engine and drivetrain Timing, fuel mixture, plug gap and smoke. Tuning questions.

[jrhone]

So I'm trying to dial in my cars tune. Runs pretty good. Not amazing but not bad. Felt a tad bit sluggish. So I was adjusting timing and fuel mixture. I got it nic and peppy by advancing the timing and I got tons of smoke when revving. I assume that was unburnt fuel. So I backed off the timing a tad and leaned the carb a tad and smoke went away. o confuse things right before I advanced the timing I swapped the black coil for the Pertronix coil. I am not confident the black coil is indeed 100%. So since the Pertronix coil should be more spark should I recap the plugs to a wider gap? Was that why I was getting unburnt fuel? I now smell the exhaust when up to now I wasn't so I still think it's rich or fuel isn't getting fully burned. Thoughts?

[jrhone]

Oh and to add to this..before I did any of the tuning the car had a horrible stumble at lower RPMs. Now the car has zero stumbles and is quite happy. So it is running better but I am a little bit curious about the smoke. Also I am wondering if I can get the tune any better. More plug gap? Dive back into the timing? Fuel mixture?

[jrhone]

gonna answer my own post again….I have it backwards.  i am setting timing and adjusting based on the carb settings…I need to set the timing, THEN adjust the carb.  Thats why I keep chasing the tuning all over the place.  ok…gonna time it, THEN set the carb mixture, THEN retime it, then reset carb mixture.  I bet my mixture is off…so I'm adjusting the timing to compensate, then re-tweaking the mixture, then re-tweaking the thing….wrong.  Lock down the timing, then adjust the mixture…

[Stevenc22]

Please set the timing by finding the fly wheel ball at 1450 rpms with a timing light and then leave timing alone. You can't play with 2 variables simultaneously.

Leave plug gap at factory recommended setting.

Unless you have an air fuel gauge you will need to read the plug color to determine lean vs rich

[jrhone]

I couldn't find the ball at 1450...there was a white line there...no ball.  I set it to that...I seem to recall I set it to a ball before ....hmm...did that, set carb, car runs pretty good, I wasn't that far off.  I'll pull the plugs tomorrow to read it...

[wegweiser]

I can't stress the importance of having an adjustable timing light, enough. It will offer you far more information, than just setting the timing to a particular advance setting at a particular rpm. 

 

With an adjustable light, you can determine where your advance is, at idle, where it is at full advance (above 3000 rpm for instance) and if your distributor is advancing properly....or at ALL. I try to graph all distributors, when tuning a client's 2002. Just so I KNOW, the thing is working! Last month I diagnosed a 74 tii that had ZERO/ZILCH/NADA advance mechanism. If I had just "set the timing by the book - at 1750 or 2500rpm or whatever", I NEVER would have known the distributor was junk. This test required 10 minutes of my time and saved me (and the car's owner) HOURS of troubleshooting.

 

I focus on where the advance maxxes out (at 3000 rpm and above) and set my tii (for example) to exactly 32 deg. On carbed motors or modified motors, I vary this based upon knowledge of the compression ratio, and other factors. 32 is "safe", but you can usually eek out more, if you're careful and use your ears and other senses, to detect detonation at full throttle under load, while driving. 32-36 is a safe range for ***MOST*** carburated street engines at 3000+ rpm.

 

You'll need to locate and mark TDC #1 cylinder, on your front crankshaft pulley - and VERIFY it, by inspecting the mark on the camshaft. From there, you can do the rest with the light. I find it SO MUCH EASIER to read the front pulley / timing chain cover than the dark little hole in the bell housing. 

 

Adjustable lights are't as cheap, but they're life savers, if you have an old car. Also - a rebuilt, properly curved distributor will wake up an otherwise lackluster 2002. Proper tuning = FREE horsepower.

 

FWIW: I use this one. I fuggin' LOVE it! It also reinforces my theory that many 2002 tachometers are off by as much as 230 rpm! (It has a digital tachometer as part of it's function.... super cool.)

 

https://www.otctools.com/products/digital-timing-light-0

Edited August 14, 2015 by wegweiser

[jimk]

by inspecting the mark on the camshaft. From there, you can do the rest with the light. I find it SO MUCH EASIER

Good information on the use of the light for checking function of the advance mechanism.

But I disagree with using the cam mark, that mark can be late due to chain wear, head thickness, head gasket thickness.  Using the cam mark you are referring to the cam timing, not crankshaft timing.  I know it's tough to see the flywheel tdc mark, but it IS the most accurate.  Also the crank to cam turn ratio is 2:1 so the eyeball error using the cam mark is also twice as much as when looking at the flywheel mark.

The term is "precision without accuracy".

 

edited spelling

Edited August 14, 2015 by jimk

[wegweiser]

Many people have difficulty seeing where the pointer is (or should be) on the timing cover of a 2002, or when the TDC mark on the pulley is getting close to it, during slow manual rotation of the engine.... and it may take a little effort to find the factory "hash mark" on the crankshaft pulley. Getting the cam lined up to TDC, easily puts the crankshaft *very close* to this ideal position.... from there, one KNOWS when to start looking for it! For people unfamiliar with this line on the pulley, it can get dizzying, trying to find it, on all 360 degrees of the pulley's edge....but when the cam is lined up, it gets the crankshaft very close - and from there, it can be identified!

 

My point is: by using the camshaft mark, it enables you to find both of the factory crankshaft pulley /timing cover marks/pointer/bolt more easily. Since you're using the CRANKSHAFT pulley mark and not the CAMSHAFT mark, it's "exact" relationship (due to chain wear, etc) doesn't matter at all for the purposes of ignition timing. And the crank pulley should be exactly as accurate as the flywheel - since they rotate equally at either end of the crankshaft.

 

I instruct folks to use the cam shaft simply to VERIFY where the crankshaft timing line should be (and when to start looking for it, as they rotate the engine by hand)  NOT (repeat: NOT) to determine *exact* crankshaft position. 

Edited August 14, 2015 by wegweiser

[jimk]

You'll need to locate and mark TDC #1 cylinder, on your front crankshaft pulley - and VERIFY it, by inspecting the mark on the camshaft

Maybe your initial post should have said ""and VERIFY you have the correct mark" and I would have not understood you to mean correct location of the mark on the pulley.  Sorry for the misunderstanding.

[Nuthatch]

Wegweiser, you are doling out seriously useful information, and MANY thanks. I agree completely with just about all you've said. My adjustable light has been a great investment, and takes all the guesswork out of the entire business. I concur that 32 BTDC at full advance (on my Metric Mechanic 2200 motor) allows the engine to produce its finest music.  

[jrhone]

LOVE the info here!!!  I do have an adjustable timing light.  I was thinking I was making things too complex adjusting the advance on the timing light...thats why I was going to look for the ball.  I have a Tii distributor so I should be using the Tii method of timing right? Time it at 3000 RPM?  I think thats where I differed from my previous timing attempts.  I timed it at 1450 and at 2400.  Not at 3000.

[Hans]

You might try setting maximum advance to the 3000 rpm range. The 1450 rpm etc are for -as I recall- 25 deg. There have been previous posts on setting teh maximum advance (over 30deg) at 3000+rpm.

Edited August 15, 2015 by Hans