• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

setting timing by ear???

Share this page

A

Adrio

Jedi Knight
Country flag
Offline
I have heard of people that set the timing by simply advancing it until it starts to 'ping' then backing off until the ping ends. I have some questions about this methode:
How obvious is the 'ping' and will I recognize it?
Can this result in damage to the engine?
Do I need to set the mixture before or after this?

Thanks,
Adrio
 
This is exactly why God made timing lights........
 
/ubbthreads/images/graemlins/iagree.gif

You can do it by ear, but I've never had any confidence in that method except as a crude and temporary adjustment; to be confirmed and finely adjusted with the timing light....
 
[ QUOTE ]
I have heard of people that set the timing by simply advancing it until it starts to 'ping' then backing off until the ping ends. I have some questions about this method:
How obvious is the 'ping' and will I recognize it?
Can this result in damage to the engine?
Do I need to set the mixture before or after this?
Thanks,
Adrio

[/ QUOTE ]
Hi Adrio,
The ping may not be obvious. At higher rpm you may get into "silent detonation". The more high performance the engine the more likely this is to happen. The most important timing number is the total advance, vacuum advance disconnected, at the higher rpm. I would say that this maximum advance should be NO MORE than 34 to 38 degrees. The advance at idle will depend on the distributor's characteristics.

Set the max advance to 36 degrees at 4500 rpm & let the lower rpm & idle advance fall where they may. Exceeding this advance setting could well lead to severe engine damage which you won't hear until it is too late. Or you might be lucky. If you experience lower rpm ping, retard a couple of degrees.

Lots of folks get away with timing by ear, or timing light at idle. It's kind of risky though.

You may want to reset idle speed & mixture after timing is set.
D
 
Thanks for the tips. One thing about the TR3 and TR4 engine is that there is no dynamic timing spec. Only the static, so setting it with a timing light it a no go. Unless I make a degree wheel and use the advice Dave gave me about the high RPM timing.
 
[ QUOTE ]
Thanks for the tips. One thing about the TR3 and TR4 engine is that there is no dynamic timing spec. Only the static, so setting it with a timing light it a no go. Unless I make a degree wheel and use the advice Dave gave me about the high RPM timing.

[/ QUOTE ]

That's correct. And every reference I've seen regarding timing for the TR3/4 engine suggests that you fine tune it on the road after setting the timing statically.

Timing by ear simply eliminates the sometimes tedious first step of getting the timing close. When I do mine, I set the idle to about 1500 rpm and rotate the distributor until I get maximum rpm. I then retard it slightly until I get a 100 rpm drop and then take it out for a test drive. If it pings under heavy acceleration in high gear, I retard it a little more. If it doesn't, I advance it until I do get a ping when I accelerate in high gear, then retard it a little - just like the Haynes manual suggests to do following the static timing procedure.

The optimum timing will vary based on several factors (fuel grade, engine wear, etc.), and therefore will likely differ from the specified setting. Whether you time by ear or using the static method, it's important to fine tune it on the road.
 
Adrio,

Part two of your question is that the ignition system timing must be in good order prior to setting the mixture.

I set the initial ignition timing with the engine actually not running. #1 piston TDC on compression stroke, #4 piston TDC intake just starting to open. Hole in fan pulley aligns with pointer. Set point gap or check to make sure it's correct. Brass end of rotor arm should point at #1 pushrod tube. Turn the micro adjusting nut to the third division on the scale. slacken clamp bolt on distributor and turn counter clockwise until the points are closed. Connect 12 volt lamp in parallel with points. (one lead to ground and the other to the low tension wire. turn ignition to on (DO NOT ENGAGE STARTER). Turn distributor body slowly clockwise until lamp lights (points open) and tighten clamp bolt. Turn the adjusting nut until one extra division appears on the scale. This should give a base setting of 4 degrees advanced. Start it up and adjust on the road (not to far from base though) The adjusting nut when turned clockwise when viewed from the end of the thread will retard, counterclockwise advances. Idle rpm is 500.

Good Luck, and I wish I never cheated during typing class by looking at the letters.
 
[ QUOTE ]
Thanks for the tips. One thing about the TR3 and TR4 engine is that there is no dynamic timing spec.

[/ QUOTE ]

Well it seems to me after performong all these arcane timing adjustments a dynamic one could be established simply using a dial back timing lite and writing the data down for future use.---Keoke- /ubbthreads/images/graemlins/hammer.gif
 
[ QUOTE ]
[ QUOTE ]
Thanks for the tips. One thing about the TR3 and TR4 engine is that there is no dynamic timing spec.

[/ QUOTE ]

Well it seems to me after performong all these arcane timing adjustments a dynamic one could be established simply using a dial back timing lite and writing the data down for future use.---Keoke- /ubbthreads/images/graemlins/hammer.gif

[/ QUOTE ]

But wheres the fun in that? /ubbthreads/images/graemlins/jester.gif
 
Back
Top