1275 Distributor

Post by **mike.perry** » Sat Sep 06, 2008 8:37 pm

Could anyone tell me which is the correct / best distributor for a 1275 Midget engine? What are the identifying serial numbers?

Post by **Kevin** » Sun Sep 07, 2008 1:23 am

Both the 23D4 and the 25D4 were used but its better to use the 25D4 as it has a vacuum unit.

Post by **RogerRust** » Sun Sep 07, 2008 8:21 am

There are lots of 25D's about you should look for one with 8 degree bob weights. I think.

Post by **bmcecosse** » Sun Sep 07, 2008 9:53 am

Probably want more than that 8 degrees. Total advance required on a 'decent' 1275 is ~ 30 degrees. Remember the dizzy advance has to be X 2, so look for about 13 degrees mechanical (= 26) and about 4 degrees static advance, and you will be about right. And yes - for economy get one with a vacuum advance unit - and check it works! Most don't after 10 years or so - new vac units are still available and easy to fit.

Post by **mike.perry** » Sun Sep 07, 2008 6:38 pm

Thanks for that info but are there any identifying serial numbers I should look for to save me stripping them down to check the numbers on the bob weights? Are MG Metro or Ital dizzys for instance any better?

Post by **bmcecosse** » Sun Sep 07, 2008 6:44 pm

Maybe - but they won't fit A series engines easily (although it has been done - I don't see the point. No idea about numbers - just two little screws to look inside! I have a few if interested - but none have working vac advance - you could transfer a working one from the dizzy you have - if you know it's working that is!

Post by **Alec** » Mon Sep 08, 2008 5:49 pm

Hello Mike,

ideally you need to know that identifying number, 25D4 means nothing other than a type of distributor (Similar to HS2 with S.U. carburettors). Even the vacuum units are variable and have their own identifying number.
I don't know if you are looking for a new one, but Holden Vintage and Classics for one should be able to help.

Alec

Post by **mike.perry** » Mon Sep 08, 2008 9:15 pm

I was just interested to know if I have the correct dizzy with the right advance curve to suit my MG 1275 engine. I am using the unit that was fitted to the engine when I bought it but I don't have any history other than the engine was supplied adapted to drop in to a Minor. The serial number is on the back of the dizzy where I can't see it and the clamps are difficult to access as I have an oil pressure gauge T piece which gets in the way.
I think I have a 13deg bob weight unit somewhere, probably the one I am using in the MM!!

Post by **bmcecosse** » Tue Sep 09, 2008 12:03 pm

You should be able to get at the fixing screws ok - I too have T etc, but dizzy slips out easily enough - undo the clamp and just slacken the mounting plate and leave it behind.

Post by **mike.perry** » Wed Sep 10, 2008 2:24 pm

Just had the distributor out and it has the serial number 41260 F with 16 deg. bob weights (and the vacuum advance works).

Post by **bmcecosse** » Wed Sep 10, 2008 2:43 pm

Sounds good - will allow you to set static advance at close to zero for easy starting and still give you at least 32 degrees total advance. I find best way to set the timing is to keep advancing it until you hear some pinking when accelerating hard in top gear and then back it off slightly.

Post by **mike.perry** » Wed Sep 10, 2008 6:28 pm

I'm glad I'm on the right track. Static timing is around 7 deg or as near as I can get it which is what Mr. Haynes recommends. Tomorrow I will warm the engine up and set it at fastest tickover, run it up the local steep hill and adjust accordingly.
Friday it is booked in for welding on the rear spring hanger and whilst it is on the lift I will give the suspension a thorough check.
There must be some literature somewhere which gives Lucas serial numbers and applications like the SU books.
Thanks for your advice.

Post by **bmcecosse** » Wed Sep 10, 2008 10:37 pm

Well - 7 plus 32 is 39 total - which is a LOT for an A series! But it could be ok - 'they' recon between 30 and 40 degrees total advance for a good going A series. The lower figure applies where the compression ratio is very high, and vice versa. You MUST avoid pinking, but I'm sure it will be fine once you make the fine adjustments. I've found it difficult to start an A series with high compression ration in cold winter weather with that much advance - needing to keep it nearer to TDC to prevent the engine 'kicking' against the starter. Not only does that stop it starting - it also breaks the starter bendix!

Post by **mike.perry** » Thu Sep 11, 2008 5:04 pm

Just run up the local hill from a standing start to foot to the floor in 3rd (too steep for 4th) and no signs of pre-ignition.

Post by **bmcecosse** » Fri Sep 12, 2008 10:10 am

Ideally then you should crank it forward slightly until it DOES pink - then take it back again. But - if it's going well, perhaps best to just leave it alone!

Post by **mike.perry** » Fri Sep 12, 2008 1:55 pm

It lacks that shove in the back acceleration off the lights, probably because of the 3.9 diff. I wouldn't want to run a 3.7.
Had the welding done this morning and the suspension checked. Just the tie rod rubbers a bit tired and a bit of play in the top link rubbers to sort out. And found a leaky rear damper.