VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 blue smoke with rebuilt 228 straight six.

I have a 1953 gmc pickup with a 228 straigt six. Rebuilt motor new carb new exhaust new cap and rotors with new points, condencer, old distributer though. It's blowing out blue smoke with oil at the exhaust pipe tip not dripping. Could the carb be jetted wrong, I'm at 6500 feet possibly to much gas not enough gas. Need to poure some down the carb to start. Could the distributer be bad. Timing is good any tips would be great. New to the site. Thanks Scotty.

Hi scotty,

If it was a carburetor issue, the smoke would be black from too rich a fuel mixture and black looking water dripping is quite normal when the engine has yet to warm up.

Blue smoke however indicates engine oil blow-by and/or valve guide problems.
If blue - hook up a vacuum gauge to the wiper hose port on the intake manifold.
If blow-by - the reading will drop to zero and return to normal (a steady 16-21) with a quick pull and release of the throttle.
If healthy, the gauge would drop to about 2-3 and return to normal.

If the motor was recently rebuilt, the valves may not have seated yet. Run her at 2000 rpm if that's the case. (make sure you have enough oil and good oil pressure). The smoke should clear if it's a new rebuild. Don't idle excessively until broken in.

Mine did too until she was broken in. There are good how-tos on the net for breaking in a new/rebuilt motor.
Hope this is helpful.

ya, the motor was just recently rebuilt probably only have 20 miles on it. i'll have to give these tips a try and see what she does. I still don't understand why I need to put fuel down the carb to get it to start. it does have a chocke and wants to start the first crank but after that it just keeps turning over but no bang until I fuel the carb. Also when I try to advance or retard the distributer at idle there is no change in the rpm's???

Yeah it sounds like you need to break her in. Drive her easy for the first 500 miles, but vary your speed and NO extended idling.
Your vacumn advance may not be working on your distributor and sounds like you may have carb issues (accelerator pump??). Did you rebuild the carb? If not now sounds like a good time.
Good luck.

Think the valves where "set" the moment the machine shop handed you the head and you paid the bill....grin

Even @ 6500 ft, I don't think your carb jetting's an issue...but Gene will let us know...

At the risk of repeating some basic stuff: Before starting, look down the carb throat to make sure you see gas squirting out when you move the throttle. If it doesn't you have a carb problem as noted earlier, or fuel feed is gummed up. Old gas will really hurt your fresh engine.
When the engine is running and you rev it even a little the distributor should rotate. If not, your vacuum advance needs to be replaced (the diaphragms go bad and leak).
You can adjust the timing also with the octane selector. This allows you to make adjustments and get back to a known setting. I am assuming that your 228 is similar to a 235.

I think it's similar with minor differences 228 to the 235. Everything is new or has been cleaned out. I had the fuel tank dipped and cleaned, new fuel lines, new vacuum advance, new carb. maybe I just need to break it in a little longer but i'm afraid to run it if its getting to much fuel and coating the cylinder walls, and getting into the oil. maybe change the oil and put more break in additive.

I don't know what plug you are running, but a hotter plug is called for.

You also need to do a bit more driving, changing speeds as you go, until the rings are well seated.

You're getting a lot of answers here ..... have not read where the fuel pump is known to be a good one or a new one. "New" does not always = "good", always keep that in mind. Check fuel pump pressure, should be near 3 1/2 punds pressure. No pressure = no fuel.

That's a good question, I'll have to see how pounds of pressure that fuel pump is pushing. This is great thank you for the tips we got some memorial day snow so once it worms up a bit right back out side.

The fuel pump advice is good. The diaphram could be ruptured and taking oil from the pan. Also if the fuel pump is a dual diaphram pump (vacumn assist) then check the vacumn pump side, if there is oil visible then there is for sure a leaking diaphram.

Generally, blue smokes means oil and black smoke means fuel.

If everything else checks out all right, then what I would do is the following:

Hook it up to a with a trailer load of hogs, furniture, or dirt. Whatever. If I couldn't hook up a trailer then I'd load the sucker up with cement blocks. If I was in Tennessee I'd just make a run. Make the springs squat. Accomplish something worthwhile whilst burning all that gas up and down the mountain. You know.

I'd drive it at about 55-60 mph for about fifty miles round trip. (It's not the speed but the load that counts most here.) I'd make sure the temperature gauge gets up at or above 190. It will. Count on it.

As long as there is water in the block and head you're not going to hurt anything. Then upon arriving back home I'd just let it set and cool down on its own. I'd not start it until the next day. Just let it peculate and cool down slowly. I'd check the water level before cranking it up the next day.

The rings will most likely have become seated and there'll be no more blue smoke. I hope you used regular steel rings. They seat quicker.

Make sure you have at least a 180 degree thermostat. Reasonable heat is your friend when breaking in a new rebuild/overhaul.

Charlie

BTW: If, whilst on the run, the revenuers show up, take the short cut. I'd have CD of "Dueling Banjos", Fire on the Mountain", "Cripple Creak", "Orange Blossom Special", or something similar a-playing. Help to keep one focused and better able to ignore the distracting blue light and annoying sirens.

I found the problem! Went to remove the valve cover to retorque the head and found the two bolts that hold the coil bracket in place on the pass side of the head block were to long and bent two of the push rods. It was only running on 4 cylinders not 6. I will be checking lifters to make sure there ok, hope the cam is fine... Fingers crossed!

Did you bother to re-torque the head...?

Not yet, need to though. Don't have new push rods yet and also want to do an inspection on the lifters and try to get a mirror and light for the cam.

Bent push rods will not make it puff blue smoke.That is still an oil issue.You will be down on power with the push rods bent.Does it only puff when you first start it?If so that would indicate valve seals leaking.Did your engine builder check the ring end gaps before assembling the engine?As far as the vacuum advance diaphragm goes,get a hand held manual vacuum pump and connect it to the advance unit and give it a few pumps.With the distributor cap off,you should see the breaker plate start to move when you pump it.If it doesn't move the diaphragm is probably bad.Also,I would recommend doing a compression test on all cylinders after you install the new push rods,just to verify none of the push rod adjustments are too tight.

Mike's got a point about the blue smoke...And I'll bet up in the Tahoe Basin ya might kinda get some frowns from other motorists...

Don't see much use in checking the lifters or the cam...Don't think you'd a done any damage there...possibly a bent valve or two but probably not...

I, myself would replace the push-rods and let it go at that...
Good Luck...Kevin

BTW : A compression/leak down test should determine your blue smoke problem...Don't Forget to Keep Tahoe Blue...grin

Got to keep Table blue! I will do further test and let all of you now what is the cause hopefully nothing major. Were going to see some snow and rain the next couple of days so the truck will be on hold till it clears.
Thanks again for all the good advise!
Scotty

Depending on what kind of rings were installed it may take a few thousand miles to break-in the rings, I wouldn't worry about it at this time.