Lightened Flywheels

[bob46320]

I am no expert,  but how will the starter work on your engine ?  Looking at the previous post, it looks like the clutch assembly would get in the way of the bendix, or that the starter ring was on the wrong way round.  I am sure I am wrong, but interested to know how it will work.
Bob

[Chris KC]

Since my flywheel was chopped up to be lightened I don't seem to have any markings on it. I would like to mark on the TDC and starting timing marks. If I am reading the books right you should start setting the timing with the flywheel 1 1/4 inches before TDC on number 1 cylinders compression stroke.

I made a little extension to my dial gauge and used that to find TDC on number 1 compression stroke. 1 1/4 inches seems to be 4 teeth so do I make the marks where the pieces of tape are in this picture? The one on the left being the BTDC mark and the one opposite the block nut is the TDC one.

I have also read (somewhere I can't find now) that with a automatic distributor the maximum advance is about 28 degrees which would be 6 teeth. Should I make the second mark there?

I know fine tuning needs to be done adjusting the distributor with the engine running but I want the marks there to get me in in the right starting spot.


Simon

Simon,

It's a great idea to mark TDC on your flywheel. To be honest this would have been done more easily before the engine went in. Once in the car it is harder to identify exactly where on the flywheel is the top, don't try to do this while standing outside the car or you'll be miles out, get in and view from the centre line. It is roughly in line with that rear block stud. It doesn't actually matter much as long as you have a consistent point of reference.

A couple of points though.

1. Where you set you timing depends on whether you have an auto advance or manual distributor. An auto advance DK4A should be initially set at 0 deg (TDC).

2. There are a large number of DK4A (and other) distributors which will fit an Austin Seven, many have been fiddled with and most are worn to some extent. So don't blithely assume the auto advance is 'correct' or even as marked on the unit.

3. The advance degrees marked on the distributor are translated to degrees at the flywheel by doubling - the distributor runs at half engine speed. i.e 28 degrees of advance AT THE FLYWHEEL is 14 degrees of advance AT THE DISTRIBUTOR.

4. My own car has about 12 degrees of auto advance (distrib) and runs comfortably if not dramatically when set with points opening at TDC - it's a good starting point.

5. 28 BTDC sounds a bit racy for an average road car to me - it's OK if you have a good solid bottom end.

It's worth setting up some time with a strobe light and observing what happens as you increase engine speed - the amount of timing scatter is astonishing. That I would say is the main justification for going down the electronic ignition route. However it is possible to improve things a bit by making sure the distributor bushes are in good shape, rotor arm a good fit and by replacing the drive gears if they are badly worn.

Sorry if teaching you to suck eggs! I hope something there is useful to you.

---

I am no expert,  but how will the starter work on your engine ?  Looking at the previous post, it looks like the clutch assembly would get in the way of the bendix, or that the starter ring was on the wrong way round.  I am sure I am wrong, but interested to know how it will work.
Bob

Forward facing starter?

[Damian GT]

I've never had the nerve to fit this, but maybe I should use it on a counterbalanced crank?  What do you think?

[Alan]

I don’t think I’d want to stand within 100yards of that.

[Charles P]

I've never had the nerve to fit this, but maybe I should use it on a counterbalanced crank?  What do you think?

There are better solutions

PS - and weight it please!

[Damian GT]

At least I can up-cycle it to make a clock.  Or lamp stand..  (Will weigh it later for you CP)

[Terrytuned]

The teeth on the ring gear are at 4.5 degree intervals so 6 teeth = 27 degrees which is the maximum advance you would need on A7 engine.
       Terry.

[jansens]

I don't mind hearing things I already know, just reinforces things in my head and other people might not know so it's always worth mentioning and is useful. I knew I had see the 6 teeth somewhere! And I do have a front facing starter. Even so I went and checked and yes, it fits!

As for distributors I have a choice of two, a converted Bosch 009 one (with mechanical points now but with a electronic points kit I can put on it) and one of the new Accuspark DK4A ones. I am unsure which is the best to use to be honest. The Accuspark looks better and more correct I think, especially if the body is painted black it seems. But with the Bosch I can have mechanical or electronic points. I would use the electronic but it is nice to have mechanical as a backup.

I was wondering actually how you start a car with an automatic dizzy on the handle. With the manual adjust you retard it fully of course so it would make sense the automatic one must start retarded or at zero. Any advance and I assume you're in danger of it backfiring and kicking back.

I definitely want to put a strobe light on it to see what's happening and Chris, I have seen the exact scatter you mean but on my MGB. When I rebuilt that I had the distributor professionally rebuilt. It worked but with the timing light the scatter was really obvious. I switched that to electronic points and that took all the scatter away. That convinced me how much difference the electronic points can make.

Simon

[Reckless Rat]

My RP has a Bosch auto dizzy and srarts fine on the handle. Never had a kick back. Full advance has been restricted though with a stop.

[AustinWood]

I have an Accuspark distributor and always start on the handle when the engine is cold. I never alter the timing for cranking.