I recently finished the rebuild of my 428. I have taken it easy for the first 200 miles or so. I finally decided to get on the skinny pedal and see what she could do.

When I hit the higher rpm about 4000 I made a huge cloud of blue smoke. I pulled over to find that she must have blown oil from the dipstick tube, which hit the headers making the smoke. Nothing else was wet under the truck besides the tube and the firewall area behind the tube.

I spaced the rings properly, along with the break-in procedure. I also have the proper PCV ventilation systems and everything is clear on that end.

I will run a compression test in the next few days when I get some time after work.

Any ideas to why this may be happening???

thanks
Nick

 

If you built enough pressure in the crankcase to blow oil out the dip stick tube, then obviously your PVC System is not working right or more likely at all.

 

I purchased a set ford racing chrome valve covers. The passenger side has a new PCV valve.While the drivers side just has the breather that came with the valve covers. Both are routed into the air cleaner.

 

the pcv valve should be hooked up to vac. source,base of carb or vac. tree. If it is hooked up to the air cleaner it is not working at all.

 

The PCV System will not work with the PCV valve routed to the air cleaner. The valve side need to go to the intake manifold below the carb, so there will be manifold vacuum on the system. That's why you are building pressure in the crankcase.

 

hmmm looks like I had a brain fart.....we will have to change that.

 

I fixed the PCV issue I have had truck out a couple if times. Between working and all this rain I haven't had much time to drive it, or work on it.

I'm still having this issue and I took a compression test. I have an average of 173 PSI across 7 of the cylinders. While the lowest being 140PSI.

All my plugs look very clean, like the engine has never been fired. I only have roughly 250 miles on the motor.

I would assume part of the excessive pressure would be from that one cylinder? Any ideas?

 

Even though you've re-routed the PCV system, it's still likely your problem if oil is being forced out the dipstick tube. Even if all your cylinders were at 140, that should still be good enough to prevent excessive blowby that could over-power a properly functioning PCV system. Double check your PCV valve is functioning properly and that the hose from it to the intake manifold is a decent size diameter, not a little vacuum line.

Another sign of excessive blowby is oil coming back out the breather on the other valve cover. As yours has a hose going to the air-cleaner, look inside the air-cleaner and see if there's a lot of oil near the hose connection. Sometimes it looks like yellow goo (a sign the PCV isn't working very well).

On the low cylinder, it could be a valve issue....sticking valve, stuck lifter, bad lash, etc. during the test and isn't a problem when the engine is hot and running. Also, make sure the throttle is floored (butterflies wide open) when doing a cranking test.

To determine how bad that cylinder really is, you should perform a leak-down test. Not owning a leak-down tester, you can still make a quick and dirty tester. All you need is a spark-plug/air-hose adapter. I made my own by welding an air-line fitting to a sparkplug shell that I knocked the porcelain out of.

Lock the engine with the piston up on the compression stroke (easy with a manual transmission...with an automatic you may have to put a breaker bar on the crankshaft end and brace it somehow). Connect air-pressure to the cylinder. Set your air-compressor regulator to limit the pressure. I use 60 psi, but you can go higher. (Commercial guages usually work with 100 psi and have a guage calibrated in percent air loss on the cylinder side of a precision air orifice).

Apply air pressure at 60, or thereabouts, then shut off the valve on the air-compressor tank and watch the guage start to drop. Measure the time it takes to drop from say 50 to 10 psi. Now check a few more cylinders the same way. If your 140 psi cylinder is significantly lower than the others, it may be likely you do have a serious blowby condition.

During a leak-down test, if the pressure is dropping faster in one cylinder, listen at the exhaust and down the carb to see if it's valves. If you hear air, but arn't sure if it's normal or not, just listen to a few other cylinders for comparison purposes.

Just so you know how valuable a leak-down test can be, I broke a piston land, second ring and oil ring on one cylinder due to detonation once. The top ring was intact. A cranking test showed no difference between cylinders. The leak down test showed the bad cylinder leaked down in 1/2 the time of the good ones.

On a more encouraging note, After my last re-build, everything was fine, but I forgot to get a good cap for an unused nipple on my oil pan (nipple was for an optional crankcase vacuum system). I had one of those little red plastic plug caps stuck in the end of it. A snug, but not tight fit. It lasted about 5 miles on my test drive before it popped out and oil sprayed on the headers and it looked like a giant wet-brush fire....clouds of smoke. And that was under spirited accleration,....same as you. So could it be your dipstick is very loose in the dipstick tube?

By the way, the clouds of smoke I got were gray/white.....blue smoke is usually from oil being burnt in the cylinders, and that comes out your tail-pipe.

 

This smoke is a blue/gray but I can defiantly tell because its pushing the dipstick out and spraying the firewall and drivers floor board with oil.

I do have a smaller line running to my PCV I can use some larger sizes, and see how that helps.

I also cannot hear any valve issues but I can defiantly check that out by pulling the valve covers.

I may just have to finally pick up one of those leak down testers from HF. Since I walk by them daily at work.

Thanks for the help

Nick