401 oil smoke on hard braking

[HuntzNSam]

Our stock 60 Invicta 401 is running great.  We are driving it regularly - no rain, we'll drive it. Doesn't smoke on start up, cruising, or acceleration, and is not using oil (10w40 conventional) abnormally. 

 

The other day, the light turned yellow at just the wrong spot, and we used firm braking from 50MPH - not 1g, not locking wheels, just firm - and were surrounded by a cloud of blue oil smoke from the tailpipe.  I saw it in the mirror from the rear, not a leak onto a hot manifold under the hood.  It was thick and it was us - no other vehicles there .  Pulling away on green, briskly, and not a speck of smoke.  Idling at work 5 minutes later, not a hint of blue at the tailpipe. 

 

We have never seen this before and we haven't repeated it (but we haven't tried).  We don't drive it like we stole it; we drive it like we enjoy the performance, but have to fix everything ourselves, so there is a degree of moderation.

 

We don't even know where to begin looking.   The PO said he did a compression test and it was fine, but we have not. His claim of rust-free proved true, so lean to believing it.  It sounds more like a drain back issue, something we might expect on an OHC with a bad PCV valve, but not a Nailhead with a draft tube.  We searched the topic and learned of upside-down rocker shafts, but that sounds like a more consistent problem.

 

Any engine experts with advise?  Our concern is not the one time, but of causing greater damage by failing to react to the symptom.  We are toying with the idea of a 4000 mile road trip and want to be well prepared.

 

Thanks in advance,

HuntzNSam

[SpecialEducation]

My wife and I test drove a convertible once. On the streets, it was just fine, but on a hard decel from highway speed we found ourselves driving blind in a cloud of our own blue smoke.  The wife (who was behind the wheel), straight freaked out. She stopped as soon as she could find a shoulder and indicated she was done. 

 

Before getting behind the wheel, I popped the hood and checked the oil. It was WAY over the full mark.  I returned the vehicle to the dealership and we bought something else. 

[JohnD1956]

Check the brake fluid level. BTW, what type of tires do you have? are you sure the rear wheels did not lock up and the smoke was from the tires sliding across the pavement?

[NTX5467]

A compression check ONLY checks the compression rings, not the "oil rings" the next notch down on the piston.

 

Did the car "miss" when the oil smoke was around?  And then run smoother after everything settled back down?

 

It might be possible that during the quicker stop, oil inside of the valve covers would be stacking up at the front of the cover inside, which could put it high enough to be higher than the exhaust valve guide seals (which might be a little worn, as well could the intake valve seals) and put oil into the intake ports of the head.  But I'd think that if it was smoking "that bad", a few cylinders of the engine would "miss" and possibly have slightly oil-fouled spark plugs.  Might need to duplicate the "firm stop" in an area where that when you stop, you can kill the engine and remove the front spark plugs and check for oil on them.

 

If, as SE mentioned, they found too much oil, the oil in the cylinders could be coming from underneath.  The oil in the pan will be forced forward in the same scenario, but will contact the bottom of the pistons and cylinder walls.  If the oil rings are not doing their job very well, they won't scrape all of the oil (from the bottom) off of the cylinder walls, to be burned with the normal fuel/air mixture.  Kind of a long shot, considering that hard acceleration should do the same thing, except at the back of the motor.

 

The only other way a combustible liquid get into the intake would be not oil, but brake fluid via the power brake booster vacuum line.  If the master cylinder leaks, it'll puddle oil inside of the booster's bellows.  Usually doesn't cause any issues, but if enough of it gets in there, the sudden deceleration might get it near the vacuum line, but this would probably not be too probable as the vacuum lines are usually well above the location of the pushrod bellows.

 

NTX5467

[60FlatTop]

The brake booster on my '60 Electra had a lot of brake fluid in it when I removed it for a rebuild and plating. I'm not one for hard braking but I bet there was enough the feed through the vacuum line.

Bernie

[HuntzNSam]

Thanks all.  We checked oil level - OK.  Front plugs, albeit 20 miles after the fact, looked beautiful.  Popped the MC cap - down an inch since redoing hoses and wheel cylinders mid-March.  Wheels and hoses dry, but a bit of wetness in the vac line, so without checking the manual first, Mr Stupid popped the master off to see if any fluid was leaking into booster.  Experience with newer vehicles doesn't necessarily apply to vintage.  After the contents of the master emptied into the booster and onto the floor, we pulled the booster.  It sure seemed like more than one MC worth of fluid in there, and old looking, so it may have been a source of the smoke.

 

Seems like a good time to have the booster rebuilt.  Any recommendations?  I see Ed Strain, Booster Dewey, and several others, but no experience with any other than A-1 Cardone from years ago at the parts store.

 

Thanks

Chuck

[Bhigdog]

PM sent.................Bob

[buick5563]

Not the guy in FLA!

[60FlatTop]

Booster Dewey did a great job for me. Fast turn around and nice plating job. I would use him again and have recommended him.

Bernie

[HuntzNSam]

Thank you all for the good advice.  We went with Booster Dewey and were pleased with the service and the results.  We were pleasantly surprised to get a postcard saying he received the unit and detailing the work to be done.  The timeline was exactly as he predicted, with re-plating taking the longest at 2 weeks.  Shipped out Monday Jun 6, received back on Jun 28.  He installed the new MC too, eliminating the possibility of me screwing it up.  The price was as agreed, and quite reasonable. 

 

Reinstallation today.  Mr. Lazy was saying there’s no need to drop the vacuum tank; it’s probably dry.  The brains of the operation asked, “What happens if there is fluid in there?”  So… I pulled the vacuum hose and got 2-4 oz fluid.  Removed the tank and got another pint and half!  With almost a quart in the booster, this had been leaking for years, but the brakes were still working fine.  Washed it out with Brakleen (and did not use a torch to speed drying as we might have done a week ago!)

 

All together, with Sam doing all the under dash work (Yay!  I hate under dash -- she has a better build for it.)  Everything is working fine. Nice day for a test drive, with Portillo’s Italian Beef for lunch as a bonus.  Thanks experts, and thanks Booster Dewey!

 Thanks,

HuntzNSam

P.S. The installed photo also shows the rebuilt wiper motor/washer pump by Steve Hackel, Restoration Service, MidlothianIL.  That too was a great experience and we highly recommend him.