Hanra,
I have a bunch of old 29Ds here, if I can find a good vacuum can that works I'll post it to you.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

WOW!!!!

Thank you very much Kevin!!!!! That would be greatly appreciated!!!!!!!!!!!!!!!

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http://www.youtube.com/user/Hanras

My understanding is that vacuum advance is there to allow more complete combustion (which is better for emissions and for engine life), and a little more power on lean mixtures (which is better for economy). It doesn't lean out a mixture - it might allow you to run a touch less throttle, but not so much that you're likely to see things change from 12's to 14's. That's a fairly significant shift.

Not saying it won't help overall, but I don't think it's your major problem right now - I don't think it'll fix your 'rich mixture at cruise' issue. Because it doesn't set the mixture. And, after all, there's a lot of Minis out there with 43D4's and other non-vacuum advance dissys.

Righteo, Ill still be giving those yellow springs a good try when I get them. Another variable for me to try. But yeah Ill fit the vac advance just so thats another thing ruled out. Can always just disconnect it again if no good.

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http://www.youtube.com/user/Hanras

Should also mention that Ive been doing all this AFT monitoring with no air filters on...

Ive got K&N pancake filters that I just bought. So I guess things may richen up a tad with them fitted???

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http://www.youtube.com/user/Hanras

Ok so these finally arrived today. Wet season is upon us and we have a looming low which could turn into a cyclone off the coast. So not sure when I will get a chance to take the car out again.... Also ordered some SU damper Oil. Will give that a shot to. The kind Dr Mini has supplied me with a vac advance unit, also bought a new vac line assy to go from carb to vac advance to. Will just put that on for interest sake, may help cruise mixtures a little?

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http://www.youtube.com/user/Hanras

Got the yellow springs and M needles fitted and some SU damper oil. It's wet here at the moment so can't go for a test drive.

Went to fit the vac advance unit that the kind Doc sent me.... Turns out my dizzy is locked!!!! Ken Nelson must have had a reason for doing so. The base plate is brazed up.

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http://www.youtube.com/user/Hanras

Hi Brad, when you say locked, is it limited so that it can't advance past a certain point ( eg modifying a pulsar dizzy so no more than 15dizzy degrees(
read 30 degrees timing light) or no movement...such as fully advanced and then locked so a black box or whatever can look after the timing????
it surely can't be unable to advance????

I think he means the top [vac advance] plate is locked to the fixed plate underneath, this is often done to run with no vac advance.
Vac advance on a race motor is just something else to go wrong, which is why a Cooper S doesn't have it stock, but a Cooper 997 or 998 did.

Brad, use the plate out of the 29D dizzy I sent up.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yep as per The Doc's description. The top plate is brazed up.

You know what Kev... I think I glued on the Pertronix Magnet to the shaft of the dizzy as it had a little bit of play in it which I wasnt happy with..... To get the plate off, I need to get the magnet off the shaft...... Doh!!!!!!

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http://www.youtube.com/user/Hanras

Got up early this morning while it was only 30 degrees, so I could beat the heat... Went for a run with the yellow springs. Cruise is now much leaner, 13:1 still not ideal but I don't have vac advance. WOT through the gears is usually about 12.5-13.5:1.

Here is a clip at cruise on a private hway, 4th gear 80kph then WOT. There is a brief lean condition 15.8:1... Is that due to the dashpot oil? Or is that just expected with SUs? In using penrite SU dashpot oil.

http://youtu.be/WfXziXqNGd0

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http://www.youtube.com/user/Hanras

Vac advance will not affect the mixture. All it will do is give extra advance at low throttle openings. This should/might improve economy.
If you have high compression and find it pings with the vac advance fitted, I'd put it back on the shelf.

Remember to disconnect the vac advance when setting the timing.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I leaned the mixture out a bit. Even at idle it was a bit rich. This has leaned the cruise mixture up quite a bit. It's now 14-14.5:1. So I'm happy with that. Still goes a fraction lean in 4th gear cruise 80kph to WOT to about 15.5:1 but only for a fraction of a second then it's about 13:1 all the way up. Is that ok??

http://youtu.be/PF1S3KJZt04

Through the gears WOT seems ok, high 12s low 13:1.

http://youtu.be/JQv6PQ2hfvo

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http://www.youtube.com/user/Hanras

That is fine.
You won't get much better with an SU, it ain't a MPI system...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I've kept popping my head in here, but only just discovered the updates.

Those are great looking figures. I'd be curious to see what happens with your economy and your spark plugs. Equally importantly... How does it feel? Compared to when you started this journey?

And your earlier question about leaning out, you're right, it's the dashpot oil. My memory's rough here, but heavier oil means the dashpot rises less quickly against the spring. To avoid the vacuum of the opening throttle from pulling the needle up too quickly and thereby flooding the engine with too much fuel. So, if it's going lean, maybe you need a thinner oil - or no oil - so that the dashpot rises a little faster transitioning from cruise to WOT.

But I think that's a well documented - and tested - story there, Hanra. You've gone from AH2's, Red Springs and Singer Oil in your twin HS2's to M's, Yellow Springs and SU Oil. And you've gone from running lean, breaking down, missing and not revving cleanly to something that sounds pretty happy in your videos. And something that's running some rather nice mixture numbers. Good job.