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

[Moph]

Woot! Update on mine now that it has a few kays on the clock after the rebuild.

Just did a trip to Koolunga (200k's out of Adelaide) with 2 people, loaded cab (125kg) and a 5x3 trailer carrying a weights machine and BBQ. Sat on 110km/h in 5th almost the whole way there

Foot was flat to the boards most times and had to drop back to fourth on some hills to keep 100km/h but for the most part it sat very happily on 110km/h at 3850rpm in 5th. Economy was poor though - 12L/100km. Normally get around 10-10.3L/100km.

Probably the last time I'll try to tow a trailer at 110 with the Zook but nice to know it can do it. Did get some scary death wobbles on the way back due to side winds gusting 50-60km/h

This was with a rebuilt 1.3L, Genie extractors, 1.75" exhaust (cat + resonator + muffler) turning stock 205/70R15 HTs.

[Sammyboy]

After rebuild, bores have a cross-hatch pattern on them as a result of the honing process. The treatment of a rebuilt engine over the first couple of hundred k's will largely determine how well the rings and cylinder wear in and mate. Keeping the revs too low during the first couple of hundred k's, or keeping revs too constant (ie long country runs), can result in the bores glazing before this mating process has completed. This will result in an imperfect seal and long-term blow-by of oil / loss of compression / loss of performance.

Moph, you are 100% correct about that! I got the 4D56 TD engine in my 1983 Pajero rebuilt when I was working in the outback ( very expensive), and judging by what you wrote previously, I guess I didn't break my engine correctly as it lasted just 97,000kms until I got rid of it (problem: Blow-by= $35 of oil per week!!). It still ran fine (didn't notice too much lacking in performance, but it would sometimes use up to a litre of oil per day).

Back on topic, as for my 1985 Holden Drover high top, I just love driving this car ... 235/75 r15 MTR's (great tyres), extractors, 2" staight through exhaust, stock engine/diffs/gears, 2" OME suspension lift. Usually I can sit very easily on 100kmh (sometimes 110kmh if I am not watching the speedo) and I reckon it's doing about 3400rpm. Once I did get it up to 120kmh, but it did take me a while so I backed off. Normally when on the highway, I like to keep the tacho below 3000rpm (which is about 90-95kmh) and that gives me excellent fuel economy in the mid to low 8's (even when fully loaded)

[RockHopper]

91 1298cc Sierra, 31 x 10.5 mud terrain tyres, 6.5:1 tranfer case gears, and everything else is pretty much standard. Was struggling to get 110km/h before I ran a t-peice off the vacuum advance hose to the secondary actuator diaphram, but now it will easily get to 110km/h and I've actually had it up to just over 130km/h on a nice flat peice of freeway.

[ZUKPOWER]

100km/h?...no probs 92 Sierra with 1.6L 8v, 31" BFG M/Ts and S4 Rockhoppers. Easly cruises on 110km/h with enough power to overtake if neccessary. I am looking at fitting 33" soon so that should suit the S4's a bit better as its a little revy

[topdown]

Was struggling to get 110km/h before I ran a t-peice off the vacuum advance hose to the secondary actuator diaphram,

Got any photos of this? Sounds interesting.

[Fpv_83]

89 softtop, 33x 12.5 MTRs, lift, S4 rockhoppers, stock diffs, extractors + 2inch system, standard 1.3 with swift carb.

Will do 110 on the flat but on hills like mittagong will drop to 70-90km/h

almost full throttle to sit on 110

[Lil'Loki]

Was struggling to get 110km/h before I ran a t-peice off the vacuum advance hose to the secondary actuator diaphram,

Got any photos of this? Sounds interesting.

x2. Standard Sierra Carb or other??

[eckeler]

cool, i like this kind of stuff, ive had my stock 1.3 carby recoed, and noticed after i reinstalled it that there was no hose on a diaphragm looking part by the throttle linkages, (a round flat topped part, on the battery side quarter of the carby) (couldnt remember if there was a hose on it wen i took it off) i rang the bloke at the highly respected carby reco shop at burwood (nsw) and they said there wasnt a secondary in that carby, (i no it only has one throat) but, im gunna put a t piece in the vac. adv. to the dizzy, and connect the now spare end of the t piece with a new hose, to that open/disused/vacant vac in/outlet, and see wot happens

[RockHopper]

Got any photos of this? Sounds interesting.

Very simple. Take the vacuum hoses off the vacuum advance on the dizzy and take it to Supercheap (or your local parts shop). Buy about a metre of similar hose and a packet of t-peices to suit (they come in a pack of two). All up it cost me less than $5. Now refit the hose you took off back onto the vacuum advance. Cut it wherever you think is suitable and fit your t-piece, and run the vacuum line you bought from the t-piece to the secondary actuator on the carby. Obviously, cut the hose to length.
I've been really busy the last couple of weeks or so, but I'll take a photo when I can.

[jonno_racing]

i have given up on my piece of crap 8valve carbi set up.

time to go efi, more cams and more valves...

[lay80n]

cool, i like this kind of stuff, ive had my stock 1.3 carby recoed, and noticed after i reinstalled it that there was no hose on a diaphragm looking part by the throttle linkages, (a round flat topped part, on the battery side quarter of the carby) (couldnt remember if there was a hose on it wen i took it off) i rang the bloke at the highly respected carby reco shop at burwood (nsw) and they said there wasnt a secondary in that carby, (i no it only has one throat) but, im gunna put a t piece in the vac. adv. to the dizzy, and connect the now spare end of the t piece with a new hose, to that open/disused/vacant vac in/outlet, and see wot happens

If its the standard carb on a 1.3l motor, then there is DEFFINATLEY a secondary. It is vacum actuated, it sounds like the carb place has left the vacum line off.

Layto....

[RockHopper]

Did one better than photos. Here is an instrucional video. Don't mind my rambling, I spin a lot of s*!t. I forgot to mention though, if you don't see the vacuum actuator pulling up when you give it a little rev, it might mean that the diaphram in the acuator is faulty, and you will want to replace it.

http://www.youtube.com/watch?v=Bk-W4EMvsBM

[topdown]

Mate that is f@#king great. You even stuck your camera into a running engine bay for us. Legend.

I'm gonna try it this weekend. I'll give you an update of how it goes.
You should start a new thread and get the mods to put it in the bible.

Thanks heaps for that mate.

[Moph]

There's actually a vacuum valve hidden down behind the secondary actuator that it should be connected to - very difficult to see with the carby fitted to the manifold, but there nonetheless. That's where you should be running the vacuum line to. Can post a service manual exploded view tonight if you're interested - very difficult to photograph due to where it's located.

[Lil'Loki]

There's actually a vacuum valve hidden down behind the secondary actuator that it should be connected to - very difficult to see with the carby fitted to the manifold, but there nonetheless. That's where you should be running the vacuum line to. Can post a service manual exploded view tonight if you're interested - very difficult to photograph due to where it's located.

That would be great. There is already a hose coming from below the secondary actuator (can't exactly see where from yet - vacuum valve?), that fits to where Rockhoppers modified hose goes, ie the secondary actuator.

The one thing that I'm thinking is that the secondaries open basically as soon as you apply throttle. Therefore fuel consumption would increase?

[Dooley]

89 WT, soft top with f/glass top. Got a lower k G13BA from a Swift (about 100ks on it now) and a 4k Corolla carby, stock gearbox and 205/70 R15 HTs, so stock tyres. Pretty easily cruises on 100 around about 4-5 thousand rpm, can get up to about 120-130 if there's a nice steep hill and wind behind you.

[Moph]

Here 'tis:

[RockHopper]

The one thing that I'm thinking is that the secondaries open basically as soon as you apply throttle. Therefore fuel consumption would increase?

No, not really. If you are hard on the throttle, then yeh, you are going to use more fuel, but driving around town, mine uses about the same.
I did this mod to mine, because that secondary actuator was getting very little vacuum applied to it from the original vacuum port on the carby, even after cleaning it out, and puting compressed air through it.
@ Moph, that carby you posted up is differant in design to mine. I'm not sure how many differant types of carbs came out on these Sierra's (apart from auto and manual chokes) but mine (91 model), my brother's (85 Drover) and my nephews (94 model) all have the same carb on them and the original secondary actuator hoses come straight off the body of the carb.

[Lil'Loki]

The one thing that I'm thinking is that the secondaries open basically as soon as you apply throttle. Therefore fuel consumption would increase?

No, not really. If you are hard on the throttle, then yeh, you are going to use more fuel, but driving around town, mine uses about the same.
I did this mod to mine, because that secondary actuator was getting very little vacuum applied to it from the original vacuum port on the carby, even after cleaning it out, and puting compressed air through it.
@ Moph, that carby you posted up is differant in design to mine. I'm not sure how many differant types of carbs came out on these Sierra's (apart from auto and manual chokes) but mine (91 model), my brother's (85 Drover) and my nephews (94 model) all have the same carb on them and the original secondary actuator hoses come straight off the body of the carb.

So what did you do to the original hose going to the secondary actuator?
Did you plug it or just simply remove it??

(Hard to see on your video or hear if you mention what you did.)

[GRPABT1]

How did this turn into such a tech thread? lol

[Lil'Loki]

At least we aren't trying to sell a second hand fastback soft top in a tech thread!

I was thinking about adding a link to the thread with 'said' soft top…



But thought a ride on the bus wasn't worth it!

[RockHopper]

So what did you do to the original hose going to the secondary actuator?
Did you plug it or just simply remove it??

(Hard to see on your video or hear if you mention what you did.)

Just plugged it, Although its a little hard to reach with the carby on the car

[joeblow]

Here 'tis:

this is a pic of a vit mikuni. and when i get a chance i'll post up some info on how to hot-rod the secondary mechanism for even more power....

[Moph]

Ah right. I don't know my carbie well enough to be able to tell whether its the one in the exploded view or not - it looked similar though. I believe mine's an Aisin, however I definitely have an existing vacuum hose from the secondary tucking back towards the vacuum switching valve position shown.

What are the advantages of a Vitara carb over a Sierra, Joe? I've heard you recommend them before, but what benefits do they have that would make me run out and buy one?

[joeblow]

at the end of the day i love efi and hate carbies with a passion,BUT, the vit carb is very well designed. for starters mikuni are a well established carby maker, they know thier stuff, and when you start getting into the details of this carby you start understanding that they were designed for 4 wheelin from the start. they are simple in thier layout, and anyone with decent jap carby skills can easily re-build one. thier best feature is the fuel bolt vent, which helps the bowl breath without throwing fuel down the chamber and stalling out. another great feature of 92 ish onwards mikuni's is the seperate fuel feed for the foot pump. this maintains fuel even on the scariest of angles. but they have to be set up right and tuned right, once that is done they are set and forget and the next best thing to efi, and after some hot-rodding provide some good power figures.

[monkeyplex]

1990 SWB soft top Vitara
1.6 Carby, seized one, blew head gasket on this one, fixed now.
2 inch body lift
40mm coil spacers
31" Buckshots on F100 sunnies
Standard gearing.

Absolute pig on the highway, especially with any sort of wind.

If its flat, the engine will pull 110, 120 easily enough. But at that point I can't turn up the stereo loud enough to drown out the wind noise. Also, the thing is jumpy, hands at ten and two, or you might end up dead.

I think the body lift and big tyres has a marked effect on the already terrible aerodynamics of a soft top. I recon the front wheel arches act like big parachutes.

The good thing about the standard gearing on 31's is I don't feel so bad, just droping it back to fourth and cruising like that. The big tyres dull the responsiveness of the engine, so overtaking is a bitch also.

The car is getting harder to live with. Do people whole heartedly recommend 6.5 diffs? or would you save that money and fork out for reduction gears to get it better off the road?

[Gwagensteve]

There are 6.5 diffs?

The only alternative vitara diffs I was aware of were the unobtainium 5.83's from Calmini/Richmond whoch have been out of production for about boggedteen years.

Steve.

[eckeler]

ok, that carby is different from mine too, so i spent $5 on a piece of vacuum hose and a t piece, and 'voila' the secondary diaphragm now opens and closes as the throttle is opened, was struggling to get to 3,000 rpm, now she is powering all the way to red line, havnt tried on highway yet, but im sure itll be better.
so now im all ears to hear about hot rodding it as well.
ps, if you want to check if your secondary actuator is working, just give the motor a few short revs while you are watching under the actuator diaphragm for movement (ie, the linkage going up and down), if not, check for vacuum (put finger over end of hose and give short revs while feeling for suction) if ok but still no movement, then the diaphragm might have a hole or linkage might be stuck .
i just looked at rockhoppers video, mines exactly like that, (a bit dirtier), since there was no pipe on it to start with, i dont know where to look for a blocked outlet or one to block

[topdown]

Did mine too, definitely gets the revs up quicker.
Going to take it for a freeway run tomorrow and see the results.

[Moph]

Hmmmm. My secondary actuator diaphragm also does not pull in when revving at idle. Pulls in fine under manifold vacuum.

Question is - what is the purpose of the 'vacuum switching valve'? What is meant to make it switch? HOW does it switch? (only appears to have single vacuum input/ouput ... no electrical connections shown). Will it perhaps pull in under load where it won't at idle?

Just seems a bit strange that all who've looked at it so far have found it's not moving when revved at idle. 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???