bbc motor smoking

[ssmonte70]

hi, i had a local machine shop build a 540 chevy motor pump gas with merlin aluminum heads, i started the motor and it smokes, did a leak down and leaks down ok, changed the intake gasket and still smokes , any suggestion, thanks

[BEAST477]

Did you run it long enough to seat the rings?

[DirkaDirka]

What color is the smoke?

[ssmonte70]

yes i did run the motor i dont like to drive it because it smokes , and white smoke,

[DirkaDirka]

If I recall right white smoke means it is burning oil.

IMO I would try a compression check to make sure all the cylinders have around the same compression. Doing this would check to see if the rings are sealing correctly and to make sure the head gasket is not leaking it in the cylinder. Like I said that is something I would check.

[ss68nova]

i will try thanks

[FullTimeRacing]

what do you mean it leaks ok, what's the #'s

you may just need to run it some more

are you losing water,is the upper hose getting hard real fast,water in the oil,fuel in the oil?

[chevynovaman]

MY GUESS IS THAT WHITE SMOKE MEANS IS BURNING ANTIFREEZE,, BLUE SMOKE IS OIL....THE BIG BLOCK CHEVYS HAVE THE GEN 4 5 6 AND SOME OF THESE DONT INTERCHANGE... GOOD LUCK...

[OneBadGMC]

Yeah, white smoke is anti-freeze or trans-fluid, not oil.

Blue is oil.

If they used trans fluid to clean the cylinder walls (that's what I use), there could be some left over in it.

If you have a transmission with a failed vacuum modulator and it's plumbed into the intake, that can cause it.

Or, could be a head gasket.

Drain the coolant out and fire it up without the water pump belt on it. You can run it for 5 mins or so (from being room temperature) without worry of over heating. See if it still smokes.

The other thing you can do with it running is to pull off the radiator cap (NOT WHEN IT'S HOT!) and see if it's blowing bubbles in the coolant.

If it blows bubbles, or doesn't smoke without coolant in it, definitely a head gasket.

[DirkaDirka]

Thanks for correcting me on the color of smoke. I alwasy get confused on what color is what.

[cepx111]

X2

White smoke = antifreeze/water - tranny fluid

Blue smoke = oil

Black smoke = fuel (rich)

[CamBirdRacing]

Another thing to think about- if they used oil on the rings to assemble the engine, might be the oil between the rings burning off. I always WD40 the cylinder walls and put the pistons in dry. Never had a problem this way. Just with fram filters.

[ss68nova]

im running water only no antifreeze,trans fluid running to a cooler, did a leak down and all cyl ad 0 percent leak, and its blue smoke not white,i will do a compression test he used total seal rings, thanks

[chevynovaman]

ALSO ONE TIME MY ENGINE WAS SUCKING OIL THROUGH THE VALVE COVER, THROUGH THE PCV VALVE INTO THE CARB.. POSSIBILITIES,, WRONG PISTON WALL CLEARANCE, RING GAPS, VALVE GUIDE CLEARANCE.. OR BEAT THE BAT HELL OUT OF IT AND SEE IF THE RINGS SEAT..... GOOD LUCK...

[JEFF69Z28]

hi, i had a local machine shop build a 540 chevy motor pump gas with merlin aluminum heads, i started the motor and it smokes, did a leak down and leaks down ok, changed the intake gasket and still smokes , any suggestion, thanks
TAKE IT BACK TO THE BUILDER IF YOU JUST GOT IT BACK.

[ssmonte70]

a blown head gasket would the cause to smoke on both sides, and how would fuel get in the oil, to much jetting in the carb, the plugs look good , no water in the oil, the motor only has about 3 hours of running time, but i never seen a new motor smoke like that even if you need to break in the motor, for the rings to seat,

[FullTimeRacing]

post a video

[fla1976]

A blown head gasket would burn oil on the side that was blown. Is it burning on both sides? Were the valve seals replaced? Sometimes the little things get overlooked. The intake could be leaking and pulling oil in from the valley.

[ejm]

im just wondering who actually posted this? ss monte or ss nova? good luck to whom ever it is

[FullTimeRacing]

:shock: :? :? :? :lol: :arrow:

[ssmonte70]

i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,

[DirkaDirka]

i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,

Just wondering shouldnt they have a higher psi than 175?? I would think that since it is a new motor that they would be in the 200 range.

[OneBadGMC]

i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,

It's not something silly, like the rings are on the pistons upside down?

Or low tension oil rings?

Or sucking oil from the intake via a vacuum leak? Are the intake gaskets oil wet at the bottom?

There's a limited number of places you can introduce oil into the cylinder above the piston.

Rings, valve seals, intake gaskets, vacuum line via carb from valve cover (pcv) or transmission...

If it's not sucking trans fluid via a vacuum line from the trans to the carb, and the intake gaskets aren't wet at the bottom, and it has new valve seals (which I don't run any and my junk don't smoke), then the only other way I can think of would be the rings installed upside down.

[DirkaDirka]

i did a compression test and all cyl have 175, new valve seals new motor, changed intake gasket, put new mufflers, still smokes,

It's not something silly, like the rings are on the pistons upside down?

Or low tension oil rings?

Or sucking oil from the intake via a vacuum leak? Are the intake gaskets oil wet at the bottom?

There's a limited number of places you can introduce oil into the cylinder above the piston.

Rings, valve seals, intake gaskets, vacuum line via carb from valve cover (pcv) or transmission...

If it's not sucking trans fluid via a vacuum line from the trans to the carb, and the intake gaskets aren't wet at the bottom, and it has new valve seals (which I don't run any and my junk don't smoke), then the only other way I can think of would be the rings installed upside down.

I didnt even know you could put rings on upside down. I thought they could go any way. I learned something today. :lol: :lol:

[fla1976]

Have you tried draining the fuel system? Maybe there is oil in the fuel. Outside of the things ONEBADGMC stated there isn't anything left. I'm inclined to belive the rings are upside down. Are all the plugs showing signs of oil or just a few?

[OneBadGMC]

I didnt even know you could put rings on upside down. I thought they could go any way. I learned something today. :lol: :lol:

http://www.totalseal.com/TechPage.aspx#trGaplessPistRings

There's a picture about mid way down on that page showing the different ring designs and the direction they are to be installed in the bore.

[DirkaDirka]

Thanks for that site. I learned even more. It was very informative for me.

[ssmonte70]

no oil in the fuel, drain the oil and there was a little fuel in the oil,i dont believe with 0 leak down and 175 compression that the rings are in upside down on both sides,10.5 pump gas motor, is it possible that the carb may be to big, 1095 king demon , thanks

[OneBadGMC]

no oil in the fuel, drain the oil and there was a little fuel in the oil,i dont believe with 0 leak down and 175 compression that the rings are in upside down on both sides,10.5 pump gas motor, is it possible that the carb may be to big, 1095 king demon , thanks

Well there's the other issue, which sounds like you hit on it...

Anytime there's enough gasoline to see it in the oil the carb is washing the cylinders dry and it's not sealing properly.

No offense, but I find it hard to believe it's 0% leakdown. A really good motor is going to leak 6-8% when hot. If you can get a cold leak of 10-12%, the rings should be fine.

If the carb is washing the cylinders down though, it's gonna smoke.

Doubt the carb is too big for it to idle. Lean out the idle mixture screws and see if it stops smoking.

[kwkracing]

Yea, i dont care who you are, your not going to get a engine to have zero leak down. What does your engine builder you got it from say?

[ssmonte70]

the engine builder is telling me to put more time on the motor go beat the crap out to seat the rings if that does not work bring the motor back and he will figure out what the problem is,

[Tod74]

the engine builder is telling me to put more time on the motor go beat the crap out to seat the rings if that does not work bring the motor back and he will figure out what the problem is,


That's what I'd do.

[cepx111]

Just a comparrison:

We stuck a fairly new motor in the boy's mustang and it was smoking and using a bit of oil.

The motor was supposedly fresh when we bought it (less than 500 miles), we did what your engine builder recomended.

The only alternative we had was to yank it and do a rebuild or run the piss out of it, we choose the ladder and it has all but quit smoking and using oil.
Sometimes moly rings take a bit to seat up anyway, this process can be aggravated by an incorrect hone job from the machine shop, a moly ring likes a smoother final hone where as a cast ring likes a rougher one." I think" not real sure but a good machine shop should know the difference, ask them to be sure, anyway mismatch the 2 and you have a recipe for a oil burner.

Sometimes they will go ahead and seal up, sometimes they won't.

I've also heard that pouring alittle tranny fluid down the carb while runnig will help the rings seat up too, I dont know about that one either, maybe just snake oil.


JMO, Cp

[OneBadGMC]

If the motor has moly rings, more than likely they seated while the valves were being set.

You didn't do anything silly like put synthetic oil in the new motor? Synthetic oil will keep rings from seating.

[MEMRACING62]

have you removed a couple of valve springs and check the seals for damage

[ssmonte70]

using 20-50 oil changed to 50, still the same, check the valve seals and they are ok, going to take the car out this weekend and put some miles, see what happens, and wj can you tell me which way to set the idle mixture screws, not sure which way to go thanks for all the help

[BEAST477]

MY GUESS IS THAT WHITE SMOKE MEANS IS BURNING ANTIFREEZE,, BLUE SMOKE IS OIL....THE BIG BLOCK CHEVYS HAVE THE GEN 4 5 6 AND SOME OF THESE DONT INTERCHANGE... GOOD LUCK...

What series block: MarkIV,Gen5,Gen6? and what heads? Some don't mix well without the right head gaskets. Just a thought.

[Scooterz]

using 20-50 oil changed to 50, still the same, check the valve seals and they are ok, going to take the car out this weekend and put some miles, see what happens, and wj can you tell me which way to set the idle mixture screws, not sure which way to go thanks for all the help

Hemi has a point... bad valve guides can cause copious amounts of blue smoke... had that problem once.

On the carb: Turn them all the way in until it is seated, then turn them back out, one at a time in 180 degree increments, & do 3 180's.. or 1 & half turns out on all for starters. Then lean/rich from there one corner, one metering block at a time. I like to use a vacuum gauge when doing this for better accuracy. Take it one adjustment at a time & note the result. I believe in (clockwise) is lean, out is rich (someone correct me if I have this backwards).

Next: what oil pressure do you have at opt temp? opt Idle?/ or WOT?

Is there any kind of PCV system on this motor? If so, how is it set up?

Do you have BLUE smoke @ idle or when under load/RPM? Both?

I think 175PSI sounds normal to me... @ about 10.5CR... mine is about 165 to 168 @ 10.2....

[ssmonte70]

oil psi 60, no pcv system on the car, blue smoke @idle under a load less it clears up not as bad, thanks

[OneBadGMC]

Pull a plug out and eyeball it.

If it's just black and wet it's fat.

If it's black, wet, and looks like it has burnt oil gummed all over it, it's burning a LOT of oil. Burnt oil will look like a burnt pork steak.

[BEAST477]

Oops, just reread the post. Smoke changed from white to blue.

[OneBadGMC]

Oops, just reread the post. Smoke changed from white to blue.

Well, now that you mention it, lol... It's gonna be kinda really rare to see a pair of blown head gaskets on a new motor, assuming the builder used the right gaskets to begin with.

Who knows... Maybe it is.

[DirkaDirka]

Oops, just reread the post. Smoke changed from white to blue.

Well, now that you mention it, lol... It's gonna be kinda really rare to see a pair of blown head gaskets on a new motor, assuming the builder used the right gaskets to begin with.

Who knows... Maybe it is.

Welcome back guys! The smoke changed from white to blue on the first page of this thread. :lol: :lol: :lol:

[Scooterz]

OBGMC:

No synthetic oil on break-in w/ moly ring's.... good to know, did not know that.

I was told that break-in on Moly Ring's should be gentle for seating purpose's.... is that not true??? Just go out & run the crap out of it??

[OneBadGMC]

OBGMC:

No synthetic oil on break-in w/ moly ring's.... good to know, did not know that.

I was told that break-in on Moly Ring's should be gentle for seating purpose's.... is that not true??? Just go out & run the crap out of it??

I break mine in at the water box at about 6-7k. :shock: :lol:

[fla1976]

Years ago , the rings were not as good and it took time to break them in.
With the newer moly rings, I break it in like its going to be run. The rings seat quickly and the rest of the engine doesn't need any breakin if you run a roller cam. Flat tappets need a breakin by keeping the rpms up to prevent flattening a lobe. (Unless that has changed).

[chevynovaman]

If the smoke does not clear up, and its not black smoke,, you should probly tear the motor down and check it, because something might not be right with the clearances and could cause some high dollar damage.. i hope it clears up, good luck...

[kwkracing]

If the smoke dont go away, Get MR. Machine Shop that built it to pay for it Or FIXXX it!!!