G'day.
Today It was necessary for me to to the full tuning thing on my bay.
I did the points, timing and idle. But the thing is where the weber progressive comes into it I'm less than certain I'm doing things right.
I had a few reasons for redoing it again.
I thought I heard a ping in #1 while idling. Also I wanted to redo the points and adjust the timing for regular ULP.
There was also fixing the tuning it after it wasn't running on all cylinders.
Anyway, I wasn't really sure what to set for a baseline advance. I ended up settling on something at maybe between 4 and 6*BTDC. It's really a bit hard to tell.
The trouble I was having is when I took it back past maybe 8*BTDC, The engine would just slow down to a stop. Cranking the dissy the other way just made it rev up and up.
Makes sense.
So I had to fiddle the air bypass screw on the weber to keep it idling while I got the timing right.
After I got it idling again, I wound the idle screw back again to find the sweet spot.
Now that I did that, and reconnected the vac line, it changed the maximum advance quite a lot. Before needing to fiddle the carb to change the idle advance without stalling, It was getting maybe 28* advance revved up.
Now it seems to be getting over 40! and this is _After_ retarding the idle timing.
I just don't know.
Incidentally what is the right way to adjust a weber progressive's idle?
I've just been doing it by tweaking the throttle shaft stop screw until it stays running, then finding the sweet spot on the bypass screw, ie a bit before it starts sounding funny and revs dropping.
Then I readjust the stop screw, and check the bypass screw again. Is that totally wrong?
It seems to work alright, but I don't know if it's the correct procedure.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
Yes, thankyou. It is extremely helpful.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
The generally accepted way of timing the TIV engine is to set the maximum centrifugal advance to 28 deg and then let the idle sit where it falls to (which is usually somewhere close to stock anyway). With the vacuum as well you will be getting over 40 deg as you have observed. You aren't supposed to have any vacuum advance at idle, but the best I could do was 1-2 degrees and this was by reducing the idle revs to around 600 rpm. That didn't seem to cause any other probs!
My biggest headache with the progressive was vacuum leaks. I think it is worth it as part of a tune up to detach each spark plug lead in turn when the engine is running to see if any cylinders aren't pulling their weight. This can be an indication of a vacuum leak (usually was in my case 😀 )
If you're doing a tune-up have you set the valves and checked the spark plug gaps? The spark plugs are also a good indication of how each cylinder is running.
The chance of vacuum leak is pretty low but I won't rule it out.
I spent so much time fighting with the duals and their leakiness that I went a bit overboard this time on the progressive.
Still, I won't rule it out as I am still a little suspicious about #4.
I'm tempted to redo the timing again in the next couple of days. I'm not happy with the result.
The rockers and the points have all been done.
Plugs on 1 and 3 are sooty. can't say I'm totally surprised. Seems to have a case of weber progressive-itis. I reckon if I turned the carb around the other way it'd have soot on 2 and 4 instead.
The biggest nightmare seems to be inconsistent running. I think I have it tuned properly, but next time I go to use it it runs like a three legged cow.
Kept stalling it today when trying to shift it back under the carport. But in all fairness it was a bit tricky. And compounded by th eaccelerator pedal being as dodgy as all hell. Well more specifically everything to do with the accelerator from pedal to carb.
Oh, in amongst all the fun I substituted a couple of old sparkies from the falcon, but to use them I needed to borrow a couple of leads from the Magna. I'm not sure if it was my imagination but it seemed to run smoother.
Today it gained a few unused lucas sparkies of unknown vintage that I found under the drivers seat, so I could swap the leads back. It felt acceptable after that.
Would changing to non-copper leads make a positive or negative difference. ignore the air seal issue. It's using a GT-40 coil not that it really matters. Extremely good sparker though.
When I was doing the remove-one-lead test a couple of days ago I was having 'fun'. Problem was the liveliness of the sparks. When I pulled #3 I was at a loss of where to hold it so it wasn't sparking off something. to add to that I was getting a nice tingle from it. even after I swapped to holding it with the elastic of a bungee strap.
Oh yeah. What I wanted to ask is what is a good baseline idle advance for regular ULP?
So I set the timing at 3000+rpm or wherever the max mech advance is? okay. I like that method better.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
I had similar problems getting the bus to move at low speed with the progressive. I now have twin weber icts (which have their own set of problems). I haven't tried different spark plug leads so can't help you there.
As for the advance, yes, set the max mechanical advance to 28 deg (it is about 3000 rpm) and let the idle advance sit where it wants to. The idea is that you (hopefully) spend more time with the engine not idling than you do with idling.
I haven't done the timing again yet. I'll be tackling that tomorrow. Today I installed a fusebox in the engine bay and will be adding a relay tomorrow morning.
I'm not so hot on the coil, choke, reversing lights and electric fuel pump running off one tiny, sickly looking unfused wire.
It seems to idle and run properly right now, although I suspect I probably set it a bit retarded.
I fixed the acceleration problem with lateral thinking and brute force. I rotated the carb to eliminate my mechanical linkage, and twisted the accelerator pedal shaft, because it would seem as though it was only getting a tiny bit of it's proper travel, which I had previously compensated for by changing the ratio of the mechanical linkage, which lead to a heavy, non-linear.movement which made control pretty much impossible.
When I do the timing again I'll report back with the results.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
I also had to make a few adjustments to the accelerator linkage to get the proper travel. Mine also had had the stop under the pedal bent up out of the way so you could get "pedal beyond the metal", which I'm sure was great for the carb as it attempted to come through the firewall! 😂 I bent the stop back out and adjusted it so that it stopped at full travel. I also replaced the metal piece that goes between the end of the accelerator pedal shaft and the cable to increase the cable travel for a given movement of the pedal.
Haha. That's classic. bending the stop wouldn't have got them far on mine. Auto pedal so there's a big switch under it.
I tried adjusting mine to stop at full throttle first. Worst Idea I could have. When I started it up, I had to kill it pretty quick so the motor didn't grenade 🙂 Anything over a little throttle in neutral and it winds right up. For such a mess of a motor it is pretty free spinning.
So you put a bigger lever on? That was my original intent, and how I realised what was going on when I pulled off the skidplate.
What holds the lever in place? I've never undone that nut.
If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.
