Odd Metallic tapping noise - Sounds like a diesel

[Andymoor94]

Morning chaps,

My 803cc has just developed a slight tapping sound in the engine. Definitely changes to match the speed and intensity of the throttle and engine speed. It's not like a knocking sound, it instead is just there enough to make my poor Eugene sound like my old diesel Insignia!

Recently installed electronic ignition and other than this sound, all has been incredibly promising - Pulls well, hills no longer an issue, very smooth running. I turned the dizzy until smoothest sounding idle.

Now it would be silly to say this is anything other than related to the installation of this new ignition, but as I'm not familiar with what could cause a sound like this, where should I start?

[Nourish]

https://m.facebook.com/story.php?story_ ... 1136149412

[simmitc]

Sounds can be difficult to diagnose, but I am thinking (a) "pinking" as the timing is too far advanced after turning the dizzy, or (b) head gasket failure. Check the compression on all cylinders. Is there any loss of power/performance?

[geoberni]

https://m.facebook.com/story.php?story_ ... 1136149412

[oliver90owner]

Altering carburettor settings for best running is OK, but not for setting the timing. Using a timing strobe lamp is the usual method, I would think, with electronic ignition system fitted. Retarding the timing is likely necessary if this ‘knock’ is only apparent due to your ignition change. Continual knocking within the engine does it no good at all.

[StillGotMy1stCar]

Simon's or Oliver's advice won't help in this case!!

I was referring to Nourish's link, apologies, I should have scrolled up.

Regards John

[Andymoor94]

Thanks for the heads up guys! Luckily, I have a toolbox at work for moments like these. I'll get it moved away from pinking and will find a strobe light for the weekend.

You guys rule

[Andymoor94]

So after messing with timing, I've finally figured out what people mean by "pinking" - It's like a very distance spoon tapping a glass. Only problem if if I turn the dizzy clockwise, it obviously pinks a great deal, but if I turn it anti clockwise until it stops pinking, the revs completely dip. Is this right?

Regardless, I drove him home on the lower rev pinkless version of "poorly timed" and could still hear this diesel like tapping

[ManyMinors]

An 803cc engine producing a metallic tapping sound?..... Surely not

[Andymoor94]

An 803cc engine producing a metallic tapping sound?..... Surely not

I know, what are the odds? However this one has only come about since changing the ignition and yet it doesn't sound like it stems from the ignition. It's similar sounding to a rattling bottom end.

EDIT: After some more scouring the forums, I'd do well to clairfy that my oil pressure is still as good as ever
The sound emits with every fire of each cylinder (or at least doesn't sound isolated to just one cylinder). With the starter handle, compression feels equal throughout each cylinder.
At this point, it could still be timing, however I have retarded it (anticlockwise?) to the point that pinking has stopped, but it's resulted in a dip in idle performance. Until I get to the usual hill on my daily commute, I'll be able to say for sure about driving performance!

A bit more potentially vital information, it's an 803cc engine that has had its 25D distributor swapped for 45D Accuspark electronic distributor. As such, I can't see vacuum adjustment on it, or at least not that over the conventional dial. The rattling sound wasn't from the get go, but instead appeared maybe a few days after having the ignition fitted, which may well have been driving with timing too advanced (at this point, I didn't have any clue what pinking sounded like, Eugene just drove very well and I was very happy).

I'm presuming that the old trick of setting the crank angle and turning the dizzy until it "pops" doesn't work with electric, so a timing light will be very much needed to properly set it?

[simmitc]

Electronic ignition can offer great benefits; but you seem to have commented that the car worked well with the standard setup, which, again as you observe, is simpler to time. Given that, why not refit the original 25D with vacuum advance and time as standard. If your new noise persists, then you know that it's not caused by the new setup, if the noise vanishes, then you know that it is definitely related ot the new ignition.

[Andymoor94]

Electronic ignition can offer great benefits; but you seem to have commented that the car worked well with the standard setup, which, again as you observe, is simpler to time. Given that, why not refit the original 25D with vacuum advance and time as standard. If your new noise persists, then you know that it's not caused by the new setup, if the noise vanishes, then you know that it is definitely related ot the new ignition.

A good suggestion but my apologies for not being clear on one aspect. The electronic ignition was installed because of repeated issues with my 25D distributor.

After changing the points and condenser, due to misfires, I experienced poor running. I was led to believe newer condensers were a likely cause, so the old condenser in and great. Unfortunately, new points needed modifying to fit, so I did that, all was well. Until it wasn't!

Too much faffing, I opted for electronic. Story leads us here haha

[panky]

Pinking can also be caused by a weak mixture. Is it possible you've disturbed something while working in the dizzy? Maybe the vacuum advance pipe is split or has come off.

[Andymoor94]

Pinking can also be caused by a weak mixture. Is it possible you've disturbed something while working in the dizzy? Maybe the vacuum advance pipe is split or has come off.

The vac adv pipe isn't ideal. The size to fit to the carb is different to the dizzy (just because of the fitting that is currently on the carb, which I can change) so it's a right bodge what I currently have, but I'm referring to pinking when idle without vac adv anyway, as this is how the late great BMCEcosse always used to suggest.

Weal mixture, given the carb setup I performed which has a richer needle and the piston test confirms good mixture, may not be an issue, but I will have a look and see if potentially richening it will help. I'm still learning all of this haha

EDIT: I'll also try a better solution to the vac pipe

[Andymoor94]

Double post, sorry! But I've got two videos to share:

Here's a 5min drive:
https://youtu.be/YZRTy4KvC-g

When I say it sounds like Perry's growl from Phineas and Ferb, I refer to this sound:
https://youtu.be/yAJ51xOndXE

[panky]

Try pulling the choke out when it starts, that should prove if it's a weak mixture. Engine sounds nice (can't hear the rattle) pulls well by the look of it. can hear various clunks and the speedo ticking but not any pinking even with headphones on.

[oliver90owner]

Tch, tch. Driving without a working speedometer!

[Andymoor94]

Tch, tch. Driving without a working speedometer!

I normally use my phone on a mount, but alas my phone was recording

[Andymoor94]

Try pulling the choke out when it starts, that should prove if it's a weak mixture. Engine sounds nice (can't hear the rattle) pulls well by the look of it. can hear various clunks and the speedo ticking but not any pinking even with headphones on.

Hopefully usual clunks of driving on British town roads
Though with that said, you can definitely hear him coming

[Andymoor94]

MUCH CLEARER VIDEO - Low revving at idle

https://youtube.com/shorts/vyqSQZoi5a4?feature=share