Moss Motors, Ltd

Okay everyone - here i am, carbs installed and car running - haven't quite finished tuning and sync'g them just yet but I'm curious as to what is (or could be) the cause for some "thin white smoke" out my tailpipe.  Of course, the more i rev, the more smoke.  It's not terribly thick smoke (disipates fairly quickly).  I'm hoping it's fuel mixture related and will disappear after i finish tuning/synchronizing carbs. 

Could this be symbolism for all the $$ I've spent so far?  LOL!!

Thoughts?  Guesses?  Theories? Annecdotal comments?  (all are welcome in this place!  haha!) 

Ciao,

Lou

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Lou
'76 MGB MKIII

Lou,

I hope I'm not right here, but white smoke isn't fuel. That's black. It isn't oil, because that's blue. Look carefully, with good light. Is it really white, and not light blue? Because white smoke is not usually smoke at all, unless you're running a cold diesel engine. It's generally steam, meaning you've got a bad head gasket or a crack somewhere. If it's a gasket, you'll be pressurizing the cooling system. If you have a cooling system pressure tester, or access to one, hook it up and crank the engine over. When there is a crack or bad gasket, just cranking the engine will cause a rise on the gauge. Also look for "chocolate milk" in the cooling system or bubbles and slime in the oil sump, on the dipstick. Geez, I don't want it to be so. Let us know what you're seeing.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

oh boy.... well, that just figures after all the work i've done.  Well, it's really white, not grey or black at all.  I had the head completely redone by a reputable machinist well experienced in these motors.  I put a brand new, payen head gasket on and torqued it to spec and nut sequence per the Haynes manual.  I don't have a cooling system tester - is that something i could get at my local auto parts store or is it a Moss item?  I sure hope you're wrong (but more than likely, you're probably right).  Dipstick is showing proper oil level and the oil is clean as a whistle (cuz i just changed it).

 I'm trying to get the new throttle cable on right now and will post again later after i take it for a spin around the block....

am i putting my motor in danger by driving it right now?????

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Lou
'76 MGB MKIII

Lou,

I doubt you'll make anything worse with a little more running, if this is a gasket problem after all. Some parts stores carry pressure testers for cooling systems. Even if this isn't your problem, a cooling system pressure tester is a good tool to have in your "arsenel".

If you are really losing a head gasket, the steaming will likely get worse and the engine will begin to run badly. Just stay close to home, watch fluid levels, and keep an eye on your gauges. I'm trying to think about what else may be causing these symptoms. Lou, what work did the machinist do on the head and or block. Hang in there.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Hey there,

well - after looking at the "smoke" last evening (nearly dusk) I guess i was wrong initially - my neighbor came over late this afternoon and is convinced this light smoke has a blue tint to it - not white.   The machinist put in new valve guides and seals and gave it a good once over cleaning.  He checked everything else and said it all looked fine.

I found this posting on an ASE website as it relates to possible causes for "blue/gray" smoke (although, this smoke is light blue):

o         Valve Seals: Leaking valve seals will cause blue/gray smoke at startup                                                                  because oil leaks past the seals into the cylinder after the engine turned off.
o        Valve Guides: Excessive clearance between the valve stem and the valve
guide will allow oil to leak past the gap into the cylinder.
o        Piston Rings: Worn or damaged piston rings will cause blow by resulting in
blue/gray smoke.
o        Worn Cylinder Walls:  Worn cylinder walls cause blow by resulting in
blue/gray smoke.
o        PCV System: A stuck closed PCV system will cause excessive crankcase
pressure resulting in blue/gray smoke exiting the tailpipe.

Of course, i guess the head-gasket could be bad (or i just screwed up putting it on) - wouldn't be terrible to replace it and retorque i suppose.  I'll try to locate a pressure tester tomorrow -- still need to fine tune the carbs and double check the timing - also picked up new points and condensor.  I'll do the points, condensor, timing and then carb adjustments and let you know if there's any change (i sure hope so) - the thought of pulling this motor & gearbox again to do a ring job isn't what i was planning for the next step (ugh).

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Lou
'76 MGB MKIII

Lou,

For some reason I can't call your other posts up from your BIO page to see what else you've done. Is this engine freshly rebuilt? If so, it's normal to burn a little oil while everything beds in. Let me know. Also, don't use heavier oil during break in running. Don't go higher than 10 W 40.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

It seems like if burning oil was causing the smoke, you could smell it. But, like Bill said, in a fresh engine that may not be a bad thing. 

Hey Gang,

First - thanks so  much to all of you who've chimed in - outside of bringing this LBC back to life, this forum has been the 2nd coolest thing since picking up this car!

Just thought you should know, I met up with a local LBC expert today - he totally tuned and sync'd my carbs up nicely - she purrs now - and that smoke?  It's not NEARLY as present as it first was - i've driven her a total of 30 miles since launch day.  I find it amazing really - several other mechanic friends have chimed in stating that since the motor has been "sitting" for 7 years, there's bound to be some smoke initially.  Now that the carbs are tuned up, and I've been driving it somewhat, the quantity (and smell) of this smoke has really, really dissipated.

To answer MotorBill -- sorry my bio page is screwy - anyway, no, this was not a complete engine rebuild.  I only had the head rebuilt.  As for the bottom end, I had it visually checked out and decided to simply clean up the tops of the pistons and clean up all we could touch (cylinder walls, etc.).  I didn't remove or replace anything on the bottom end.  I'm sure that was a risky move, but given my budget, was a necessary decision.

Driving it home after the carbs were done was such a relief (only to now start focusing on all the front suspension work i need to do haha!).  And I'm cautiously optimistic that this smoke-dissipating thing is not an anomaly.  Hopefully all this good karma you all are sending me will pay off 

I'll keep you posted.....

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Lou
'76 MGB MKIII

Lou, I will offer the same advice that motorbill gave me when I experienced a similar situation, (after a complete engine rebuild), "Just drive it!"

The first thing I must do when finally exiting an airport, movie theater, restaurant or the like, is light-up. Your engine has been sitting for 7 years, don't you think IT deserves a little smoke?

Use the 10W-40 for now as a break-in oil. You should change it shortly after running the engine for the first time, and then don't be so quick to change it again, a little friction helps things break-in (how am I doing motorbill?), also, don't forget about the ZDDP! I bought the bottles from Moss, this way I'm SURE that it's in their.

After about 4000 miles, mine still smokes (oil) a bit on deceleration before the engine really comes up to temperature, but then it's fine for the rest of the day. I can live with that.

Enjoy that puppy, but keep an eye on the gauges, as well as the looks of the oil and coolant. Driving season is getting shorter every day!

 

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

davey,

your doing fine on the car advice, but cars are machines, and smoke naturally. People don't. Tsk, tsk. If I could quit (20 yrs now), anyone can. I just said "This is dumb.", and threw a half a pack in the trash. I haven't looked back. I won't preach anymore man, I just care about you.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Thanks for the inspirational story motorbill. For the record, it's a pipe that I light-up not a cigarette. Even my doctor tells me that the pipe isn't nearly as bad as the little white killers, having just had had a physical 2 weeks ago, doc says I'm fine.

I know I'd be better off if I gave it up entirely, and perhaps I will. You wouldn't happen to have a round tuit I can use?

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On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"

OK davey, that's a relief. And while we're engaging in true confessions I'll admit to a cigar now and then. However, I don't inhale (the name is Bill, but not Clinton).

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

You guys are the best!!   I'm so grateful for ALL your insight.  Unfortunately, as I was advised by a long-time LBC guy, I put Castrol 20w50 in for motor oil.  Guess i'll be changing it here this weekend to 10w40 huh?

The "smoke" is not nearly as dominant as it was... (maybe i'm getting used to it who knows).  My oil looks and smells fine and coolant level is fine (as well as running temp - i.e., it's not getting "too" hot, hovers around 180 - 190 per my guage).  Oil pressure seems to hover around 40 - 70ish depending.

My bigger problem (just noted this morning as we drove her to work) was one of the carbs was overflowing.... PPPP-UUU!! what a smell !!!  So i very gently brought her home at lunch and there she sits waiting for me to come home and look over that bowl and float.  Carbs were tuned and sync'd Saturday and there was no overflowing - not sure why now - maybe some "junk" got in there.  Not going to drive it until i take care of that.

Seperate note [insert Davey here] - my tach isn't working - any quick thoughts before i start tracing per schematic?  Needle is just resting at zero - doesn't peg when motor is running so i think it's all electrical (probably ANOTHER ground issue)  haha!!

Sorry for the length - yes, you're right Davey - driving season is coming to an end quickly here in Pacific NW - we got a glimpse of rain today as a matter of fact. 

Will keep you all updated with what i find out....

thanks a million!

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Lou
'76 MGB MKIII

Lou,

10W40 is for break-in. If the lower end has any significant mileage it will benefit from 20W50. However, a "rinse" of 10W40 is a good idea if the engine has been sitting. I think you're on the right track.

The first thing to try with an overflowing carburetter is a loving but sharp crack with a screwdriver handle on the offending float chamber. Sometimes the needles just plain stick, regardless of crap in the fuel issues. The solution here is to install the Grosse Jet improvement. They're still susceptible to dirt, but they don't "just palin stick".

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Gotcha Bill - so, if i understand correctly, since i have the 20w50 in there now, I'm okay - but if i drain that, and put in 10w40, i'm still okay, right?  I only have one spare filter, so if i put in 10w40, how long should i leave that in before going back to 20w50?  I've always been schooled to change he filter with EVERY oil change -- that overkill? 

As far as the carbs -- all is well with the world again - i took the offending float out, double checked the pin holding the float (looked like one end wasn't all the way through) and then checked the tightness of the jet (? - the place where the needle sits in) - it was finger loose!!  I'm gonna have "words" with the guy that rebuilt these for me for sure....  (maybe not, that'd be bad Karma)... anyway, got her running and no overflow of fuel !!  I'll keep the sharp tap with a screwdriver handle idea handy in case it happens again.   Must've let her run for about a half hour total and no fuel overflow.

The tach on the other hand is a different story - i think mine is just plain bad - i've got voltage on the doubled-up green wires (to one female conn) and the black has continuity to ground.  The white wire is looped with this plastic thig-a-ma-bob (i never touched it).  so, i'll try to snag another one from my local LBC guy give that a try.  At least the ignition light and dash light work on the tach.

For now..... I'll be just driving, driving, driving, driving, driving, driving (just local)....... weeeeeeeeeeeeeeee!!!  Then when the Pacific rains come, I'll garage her and get started on the front suspension.

Will try to send you guys a quick video and update my photos...... 

Haven't forgotten you Davey - i'll get some pics of that AWESOME rear panel soon....  promise!

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Lou
'76 MGB MKIII