Distributor advance stuff

Post by **toolsntat** » 25 Feb 2006, 19:51

Hi Keith, how you getting on with this??
Had another go at mine today.Set it as above but it didn`t like it,maybe there is something wrong with my dizzy although I have tried my spare one as well!!(could be knacked as well I suppose)
Is there ought else we should know??
By the way when set at 30`@3000 BTDC the timing at tickover (rough) was 4` ATDC!!

Post by **cumbriankeith** » 26 Feb 2006, 08:09

I'm still working at it - I know how to strip down a diz now - and I'm trying to get one (pref two) good ones out of the four I have!

[Not much time to play with the camper this weekend - popped up to Edinburgh yesterday to watch a bit of rugby! My wife, who is very English, enjoyed her birthday treat but not the result; whereas I'm more Welsh so have to wait for this afternoon to see how the boys do in Dublin.]

I'll report back asap on my progress...

Post by **camper** » 11 Mar 2006, 08:06

cumbriankeith wrote:Just been looking at the Haynes again and puzzlement continues - I also have a printout of a web-page Simon Baxter did a few years ago which differentiates between the timing setup using the idle-stabilising-unit and not using it - that is, it seems to be 7 btdc if you intend to leave the unit out and 5 atdc if you intend to reconnect. Maybe Simon or Steve S will confirm or clarify - or I might give Steve a ring and report back...

Keith have you any further info regards the timing setup?.I am not using the idle-stabilising unit as the wires in the plugs are damaged.

Post by **cumbriankeith** » 11 Mar 2006, 09:21

What I said last time is wrong. Whether the ISU is used or not is immaterial to the timing which should be 5ATDC, provided a distributor with both vacuum advance and retard is in use, working properly and left connected.

Another approach, which should arrive at the same setting if everything is working, is to do the basic timing adjustment with just the mechanicals in use - disconnect the vac pipes (plug the retard one - the one that comes from the idling supply - behind the airbox), time it at 7BTDC at 850rpm, then check that it advances to no more than 30BTDC at 3500rpm. If it does then the weights/springs in the mechanical advance are suspect.

To check the vac stuff - reconnect the vac advance (goes to the cone-shape part of the vac unit) and when you open the throttle there should be a virtually instant advance of about 10 degs. Then reconnect the retard pipe and the idle timing should move to 5ATDC. If one or both of these fails to occur then either the vac unit is faulty or the basic throttle setting on the carb(s) is wrong (too far open - the retard vac at idle relies on the partial vacuum beyond the throttle plates - called "manifold vacuum" and this collapses when you open the throttle. The advance vac relies on "ported vacuum" taken from just above the throttle plate - this quickly develops when the throttle is opened).

All this has been gleaned from various sources, including The type4rum and the Samba - if any corrections or clarifications are needed then I hope others will contribute...

Post by **camper** » 11 Mar 2006, 14:03

Keith that sheds some light on my idle speed .When i run up the engine i had the airbox vac off i was wanting to check if it would run okay after the recent rocker problem.When i reconnected i had a high idle speed and difficulty in starting again.I connected and disconnected the vac pipes and the idle speed came down.I think i may have a sticky advance plate in the distributer.I am on the occassion getting starting problems i think its rich fuel on one carb.Its early days yet as i have only just got the devon going i will check out the fuel float to its valve.

Post by **TimL** » 15 Mar 2006, 19:52

regarding rich weak mixtures etc what would be performance symptons of a over rich or weak mixture.
the reason for asking i hope i have got the timing just about right but feel the vehicle is holding back on acceleration from say 30mph onwards performance may seem better in this area when engine is cold ie chokes working, ( this may be just my imagination as ive had no time to do some runs in the van )
obviously ill check plug colours etc

Post by **cumbriankeith** » 15 Mar 2006, 20:57

Hmmm - getting out of my league now! I have still to get mine sounding and feeling right (loads of snow round here has thwarted my attempts and enthusiasm over the last few days...) I have partially serviced my carbs (stock Solexes) but have yet to put them back on and have another
little tinker. I'll keep you both posted - probably after the weekend.

Post by **TimL** » 15 Mar 2006, 21:11

the weather does seem to be thwarting my attempts to make progress on my own bus too keep me posted and if you put together a spare dizzy let me know thanks Tim

Post by **toomanytoys** » 15 Mar 2006, 23:15

Oh and dont be tempted to fit an 009 as they are useless for a type 4 engine.. not enough advance and not fast enough advance ramp..

From what I can remember reading, its not unusual to see 40 deg with all hoses connected correctly on a very light throttle.. from a type 4 guru...

30 sounds a bit too retarded for max advance.. I would have it at about 32-34 max mech (only, disconnect and plug vac hoses) advance, especially if running on LPG..

If you have a head temp gauge, then you can do a few tests to find the optimum setting for your bus.. but then most dont have...

Post by **TimL** » 16 Mar 2006, 19:49

have either of u tried a 050?

Post by **toomanytoys** » 17 Mar 2006, 17:31

Dont think an 050 is good either.. unless you reset the advance curve..
stick with a proper points or electronic type 4 one.. or a mallory.. ££££..

if seriously tuned...

Post by **cumbriankeith** » 26 Mar 2006, 18:22

I have been tinkering around and now have an extra that I don't need - fully stripped, cleaned, serviced, lubed and tested. No pinch plate but they don't really wear out!
TimL has first dibs and I think someone else expressed an interest.

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