Distributor position

[geoberni]

Hi Everyone
So, have finally got around to using my nice new Timing Light.
We've barely done 300 miles in Basil since we brought him and I've always thought the fuel consumption was a bit poor.
So today, I got underneath and strobed those conveniently positioned timing marks.

The Timing was well off, being about 20-25 BTDC

So slackened the bolt on the Acuspark Dissy and started turning it, moved it anticlockwise a bit and took a look, the timing is now about 15 before TDC. Turned it a bit more and realised it's now fouling on the Oil Pressure switch.
Took a look underneath and it's down to about the 10 deg mark.

The book say for the 948 Engine I should be 2deg BTDC so I don't suppose I can turn the thing far enough to get the other side of the Oil Switch without being way out the other side of the timing marks......


Any ideas??

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[philthehill]

I suspect that the distributer has been fitted one (or more) tooth out so when trying to set the timing it causes the distributer to foul the oil pressure switch.
See wksp manual for details in fitting the distributer shaft.

[RobThomas]

Turn the dissy 90 clockwise and then move all 4 plug leads anticlockwise round one position?

[mogbob]

A few drops of oil around the external base of the distributor / clamp area ( when you've slackened off the clamp ) wouldn't go amiss. It will be less of a struggle to make the adjustment.
Bob

[geoberni]

OK, so the last time I took a Distributor off an engine was a Ford Escort Mk 1 1300 Crossflow in 1975.....

Thus, I was expecting to have an angled Cog on the bottom, but apparently these A Series engines don't, they're just an offset key.

So, put it back on and having looked at a few images of A Series Engines (isn't the internet wonderful) decided that the rotate 90 degrees option was the better option.

I did have to rotate the Coil 90 degrees, as the red cable was a bit tight having rotated the Dissy so far.

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I've now got timing at about 2-3 BTDC and having Checked the Colortune the mixture is also pretty good.

Lets see how much better it runs over the next few trips....

What I find very strange is why it was so far out?
The guy we brought the car from was a self confessed technical Luddite, who said he had everything done for him, so who on earth fitted the Dissy without setting it up correctly? He told us it had only been fitted a couple of 1,000miles before he sold the car.

Thanks for the input everyone.

[philthehill]

The angled cog is on the bottom of the shaft which is located below the distributer and on its top is the offset slot.

Misaligning the distributer shaft is easily done as the shaft is placed into the block the shaft rotates as it meshes with the cam gear.
Seen it happen many times.
For what it is worth - the BMC workshop manual is not that clear either.
Phil

[geoberni]

Hi Phill
After reading your post, I've just got the book out again and found Fig AA.20 and read Section AA.28, so now your earlier post makes more sense... I think I'm glad I was able to sort it out without removing the Drive Spindle, if only because I didn't have time to recover the situation if I messed up!
It was a bit of a surprise not to find the gear wheel attached to the actual Dissy

[StillGotMy1stCar]

Just an observation and I realise it was 90 degrees out to be properly fitted, but they probably timed it nearly right when they fitted it and you did have an unexplained running issue a while back.
It does make me wonder if your advance weights and/or vacuum advance are sticking, did you rev the engine and see the timing advance and return to same position at idle. May be worth checking
Regards John.

[geoberni]

Good point John

Played with it loads to confirm the huge advance the strobe was showing, because I simply couldn't believe it was so far off.
Played with it loads after adjusting, took it for a short run which was fine and I also went out this morning to see how it started from cold, and all appears good so far...
Will keep an eye on it though.

[StillGotMy1stCar]

That’s the best bit of doing it yourself, you know it is correct.
Regards John

[pgp001]

If you do ever decide to re-mesh the distributor drive shaft gears to get the position back to normal, be very carefull not to drop the shaft into the engine when inserting it. If that happens you will have to take the sump off to recover it.

I learned the hard way when I was a teenager, but mine dropped into a "Mini" engine. That meant taking the whole engine out of that car and splitting the crankcase from the gearbox to retrieve the shaft.

You are supposed to thread a long bolt into the shaft to use as a handle for removing and replacing it (5/16" UNF if memory serves)
Guess who didn't have a suitable bolt and tried to screw a round file into the tapped hole instead.
It came out OK, but dropped off on the way back in !!!

Phil

[geoberni]

You are supposed to thread a long bolt into the shaft to use as a handle for removing and replacing it (5/16" UNF if memory serves)
Guess who didn't have a suitable bolt and tried to screw a round file into the tapped hole instead.
It came out OK, but dropped off on the way back in !!!

Phil

The book says to use one of the Tappet Cover bolts

[philthehill]

Whilst the workshop manual does indeed state that you should use a reversed rocker shaft retaining stud it is better if you use a 5/16" x 24 TPI UNF piece of 'L' shaped threaded rod as you can still drop the shaft into the sump even using the rocker shaft stud.
Using the threaded rod alleviates disturbing the rocker shaft and the 'L' shaped rod removes any possibility of the distributer drive and stud falling into the sump.
The threads in the top of the distributer drive are most likely full of crud so screwing the stud or rod into the drive can prove

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difficult.
File a flat on the stud or threaded rod to just below the thread root and then screw into the distributor drive. The flat will clean the threads without cutting or damaging the threads.
Below is a picture of the Minor distributer drive - the shiny narrow shaft at the bottom is one I have lightened, the top shaft is original spec.

[Ian Jones]

Sorry to jump into this thread so late but am I understanding correctly that engine was running relatively ok about 20 deg too far advanced? Not pinking? I'm amazed. My usual way of timing an engine is to set it to the book (which was written for the fuel of the day), then advance it until the engine pinks under load, then retard it a bit so it doesn't pink. Maybe I need to rethink.

Regards

Ian

[philthehill]

Ian
Continue doing as you are doing - there is nothing wrong with setting the timing to suit the engine and fuel. No two engines are the same.
The book setting is only the start setting.
Phil

[RobThomas]

Had a Mini once that ran like a dog, hence was cheap. turned out that the cheese headed screw that held the points down was too long and snagging on the baseplate, thus preventing vac advance. Worth keeping an eye out for that little issue.

[oliver90owner]

If the engine is likely a ‘bitsa’, the timing marks could be in a different position, I think?

Just thought of that as I have encountered it before. Proper way is to check TDC with a dial gauge before and after, but close enough is close enough - as per whoever said get it close and adjust for best running.

[pgp001]

I found it all but impossible to set my timing with the strobe light from under the front of the car.
So I initially set the pulley to the timing mark by just looking and using the starting handle to pull it round whilst laid under the car.
I did check at this stage that N°1 piston was indeed on TDC when aligned with the TDC timing mark.

Once I had it where I wanted it, I then moved back into the engine bay and painted two thin white lines, one on the edge of the pulley and one in line with it on the front of the timing chain cover where I could easily aim the timing gun at them.
This makes it much easier to adjust the distributor and see what the results are in real time, whilst being able to rev the engine as well.

Which nutcase thought of putting the timing marks underneath ?

Phil

[philthehill]

I also got fed up with scrabbling under the front of the car and painted the marks on the front cover and crankshaft pulley after determining TDC on compression.

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If you want to go one better fit the later classic Mini timing chain cover which has the timing marks above the pulley so that you look down to read the timing marks
https://www.ebay.co.uk/itm/Classic-Mini ... xy3JtRe4Bf

However you read the timing marks do just mind that rotating fan.

[Chipper]

Sorry to jump into this thread so late but am I understanding correctly that engine was running relatively ok about 20 deg too far advanced? Not pinking? I'm amazed. My usual way of timing an engine is to set it to the book (which was written for the fuel of the day), then advance it until the engine pinks under load, then retard it a bit so it doesn't pink. Maybe I need to rethink.

Regards

Ian

I suspect the installer possibly faced the same snag I came up against when first fitting an Accuspark to my Traveller; on following the fitting instructions, it wouldn't start at all! I had to rotate the dizzy by a good few degrees (between 30-45, at least) just to get it to fire up, then I did the usual take it for a run and adjust it so it just didn't pink on hills/accelerating in a high gear. I later tried a timing light on it, which suggested it was way over-advanced, so I retarded it a little. I'm still not convinced it's quite right, but it starts and runs reliably enough, so if it ain't broke, etc...