Distributor advance springs?

[The Original Tom]

Because funds won't strech to a nice shiny EDIS system (see my other post), I'm wondering wether replacing the advance springs would help my poor power curve (gets shaky and looses power at the top end unless I advance the dizzy at the expense of idle).

Where can I buy the springs, what sort of price ar they, and are there different rates you can buy? I have a more torquey cam than standard.

The other possibility is that my vac advance it knackered, but I think they're very pricey aren't they? Can I rob one off another distributor (say a 4-cyl) or will it not work?
The only other possibility then is if someone on here has a spare dizzy that they wouldn't mind letting go for cheap (I'm a poor student!) I would be most grateful.
I currently have the 35DM8, but I'd guess the 35DLM8 or the 35DE8 would be fine as I'm using an RPI A&R Power amp with automatic LPG ignition advance.

Thanks in advance,
Tom.

[ChrisJC]

You can test a vac advance unit easily enough by:
- Check that the movement in the distributor is free
- Put some vacuum on it and see if it moves.

You could try somebody like Rimmer Bros to see if they do just the springs. I expect they would be quite cheap, certainly cheaper than another distributor (£25-30 on eBay)

Chris.

[sidecar]

Because funds won't strech to a nice shiny EDIS system (see my other post), I'm wondering wether replacing the advance springs would help my poor power curve (gets shaky and looses power at the top end unless I advance the dizzy at the expense of idle).

Where can I buy the springs, what sort of price ar they, and are there different rates you can buy? I have a more torquey cam than standard.

The other possibility is that my vac advance it knackered, but I think they're very pricey aren't they? Can I rob one off another distributor (say a 4-cyl) or will it not work?
The only other possibility then is if someone on here has a spare dizzy that they wouldn't mind letting go for cheap (I'm a poor student!) I would be most grateful.
I currently have the 35DM8, but I'd guess the 35DLM8 or the 35DE8 would be fine as I'm using an RPI A&R Power amp with automatic LPG ignition advance.

Thanks in advance,
Tom.

Real Steel do a spring kit for a tenner.

I've spent ages messing with my dizzy (35DLM8) to get the settings that I want. I now run 8 deg BTDC static and 32 full advance. I've left the vac connected as you get better part throttle responce. I have also made sleeves of varrious thicknesses that I can slide over the peg-stop to control the total mechanical advance that the dizzy can give. If you hold the dizzy in a vice and attach a 360 deg protractor on to the shaft where the rotor arm fits you can work it out. (Remember to double the figure as the dizzy spins at half speed). The kit comes with one sleeve but it is too big to fit. (WHS sell a protractor with a bit in the middle that slides over the shaft nicely once you've wrapped a bit of cardboard round it, you also need to knock up a pointer from a bit of coat hanger wire).

If you can not get enough advance you can grind the part of the bob weight arm that hits the stopper if you have a dremel or something similar. (It has been heat treated so it takes a while!)

I found that one gun metal gray spring and one bright silver spring gives max advance at 4k. Two silver springs at 3.5K and two gray springs at 4.5k. (I use the 4k setting). I don't know what the standard springs give as I don't think mine were standard when I got the car. They looked crap!

The copper coloured springs in the kit are too weak to be any use.

If your dizzy uses points then IMHO it's "pointless" messing about with it until you fit something better. JRV8 is a good bloke to talk to and could probably sort you out.

HTH,

Pete

[IanT]

Agreed, I used the advance curve kit from Real Steel, Part # BY72310, price 8.89 + P&P (Tel 01895 440505)

( You can now download & save just the RS Rover V8 price list in PDF format from http://www.realsteel.co.uk )

As I don't want to throw too much money at it before I know what I'm doing, I'm still with a points dissy.

The old advance springs seemed sloppy, there was a little free play before the springs took up.. and the heavy spring really didn't feel like it had any spring in it..

The new springs can be used in any combination - I used one light and one heavy spring from the kit to approximate the original spring strength. It's certainly removed that bit of slack in the dizzy, and by grinding away a little of the arm I can get a bit more advance. So it can be a cheap improvement if you want to retain the points dissy for the moment.

[The Original Tom]

Cheers fellas!
I looked at the real steel catalogue and I must have been blind because I didn't see that!
As my V9 is in a defender, and the only performance mods are torquey (not wild power) cam, and a freeer air supply (and maybe soon tubular headers), so I think introducing full advance at 3500 would be too much?
Where would be an appropriate point? I was thinking about 28deg at 4000rpm would be about right for it? What do other people run at what stages of tune?
Does one configuration give better torque than the other so is one more use on a Landy than say an MGB?
One more thing - how long did it take you guys to strip down the dizzy (NOT a points type). I'm certainly no stranger to a screw driver and I can't imagine it being much more complex than that really? (except removing it!)

Any advice greatly recieved.
Tom

[Paul B]

Real Steel do a spring kit for a tenner.

I've spent ages messing with my dizzy (35DLM8) to get the settings that I want. I now run 8 deg BTDC static and 32 full advance. I've left the vac connected as you get better part throttle responce. I have also made sleeves of varrious thicknesses that I can slide over the peg-stop to control the total mechanical advance that the dizzy can give.

I've done basically the same as you, but I ground a little off the internal stop on the dizzy as well as fit the springs, so I can get a full 36 degrees advance whilst still keeping the book recommended 6 at idle. I can't remember what colour springs I fitted, probably the medium strength ones though, mr middle-of-the-road me.

To find the most advance it would actually take I basically set it to 36, then I went out, found a long empty stretch of road, floored the throttle through the gears and listened for pinking: it pinked at about 3500rpm.

I then stopped, tweaked the dizzy back a tiny bit, did the test again, until all was quiet. It works best if you find a very slight hill, just to get the car in a real high load situation.

My motor is basically stock, with the usual Edelbrock/Weber combo. I guess it is impossible to tell anybody what their advance should be as it will vary from car to car, spec to spec, so the above method is the easiest to use. I still have no real idea what advance I actually have. Got to get the strobe out so I can mark it for future reference.

[sidecar]

Cheers fellas!
I looked at the real steel catalogue and I must have been blind because I didn't see that!
As my V9 is in a defender, and the only performance mods are torquey (not wild power) cam, and a freeer air supply (and maybe soon tubular headers), so I think introducing full advance at 3500 would be too much?
Where would be an appropriate point? I was thinking about 28deg at 4000rpm would be about right for it? What do other people run at what stages of tune?
Does one configuration give better torque than the other so is one more use on a Landy than say an MGB?
One more thing - how long did it take you guys to strip down the dizzy (NOT a points type). I'm certainly no stranger to a screw driver and I can't imagine it being much more complex than that really? (except removing it!)

Any advice greatly recieved.
Tom

Your total advance will depend on a few things:-

1. The static compression ratio
2. The volumetric effeicency of the engine, i.e. if you have a good inlet system there will be more mixture to compress and therefore a high dynamic compression ratio. (VE)
3, The octane rating of the fuel that you want to use.
4, The displacement of the engine.

I run a stage III 3.5 (9.75:1) on super unleaded with 32 degrees advance, bigger motors tend to run less advance.

The dizzy is easy to strip but there is one thing you need to be careful with, it cost me 45 quid to find out! When you push out the roll pin that holds the drive gear on to the shaft make a note of how the gear was fitted. Failling that when re-fitting the gear check the alinement of the holes in the gear with the hole in the shaft, try the gear both ways round. You will find that the holes line up OK one way but not so good the other way, if you don't do this and just force the roll pin back in you could crack the gear! Check for end float of the dizzy shaft, I've shimmed mine to give 10 thou. I recon too much might cause problems with the gears riding up and down each other messing up the timing. No clearance will cause lubrication problems.

I imagine that a torquey cam gives good cylinder filling at low to meduim revs so you might want to hold the advance back a bit. At the top end the cam may not be allowing the cylinders to fill so well so you could run a bit more advance. You've got me thinking now that I could run more advance in the mid range on my motor as my cam is revvy.

I recon a good start for you would be 32-34 degrees total advance then mess about with the springs. I don't think less advance will give more torque, you should aim for as much as possible whilst having some degree of safety and no pinking. 8 to 10 degrees is about the max static that you can run. It will tick over well with more but stumble as you pull way because the vac kicks in and over advances the timing. Less then 8 and my motor does not tick over too well. (More than 10 might give your starter motor a hard time if it kicks back). Use a timed vac port!

Be aware that the TDC mark on the damper might not line up well with the pointer. You need to find the EXACT TDC then adjust the pointer so that it lines up properly. By exactly I don't mean a screwdriver shoved down a plug hole! You need to to use a DTI gauge. Unfortunatley it might not work well as the plug hole is at quite an angle, the rod on the gauge may bend when the piston hits it. I did mine when the heads were off.

Heed my words about finding TDC, if you don't get this right then every other measurement will be wrong.

If your damper is off you can mark it further round to give you 28,30, 32, 34 marks as well.

To work this out measure the diameter in mm, X by Pi (3.14) Then divide this by 360. this will give you the distance in mm for every 1 degrees round from TDC (About 1 mm from memory). Times this number by number of degrees that you want to mark, and this number will be the distance in mm round the damper from TDC that you need to mark.

(The number won't be exactly 1 mm, it was something like 1.1xx?)

I used a junior hack saw blade to make the mark then filled in the cut with white paint using a single bristle from a brush.

You could say sod it and buy some degree tape from RS but that's less fun!

You need a good timing gun and one last point don't be surprised if whilst gentley reving the motor the timing retards a fraction before the bob weights kick in. This is not ideal but its due to "cam walk".

Oh one last, last thing, when you mark the block and dizzy to aid refitting don't think for one minute that lining the marks back up is good enough, my timming is always at least 2 degrees out when I re-fit the dizzy!

HTH,

Pete

[The Original Tom]

That's a post and a half Pete!
Re marking the crank you've just confirmed what I was already planning - I'm aware that often pulley markings are really inaccurate! .

I'm running: 3.5 at 9.35:1 CR. It runs on standard Unleaded but mostly LPG. My A&R allows me to change the static timing between LPG and petrol any way, between 8 and 12 degrees. I just set it at a bog-standard 10 and left it.
When I set this up, I'll do it on gas first to get it right, and then adjust the petrol (because the box can't pre-empt a spark, I assume it must mean running permanently 10deg over standard, and retarding the signal for petrol, i.e with a timing strobe, when running LPG I'll have 16degs adv at idle on LPG, and 6 degs with petrol)

My inlet system is very open (not ported, but un-restricted by filter & pipes)

Point about the gear noted with care!!

Thanks for the help all, if you have more, keep it coming

[sidecar]

That's a post and a half Pete!
Re marking the crank you've just confirmed what I was already planning - I'm aware that often pulley markings are really inaccurate! .

I'm running: 3.5 at 9.35:1 CR. It runs on standard Unleaded but mostly LPG. My A&R allows me to change the static timing between LPG and petrol any way, between 8 and 12 degrees. I just set it at a bog-standard 10 and left it.
When I set this up, I'll do it on gas first to get it right, and then adjust the petrol (because the box can't pre-empt a spark, I assume it must mean running permanently 10deg over standard, and retarding the signal for petrol, i.e with a timing strobe, when running LPG I'll have 16degs adv at idle on LPG, and 6 degs with petrol)

My inlet system is very open (not ported, but un-restricted by filter & pipes)

Point about the gear noted with care!!

Thanks for the help all, if you have more, keep it coming

Tom,

That last post was the entire "file in my head" on the dizzy...there is no more!

LPG....I know nowt about that!

Running 9.35:1 may allow you to run 36 degrees total advance but I doubt you notice much difference between 32, 34, and 36 anyway unless you have a RR handy.

The protractor thing from WH Smiths is worth doing because a lot of dizzys fitted to RV8 lumps won't give you the total advance that your after.

If you want to run 6 static, 36 total you need 15 out of the dizzy measured at the dizzy. You'll see the bit that needs grinding with a dremel, you can grind a cresent out of it rather than keeping the edge straight. The surface is rock hard but it gets easier once you've got 0.5 mm off it. Don't grind the spring peg as it will get too weak. Keep checking for the 15 degrees (or whatever number you decide to go for), it's not easy to put metal back on. (I know, I had to do it with a mig welder!)



Regards,

Pete

[The Original Tom]

First thing I'll do is check my max advance now. Then I can strip it down and increase max advance if needed, and fit new springs.
I assume that my full advance will be the same, regardless of springs if I turn it by hand?

I Think I'll aim for 32deg then as it seems a safe, yet reasonably high number (compared to now at least!)

Thanks, I'll re-post when I have the job done, with piccies for later use so someone else can see how to do it!

Tom.