5 replies to this topic

[Trissy B]

Hi. I have a 1971 saloon with a standard 1275 metro unit in it. It has the standard head currently but has an MG camshaft (over winter I hope to get an MG head on it too). I've have an electronic distributor from a later carb cooper (AAU1529, 42657A) which I THINK is a 65D Lucas dizzy. Always use Shell V-Power fuel.

 

The car is a bit lump at idle but this is probably the cam, however, it behaves pretty poorly in general when cold and at lower revs. When doing +2500rpm it drives nicely, this could be fine but occasionally there's traffic! :-(

 

I've recently checked the timing and it seems way too advanced at low revs but when I retard it, it then doesn't advance well at higher revs! Can't seem to win.

 

My current advance curve is as follows (vacuum disconnected):

 

Idle..............24 deg

1000 rpm.....26 deg

2000 rpm.....28 deg

3000 rpm.....30 deg

4000 rpm.....32 deg

 

I'm thinking my dizzy doesn't advance by enough degrees.So I took it out and split it, pins and springs seem to be complete and the weights seem to move freely enough.

 

When I put the vacuum pipe back on it goes way up to 38 degs at 1000 rpm.

 

I've been reading all the miniforum arcticles I can find and Calvers corner etc but can't really find the answer! Very confused and have loads of questions which basically amount to:

 

i. Is my dizzy suitable and might it be faulty and not advancing enough?

ii. Is the advance at 2000-4000rpm about right?

 

Any advice much appreciated! Cheers

 

[ACDodd]

The advance curve is way off. Simple to fix, send it off and have it curved to suit your engine spec. Compression can be too high on the old mg metro engines for modern fuel, timing curve should be more like 10 at idle, 18 to 20 at 2krpm and 30 at 4krpm. Figure with vacuum disconnected.

Ac

Edited by ACDodd, 04 September 2016 - 06:40 PM.

[floormanager]

Just had mine recalibrated by The Distributor Doctor as it was not advancing correctly.. Great service; posted Monday, back Friday.  I had to book a few weeks in advance though.  Not cheap but very pleased with the results

[Trissy B]

The advance curve is way off. Simple to fix, send it off and have it curved to suit your engine spec. Compression can be too high on the old mg metro engines for modern fuel, timing curve should be more like 10 at idle, 18 to 20 at 2krpm and 30 at 4krpm. Figure with vacuum disconnected.

Ac

 

Thanks, for now i will retard by a couple of degrees but in the long run get the dizzy re-curved. Racing Bob was pretty happy with his one so I might be sending you a message soon.

 

Think I should do the head mod first before I get the dizzy done? i.e. if you re-curve to suit the MG head, will it still run poorly until I put the head on?

[ACDodd]

Yes get the head done (gas flowed). Ensure you set the compression ratio to suit modern fuel and the cam. Ie 9.75:1 max with the mg metro type cam.

Ac

Edited by ACDodd, 05 September 2016 - 06:13 PM.

[Trissy B]

Thanks very much