I've basically come to the conclusion that it isn't worth my time to try and get this engine up and running anytime soon. Soo, the heep's getting stored until about November when I can free up some money to get the old engine machined out and rebuilt by the local shop... it sucks to have wasted 300 dollars on an engine that, as advertised should have lasted a good while, but it's another lesson learned. The lesson: sometimes not having the cj running for long periods of time is the quickest way to get it back up and running. Now i'm a good 400 dollars less saved for the machining... BUT I have a core engine for another rebuild somewhere down the line (although a 4.3 is mighty tempting for the next incarnation...)

Thanks for helping me out on the subject though. This is honestly the first engine that's given me this much trouble. Funny thing is, I've pulled four jeeps out of people's back yards with the assumption that the engine was toast only to have them fire right up when the cobwebs were cleaned up. But the engine advertised as good is the one that was not worth my time to fool with. Go figure...