Mk1 3 litre Timing - Pinging Badly

[ozriderp5]

Reset everything to the factory (static) settings as per the manual. Plugs, Point gap, Vacuum retard.

Book says 3Degrees, not so sure if that's correct.

Engine starts better, runs smoother but now pings badly under acceleration and runs slightly hotter.

Any suggestions???

I'll pick up a timing light this week and check the running motor.

[Phil Nottingham]

Timing light is essential but try retarding using Octane selector a couple of clicks a time

[ozriderp5]

More the point, what should I be setting it too?

[Phil Nottingham]

Depends on the year 10-3 deg variance but in the end it has to be adjusted to run smoothest with pinking as the petrol is not the same as 50 years ago

[djm16]

In order:
1) as Phil says, repeated testing, retarding 2 clicks until you can thrash it uphill at WOT without pinking.
2) if fully retarded it is still pinking, then swap to 98 octane and start again.
3) if still pinking then head off, de-coke, and / or thicker head gasket.

I suppose it really is pinking and not just blowing around the exhaust manifold? They can sound similar.

[ozriderp5]

Thanks All

Just a note, car wasn't pinging before I reset everything, just slugging and running really rich.

I'll have a play at the weekend.


NB. Manual has two settings, one for high compression one for low, any idea which is standard?

[enigmas]

Now that you have some traditional methods to cure the problem, there's another 'alternative' way to sort the issue if you're willing to try.

I'm assuming that the electrical/ignition system in toto is in reasonable operating condition. Spark plugs, leads etc all check out. Verify your leads with a multimeter for correct resistant and no breaks or open circuits. Similarly the fuel system from the tank to the carburettor is in good working order and there's no vacuum leaks.

First thing to consider...fuel/ petrol is not the same stuff as was available in the 50s _70s. I trust you're not using anything containing ethanol as you may find metal and alloy components have been eroded/damaged severely by it's use.

To begin...set the the intial locked distributor timing with a vacuum gauge (just forget what the manual tells you or what a timing light shows.) Start and warm the engine. Note the reading on a vacuum gauge and keep advancing it till the reading peaks. Then back it off a small increment. Adjust the idle speed to where it should be. Now lock the distributor and mark the position. This will provide the best torque for take-off (especially noticeable on an automatic) and optimum fuel burn.

For the moment disconnect the vacuum advance capsule and plug the line with a screw. It is only there to provide improved fuel economy during cruise conditions on light throttle by adding to the total centrifugal advance. At times (especially on an engine of unknown history) the additional advance can cause pinging during light load situations. (Especially if the compression has been raised by too much cyl head millingover the years)

I also assume that the vacuum capsule is hooked up to the correct port...thats the one in front (air cleaner side) of the throttle plate not behind! If on the wrong port it will pull in too much advance too early.

As an aside, running too litle initial/static advance causes an engine to slowly overheat ( in traffic) as the fuel burn heats the block rather than uses the energy to push down on a piston. The cycle is too late!

Take if for a drive. Initial take off will be strong. If you find it still pings further up the rpm range then the centrifugal not the static/locked timing needs to be reduced. This can be done with a simple, cheap, school boy plastic protractor.
This is part 2 if you're still interested?

PS. Having a timing light and tacho simplifies the task.

[ozriderp5]

I'll adjust the octane thingy first, I didn't realise it actually changes the timing and not just the vacuum retard.It's been a lot of years since I played with old school timing etc.

Ill check with the timing light and pick up a vacuum gauge.

I'll need them all for the mini and other future purchases.

[ozriderp5]

Reset everything with the timing light last night, I'll move some cars around and test it Saturday.

So I've...

1. Set all the carb screws back to standard.
2. Removed, cleaned and reset the plugs.
3. Checked and reset the points gap.
4. Marked the flywheel at 3 degrees BTDC
5. Plugged the Vacuum Retard
6. Set idle to roughly 800rpm
7. Set Timing.
8. Checked timing changes with Revs
9. Checked vacuum retard is working.

Leads are all new, coil is fine, distributer has been replaced in the last couple of years.

[enigmas]

So are you winning Oz?

Since you're car is still using a points distributor try this (you state that it is new). Ign off. Turn the engine over until the distributor lobe has opened the points (it doesn't matter which cyl is being fired.) Hold the top of the distributor cam and physically push and pull it back and forth. It there is any movement (shown by the points gap being opened to a further or lessor extent) then there'll be dwell variation...which can be as much as 6°.

This issue can be overcome simply by fitting a pertronix/clone (ignition module) or similar.

[djm16]

For the benefit of others with a similar problem:

Following the workshop manual to set the static timing is at best a very vague approximation to "best" timing. What we really want is perfect timing at WOT.

Static (idle or fully retarded) timing will only give good WOT timing IF all of the following are true:

1) the distributor is new, with no wear or play, advance springs with original tension. Wear or play will lead to failure to fully advance.
2) the compression ratio is exactly as designed with no coke build-up and no head skims raising the compression ratio.
3) the carburetor is set up perfectly with no wear or air leaks (not workshop initial settings or idle settings, but set with a stoichiometer for WOT).
4) there are no exhaust leaks.
5) the fuel you are using is identical to the fuel available when the workshop manual was written.

If any of the above are false, then using static timing as anything other than an approximation is futile.

If you are lucky when you set the static timing, the wear in your distributor leading to retarded timing at WOT will just about compensate for the raised compression ratio from head skims and needing a de-coke. But that will be luck, not judgement.

This is pretty much what everyone else is saying, I am just summarising.

[enigmas]

Nov 2, 2017 22:57:42 GMT djm16 said:

For the benefit of others with a similar problem:

Following the workshop manual to set the static timing is at best a very vague approximation to "best" timing. What we really want is perfect timing at WOT.

Sorry djm16...I don't comprehend best timing at WOT! Lots of racers (bikes & cars pre computer technology) and still done by racers of historic vehicles...and I'm not referring to vintage stuff lock their distributors at full advance for WOT as that is the rpm that their engines run at. It's the in between stuff that takes time to setup. WOT is not about best stoichiometry...it's usually on the rich side.

[ozriderp5]

Nov 2, 2017 22:57:42 GMT djm16 said:

For the benefit of others with a similar problem:

Following the workshop manual to set the static timing is at best a very vague approximation to "best" timing. What we really want is perfect timing at WOT.

Static (idle or fully retarded) timing will only give good WOT timing IF all of the following are true:

1) the distributor is new, with no wear or play, advance springs with original tension. Wear or play will lead to failure to fully advance.
2) the compression ratio is exactly as designed with no coke build-up and no head skims raising the compression ratio.
3) the carburetor is set up perfectly with no wear or air leaks (not workshop initial settings or idle settings, but set with a stoichiometer for WOT).
4) there are no exhaust leaks.
5) the fuel you are using is identical to the fuel available when the workshop manual was written.

If any of the above are false, then using static timing as anything other than an approximation is futile.

If you are lucky when you set the static timing, the wear in your distributor leading to retarded timing at WOT will just about compensate for the raised compression ratio from head skims and needing a de-coke. But that will be luck, not judgement.

This is pretty much what everyone else is saying, I am just summarising.

All good, but you need to start somewhere. Factory settings will always be the default when setting something up.

[ozriderp5]

Nov 2, 2017 22:54:49 GMT enigmas said:

So are you winning Oz?

Since you're car is still using a points distributor try this (you state that it is new). Ign off. Turn the engine over until the distributor lobe has opened the points (it doesn't matter which cyl is being fired.) Hold the top of the distributor cam and physically push and pull it back and forth. It there is any movement (shown by the points gap being opened to a further or lessor extent) then there'll be dwell variation...which can be as much as 6°.

This issue can be overcome simply by fitting a pertronix/clone (ignition module) or similar.

<sub>Hi Vince, getting there, I just want it in a decent running state for the moment as I'll be starting on the Mini again over the Xmas break.

Electronic ignition is on the list, I'll do both cars.</sub>

[djm16]

Hi Vince,
"Sorry djm16...I don't comprehend best timing at WOT! "
I suspect we are understanding the same things, that the critical setting for the distributor is the fully advanced state. In practice this means for my cars what the distributor is doing while I am thrashing the the car uphill at WOT. Whether or not the rest of the ignition curve is ideal depends on all the other conditions I summarised.

A question though, are you suggesting that there is a simple way to adjust the total centrifugal advance without physically removing / replacing components?

Ozrider,
"All good, but you need to start somewhere."
Sorry, did not mean to sound critical. Yes I agree you have to start somewhere. Because I am familiar with IOE 6s I do not bother with flywheel timing marks, but just set the distributor where it looks about right and experiment from there with the "thrash / ping" cycle until it does not quite ping. Then I am done.

It is of course fine to instead start with setting fully retarded timing at idle and work from there, as long as it is understood that the sum of all the timing errors due to age and wear etc can amount to something like 20 degrees.
My P4:
13 (from incorrect selection of the two choices of full centrifugal advance - 26 or 13)
3 guesswork on the wear in the advance posts / weights
4 guesswork from centrifugal spring stretching and wear on the spring posts.
20 TOTAL (estimate).

[ozriderp5]

Nov 3, 2017 23:48:38 GMT djm16 said:

Ozrider,
"All good, but you need to start somewhere."
Sorry, did not mean to sound critical. Yes I agree you have to start somewhere. Because I am familiar with IOE 6s I do not bother with flywheel timing marks, but just set the distributor where it looks about right and experiment from there with the "thrash / ping" cycle until it does not quite ping. Then I am done.

It is of course fine to instead start with setting fully retarded timing at idle and work from there, as long as it is understood that the sum of all the timing errors due to age and wear etc can amount to something like 20 degrees.
My P4:
13 (from incorrect selection of the two choices of full centrifugal advance - 26 or 13)
3 guesswork on the wear in the advance posts / weights
4 guesswork from centrifugal spring stretching and wear on the spring posts.
20 TOTAL (estimate).

Not a problem djm16, I understand where your coming from.

I've been involved in engineering all my life both hands on and as a manager, even today working as an operations manager for an IT company I still tell engineers to start at the default setting, whether that is a manufacturers settings or the as built setting for the environment.

Settings can then be tweaked from that datum point to suit current situations as per your examples.

Without a datum point you have no reference if you have to roll back a change.

[enigmas]

Nov 3, 2017 23:48:38 GMT djm16 said:

Hi Vince,
"Sorry djm16...I don't comprehend best timing at WOT! "
I suspect we are understanding the same things, that the critical setting for the distributor is the fully advanced state. In practice this means for my cars what the distributor is doing while I am thrashing the the car uphill at WOT. Whether or not the rest of the ignition curve is ideal depends on all the other conditions I summarised.

A question though, are you suggesting that there is a simple way to adjust the total centrifugal advance without physically removing / replacing components?

No (altering yes)...but I am stating that it's not that difficult to pull the centrifugal timing back with a few simple tools and a modicum of patience. Simple backing off the timing by rotating the distributor to retard it (across the range) is no fix...it just kills performance, produces slug like motivation and a possible hot runner due to the retarded timing. Engines generally don't ping across their entire operational range unless compression ratios are excessive. If they do ping/knock under load it's usually at a specific rpm/load level.

Currently I have no first hand idea what condition OZ's engine is really in. For instance what is the current compression at cranking speed. 7:1, 8:1, 9:1, 10:1 or more. These are just average numbers but they indicate at what level the engine is working at. If it's at 8:1 or less it shouldn't ping no matter how it's driven! Does it ping/knock under load when cold or only when at operating temperature?

I've already suggested setting the intial timing using a vacuum gauge. Try it you might be surprised at the difference it makes on an automatic especially during initial take off. It will have a lot more torque down low. Yes, it will bring in too much advance further in the range, but it gives you your starting point. It's where the engine wants to be initially. Why not try it (DJM16) and see if I'm talking hocus pocus or not! Nothing has been altered irreversibly.

[ozriderp5]

Nov 2, 2017 20:31:51 GMT ozriderp5 said:

Reset everything with the timing light last night, I'll move some cars around and test it Saturday.

So I've...

1. Set all the carb screws back to standard.
2. Removed, cleaned and reset the plugs.
3. Checked and reset the points gap.
4. Marked the flywheel at 3 degrees BTDC
5. Plugged the Vacuum Retard
6. Set idle to roughly 800rpm
7. Set Timing.
8. Checked timing changes with Revs
9. Checked vacuum retard is working.

Leads are all new, coil is fine, distributer has been replaced in the last couple of years.

Finally got the car out today for a test drive, I've driven it around all the back streets where I live and I'm happy to report that it is running exceptionally well.

No pinging and it is pulling better than it has since I got it.

I'll take it a decent run tomorrow which will be mostly freeway speeds, if all goes well I'll take it up the hills.

I'll still run through all the tests with the Vacuum Gauge when I get it but so far so good.

[djm16]

Hi Vince,
I usually have the opposite problem, that there is too much advance at low revs when the timing is set optimally for high speed / load. In the P4 this was to the extent that the engine used to ping when being cranked by the starter. Fixing the wear in the distributor cured all that to my satisfaction.

[ozriderp5]

Got my Vacuum Gauge today, timing was out based on vacuum.

It now sits at about 19-20 inches of mercury which is pretty much smack in the middle of the green.

Idle speed increased quite a bit so that had to be adjusted, mixture was adjusted so it's in between running rough either way.

It pretty much passed all the tests that all the instructional videos lay out, needle sits pretty solid and does what it's supposed to when the throttle's blipped etc. 

This one is pretty good, same gauge as mine. www.youtube.com/watch?v=SdlNwm8OHco


I'll run it at the weekend.


One thing I have noticed since I've redone the timing etc is the amount of soot being spat out the exhaust, I'm guessing it will clear up as the inside of the exhaust cleans up. 

[enigmas]

19 - 20 inches of vacuum at idle is a good reading...it also illustrates that the engine has decent ring seal.

[enigmas]

Nov 7, 2017 3:34:32 GMT djm16 said:

Hi Vince,
I usually have the opposite problem, that there is too much advance at low revs when the timing is set optimally for high speed / load. In the P4 this was to the extent that the engine used to ping when being cranked by the starter. Fixing the wear in the distributor cured all that to my satisfaction.

Interesting...I've never heard an engine ping at/during cranking speeds. An engine will kick back and fight the starter motor if over advanced initially (too much static/ fixed ignition timing). This is more an issue with a high compression engine 10:1 or over.

If timing further advances just off idle or at very low engine speed when driving (causing the engine to ping or detonate) you need to pull the centrifugal timing back. Either the springs have lost tension, or the posts the weights act on are worn or grooved. Either way by increasing the spring tension (substitution) or slightly bending a spring post further out (measure the distance and record with a pair of dividers) will pull the timing back.

Try this. Mark the rotor button position at rest...the pointy end against the outer distributor body edge using a white out pen. Now twist the rotor button to full advance and mark the position again. Using a clear plastic protractor measure the difference in degrees using the centre of the rotor button (the advance cam spindle as the centre point). Measure the degrees and double it. This is your mechanical distributor advance.

None of this takes into account wear/slack on timing chains, etc...but it does give you a number to work with.

Add your static timing to the above number and that gives you the total advance. (For the time being forget about the vacuum advance capsul as that should only function during cruise situations)

[ozriderp5]

Nov 9, 2017 10:09:37 GMT ozriderp5 said:

Got my Vacuum Gauge today, timing was out based on vacuum.

It now sits at about 19-20 inches of mercury which is pretty much smack in the middle of the green.

Idle speed increased quite a bit so that had to be adjusted, mixture was adjusted so it's in between running rough either way.

It pretty much passed all the tests that all the instructional videos lay out, needle sits pretty solid and does what it's supposed to when the throttle's blipped etc. 

This one is pretty good, same gauge as mine. www.youtube.com/watch?v=SdlNwm8OHco


I'll run it at the weekend.


One thing I have noticed since I've redone the timing etc is the amount of soot being spat out the exhaust, I'm guessing it will clear up as the inside of the exhaust cleans up. 

Ran the car today and it pinged something shocking......

Back to the drawing board with the timing light etc. Ended up getting everything set again and the Vacuum Gauge still sits in the green but at a lower level. (it moves up a bit if you increase idle speed)

The car has a cone filter on it so very little restriction with the intake. I'll pull it all off when I replace all the hoses I've ordered and clean the the throttle body etc. If it's all pretty good I won't bother with a carb kit at this stage.

[enigmas]

Unfortunately...an engine's condition and state of tune can/does change somewhat over a 50 plus year period. Things like timing chain stretch will also affect it's tune and how it behaves by altering valve timing slightly . Alterations in exhaust systems/intake systems also logically affect things. But it's not all bad news...it justs means that it might need some parameters altered. In your current situation its improved the bottom end but obviously induced some pinging higher up as more advance has been dialed in initially. This can be curbed by slowing the advance rate of the centrifugal weights (by slightly bending out their spring posts...this imposes more tension on the advance springs...slowing the rate of advance. Use a pair a calipers/dividers to record the changes made. You can also pin them to limit any total advance.)

The easy way out though is to retard the total timing by simply twisting the distributor around which reduces timing overall, but this kills performance across the range and just make it run hotter.

[ozriderp5]

Nov 11, 2017 8:18:10 GMT enigmas said:

Unfortunately...an engine's condition and state of tune can/does change somewhat over a 50 plus year period. Things like timing chain stretch will also affect it's tune and how it behaves by altering valve timing slightly . Alterations in exhaust systems/intake systems also logically affect things. But it's not all bad news...it justs means that it might need some parameters altered. In your current situation its improved the bottom end but obviously induced some pinging higher up as more advance has been dialed in initially. This can be curbed by slowing the advance rate of the centrifugal weights (by slightly bending out their spring posts...this imposes more tension on the advance springs...slowing the rate of advance. Use a pair a calipers/dividers to record the changes made. You can also pin them to limit any total advance.)

The easy way out though is to retard the total timing by simply twisting the distributor around which reduces timing overall, but this kills performance across the range and just make it run hotter.

As with everything mechanical it's a compromise. Everything you adjust from timing to idle speed make a difference on the testing.

Now that I know the engine is pretty healthy I've reset the timing in conjunction with the vacuum gauge, it's still sitting in the green but a bit lower. Car runs fine now.

Says a lot for modern cars that are making these adjustments instantly depending on which sensor is telling them what.