Can your zook cruise at 100km/hr in top gear?

[RockHopper]

Is this maybe because the 'vacuum switching valve' only puts vacuum through when the engine is loaded, not at idle, and that it actually is working properly by not pulling in the secondary under no load???

Supposed to be working only under load, but in the case of my carby, it wasn't pulling it in all the way under load causing the engine to struggle past around 4000 rpm. By hooking it up ot the vacuum advance, it makes sure it opens all the way and now it'll power all the way up to over 6000rpm.

[Moph]

Yeah, but is there a difference between free revving and being under load? As in my secondary actuator doesn't pull in when free revving, but who's to say it doesn't pull in when loaded (eg 5th gear, 100kph, uphill)?

Only reason I say that is that there must be a *reason* why there's a switching valve there. If it were meant to be hooked straight up to manifold vacuum then there'd be no reason for the valve. They'd just select a diaphragm that had sufficient spring pressure to be inactive at idle vacuum and then pull in once revs increased.

I think there could be some negatives result from having it permanently connected to manifold vacuum. I just did an experiment with mine where I connected it to the 'idle up' vacuum hose that normally increases engine revs when AC/rear demister/lights are on. So secondary actuator diaphragm was inactive the whole time with headlights off; active (pulled in) the whole time from idle with headlights on.

Fanged it down my private testing road and found that with headlights on it was sluggish from idle to about 3500rpm. Went well above this, but no better than with headlights off (secondary actuator disabled).

Sounds like they're fickle beasts. Yours struggled past 4000rpm without it - mine will happily rev out to redline without it, and can't honestly tell a difference with it engaged. Even flicking headlights on/off (opening/closing secondary) while under acceleration made no difference to how quickly it revved out.

One thing I *did* notice was that engaging the secondary at idle made it idle faster. I think that's because my carby is running quite rich (needs a tune) and so more air = closer to stoichiometric = more revs for same fuel input.

[RockHopper]

I'm not 100% sure, but I think the reason the valve is there is to help the engine meet emission laws, remebering that the Sierra was produced right up to the late 90's when just about every other passenger car at the time was coming out with more effecient fuel injected motors. Applying vacuum to the actuator only when under load ensures the secondaries don't open when not needed keeping the CO and hydrocarbon levels down.
I'm not sure about your carby Moph, but mine runs like a dream from idle to redline (No flat spots, not sluggish, no idle problems etc). Sounds like though, if your engine will happily run to redline with the vaccum hose hooked up to the original port on your carby, then that port on your carby is working fine.

[eckeler]

that all sounds correct, theres a strong possibility that if i could find where the original vacuum feed to the sec. act. came from and connected it up standard, i might have similar performance to moph, it used to go hard, but had a sticky part in the choke or the needle and seat for the float , needing to be tapped to release it, meaning it ran rich and konked out at idle once warmed up, at least i know im on the rite track

[Moph]

I have to take mine in to the local carby shop sometime over the next couple of weeks as I have (I think) choke problems ... needs 4-5 accelerator pumps to get it started when cold, and then needs to be kept at 2500rpm until it warms up or it will just die. Smells rich, too. Starts and runs perfectly once warm.

Will ask the carby bloke about the secondary actuator switching valve and see if he knows what the go is.

[Longbaser]

Back on topic (sorry to interrupt.)

'85 LWB styleside softop.
Diffs and transfer are what it left the factory with 23 years ago, never been opened up. Ratios? Umm... the same, whatever they are.

S/H gearbox and S/H stock G13A fitted in 2000.
Stock airbox feeds from intake behind grille. Extractors and 1.75" exhaust with free-flow muffler.
7" alloys and 235/75 Pirelli Scorpion ATs.

On last decent run (loaded for a week of camping through Murchison goldfields), it sat comfortably on 110. Not many hills around there, but in normal empty mode it has no problem with what we call 'hills' in this part of Australia. On the flat with no headwind it feels good up to 120 at around 4700rpm. Maybe a bit more in reserve, but only a whisker.

My speedo is probably pulling my leg, but I don't mind, Zuke still feels fine after 21 years in my hands!

Cheers - Longbaser.

[Moph]

Back on topic (sorry to interrupt.)

[eckeler]

its all good gents, comparisons are being made, possible faults diagnosed and repairs suggested, maybe not the intent of this thread, but one of the outcomes never the less, keep em comming.
another point bought up was speedo/tire combo, ie accuracy of speedo with over size tires, i know mine is not accurate with 235nanking wide conquers, funny thing, i still try to push her along, speedo was affected after these tires were fitted (obviously).
but for me, after carby reco there was something missing, although she ran smooth as,(the secondary actuator was not connected to anything) therefore, i philosophize that, if somone wanted to save money on fuel, (govern their motor) at the cost of performance, they simply disconnect their secondary actuator, not sure of the magnitude of saving. way off thread i know, but another outcome, not that anyone would actually do this, unless fuel costs went even more through the roof

[GRPABT1]

This thread wasn't intended to be so accurate as to stress about speedo's that are all out anyway lol. I just thought it could be used as a reference for engine/gearing combos for noobs looking to speed up their zooks instead of starting a new thread.

[Gwagensteve]

its all good gents, .....maybe not the intent of this thread, but one of the outcomes never the less, keep em comming....

eckeler - do you own this thread? It's not really up to you to authorise a massive hijack that's taken this thread miles away from the topic.

Personally, I think all the carby crap infecting this thread is spoiling it. I think all the carby stuff needs it's own thread so those of us with EFI (like grpabt1, who started the thread in the first place) can avoid it and this thread can stay on track.

There's good carby tech here but by being lost in a thread about cruising speeds means that the search function becomes even less useful.

Steve.

[wideaz]

i can cruise at 100kph at 4000rpm
got her to 120 but its reving way to high to sit at it
4000rpm is too high to sit at but nothing i can do

i have 33s 5.12s 1litre trans gears 1.6litre motor

speedo is perfect

[GRPABT1]

There's good carby tech here but by being lost in a thread about cruising speeds means that the search function becomes even less useful.

Steve.

Good point, STOP HIJACKING.........now