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No power on hills, blue smoke, jerky engine - all timing related?


backeis

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So I did a fair amount of driving this weekend. I know that my engine produces a good amount of blow by, so I'm used to seeing some grey exhaust smoke coming from the catch can (behind left headlight).

 

I noticed now that on steeper hills, the car wouldn't be able to do more than 45mph (in 3rd gear), and would produce a lot of blue smoke in those situations. In flat terrain I get no blue smoke and barely notice the usual blow by. Car will also happily accelerate to 70mph then. I want to add that I had one passenger and some luggage.

 

Also, anything but full throttle will have the engine jerking, as if it's missing beats. I also notice some misfires in idle (irregular braps and shakes).

 

I wanna say neither of this was the case before I slightly advanced my timing to help cold start (which is still abysmal though and only works with starter fluid).

 

So I'm led to believe that I have a timing issue here.

 

Current setup:

- '76 engine, desmogged

- Weber 32/36 electric

- Petronix

- Electric fuel pump

- Oil level near lower mark

- No timing light, so no idea where I stand

 

Any thoughts?

 

Thanks, as always!

Erik

 

 

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First off, you need to know your timing before anyone should or can comment on your timing. Also if you are burning that much oil under load or normal driving conditions. Check and change your spark plugs often. Possibly go to a hotter plug, depending on what you have already. Check valve adjustment also. I am also assuming you don’t know your AFR coming out the tail. Mixtures will also play a part in all this. Grey/black smoke = rich. Blue smoke = oil. They all affect each other, as far as power/smoothness/efficiency.
Matt


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1 hour ago, backeis said:

 

So I did a fair amount of driving this weekend. I know that my engine produces a good amount of blow by, so I'm used to seeing some grey exhaust smoke coming from the catch can (behind left headlight).

 

I noticed now that on steeper hills, the car wouldn't be able to do more than 45mph (in 3rd gear), and would produce a lot of blue smoke in those situations. In flat terrain I get no blue smoke and barely notice the usual blow by. Car will also happily accelerate to 70mph then. I want to add that I had one passenger and some luggage.

 

Also, anything but full throttle will have the engine jerking, as if it's missing beats. I also notice some misfires in idle (irregular braps and shakes).

 

I wanna say neither of this was the case before I slightly advanced my timing to help cold start (which is still abysmal though and only works with starter fluid).

 

So I'm led to believe that I have a timing issue here.

 

Current setup:

- '76 engine, desmogged [?}

- Weber 32/36 electric

- Petronix

- Electric fuel pump

- Oil level near lower mark

- No timing light, so no idea where I stand

 

Any thoughts?

 

Thanks, as always!

Erik

 

 

Sent from my iPhone using Tapatalk

 

 

Improper Ignition timing (either early or late) may cause an engine to perform poorly, but it is not directly related to the oil consumption you seem to be describing.  Unless the car is parked in an igloo, resorting to ether to help start the engine is abnormal.  It suggests any number of things from a carburetor with a simple non-functioning or maladjusted choke and/or fast idle setting - to an engine in poor health due to wear or improper mechanical settings.  The latter includes proper valve lash settings. 

 

How about posting some pictures of the business end of your spark plugs and your engine bay?

 

I think you would be best to invest in some general shop diagnostic equipment.  A compression gauge will give you a general health checkup, possibly indicating the condition of your valves, let alone piston and cylinder status.  If any of the foregoing are below par, any steps short of a tear down will be short term band aid fixes.  An inexpensive vacuum gauge might also be helpful regarding what kind of vacuum your engine is drawing.  I am less of a subscriber to the timing light requirement, unless all of your engine is original spec. or close to it.  Otherwise, any attempt to apply recommended settings will be a compromise and acceptable performance can achieved by ear (search Big Dog method) and carefully reading spark plugs.

 

A spewing blue tail and a low oil level allows for an easy conclusion that excessive oil is reaching one of more combustion chamber, the source being from the lower end, the upper end, or maybe both ends.  In any event, it is not a stretch to presume that the abundance of oil in a combustion chamber will cause an occasional misfire, especially under load.  The fix is to go to the source of the oil and not necessarily to find a spark plug capable of burning it.  Otherwise, try a hotter plug.  Alternatively, try an anti-fouler on the plug or plugs that are subject to fouling - until you can obtain a proper fix.  It may not make your engine Nurburgring-ready, but it might improve the current situation you describe. 

 

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Edited by avoirdupois
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Thanks so far. I figured I probably need to invest in some equipment.

I'm not getting black smoke.

Plugs are NGK BP6ES - will check their condition next time I'm in the garage. Put them in rather recently. Less than 500 miles ago I think.


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1 hour ago, backeis said:

I'm led to believe that I have a timing issue here.

 

1 hour ago, backeis said:

No timing light, so no idea where I stand

 

21 minutes ago, backeis said:

I probably need to invest in some equipment.

 

I am a subscriber to the timing light requirement.

 

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     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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22 minutes ago, backeis said:

Thanks so far. I figured I probably need to invest in some equipment.

I'm not getting black smoke.

Plugs are NGK BP6ES - will check their condition next time I'm in the garage. Put them in rather recently. Less than 500 miles ago I think.


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Sight unseen, I might suggest BP5ES.  Although the difference is far from critical, the "5" is a hotter plug.  A hotter range plug may be better suited to your presumptively lower compression (and higher emitting) engine - by remaining cleaner and less susceptible to fouling.  However, this is far from a panacea for oil burning.

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+1 for timing light (adjustable is preferred with a tach)

 

Erik,

To properly diagnose your engine before tearing it down,  rent, barrow or buy a cylinder leakage (leak down) tester, its money well spent.  This tool will tell you which cylinder and from where you engine is leaking from.  Do a Google search or a Youtube search for leak down test.  this test will tell you if you valves, guides (intake or exhaust) and guide seals are leaking or its your piston rings that are causing all this oil burning and lack of power.   Have you tried an oil additive to reduce your oil consumption?

Edited by Schnellvintage
correction
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2 minutes ago, Schnellvintage said:

+1 for timing light (adjustable is preferred with a tach)

 

Erik,

To properly diagnose your engine before tearing it down,  rent, barrow or buy a cylinder leakage (leak down) tester, its money well spent.  This tool will tell you which cylinder and from where you engine is leaking from.  Do a Google search or a Youtube search for leak down test.  this test will tell you if you guides (intake or exhaust) and guide seals are leaking or its your piston rings that are causing all this oil burning and lack of power.

 

A leak down tester and timing light are all excellent tools, but not absolutely essential for a decent running M10.  It is probably a fair bet that an engine that has been in service for decades has some wear.  A less expensive compression gauge may not indicate the exact source of low compression (leakage), but if the pressure is unacceptably low, the head is typically removed to access the lower end for rings and honing, etc.  And, if things below are ship shape, a valve job is probably on the menu too, especially when the engine has exhibited signs of oil burning.  Again, nothing wrong with the leak down, but it does require a compressed air source, which is not in every shade tree's kit.  I have nothing against timing lights, distributor testing machines, osilliscopes, rolling dynamometers and, of course, exhaust gas analyzers either.  But they are not always essential to obtain a fair running M10 engine.

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12 minutes ago, avoirdupois said:

 

By any chance, were you driving in heavy rain?

 

I focused on the oil burning, but note the mention of "jerking."  This could easily be due to an ignition short caused by a weak coil, plugs that are improperly gapped, leaky spark plug wires and boots/terminals, or even a worn distributor cap and rotor. 

Edited by avoirdupois
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2 minutes ago, avoirdupois said:

I have nothing against timing lights ...  But they are not always essential to obtain a fair running M10 engine.

 

They are quite useful though, no?

 

educational too --  assuming they have the variable-advance/tach/dwell/voltage features

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     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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31 minutes ago, '76mintgrün'02 said:

 

They are quite useful though, no?

 

educational too --  assuming they have the variable-advance/tach/dwell/voltage features

I'm not disputing the tool's usefulness, and certainly not arguing with someone who has very ingeniously and capably adapted the GM-style adjustable ignition points to a Bosch distributor.  (Bravo)  A Fluke multimeter can be invaluable too, along with the latest big display digital torque wrench, but let's not completely discount a reliable set of feeler gauges, a simple circuit tester and ye old beam-type torque wrench (with glasses).?  That said, a savvy mechanic's five senses can, on occasion, be very useful too.

Edited by avoirdupois
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How many miles on the engine? Does it see track duty? From your symptoms I'm not convinced it is timing. You know the engine is tired and the smoke from the breather, blue smoke from exhaust and lack of power say rings to me. Years ago I had a lot of smoke from the breather, then started using oil like mad. Made it home from the Glen, pulled the engine apart and all of the rings fell apart in pieces. Amazing it even ran. As many have said, at least do a compression test. That is diagnosis 101. --Fred

--Fred

'74tii (Colorado) track car

'69ti (Black/Red/Yellow) rolling resto track car

'73tii (Fjord....RIP)

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2 minutes ago, FB73tii said:

How many miles on the engine? Does it see track duty?

About 90-100k (odo stuck).

Don't think it was ever tracked.

 

I'll post photos of the spark plugs next, and then let's take it from there.

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