Good to know!

I found a curve on line for the 123 to get it running.  

Got the dizzy in the car yesterday and can tell a difference right off.  The bluetooth feature is outstanding. I can program the curve as the car runs right from my phone.

Peppieandmister emailed me off-line asking about programming 123 curves using Bluetooth. To my great surprise, there are now Bluetooth and USB versions. Apparently, you can now custom program your very own curve. Promising concept for experienced tuners and for the nay-sayers who complain the 16 pre-programmed curves might be close but not exactly right for a Mini engine.

Thanks Dan...I just ordered me one.

Heading down to California in Dec to get it dyno'ed.

Find a dyno and spend a couple of hundred bucks, you'll get the timing and fueling right and safe in the knowledge your not hurting you engine!!

Peppieandmister: I have a 123 and I love it... completely satisfied. I think the water/corrosion issue is an anomaly (...my opinion). Too many other satisfied owners not having that problem. For the money, it was the best solution for me - 1275 Metro engine, HIF44, Cooper Freeflow header to single box RC40... nothing 'standard'. I found a curve that my motor told me it liked best, and it wasn't one of the curves suggested based on engine spec. No opinion on other systems.

John: What do you think about the yellow carb spring he has in his HIF44? Too hard? too soft? Just right? (Goldilocks spring?)

Thanks Jeg,

I am running straight 20W in the dashpot.

My 2¢ - buy or borrow a dial-back type timing light, slowly bring the engine to 4000 rpm and rotate the distributor such that when the timing light is set at 30 or 31° BTDC, the mark on the crankshaft pulley aligns with the large tooth on the timing cover scale.  The distributor should be all-in at or pretty darned close to 4K, heck, many are at max mechanical advance by the time the engine reaches 3500 rpm.

The attached image shows the notch on the pulley nearly in line with the large ignition timing scale tooth; in order to get it to line up properly, I'd need to retard the timing light just a tad and once it's aligned, I'd look at the timing light and make a note of what it's currently displaying.  If it's showing 27°, rotate the dizzy clockwise a small amount and try again.  If it's showing 35°, turn the dizzy counter clockwise and try measuring again. 

Now it'd be time to test drive the car, listening carefully for any 'pinking' or 'valve rattling' when accellerating in top gear at 2500 rpm - test it again at 2800 rpm, listening for any pinking or valve rattling.  NOTE:  This is not a drag race - don't just floor it - use partial throttle and gradually progress with more gas pedal until you're up to around 3500 rpm.  TIP:  Light use of the hand brake can be useful to increase the load on the engine.

If it does 'ping or rattle', there is the chance that your distributor isn't suited to your engine.  Try dropping the max. ignition timing from 30° to 29° and road test it again.  

After you've got the ignition close to good, make a note of where it lies at 1000 rpm - vacuum advance disconnected and plugged.  Put a set of fresh spark plugs in it and drive it around (conservatively) for a while.  Pull the plugs and examine them under a strong light and use magnification to check for peppering or small shiny aluminum balls that have welded themselves to the insulator tip.  That's a tell-tale sign, in fact, one of several, that you've got a detonation issue and the aluminum is from your pistons.  If you see any, you need a different dizzy.  (I posted some info on RMF a while back - you might want to join the group)

I might have missed it if you wrote anything about it earlier - did the distributor come with the engine?

Not knowing what advance curve the dizzy is equipped with and trying to time it at idle won't yield any usable result beyond getting the engine started.  Once started, your engine will tell you what it wants.

 

Personally, I think you've got a carburettor suction chamber damper oil issue.  The damper oil provides enrichment upon acceleration - more fuel gets drawn from the jet before the suction chamber piston rises to the next station on the carb needle.  A thicker oil will delay the pistons rise fractionally longer, thereby creating a greater depression over the jet and allowing even more fuel to be drawn from the jet.  A thinner oil will allow the suction chamber piston to rise quickly, sometimes too quickly, creating a momentary lean condition; yes, even though the needle is thinner as it gets drawn up.  It's a complicated yet simple concept.

You should be using the LZX2085 damper in the HIF44 - check that you've got the right one, as this also plays a role in the speed at which the piston drops down to the bridge, for example when you change gears and have your foot off of the gas pedal.

(Berlen Fuel Systems has some great information on their website - look for 'Technical Pages' on the SU tab.)

Standard SU damper oil is 20W, and if you haven't any of the real SU oil, motorcycle fork oil does nicely; it's also available in 25W, 20W, 15W, 10W, 5W.  I make it a point to have a complete assortment on hand; small nalgene bottles are handy for keeping a bit in the boot.

Good luck -

Dan,
It stumbles as soon as your are done shifting and get back on the gas. Once it picks up again its all good.
Also stumbles a bit if your running at a steady speed and then floor it but once it gets going its fine.

The engine is a 1380 from MED.

I've been using the Orange Mini book...not the hanyes. It shows 13 degrees for a 1275.  I have run less advance and it gets worse. But I'm afraid to go past 13 degrees.

Currently is has a  59D4 dizzy in it.  I have been watching the forum about the 123 dizzy. Are you a fan of them?  What is the thought about the Aldon's?

Agreed...I need to get this sorted first.  I thought it was in the carb to begin with but now I'm 98% sure its the timing. 

I notice elsewhere you are asking about carb needles. Get the ignition optimized before touching fueling. 

Most distributors would max out on advance at about the same place, give or take a few degrees.
I suspect you may have too much advance.

Does it stumble immediately after you shift, or does the engine accept the shift and stumble somewhere mid-range between shifts? You may have too much initial timing advance, and the vacuum advance is not coming off soon enough, so you are getting too much advance for the rpm of the engine when you open the throttle.

You say 13 degrees but at what rpm? If you look through the chars on page 5B.2 and 5B.3, a MkIII Cooper s 1275 only got 4 deg. at 600rpm; Mini 1275 GT (1969-72) 10 deg @ 600 rpm. Mini Clubman 1275GT 13 deg. @1000 rpm. Big differences, depending on the dizzy specified and the curve they produce. Presumably, timing set at 600rpm is to ensure that no mechanical advance is occuring, but at 1000 rpm, the dizzy is definitely on-curve somewhere. (The 123 ignition provides 0 (zero ) advance until the engine gets to 500rpm, then steps onto the selected curve.)

You also say your engine is a 1310 with 10:1 compression, fast road cam etc. That's not stock, so a stock dizzy is probably not right for your engine (would be coincidence if it was). That means the dizzy it was originally built with (if that's what you are running) is not exactly right for your build.

Try retarding the timing by one notch, test, try another notch, test. If you see improvement, you are heading in the right direction. If not, try advancing CAREFULLY. Too much advance will damage your engine badly.

My manual said 13 degrees for a 1275 so thats what I went with.  

Still bogging down when shifting and back on hard or med throttle.

Maybe my dizzy doesn't have enough mechanical advance in it for my 1380??

Any ideas? 

Have a look at page 2A.3 of your Haynes - Diag. 3.4c shows the timing scale for a later manual transmission car. On that diagram, each point is 4 degrees. Yours may be different.
Over on page 5B.3 is a list of static and stroboscopic timings. Try one closest to your engine spec. My WILD guess would be to start about 8 deg. BTDC @1000 rpm. Then road test carefully. If you have one of those fancy set-back (?) timing lights, make sure you are using it right ( I don't know how they work, so can't advise). If you do, you should be able to read maximum advance at any rpm.

Note: my car has a 1275 high compression engine and came with an un-labelled, tired dizzy probably from a 998. When I could afford it, I went for a 123 system.

Thanks Dan,

Yes I pull off the vac advance hose and capped it off. 
Perhaps I still don't have enough advance in it.

How many degrees are each tooth on the timing cover?

The answer is "probably not".

First you need to understand "vacuum advance" in a distributor.

The spark advance curve during acceleration is governed only by the mechanical advance (or its digital equivalent) that produces the advance curve. The faster the dizzy shaft turns, the farther out the weights move by centrifugal force. The size of the weights and the strength of their springs determine the advance curve. The basic idea is that at high rpm, the pistons are moving so fast, the spark must be provided earlier to allow for the time combustion takes (it is a spreading flame).

Vacuum advance works when you are NOT accelerating. It is a fuel efficiency device, simply put. When at idle, the manifold vacuum is applied to the orifice in the carb. Since you are providing very little air/fuel mixture and are not needing much power at all, less fuel is needed if the spark is advanced to give a more complete burn while both valves are still shut. When you open the throttle, you let air in, reducing the vacuum draw on that orifice. The vacuum advance relaxes, allowing the mechanical advance to do its programmed job. When you get up to the speed you want and lift your foot off to cruise (or decelerate), the vacuum advance reactivates, but depending on the rpm and the status of the mechanical advance at that rpm, it may or may not have any actual effect.

Racers usually are not concerned with fuel economy (and cruising), so they do not need vacuum advance.

Now, about your problems:
Did you disconnect and cap off the vacuum advance tube/hose while setting your timing? If not, you may have not enough advance. If you thought you were setting for say 10 degrees at 1000 rpm, the vacuum advance may have been inputting say 15 degrees (I"m guessing), so your true advance might only be -5 degrees, so your mechanical advance curve is way behind the game. so, when you accelerate, the timing is all wrong.
So, set your timing by disconnecting the vacuum advance, plugging the hose to the carb with a small bolt etc. , set the timing to the specified advance at the specified rpm. Then return the rpm to idle and reconnect the vacuum advance (which will probably shift the idle speed on you... readjust).

1380cc, 10:1,  HIF 44 (BBW) with Yellow spring and K&N cone filter, fast road cam, Vacuum adv dizzy.

I am having a ton of hesitation and stumbling when under hard acceleration after shifting gears. I have tuned and tuned on the carb so I don't think its totally due to the carb.

I am thinking that under hard acceleration I am losing most if not all vacuum causing the spark to retard hence the ending is having a hard time running.

Seriously considering switching to a non-vac dizzy.  Will this help?

Thanks!