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Z24 Carby Fuel Pressure ?


deanslost
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I've just received a 32/36 Weber kit to replace the original carby on my 1989 WD21. I was just wondering what the fuel pressure should be and do I need to fit a fuel pressure regulator to reduce it to the 2-3lbs required for the weber.

Thanks

Dean

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Was it a factory carbureted engine or TBI? If it was carbureted to begin with you don't need to mess with the fuel pressure, just put the Weber on and go. I found the main jets at 140/135 to be too lean on my Z24.

 

It's also easiest to use the factory throttle cable bracket and bend it to shape.

 

photobucket-4787-1356241004687.jpg

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Thanks, It was factory carbureted.

My instructions say I that I needed one but suspect that the instructions were designed to cover both throttle body and carby vehicles.

I know what I'm doing today.

 

Thanks for the pic and the tip.

Dean

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She's done,

Carby's on, it was an ebay one from America and every thing seems to be adjusted right straight out of the box.

I ended up using the new throttle cable bracket that came with the kit. After a little adjusting it was easier, the original one wouldn't clear part of the carby.

It's still no racing car but wow what a difference it actually accelerates now.

 

I need to do a proper road test with hills etc. but it certainly sounds better and seems to go harder.

 

Next on the list engine rebuild.

 

Thanks

Dean

Edited by deanslost
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  • 2 weeks later...

Hi Dean,

 

Can you send me the details of where you got the carby? I've got a bung original carby where the throttle body housing is so worn it's sucking air in places that air was never meant to be sucked... so my fuel economy is messed up by that alone.

 

A friend has offered me a Weber carby off a 2.0 litre Cortina, not sure of the size of it but he reckons it'll go straight on and offered to fit it next time I pass by (it's only in the Hunter Valley NSW and I'm living in Alice Springs NT right now about 3,000 kms!).

Anyway, if there is something out there that bolts straight on and works out of the box then that's a good thing.

 

Also, does your Pathy have air-con, if so did you have to do anything to keep the idle up working with the carby change over - after just spending $1,500 on my air-con (yep, you get ripped off in Alice Springs but with ambient shade temps of 49 degrees two weeks ago you PAY to get it working), I definitely don't want to lose my idle up again as it makes such a difference when you aren't driving and keeps the air-con cooler overall.

 

Anyway would love to know what your fuel economy does with the new carby as well (my economy has improved greatly with my new set of extractors that went on last week), but my economy (without running the air-con) was at best 11.2 litres per 100 km, at worst doing 130 kph (NT roads limit) was 16.5 litres per 100 km. I think it'll be a little better with the extractors.. and probably heaps better with a new carby.

 

If you've got an android phone get the app "aCAR", absolutely brilliant and it keeps track of everything like fuel use/economy etc..

 

Cheers,
Simon

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  • 2 weeks later...

Hi Simon,

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=271146866186

The above link is the guy I got mine from. Like others before me I had to enlarge the bolt holes in the base of the carby as the adapter didn't line up perfectly. But it was no biggy.

 

Mine has A/C but I haven't worried about the idle up for it as yet. I did see a way to do it on a thread (I think it was in the NPORA forums) but would have to search again to find it.

 

Fuel economy ? Don't have an android phone yet and I haven't worked it out yet. My Pathy is a second car, I have a work vehicle for day to day driving and my Wife has a nice comfy family car for highway work etc. So the old gallopy doesn't do a lot of Km's and most of them are from home to the bush and back.

 

It does seem to drive a lot better and sounds better if that means anything.... So far I am very pleased.

 

Dean

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A question for those that have done this before, underneath the original carby was a plastic looking spacer that I believe was for insulation purposes and under that there was a plate with two round tubes/flutes that penetrated down into the manifold. When I did my conversion I removed both of these.

 

Is there any benefit to performance in putting these back in ? in hind sight I should of asked more questions before I did the job.

 

I can guess that the insulator may help the carby to stay cool and possibly therefore increase its efficiency ? better fuel atomization ?

And I guess that the flutes penetrating down into the manifold may help the carby to draw, kind of like a highrise manifold with out the height.

 

when I removed them I was thinking about reducing the potential amount of vacuum leaks and the flutes looked like they could be a restriction.

 

Anyone have any experience with this or any suggestions/thoughts about if I should put one or both of these bits back.

 

Thanks

Dean

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Hey Dean, thanks for the info mate, absolutely brilliant.. Would definitely like to know if your fuel use goes up or down.. But I guess only time will tell.

 

Was the drive quite improved then with the bigger carby?

 

I'm really keen to know as much as possible about this one as I love my Pathy to bits and it's my daily driver, so if I can get a bit more fuel economy with normal driving and just a little bit more power on acceleration then that's a wonderful modification to do.. and to be honest if I don't increase my fuel use by much I'd even consider still doing it, specially as my current carby is stuffed (it's almost 500,000 kms old). Of course the fact that I've been offered a Weber carby (though not sure of the size yet) is also a good bonus...

 

Sim

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Forgot to ask... was it particularly difficult to fit mate, ie how long and did you need any specialist equipment (good to be prepared before I try to do anything and end up with an undriveable vehicle for want of a pink electroplated skyhook and a fuzzy equalising lefthanded screwdriver!

 

Sim

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Hi Sim,

It took me approx 4-5 hours with the Kids helping, If youve got kids you know how much fun that can be. No special tools and the carby comes with a fairly good set of instructions that gives you a list of all the tools you might need before starting.

 

using the seat of my pants as a judge, I am happy with the improvement. It seems to do everything better and when you do plant your foot the secondaries open and you can actually hear the engine growl as it accelerates. Ok maybe growl is an overstatement but there is deffinately a deeper more throaty sound when the secondary opens. normal driving you can hear it sucking in air.

 

I think it could be improved even more by some fine tuning from a more knowledgable hand, but right out of the box it is better then the factory option. The only thing I think the carby needs is weeker return springs as the pedle is now a bit heavy, but maybe they will relax with use.

 

Taking into account that my engine is shot, it has significant blow by, so much that I have now run a hose down beside the engine as the oil was soaking my filter fairly quick. I really should get a catch can.

At the price I paid It was well worth it.

Next step is an engine rebuld. I have seen rebuild kits on ebay in america delivered here for approx $350.00

 

Dean

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Damn, that's not a bad price for a rebuild kit.. but is that for the Z24i (8 plug head)? One of the other differences I've found and been unable to get confirmed 100% was with the timing chain, is it double row or single row? because I could only find a double row chain kit and I'm not pulling my engine apart to find out what chain it is until I'm going to replace it (which should probably be done some day sooner rather than later)..

 

I'd love to rebuild my engine but with over 470,000 kms on the clock she still starts first go every time, idles lovely except for a slight tick, and still gets an easy 11.2 litres per hundred km fuel economy without running air-con on a long trip... though can use up to 16.5 litres per hundred on a quick 130 kph run down the Stuart Highway (130 limit these days sadly), but yeah, acceleration is a little lacking - probably my shagged as hell carby that sucks air in places they were never designed to! Though my engine is old and high kms it doesn't blow any smoke and doesn't use any oil and after 5,000 to 6,000 kms when I dip the stick the oil is still almost clear like new oil - but I change it and the filter at that point - that's why she's still going strong, always has good fresh oil.

 

A full reco of my engine would be $2,300 'ish from some place in Brissy and would take approx 1 week. Would love to go there as I imagine even with a rebuild kit the 'mechanic rates' would add up to around $1,500 anyway.. and I just don't have the time or even the experience for a full rebuild, I can strip down a motor and do most of the work but if I stuffed up one little bit due to my lack of knowledge of that particular operation that's a big cost to fix it..

 

I love the sound of what you've described as a throaty sound when you plant your foot.. a bigger, better, double barrell carby combined with my nice new Lukey extractors and 50 or 55mm exhaust - can't remember which and too lazy to climb under and measure it again - (which only has a centre muffler and Cat) should make for some nicer sounds all around..

 

 

 

 

Just on a side note I've heard from 'many' people that the Z24 engine is almost unkillable and that if it's given fresh oil all the time it'll last for a 'very, very' long time.. and I met a guy with an 89 Pathy 2 dr out here in the NT who had clocked up a whopping 950,000 kms on the original engine, he was just starting to have problems with the distributor system (because it's slightly complicated)..

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Mines a z24 (carby) twin spark (8 plug) with a double row timing chain. They did make z24 single sparks also.

I believe all z24 engines have a double row timing chain that is part of what makes these little trucks so indestructible, but I will also add that I am by no means an expert on these cars. To confirm which timing chain you have you should be able to take off your oil fill cap and take a look. on mine at least the oil fill cap is right at the front and by climbing up and looking through the fill hole I can see it.

 

By your description I would not touch your engine except to continue with the oil changes. If it ain’t broke don’t fix it. Maybe with the slight tick you could check or have someone check your valve clearances.

 

I brought mine for $1500 of ebay with 360,000 on the clock. I knew little about these vehicles other then Nissan made good ones (my dad owns a GQ 4.2 aftermarket turbo diesel patrol and its awesome). Oh and the two door pathfinders looked cool. I was happy with my purchase when I made home.

Since I got it I've replace shocks and suspension bushes welded the chassis where the front compression rods had flogged it out and repaired a lot of other little things.

It's quite obvious that mine was not looked after.

From what I have learnt about them these little 4x4s go for ever. Mine still starts easy (especially now that it has a choke) and drives well but it is tired.

 

I have been offered a V6 wd21 that has been rolled and missed out on a diesel one that was rusted out but I don't know if I am up for an engine swap.

I am starting to think that The little Z24 that could deserves a second chance to be all that it can be. Maybe a rebuild some A.R.P head studs and a small turbo are in order.

I would love to find a spare engine I could rebuild and then swap but Z24's seem to be hard to find cheap.

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Yeah, I think finding a decent Z24 will be a mission and a half mate. I agree that they are a good engine and I'm definitely hesitant to change anything more with the engine (apart from the carby) until I have to, though the tick isn't anything to do with the valves, they've been adjusted (sent it to a mechanic to do that because I was going on a big trip a couple of days later and didn't have time)...

 

I've not noticed that I could see the timing chain from the filler cap, I'll have to climb up and have a look, it's a little more problematic with a bullbar in the way and a suspension lift to add to the fun... I dare say it's exactly as you say, double row timing chain.. (to be honest I should've thought) :laugh:

 

I got my Pathy for $1,500 as well.. though it was up for $4k and I just got lucky.. I was overseas and bought it sight unseen.. I got very lucky!

 

I'm just working my way through the rest of the front end and replacing stuff with neo. Then I'll look at doing the rear brake shoes and possibly drums, but one step at a time. I've put thousands into this 4WD but she'll just keep on keeping on. She's done 2 x trips over the Plenty Highway between the Stuart Highway 70km north of Alice Springs and Boulia in Queensland, it's one of the roughest roads in Australia.. a real suspension killer. Pathfinder ate it up, I did end up with the centre muffler shaken to bits and needed 2 new rear tyres as they'd been chewwed to bits.

 

I think rebuilding an engine and just doing a swap over is a great idea, it also means you can take your time knowing you can still use the vehicle as needed.

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  • 2 weeks later...

A question for those that have done this before, underneath the original carby was a plastic looking spacer that I believe was for insulation purposes and under that there was a plate with two round tubes/flutes that penetrated down into the manifold. When I did my conversion I removed both of these.

 

Is there any benefit to performance in putting these back in ? in hind sight I should of asked more questions before I did the job.

 

I can guess that the insulator may help the carby to stay cool and possibly therefore increase its efficiency ? better fuel atomization ?

And I guess that the flutes penetrating down into the manifold may help the carby to draw, kind of like a highrise manifold with out the height.

 

when I removed them I was thinking about reducing the potential amount of vacuum leaks and the flutes looked like they could be a restriction.

 

Anyone have any experience with this or any suggestions/thoughts about if I should put one or both of these bits back.

 

Thanks

Dean

 

So I answered one of the above questions myself this weekend, went impromptu reasonably hard core wheeling this weekend. The hardest terrain I have put the sloppy jalopy (my daughter named it not me) through so far.

I got halfway along Oula Creek Fire Trail and half way up a hill/mountain called Babies chair (or something like that) and the old girl just stopped. Stopped dead. I very tentatively rolled back to the next spoon drain got it started then tried again and it stopped.

 

The worst thing was because we weren't planning on wheeling we had no towing or recovery equipment onboard.

 

Now I had plenty of power and for such a worn out engine I was quietly impressed.

It was obviously a fuel issue and because the fuel gauge has never been accurate I thought even though the gauge showed a quarter of a tank it must have been wrong. I spent three hours waiting for fuel to come and that wasn't the cause.

 

What I think happened is that without the bakerlite? insulator/spacer the carby when travelling so slow in 1st gear low range and working it hard was getting too hot and the fuel was evaporating before the engine could get it.

I think that the other part of the problem is the original fuel pump may not be up to the task any more, in such steep country it may not have been able to overcome gravity, and the combination of the two problems caused the symptom.

 

So Simon if you are planning on doing this conversion I would leave the spacer in there.

The removable flutes under that, the jury is still out on and I am hoping to get some feedback from others who have gone this route before.

 

So next weekend I will be remounting my carby with the spacer included this time, and if I can get the parts by that time I will be changing the fuel pump and the fuel filters. I may also fit a second pump up front to help with fuel lift in steep country.

 

 

Dean

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If it wasn't for a family friend with a Land Cruiser and a winch I would still be there. Although I must mention that even with a front diff lock he still had some traction issues in the country we were in. This makes me even more impressed with my little old pathy

 

Dean

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Hey Dean,

 

Thanks for the feedback on that one..it's good to know.. I figured that there would've been a good reason for Nissan to put those bits in under the carby, if nothing else it also gives the fuel/air mixture a few more milliseconds to mix better before being sucked in to one of the cylinders for combustion. I would say you are too right with your thoughts on what happened, I'd certainly be thinking about that myself out here where our daytime temps are in excess of 40 degrees for 5 to 6 months a year and you worry about the fuel evaporating before it even reaches the carby when it's 46 degrees and the tarmac is melting on the roads!

 

I'm still waiting on my mate to get back to me with the info about the carby he's got.. then I can arrange for a carby rebuild kit to be ready for when I visit him, likewise I can also arrange for an air filter and so on to fit it as well.. all sorts of stuff that needs to be obtained before I go fitting stuff like this onto the vehicle - sadly I get everything ready long before I fit stuff, means it takes me a long time to do some things...

 

Hey, lesson learned on not having recovery equipment with you right? :laugh:

I always have a snatch strap, and a long handle shovel in the vehicle even when I'm planning on just driving to and from work.. as a consequence I was able to assist some government workers who managed to get their Hilux bogged to the sills, my little Pathfinder pulled this Hilux out of it's bog in 2 goes, thankfully Nissan put that LSD into the rear, it always impresses me the places that my Pathfinder can just 'go' without any difficulty, even in 2WD it is pretty amazing with the LSD helping out.. but in 4WD let's just say I've never yet had it stuck..

 

Before jumping out and grabbing a new fuel pump check your current one out.. according to the Haynes manual I managed to find on eBay - what a find!! - it states that a normally operating electric fuel pump will deliver 47.3 fl oz or 1400 ml into a container in one minute, so grab a decent size measuring jug, disconnect your fuel pump from the fuel filter inside the engine bay and put the pipe into the jug and turn on the ignition for exactly 1 minute. If you are getting 1400 ml or around that amount in 1 minute then I would say that it's ok.. that said though, my fuel pump completely died in the ass one day, no explanation it just stopped working, the mechanic that I broke down 200 metres away from told me that normally fuel pumps last between 100,000 - 200,000 kms, he was shocked to find that mine was the original - and with 470,000 kms that makes for one hell of a pump! Anyway, he found a replacement from Repco for $90. On the shelf!!!

 

Let me know how you get on with the fuel pump test and the rest of it, hopefully you'll get it sorted out soon enough.. Shame you are so far south or I'd call in and say Hi on my next trip across to the Nth Coast of NSW (where my family and property is).

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