Engine smoking...and I don't know why
 

Hey all-

Need a little help on this one. '31 SW, stock engine. Did a few things to the engine today (exhaust manifold w/gasket, cap/rotor) and double checked the timing. She starts right up and seems to run pretty smooth (much quieter as well with the new manifold gasket!). The timing appears to be about 0 deg. at idle with the lever all of the way up - about 2/3 down and I'm 20+ degrees advanced - so I'm pretty sure I could get 30+ degrees if I wanted to. All verified by timing light.

The problem is that the darn thing has started smoking quite a bit. It's a blue-ish smoke, like she's running way too rich - or burning a little oil. GAV setting about 1/4 to 1/2 open with the engine warmed up. Doesn't seem to matter what I tweak or fiddle with, the smoke won't go away completely.

I don't remember it doing this the last time we went for a drive, so I'm puzzled.

I don't really want to tear things completely apart, but I guess I will if I have to. If you need further information, ask away.

Thanks in advance for any insight.

Re: Engine smoking...and I don't know why
 

White smoke is water steam

Bluish is oil burning

Black is too rich

Anything done or changed just before the smoke started?

Re: Engine smoking...and I don't know why
 

First off let's see iF the GAV is working. When the engine is warm can you turn it in enough to make the engine run rough and then turn it out enough to make the engine run rough and then find a sweet spot somewhere in between? A GAV can be physically closed too tight where the tip gets a ridge or groove cut into it and it no longer will work properly and goes from being totally shut to letting too much gas past and results in a rich mixture.

Smoking may also be from a too high oil level in the sump. Oil level ok?

Re: Engine smoking...and I don't know why
 

Well, it's not black - so we can rule that out

Not losing any water level, and it doesn't appear white (seen that before on a different car) - so I'm pretty sure we're not talking about coolant.

Which leaves burning oil - blue-ish in hue. And frankly smells like it as well.

And no, other that setting the timing and an entire new exhaust system, nothing has been done in recent history.

Rings? Valves? Genie looking for it's freedom?

Re: Engine smoking...and I don't know why
 

how about a compression test before we go any further

have you been running MMO in the gas as upper cyl lube? Could be a stuck ring

Re: Engine smoking...and I don't know why
 

GAV fully closed and she roughs up a bit.

As I open up the GAV, she smooths out at about 1/4-1/2 turn, but I can keep opening it up w/o having any impact on how the engine is running. 5 turns open and she still purrs. Thought that was a little odd.

Re: Engine smoking...and I don't know why
 

Don't have a compression tester, so that will take a little time to procure and perform.

However, I agree that it would be prudent.

And oil level is fine - not overfilled. Just triple checked it and level is just below the "F" on the stick.

Re: Engine smoking...and I don't know why
 

Ck oil level and run it. "entire new exhaust system", it may just be the "newness" burning off. JMO
Paul in CT

Re: Engine smoking...and I don't know why
 

I had that thought as well, but I have run the engine for some time and would have a hard time believing that this is still the "newness" burning off the exhaust system.

A little at first I could buy. But this goes beyond what I would consider burn-in.

Re: Engine smoking...and I don't know why
 

Have not run any MMO as of yet. I've only had the rig for just under a month, and only filled the tank once during that time (non-ethanol btw).

Was seriously considering running some MMO or Seafoam - have had good results in the past with other rigs.

Re: Engine smoking...and I don't know why
 

I just guessing you may have disturbed some carbon in the ports that has gone in to the cylinder
pull the spark plugs and do a leak down

Re: Engine smoking...and I don't know why
 

Further info:

Aries exhaust is a couple weeks old - so it's well "burned in". Only did the manifold with gasket today, as it was discovered to be toast when the Aries was installed.

Re: Engine smoking...and I don't know why
 

my guess is either a stuck or broken rings, wont be able to tell till you do a compression test, a compression tester can be your best friend when trying to find engine problems, buy or borrow one

Re: Engine smoking...and I don't know why
 

Years ago, a good friend complained about his engine smoking, but it turned out that a previous owner had replaced the vacuum fitting in his intake manifold with a grease fitting and he had been pumping grease into it whenever he greased the chassis.

Re: Engine smoking...and I don't know why
 

If you have an air filter on it take it off and see what happens. Some cars don't seem to like them.

Re: Engine smoking...and I don't know why
 

Check the crankcase/oil filler tube any kind of restriction will cause back pressure in the crankcase and oil burning.

A oil change refill is 4 qt's, 5 only after a totally dry rebuilt engine.

just my WAG at the problem.
JB

Re: Engine smoking...and I don't know why
 

Pull the spark plugs to see what they look like and if any one in particular is different than the rest.

Re: Engine smoking...and I don't know why
 

Any chance the manifold had some oil residue in it?

Re: Engine smoking...and I don't know why
 

- No air filter

- Plugs look reasonable - nothing way out of the ordinary - and they all look essentially the same.

- No obvious restriction in the oil fill tube

- New manifold did have some (machining?) oil on it, but with as much as I ran the engine today, all of that film had to have burned off by now.

- And last but not least, I am absolutely certain that I'm not greasing the intake.

Re: Engine smoking...and I don't know why
 

Were you driving the car or just running the engine?

Re: Engine smoking...and I don't know why
 

we'll all be guessing until we get some readings

Re: Engine smoking...and I don't know why
 

Art - Just running the engine here at the house - didn't go anywhere.

I'll get a compression test done (won't be til next weekend), and update with that information.

Re: Engine smoking...and I don't know why
 

Now we'll have to add grease to the MMO and SeaFoam debate. :D

Re: Engine smoking...and I don't know why
 

I think I'd get it out and drive it a bit, probably can't really get it very hot just sitting there running. Since it was OK before the exhaust system install, seems to me to be pretty unlikely that anything major in the engine "all of a sudden" broke. Compression testing won't be able to check for bad oil rings... will it?:confused: I had a thought that maybe oil it collecting in the valve chamber and under high vacuum conditions (like idle) it's drawing some oil through the valve guides? Heck I don't even know if a flat-head can do that! Don't you just hate "arm-chair" quarterbacks? I've heard some rumors if you put straight MMO in every orifice (on the car, not anywhere else:eek:) and grease the intake manifold, probably that mystic red stuff, that it will fix everything!:)

Re: Engine smoking...and I don't know why
 

In high school I installed a dual exhaust on my 56 Chevy 265. All new pipes and glass packs were used. On my first drive it smoked like crazy for a couple of miles.
Hugh

Re: Engine smoking...and I don't know why
 

to answer the person wondering how a compression test affects oil rings,
if the test shows low readings dry, and the numbers don't increase wet, then the valves are leaking. If the numbers get better wet, then the rings are worn. If the compression rings are worn, it is a sure bet the oil rings are worn, too.

I am gonna bet one cylinder gets better when wet......probably #4

A leakdown test would not hurt either

Re: Engine smoking...and I don't know why
 

I would go for a good drive, that is the only sure way to get things cleaned out.

Re: Engine smoking...and I don't know why
 

Curious....my 30 has developed the very same affliction. I know it's been a while, but what did you find out ?

Dave Eddie

Re: Engine smoking...and I don't know why
 

Are we sure it was put together right. After working on some of the A,s I found out some guys can do anything wrong. Maybe it has a scraper ring on the number two groove up side down. Then it would scrape the oil up instead of down.

Re: Engine smoking...and I don't know why
 

Unbelievable some of the shit ya see...you gotta work on these cars with blinders or you'll never finish fixin all the botch work, it keeps snowballing ..

Re: Engine smoking...and I don't know why
 

Without any test results, we're shooting in the dark but here's my wild guess at this early stage.
Do you have one or three piece oil rings? The one piece ones are as useful as fly screens on a submarine.
If you have the 3 piece ones, the scrapers have an up and a down side. Install them up side down and they won't work so well yet I've never seen this mentioned with any of the sets I have installed over the years.
Is there any chance something has found its way into a cylinder and scored the bore?

Re: Engine smoking...and I don't know why
 

Also ,maybe the guides are loose in the block,mine were.
Lawrie

Re: Engine smoking...and I don't know why
 

Hey all-

Wanted to chime in and thank everyone for their thoughts and suggestions.

I've been out of town for work, so I haven't had the opportunity to perform a compression test or a leak-down test - though I now have both of those little goodies sitting on the bench.

If I get lucky, perhaps tomorrow or at some point this weekend I can get some testing done and post the results.

Thanks again!

Bob

Re: Engine smoking...and I don't know why
 

Try MMO in crankcase and put some in a spray bottle and with the car running spray into carb, with car running. You could have a sticky oil ring. What the heck this can not do any damage and it worked for me on my Friends Packard Eight that was not run for ten years, in that case we put a full bottle in the crankcase and drove the car for ten + or - miles and it worked. :D

Re: Engine smoking...and I don't know why
 

OK - finally a bit of additional info:

Ran downtown today to grab a burger and pick-up a few things at the store, and she didn't seem to exhibit the smoking that I had observed before. Perhaps it was just some gunk in the works from the new exhaust system that I needed to burn out.

Upon returning home, I did a compression test and came up with the following:

60, 60, 58, 60 (warm engine, dry, throttle wide open, sea level, 8-10 revolutions)

Not great (I think), but at least consistent. I was going to perform a leak-down test as well, but I'm in need of one air hose fitting for my compressor, so that'll have to wait for another day.

I do have another question, kind of in the same vein. When I rev the engine up, think revving in second to get to third, there's a notable knock that develops. It only occurs at higher RPM's - but you can "feel" it as well as hear it, and adjusting the spark advance doesn't seem to make a difference. My first thought was perhaps I needed to check the clearance on the main bearings, especially since I have no history on this engine. Hell, maybe I should just take the damn thing out and go for the full rebuild. At least then I would know what I'm dealing with.

As always, your thoughts and input is greatly appreciated.

Bob

Re: Engine smoking...and I don't know why
 

those are very respectable compression readings; leave it alone.

If the motor is an unknown to you, and you have a knock as you describe, I would drop the pan and inspect/adjust the bearings. Not all that hard to do, mostly time-consuming

Re: Engine smoking...and I don't know why
 

Yep, and check the center main first because that's the one that usually goes first. My 29 Tudor sounded great at the swap meet, but after I bought it and drove it past 15 MPH, a deep knock started and it could also be felt and heard. My center babbit was completely gone.

If you need to do a rebuild, be sure to add counterweights to the crank.

Re: Engine smoking...and I don't know why
 

Ditto the counterweights and if the budget runs to it, put in inserts then, so long as you don't flog it, it'll outlast you ( a brave statement I know coz I don't know your age.:D)

Re: Engine smoking...and I don't know why
 

Is your knock a low thud noise or is it more like metal on metal pinging sound? I'm just wondering if you are having an intermittent sticking valve. It could affect compression and give you some blowby from the cylinder. It would probably cause the exhaust to miss intermittently as well.