RLY240

Repco have a listing for a conversion set.

Geez Mick, it would be hard to let that go surely? Roger

Mixed weekend for the Zed's at this year's high country. The Knappsteins were very fast in Classic but unfortunately suffered engine dramas on day 2 and retired early, Jones and Guest were having a ball in the Thoroughbred class before crashing out late on day 3, Greig and Harris came home 9th in the TSD class (regularity) while Annie and I survived to take 3rd in the Early Classic handicap and 5th in Classic Outright. Just might have to go back next year once we get the Mikunis back on... Roger

Mixed results on this one unfortunately and still some work to do. Blocked off the float vents and fitted a separate external vent on the float cover and bingo, the right hand corner misfire is completely fixed. But. Now have the same misfire on left hand corners that didn't exist before. Bugger. Moved the float level up and down to the point of flooding or starving and while changing the severity I just can't get it to clear. There is absolutely no fuel getting into the jet block housing or flowing out the breather into the intake so I'm clueless as to why this is happening. So the SU's are back on and all trace of the miss is gone along with some horsepower but I need the reliability for now, will have to dig further in the off season. Again, thanks for everyone's feedback, hope to have better news in the coming weeks. Roger

Update on this one, finally got some track days in and I'm happy to say that the knock back issue is solved and even survived a 35 degree day at Mallala today with two drivers and still no dropping pedal. Unfortunately I have done two changes at once (bearing spacers and springs inside the front pistons) do I can't give a definitive answer as to which solved the problem. Either way I'm happy it's fixed and would recommend both to anyone experiencing this problem. Thanks as always for your feedback and suggestions. Roger

Isolators not soft mounts. I agree the jet block is sealed from the float chamber but it also shares the vent arrangement. If you remove the jet block cover you can see all the way down into the fuel bowl. I have been able to replicate the g forces on the bench and you can see the fuel coming up the breather holes into the jet block breather. I have found some examples of breather mods on type S carbs but not for my type R style although Todd from Wolf Creek confirms that they can also mod these, I'll have to work it out for myself. Going to try a few things this weekend and hope to get on to Mallala Friday for a practice day to confirm. Need to sort this before Targa High Country in a couple of weeks or the SU's are going back on.

Thanks for the responses guys to answer your questions, it's hard to know where the misfire is but on the worst corner (160kph brake to a 2nd gear hairpin) the engine almost dies completely for a few seconds until you wind off some lock on the exit and then it comes back to life in an instant. My best guess is that it's across all three carbs to some degree depending on the g load. On removing the float cover it's obvious that there is fuel in the float breather chambers where the only possible way it can get into there is by splashing up to the jet block cover and then down into the breather spaces. If fuel is getting into the jet block it will be drawn straight down the air jets and significantly richening the mixture. The car has been Dyno tuned in this configuration and jetted to give an even 12.5:1 mixture right through the rev range under load so I'm happy that the configuration and tune is adequate. I don't believe the issue is related to tune or jetting but something else such as surge. There is some info around ( from wolf creek and others in the US) that shows a process of blocking up some breather holes that directly link the jet block housing to the float chamber. In my carbs there is nothing to stop fuel from splashing through these holes onto the air jets. All the examples of this mod I can see also add an external breather for the float chamber but my carbs have a different layout and I don't think it is necessary but I guess will have to try it to find out. Roger

A bunch more googling has dredged up some info from the sports car guys in the states, looks like it's a common problem with the PHH carbs and there are some internal mods that can be done to change the vents to stop fuel splash getting onto the air jets. Will see if I can find some decent pics or instructions. Roger

I've recently replaced the original twin SU carbs for a nice triple Mikuni 40PHH setup (thanks Mick) and while the power and the sound has certainly improved I'm experiencing a significant misfire that is making the car undrivable on the track. I believe it's a fuel surge issue inside the carb floats as the problem is specific to tight right hand corners only and clears immediately when the corner straightens out again. My thoughts are that the float level is too high and the fuel is flooding into the intake under corner load. My setup includes an electric pump and a pressure regulator set to about 4psi. Problem occurs consistently from stone cold on a hillclimb through to a 35deg day at Mallala (all right hand turns of course....) What I have tried so far: First, filled the fuel tank until it came out the filler cap just to prove that it wasn't a pickup issue inside the tank. Then blocked the return line to the tank (as at this stage I though it was under fuelled). No help. Removed all the floats and set the float height as per the Mukuni manual (12mm when the needle is just seated without compressing the needle spring). No change at this stage so started raising the float level - problem got worse. So then started lowering the level - seemed to get better but not fixed Kept lowering the level until the car would misfire even in a straight line - bummer. So I think it's fuel surge related but can't find the sweet spot for the float level. Another Zed running 44PHH setup on the same day (and much faster than me) has never experienced this problem but can't tell me his float level. So my question is, does this sound familiar to anyone? Is there something that can be done such as baffling or modifications inside the carb float chamber that might help? Anyone got a different opinion to the Mukuni manual about appropriate float levels or aftermarket floats that might help? Anyone think I'm barking up the wrong tree? Any thoughts please let me know. Thanks, Roger

I've driven this car, it belongs to a mate, and it is a beautifully finished and very capable car for both weekend cruises and track days. I need another bay in my shed. And another mortgage.... Roger

You still need to cut the slot for the bearing assembly to protrude through the strut top.

Out of curiosity, where did the bar break? On the left or right and how far from the middle? I have one that has been cracked and patched and wonder if it's in the same location. The one I have is cracked on the left side, about 50-60mm to the left of the LH diff mount hole. Roger

True I'm afraid, NSWRRC regularity slots have been allocated to race categories instead. Porsche still have their regularity event but you need a porker to enter. Roger

SL6 six piston front and 4 piston rear. AP J hook rotors and the AZC mounting hardware. I'm actually very happy with the AZC package for the price, just need to resolve this issue to make me happier. On the road this really isn't a problem that comes up and I know others with the same parts as me going quicker on the track and not experiencing the knock back. Roger

Yes, I used the hubs and bearings from the car (after cleaning the grease and lightly oiling the bearings) and a spare strut. The spacers need to be matched to the hub/bearing combination and can't be switched around. Label everything. New bearings in future may require a repeat of the process. We ended up with more than a few thou difference left to right (more like 15 thou) and as we got close to the end we are taking .002 each pass. The spacers were about 3mm (120 thou) longer than required so basically went 100, then 10, then 5 then 2 then 2 then 2 until we got to the tolerance/preload we were looking for. Have to take your time with this as you can't add that .002 back on if you go to far. The instructions suggested to get the slightest drag and then remove another .001-.003 off for preload. The preload of the oiled bearings on the bench was very close to the preload once greased and fitted to the car, aimed for about 1kg drag force when measured from a wheel stud. I wasn't convinced this process would yield results as I feel the issue lies in the calipers somehow but it's all part of the process. During this work we also determined that the LHS hub face was not true (looked like some impact damage from an FB hammer) that I hadn't noticed before as only just started using these hubs. Not related to the current problem but nice to pick it up before it caused a loose wheel or worse. Getting this trued up along with clocking the rotors for run-out. Roger

So I fitted my bearing spacers on the weekend, the setup of the spacers is a little time consuming as the assembly needs to be installed in the hub and the play measured then accurately mount the spacer in the lathe to zero the run-out then machine some off and trial fit. Repeat. About 6 or 7 times to creep up on the correct tolerance. Probably took about three hours using a spare spindle on the bench plus the time spent removing hubs from the car cleaning etc and then repacking and assembly. The most time consuming part is clocking in the lathe to zero the run-out. Unfortunately a quick run on the road suggests that the problem isn't fixed and there is still knock back but wont know the full extent until the next track day as you can't experience track loads on the street. Next step is to install the piston return springs in the calipers and see if that helps.

Thanks Peter, ordered these today so will see how they go. Roger

In talking to people about this today I was told about a "stub axle stiffener" that was available from Otomoto or AZC or similar. Basically a bearing spacer sandwiched between the inner and outer bearings inside the hub similar to how the rear hubs are done. I can't find anything from either of those companies so has anyone else seen this sort of setup on a Zed? Roger

I'm running 260 hubs. Run-out isn't an issue as the knock back only occurs after cornering, 10kms country road drive and the pedal is still firm. Calliper flex shouldn't be an issue here, the calliper or mount will only move if something else (rotor) moves it first. Sure the Wilwoods are a cheap racing calliper though. In my mind it's either the hub moving on the bearing or the spindle flexing relative to the strut. I never has this issue with the previous setup (Hilux) which leads me to think that perhaps the Wilwoods do a worse job of recovering from knock back than factory style callipers. But I couldn't say why (seals perhaps?). There are a few ways to combat this (residual pressure, springs in the pistons, larger master etc) but I'd like to know what the actual problem is and short of having someone hanging under the car with a dial gauge I'm not sure what else I can do. Might try a go-pro under the guard somewhere... Appreciate the replies guys. Roger

I'm starting to experience very bad pad knock back in the 240 during track sessions at Mallala. It's not something that has been a problem before but since moving to the wilwood setup it is quite pronounced. Even doing some weaving on the warm up lap is enough to make the pedal drop significantly. I have new wheel bearings front and rear with the front's tightened to factory specs (20ft/lb I think then minus 60deg) and there is no play to be felt either front or rear. A quick tap is enough to get the pedal back up but it's quite disconcerting. Anyone else experienced this with the wilwood setup? Roger

CAMS manual says 1.75x0.095 for the main and lateral roll bars and 1.5x0.095 for other components. CDS or CDW in 350N/mmsq tensile strength. Looks like the Jester complies by size but you would need to clarify the tensile strength rating of their mild steel. You can build your own cage as long as you follow the diagrams in the CAMS manual and use the right material. Then you sign the paperwork. Simple. Can you buy a suitable bender and mandrels for that kind of money? There's no reason why you can't do this yourself either with a pre fab kit or bending it all yourself if you have the time. Roger Schedule J http://docs.cams.com.au/Manual/GeneralRequirements/GQ11-Schedule-J-2014-1.pdf

Hi Mick, it's a tough decision to make but tyres will make the biggest improvement but of course they are an ongoing expense. I think the most important issue is set-up and alignment so would argue this should be the first step, either adjustable lower arms front and rear or standard ones modified to change camber/castor. A decent geometry all round will also help you maximise those new semi's too. Then springs and shocks. Then more horsepower.... Roger

Hi Mick, I'll take them. Pm sent Roger

Looking forward to seeing the new projects emerge, at your normal work rate you should have them all done next month! Must be time for another meet.

Price drop on 1975 2+2 in SA. Beautiful car, immaculately presented and maintained by enthusiast. http://www.carsales.com.au/private/details/Datsun-260Z-1975/SSE-AD-2611076/?Cr=3&sdmvc=1