Timing

[Richnd1974]

I am yet to get the right timing, assume I need to get 7degs BTDC and based on this picture have others colored in the timing marks for easy.. on the fly wheel is the marker just a notch ?

 

[harbourseal]

Richard,
Forget about the Haynes manual.
It was written when the R4 was still in production.
And back then we stil had lead in our fuel.

Now we have unleaded fuel of other quality. In other words. It does not burn as good as the old stuff.

Advance as far as possible without
Pinking.

Go for a ride and listen for pinking in fourth gear under load.

If it does, retard.
If not, your timing is ok.

 

[Richnd1974]

I've timed it up to 7/8 degs btdc, will test drive it in the morning and see how she goes, I don't think I was that far off before

 

[mojobaby]

Hello Richnd,
in answer to your question, yes, there is a notch on the flywheel. The best way to find it, is to jack up your front wheel and support it with a jack stand. Put the car in 2nd gear and then turn the front wheel a little bit at a time until you see the notch.

then mark the notch with white paint so that you can find it easily in the future.

don't forget if you're setting your timing with a strobe light, you should disconnect and plug the tube that leads to your vacuum advance unit .

 

[JdeW]

In addition to the modern day fuel composition and why our older R4's can't cope with it.
Premium unleaded fuel was introduced since 1985 and was never a problem for our R4's in those days since I drove 90.000 km per year without any problem whatsoever
The "problem" started with the introduction of premium unleaded 95 (or E5) with an addition of 5% ethanol and lower amounts of benzene and octane.
Ethanol takes more time to start burning and that's why the ignition has to start earlier (advance) and as Robert (harbourseal) correctly explains, as fas as advance and beware of pinking.
The ethanol is causing the trouble and has to be replaced with octane, ethanol also increases fuel consumption and ethanol decreases power performance of our elderly engines.
Better is to fill your tank with Shell V-power (97), Total Exellium (98), Texaco Superplus (102?) en Aral V-power (98).
I live nearby the German border and luckily there's still the old super 97 and much cheaper than the greedy dutch fuel prices, sadly greed rules the world...

In the near future things will be more problematic with more ethanol coming up.
The only technical solution for our R4's in the future is to switch to a full electronic ignition AND a new camshaft. We can advance the ignition but the camshaft timing e.g. valve opening and closing has to be adjusted accordingly.
Or as an alternative one could experiment with changing the punch rod length and rocker gaps

 

[Richnd1974]

Thank you all for your help, so quick summary, it's now running on the accu spark electronic ignition, timed it up to 7 degs btdc and runs sweet but I'm good going to retard it a little as it pinks a little, filled it up with shell vpower unleaded this morning as it was nearly empty, so next couple of days I shall see how it's running. Apart from the burn to my arm all good... Cheers all.. Have a good day

 

[petak]

I have little bit different picture for timing marks on gearbox housing.


My timing is set to 7° according to this picture, and car is working nice.


But definitely when you set it "by the book" need to make test drive whit some uphill and with short spanner 11 and adjust it little bit more "on the road".

Preferably exhaust fumes should be set to 1% CO before doing adjustment.

This way I have got maximum out of the R4 engine.
It starts easily, it drives easily, it accelerate easily. 100km/h is not an issue any more.

 

[mojobaby]

Yes Petak, I have set mine exactly like you and road test afterwards.

7 degrees equates to 11mm before TDC which is easier to understand

 

[Richnd1974]

off to road test mine again later, think from looking at the above I need to retard it a little and bring it back back to 11mm as I think I am nearer to the end of the scale at the moment

 

[JdeW]

My timing is set to 7° according to this picture, and car is working nice.
.....
It starts easily, it drives easily, it accelerate easily. 100km/h is not an issue any more.

For my R4 GTL, before I started my restoration project, I used the same setting and I "finetuned" it with my ears, just listening to the engine and making small adjustment by turning the distributor housing, at different rpm's.
At road testing 140km/h was never a problem.

 

[petak]

I managed 130km/h without problem....did not want to go more. 110-120km/h is more than enough for me and my R4

 

[Richnd1974]

Mines a 956cc and managed just over 120km/h

 

[Richnd1974]

Been out again today, took a while to get started, warmed it up on the drive and took it for a blast along the sea front, was struggling, could of been that I have changed the fuel to Shell V Power Unleaded so manually retarded the timing while on the road and it was worse, came back home set the timing to 7 degs with the timing light as per Petek's picture below. was running nice and smooth, took it for another blast and hey presto it's running like a dream. Will run it out later for a longer run and then recheck the timing when I come back. The timing does appear to need a little fettleing to get it right

 

[Richnd1974]

So been out and about today and noticed that since fitting the electronic ignition the rotar arm is sitting a little proud causing damage to the disi cap internally, appears that the vacuum advance cog is causing it to sit a little higher, do I need to remove the advance cog??

 

[mr-reno-139]

Each r4 will be different no exact figure will suit every car
Basically more advanced equals more power until it's too much and it pinks or melts pistons worse case
Can't comment on rotor arm some cap's and rotors manufacturer tolerance differ on heights
Also some rotors tight fit and may need tapping on further gently

 

[Richnd1974]

Thank Paul, I'm going to replace rotar and cap and see what happens

 

[petak]

Hi! Richard1974. Had that same problem.
Rotor arm was sticking half an mm to much and was "brushing" cap near electrodes.

I have noticed instantly that sound is little bit different than before but when i pulled cap off i could not see what is going on.
Only few days after opened cap and find nice brownish dust inside. Than i noticed that cap is brushed off.
Press rotor arm little bit more, and now it works better. Or rotor made himself enough room to spin freely.
Obviously ring from accuspark that goes on shaft is not allowing for rotor to set nice unless you press it in little bit strongly.

It did not damaged cap to much so believe it will all be fine.
Next time will know how to install rotor.

 

[Richnd1974]

Thanks Petek, I think you and I have had the same issues, I might need to replace my cap as the rotor has carved a chunk out of one of the connectors. I will remove the ring and push it down again and make sure the rotor arm sits down.

Will report back :-)