Potentiometer and timing question

[siteunseen]

Anybody with this fuel tweak found a timing degree that is better than 10 BTDC? I'm thinking of trying 15 but I don't really know what "Pinging" is. I guess it's a noise that's noticeable? Thanks for any advice.

[Wade Nelson]

I suggest you first learn how to PROPERLY set your Z to the factory recommended timing, Leon.

Get in the factory service manual and see what the procedure is --- it may involve disconnecting the vacuum advance, plugging that line, etc. You'll need a timing light. You'll probably have to do some scrubbing to see the timing marks.

Then go drive it.

If the factory setting is 8 BTDC, now re-set it to 16 BTDC and go drive it. Lug it (4th gear, low rpm's) up a hill and you'll hear it pinging.

Now dial it back to say, 10BTDC, and go drive it again. Try it on regular and then premium gas. The more timing advance the higher octane fuel you need to avoid pinging.

Generally you can "get away" with an extra couple of degrees of timing advance (further BTDC) without a lot of pinging. Depends on your altitude, the grade of gas you normally run, humidity, lots of factors.

You do NOT want to be pinging ALL the time, although "just a touch" when accelerating up a hill means you're set just about perfect. Any less and you're leaving performance on the table.

[LeonV]

I suggest you first learn how to PROPERLY set your Z to the factory recommended timing, Leon.

Is siteunseen's name Leon, or am I missing something?

Get in the factory service manual and see what the procedure is --- it may involve disconnecting the vacuum advance, plugging that line, etc. You'll need a timing light. You'll probably have to do some scrubbing to see the timing marks.

Then go drive it.

If the factory setting is 8 BTDC, now re-set it to 16 BTDC and go drive it. Lug it (4th gear, low rpm's) up a hill and you'll hear it pinging.

Now dial it back to say, 10BTDC, and go drive it again. Try it on regular and then premium gas. The more timing advance the higher octane fuel you need to avoid pinging.

Generally you can "get away" with an extra couple of degrees of timing advance (further BTDC) without a lot of pinging. Depends on your altitude, the grade of gas you normally run, humidity, lots of factors.

You do NOT want to be pinging ALL the time, although "just a touch" when accelerating up a hill means you're set just about perfect. Any less and you're leaving performance on the table.

That isn't the correct way to set timing. The correct way is on a dyno, anything else is just guessing. Seriously, an hour on the dyno will cost you maybe $100. I consider that a worthy investment.

Maximum advance DOES NOT equal maximum torque. Read up on MBT (Max Brake Torque) timing.

[madkaw]

Wade is describing 'old school' timing tricks- which can be effective in some cases where factory setting are very conservative. I would be a little worried if you couldn't recognize pinging though.

Like Leon said, dyno is the only real way to see if there is any gains.

[siteunseen]

Thanks for the replies. I went ahead and set it at 15 BTDC and when I was turning the distributor I could hear the difference in the motor, it kind of quietened itself and seemed smoother?, as always I had a wrench in one hand and a beer in the other one so going out to test the car wasn't in my plans but....I couldn't stand it! With 87 octane already in there I went out to a Connector Highway, nice and flat and about 5 miles long. After fiddling with the potentiometer and scanning for the cops I turned around and gave it a romp. When the wipers lifted off the windshield I lifted off the pedal, looked down and saw a little north of 115 MPH and the temp gauge was in the "E", much cooler than usual. Couldn't believe how quick it got to that speed. Leon I'd love to give somebody a $100 for a Dyno run but those aren't too common in my neck of the woods. Anyway I've got something to play with until the weather cools off. Thanks again for your replies

[Captain Obvious]

I lifted off the pedal, looked down and the temp gauge was in the "E"

Wow... The temp was at "E"??? You must have been really flying!! :laugh: