Bosch dizy VJU4BR9
 

Hi, received my 123 dizy today and encountered my first problem. The original dizy fitted now is VJU4BR9. The guidance attached below makes no reference to this number. Is there an equivalent ? would it in your opinion be OK to use curve 3 ?is there much noticeable difference between each successive curve?

Addendum. Just had a look at hand book and it lists the dizy as VJU etc. i think that i will try curve three. Advance starts at 800. What do you think?

Edit: deleted as non responsive. I misread your Bosch distributor #

Anybody on this?

Arcturus;

I don't have any experience so don't have much of an opinion other than if the identical advance curve was not available as a preset, I'd start with advance curve nearest the factory one, and do a road test to evaluate result.

Cheers

My understanding of that is that curve 3 is the correct one for a direct replacement for a VJU4BR9. To me that says it gives:

• Max advance of 27degs at 3,800 rpm,
• It starts advancing at 800rpm,
• There is some vacuum advance as well of 16 degrees.

Curves 8,9 and A give max advance at rower rpm (3,400rpm), but only 20 degs, 23 degs and 26 degs.

I wonder if it will feel more responsive with 26 degs at 3,400rpm, but a bit flat further up the rev range. It might feel a bit more peppy perhaps. But it might pink too.

I would be inclined to have a test drive on curves 3, 8 ,9 and A and stick with whatever feels best, but knowing that curve 3 matches what was originally in the car.

You might want to try curves 4 and 5, but I presume it's suggesting 2.0 litre somehow. Curves 6 and 7 are for LPG conversion. Curves 1 and 2 are for 1.4, not 1.6.

Would static at about 5* for easy starting seem OK?

Dunno! What are you trying to achieve?

Just general reliability and reasonable pick up. I don't tend to drive this car very hard. A nice steady 60 mph with occasional bursts to 70 for overtaking.

Personally, I set up the timing so that the thing runs best at speed. In other words, I concentrate on the max advance at say 2,500 rpm seeing as most driving you do is around those engine speeds. What happens below affect slow engine speed running and idle. It's just me, but unless there were significant starting problems, I would never set up timing just based on what it starts like.

All said, you need a good in the region of 8 - 10 degrees minimum to achieve a good smooth idle. As such, as long as the max advance gives me the best performance AND it drops back to a good idle with no signs of pinking from idle to 2,500, all good. And with that, it should start absolutely fine. If setting it at just 5 statically results in all that, all good too!

In the end I did it by ear. Just rotated the dizy incrementally until I achieved smooth tick over, starting, and good pick up. I will get round to checking the numbers later. Never fails to amaze me just how good this motor is for a unit probably designed in the forties. Not as robust as the B18 etc but then again I don't thrash it. Very seldom go much above 4000rpm