rodan

Hi everyone finally got my 350 started today. It's a fresh rebuild , flat top pistons,a sizeable cam ,#7 heads reworked with oversized valves roller tip rockers ,rpm performer intake & 750 com Demond carb and a pertronixs flame thrower HEI distributor.Runs like a champ sounds great . Primed it with Amsoil break in oil 10w30 ran it for 40 minutes but it's blowing blue smoke fairly heavy.The only vac I have hooked up is for the distributor? Any ideas of what it could be??? Stumped!

oldcutlass

It may have had some contamination in the exhaust system, take it for a drive and see if it burns out.

MDchanic

Yup. Probably just burning off oil that got into the exhaust system. It won't get hot enough to burn it off until you drive it.

- Eric

rodan

It ran for 40 minutes and seemed to get progressively worse . The exhaust is new ,but I used it with the old motor for about a week before I did the rebuild

MDchanic

I don't know what to tell you. Usually smoke after a proper rebuild is because oil or water got into some place in the exhaust that doesn't get hot enough to burn it off unless you're driving for a while.

I ASSume you've checked your plugs and that they are all clean. That much smoke at idle would show up on the plugs very quickly if the oil were in the cylinders.

- Eric

oldcutlass

I wouldn't use synthetic oil until you have a few thousand miles on it. As Eric stated above, it's not unusual for water and oil to get in the exhaust system. If nothing really abnormal is indicating a problem, take it for a drive.

rodan

Drained the Amsoil break in oil an put in 10w30 conventional oil and a bottle of zinc additive. Ran it for 20 minutes at around 2200 rpm and she still smokin

stan 65 cutlass

sounds like the rings havnt seated???? was the hone done correctly???

my 2 cents

steverw

Is your vac connected to the tranny modulator? could be a bad modulator and is sucking tranny fluid straight into the intake.

rodan

Built by a professional he's helping me out and he's baffled as well. Tranny vac is not hooked up yet so that's not it. I think he wants to do a compression test or I think he said a flow by test? I donno . I'll keep you guys posted. Thanks for the suggestions.

captjim

Is the PCV valve connected?

oldcutlass

The question that Captjim is alluding to is the engine sucking oil through the PCV valve.

bccan

Following the possibilty of PCV pulling oil, are the baffles in your valve covers present/intact? Intake leak in valley? Valve seals in place? i know that's a longshot, just hoping it's something simple in the upper end.

One of Sugar Bear's ideas from below. As soon as I have checked leaks, broken in the cam (if not a roller) & checked linkages etc, I take it out in low gear & do a series acceleration/deceleration cycles to ensure proper ring seating. 1/4 throttle accel & let it decelerate, 1/2 throttle accel & decel a few times just keeping the car in low gear, regularly checking gauges. If all is well, 3/4 throttle then decel a couple of times. Back to the garage for cool down, retorque exhaust & intake, check accessories etc. After that do whatever tweaks, MAW's, adjustments and if all is good, it's good to go & should be ready for just about anything. Oil & filter @ whatever stage is appropriate, I don't even change the oil in roller cam cars. I do like filtermags on every engine especially during break in.

Sugar Bear

What was done during the rebuild? Was it bored? If not were the cylinder walls deglazed? Are any of the plugs oil fouled? Single or dual exhaust? Smoking from one pipe or both? Has it been on the road yet and have the rings been seated through cycles of acceleration/deceleration? Can you find out what valve seals were used? Is the tailpipe(s) wet with oil?

Good luck!

captjim

Here is a nice read on the PCV system, if anyone is interested,
http://www.agcoauto.com/content/news/p2_articleid/197

rodan

Well guys we just did a compression test turns out the darn rings didn't seat so we're pulling it out going to rehone the block and rering the pistons. Hopefully get er dun by this Sunday ! Wish me luck!

Thanks guys

Sugar Bear

Have you tried seating the rings by warming up the engine and then accelerating at full throttle up to about 50 mph and then letting the engine coast back to 20 mph ten times? I would try this before pulling it apart. What were the compression readings and were the cylinders honed/deglazed?

rustyroger

Thanks Jim. I learned a little more today.


Roger.