jamo240

Hey guys I haven't seen anyone identify a mode of failure here...what caused the relief valve to fail and come adrift? It's unlikely to be pressure, as that is not much higher than standard. So is it vibration? If it is, then why not stake the block where the valve is retained...this might allow you to retain the valve's function while reducing the likelihood of it failing?? When I was at Nissan Motor Sport in the Skyline days, I saw some dumb things done to race engines on the basis they were a race engine, and therefore had to change everything away from factory designs....as often as not, the factory setup could be made to work just fine provided it's function was adapted to the competition application. The complete removal of factory installed systems should be done with due consideration, as the factory does not include these systems because they like wasting money on unnecessary parts! Cheers Jamo

What's the 57 like?? Cheers

Everything on this posting is on the money, and if you follow it you'll be right. BUT, as a qualified mechanic, I would suggest you try to find a mate of a mate who knows what he is doing to show you. L series engines are relatively easy to work with to sort out the problems you're having, but it can be a complete mystery to try to sort it out from written instructions and manuals without knowledge of what those instructions mean... You will be amazed how much quicker you will get to the bottom of it, and understand the problems if you can have someone show you how to do the things that are being suggested on the forum. Cheers

Hi Kato While I was at Holden, I saw some remarkable results achieved regarding attenuating exhaust booms (aka droning) by pinching the cross section of the pipe down where it enters the rear muffler (such as a Z is configured...main muffler at the rear of the car). The N&V engineers told me at the time that the attenuation is related to the ratio between the pipe area to the expansion area (inside the muffler). Muffler volume comes into it as well. The added benefit is that you are reducing the area the farthest from the engine where the exhaust gas is cooler and of less volume and hence the restriction to flow is lowest. This minimises power losses compared with attenuating closer to the engine. In my case, I custom made a rear muffler to maximise the volume available in the cavity beside the fuel tank. I run a 3"single all the way, and the rear muffler is configured as a tri-flow...the gas goes thru to the back, then internally forward to the front chamber, then out to the ambient air. The center chamber is only used to expand the gas into, and there are a series of holes in the muffler internal transfer tubes that facilitate this process. It does a pretty fair job of keeping the engine quiet for a relatively large diameter pipe...I expect this would work even better with a 2.5 of 2.75" system. The starting point for exhaust attenuation is muffler volume however, and this is problematic in early Z cars when modified for relatively high horsepower engines....there just aren't any places where a big muffler can reside unless you relocate the fuel tank! Cheers Jamo

I Know this is an old post, but I thought I'd add to what Lurch said about cam tower changes. It absolutely is an old wives tale that you can't do it! I took the towers off my early 240 head and put them on a late model N42 head so I could retain the spray bar oiling system....therefore not only did i take the towers off, i put them on a different head! There was never a wiff of a problem....I just kept turning the cam as I torqued the head down, and no problem emerged, and when the bolts were all done up it turned just fine and then I put the rockers back in, and it's been going for many years now with no issues. Cheers

Thanks Kato...may be a plan.. What do you know about the gear set you have? Did you ever hear it run in a car? Signs of wear on the teeth? Cheers

Hey guys Has anyone got a 3.7 ratio R200 gear set they want to unload? I have one in my 240 now, but it has a touch of noise on overun, and slight feathering on the teeth, so I am looking to put a younger gear set in. I have a 3.9 in top knick for a swap if anyone is interested....I am turbocharged, so prefer a taller gear set, hence not installing the 3.9. Cheers, Jamo

Hey all I am chasing a fuse panel for a 73 240Z. It's the one at the front of the centre console behind the inspection door, in front of the gearstick. Being a late 240Z, it's the one with the two short harnesses coming out of it that connect into the dash/body harnesses. Please give me a shout if you've got one you could part with. Cheers Grant

Thanks Kato...I agree that the engineers will get all excited about welded steering components, so probably best to modify the X-member, but provided it's done properly, it's no problem, and it fits a bit better in my view, with the valve re-indexed. My valve housing is aluminium....possibly a bit easier to weld than the cast iron ones. Cheers Jamo

Here is the car too. Jamo

Hey Kato Rob (Robco engineering) organised the welding via a local bloke...see pics below. I am happy with the work...the welds look good, and there is no distortion in the housing assembly, and it all went back together with no fuss. Just need the tie rods and rack to pump lines now. Cheers, Jamo

Thanks very much Kato...that and the fluid lines between the pump and rack will see the install done. Cheers, Jamo

Hey Peter I think you may have been a little lucky, but the engineering in your car indicates you have a good eye for details that matter! I am happy with how the subi install is going...it looks factory and will come turn out well...the biggest compromise has een the cutaway of the engine mount pedestal on the xmember to clear the rotary valve input, but it's only cosmetic...it will all work fine. Thanks for the info on the tie-rod ends. Kato Kid is also recommends using the Toyota Soarer ends, so hopefully one or the other will work. Cheers mate Jamo

Hey Kato Thanks for that...I picked up on your post to that effect after I wrote to Peter! That said, when I hunted for them, I couldn't find a part number or supplier...you didn't get that kind of information when you were researching did you? I am hoping to get them via Repco or similar, but happy to go genuine if I have to. Cheers Jamo

Hey guys Well, Rob is through with my rack now, and I ended up going with the rewelded lugs on the rotary valve body (to relocate it to clear the cross member). I made up the fluid lines now, and it all looks factory, like I wanted it to. I am feeding it with the standard Skyline pump (on the RB25DET engine)...plumbing to and from the pump runs around the rear face of the cross member and up to the pump/reservoir. All in all it's come out well. Unfortunately won't be ready for the xmas party, so I will have to show you all at the next event...I reckon it'll be fully finished by March. Rear trans mount has come out well for the RB25 install as well...I drilled the spot welds and moved the lateral mount back about 80mm and then rewelded it into the body, and re-applied the body deadener etc...all looks factory, and very stiff mount. I cut down the Skyline Xmember to fit the Z body (much narrower), but it's all good now. Cheers, Jamo

Hey guys For my RB swap, I actually removed the trans 'saddle' mount from the body (drilled the spotwelds out), and then sectioned it and re-welded back onto the body about 80mm rearward...this puts it in the right spot (in longitudinal line with the trans mount), and then i modified the R33 skyline mount to bolt to the repositioned body mount. This requires a change to the configuration of the interface between trans mount and body mount, as the original 240Z mount uses a clevis bolt through a vibration isolator, whereas the R33 skyline mount bolts solidly to the body mount. THis is pretty easy to make out of 2mm sheet steel, and then MIG weld it onto the repositioned saddle. You also have to section and narrow the pressed steel mount that came out of the R33. When finished, the whole lot looks factory standard, does not cantilever the mount like the kits do, and restores the required stiffness to the mounting structure...this is important for durability and attenuation of powertrain noise. It takes a bit of fabrication experience to do, but if you can't do it yourself, I reckon it would take a shop experienced in such things about 2 days to complete. Cheers Jamo

Sounds like a plan HUW...just to round out the topic, cooling system theory goes like this.... When the car is cruising and the cooling system has more capacity to reject heat than the engine is discharging to the cooling system, the engine is said to be under thermostat control...that is, the thermostat will restrict flow to the heat exchanger (radiator) to prevent the engine running too cold. So, if the thermostat is an 87C unit, it will maintain the discharge temp of the coolant from the engine as about 87C. As the coolant flow is restricted, the coolant entering the engine from the radiator will have rejected more heat than is necessary to balance the system, and hence will enter the engine colder than when in balance (when in balance, the coolant loses about 6 deg C from the hot side to the cold side of the radiator). Balance is the preferred condition, as the temperature difference across the engine is relatively low...this is why trucks sometimes put blinds across the radiator in cold climates to prevent very cold water entering the engine due to low coolant flow. Now, when you come to idle, or on a hot day, when the ambient air flow is low, or the high ambient temperature means the thermal efficiency of the system is more challenging, the car may go out of thermostat control. That means that the cooling system does not have excess capacity, and the thermostat will fully open, allowing maximum flow to the heat exchanger. Under this condition, maximum heat is rejected, resulting in the 6 deg C temp difference I mentioned above. If the system is not in balance, the coolant temperature will rise until balance is achieved between the heat being input to the system vs that being rejected. You see this as your temperature gauge rising. If the system cannot achieve balance (eg you are sitting idling on a 46C day in a strong tail wind), you will see the temperature rise, possibly up to the point where the engine will boil. This condition is known as Air-To-Boil (ATB)...OEM's have engineering specifications for this, and GM's is 55C...that means that if the ambient air is 55C, the car will boil...this allows some margin for sub-optimal conditions, such as tail winds, or radiators clogged with bugs etc, because a 55C day is a rare event. Good luck! Jamo

Hi Huw When you say it has 'started doing it', what new thing is it doing? All cars will get hotter when they idle, as there is no cooling ram air (produced by vehicle movement) to allow the radiator to exchange the heat from the coolant to the ambient air. As you state, the only air movement is created by the fan, which is no where near as much air flow as ram air while you're moving. My 240Z always gets hotter when idling, and the ECU (it's injected) manages that the temperature by turning the fans on at 93C, and turning them off at 89C. As for your mechanical fan (bolted to the water pump drive), the thermatic hub is designed to couple as it gets hotter, and therefore produce more flow, and decouple as the temperature drops and it does not need to pump....this characteristic is there to reduce engine load and noise at times when the fan is not required. Provided your fan is pumping at idle (you can tell by putting your hand in front of the radiator and you will feel air flowing over your hand), then that's working fine. The other thing to be sure of is that the thermostat is opening properly and allowing full coolant flow so that the radiator can remove the heat from the coolant via the airflow I just mentioned. If you're getting worried because the gauge is going up at idle, I wouldn't worry too much, unless it's getting right up into the red. When I worked at Holden engineering, we did all we could to eliminate temp gauges from cars, as the movement of the gauge usually just caused people to worry, while adding no useful information that they could action....best just to have a light that goes on to say 'there's a problem, stop now!' If it's none of the above, then you could have a more significant problem with the head gasket or cracked head etc, causing the cooling system to malfunction....I would also suggest you check the coolant and engine oil to ensure both are in the correct condition, and there is no evidence of mixing. Cheers Jamo

Hey all Does anyone know where the next NDSOC nationals are likely to be held...I believe they will take place in 2011 some time...last time I went was in 2003 I think, when they were in Shepparton, Victoria. Cheers Jamo

Hey Zac The advice here is all good in my view. I started with my Z 23 years ago when I also had no money, so couldn't do much. I agree the tyre, brake & suspension mods will yield the most noticeable improvement to the car. As far as engines go, you gotta decide what you want the car to do. For a good road car, you want low end torque and responsiveness over top end power any day. For track work, power may be a greater factor. Factory camshafts are set up to compromise the engine the least where it matters the most, so often they're the best choice for a fun road car. Lumpy cams sound hot and all, but can take the car backwards for road manners. In my current engine (turbo L28, 400 FWHP), I run a standard A grind cam (you can find the grind stamped into the back of the cam...240's had an A grind, whereas you'll probably find F stamped into the back of a patrol L28 cam). I messed around with all sorts of exotic grinds, and they would pick up 15 HP here, and lose 25 over there. I gave the hot cams away in the end and went back to the standard cam...gives the best startup, idle and transition to boost, so keep that in mind...even with NA engines. You will find the block type (eg N42, P90, F54) cast into the LHS of the block, right behind the engine mount boss. N42 is the one to have for the thickest bores...I have one, and the bores were not less than 5mm thick when I had it ultrasonically checked. Not sure it's a big issue for a NA club car though...more of an issue in turbo engines where cylinder pressures get very high. Also, any of the factory Nissan blocks are pretty good quality, and they are not known to give a lot of trouble in road going applications, so don't stress if you don't have one of the 'good' ones. F54 was common in patrols, with the N42 head. You'll hear all sorts of talk about the need for exotic components, and you just gotta think it through in terms of what you actually need. For example, forged pistons are all the rage at the moment (esp in turbo engines)...why, other than being cheap cos they're made in China? I have run factory cast pistons in my turbos for years, and never failed them. If you're consistently revving the engine super hard and you need greater ultimate strength to deal with the reciprocating forces then fine, but if you're running them for their resistance to detonation, then forget it. A cast piston melts in a millisecond, while a forgie will hang on a second or two longer and then do the same thing! They all end up busted if you have a big rattle! Any modification you do, should consider what you're trying to improve, and what compromise you will have to make to get the improvement. If there aren't more ticks than crosses, then don't do the mod!! I will have my turbo engine available for sale soon, as I am going to an RB, so let me know if you want to go the turbo route when the time comes. Cheers Jamo

I will post some pics soon...the car is up on stands getting a power steering transplant at the moment, so it's not looking its best. I have no idea where my old photos are now! I will have to put it back together as-is to make the xmas party, but will see what I can do, as it sounds like a fun event. Cheers

Thanks for the welcome chaps. I am not sure what I'll do with the L28T that comes out...I have a mate with a 240 who has his eye on it, otherwise, I am open to offers from people who may want it. It's got Motec injection and it's all sorted out, so probably a good deal for someone who doesn't want to go thru all the pain. It also has a Canadian spec 5 speed behind it, that I imported a while back. They have about a 0.745 ratio 5th gear, and they're much nicer to cruise in than the 0.861 or so ratio of the Aussie box. I will try to get to the Xmas party...I won't have the new engine in by then, so I might just leave it with the L series in so I can bring it along...not much good turning up in a Commodore hey?!!

Hey guys My name is Grant, and I have been into Z's for 25 years...I got mine about that long ago. It's a 73, and has a turbo L28. It will soon have an RB25DET in it though. I have a long history with Nissans, and worked as a fabricator at GIbsons during the R32 Skyline days. Looking forward to learning a bit here, and showing you a bit more of the car as we go along here. Cheers