[Sidecarbod]

Originally Posted by RCCob

Hi every one, I was checking my dissy over the other day after I developed a slight misfire, I found that one of the springs on the advance weights was stretched and loose, the other one was tight and still springing back ok. I dont know much this would effect the timing curve? Question is, is this supposed to be like this? if not should I replace the springs? and where do I get them from? I understand there is different stiffness of springs available, So which should I buy?

any help appreciated Russ

Hi Russ,

I presume that its a Rover dizzy that you are talking about.

I did a lot of experimenting with my dizzy on my 3.5 lump (now 4.6 ).

You will be getting too much advance too early with your setup which could cause problems unless the slack was compensated for when the timing was first setup by retarding the dizzy.

Real Steel sell a kit for 10 quid that has several springs in it. I found that two of the silver springs will give you full advance at 3k RPM which is just right. (One silver spring and one gun metal spring will do the same at 3500RPM).

Whilst you've got your dizzy off you can check out what the total advance is by fixing a 360 degree protractor on the end. (You get one from WH Smiths). It is easier to check when no springs are fitted.

Hold the dizzy in a vice and setup a pointer to the protractor then work the advance mechanism. Whatever the number is needs to be doubled for crank degrees. The reason that this is important is that you want to be running your 3.5 lump at 36 degrees total advance, any less than this and you will be losing BHP. (Don't go more than 38 )

If for example your dizzy measures 12 degrees then that is 24 at the crank. You will then want to set the static at 36-24= 12. The standard damper marking don’t go past 10 from memory but I made a load more at the static range then even more at the max advance range.

6-8 degrees static is often quoted as the static for one of these lumps but this gives bad low end BHP and bad top end! Rover were just playing safe due to wallies loading up the engine instead of changing down and/or poor fuel.

Up to 14 static is fine and infact 14 is good!

I modified my dizzy so that I could restrict the total advance to allow me to run 14 static.

I did loads of mods to my 3.5 lump to get more BHP but the only one that made me go "hey I can feel a difference" was setting the timing as described above. (Even fitting stage III heads was only just noticeable)

The extra advance makes the 3.5 pull a lot better from low RPM, I'd guess at 30 BHP more between 2-3.5k RPM. (Seat of the pants dyno!) It’s the cheapest 30 BHP you’ll ever get assuming that it was set at 6-8.

Regards,

Pete