DAZDA

Results can be found on the Sydney Z Car Club site. Full track times can be found by clicking here

How much smaller (diameter) would that belt drive (water pump/alternator) be than the factory pulley?

Sorry if this has been asked before guys, I did a search and couldn't find what I wanted. It is probably a stupid question but I don't have a Service Manual yet... For a 240Z, how do you get the filler plug out of the diff cover when the rear suspension sub-frame is in the way? Is there some kind of trick? Or do you just put the required volume of new diff oil (900ml for an R180???) in the breather hole? Thanks in advance.

This 'Click Here' appears to be the entry list.

I'm terribly sorry I didn't make it guys. I managed to double book myself. :'(

Well the steam certainly cleaned the carbon off #6 piston for you.

Peter fair point, and I agree. However, it's a bit difficult to impart years of practical experience on someone else at the best of times, let-alone via an internet forum... So I guess the best anyone can do on here is sprout technical info. At least it might help others make slightly more informed decisions.

Yep - I should have worded that better. The amount of fuel (petrol & air mix*) entering the cylinder is a function of on the pressure difference between the cylinder and behind the valve. The greater the pressure difference, the more fuel will be pushed into the cylinder once the valve opens. In the case of ‘charged’ engines, this pressure difference is significantly increased. Unfortunately, this is where it starts to get into mass flow rates, density, temperature, harmonics, laminar & turbulent flow, open and closed systems, etc (AKA fluid dynamics and thermodynamics), but I'm really rusty and would get even more of that wrong, so I'm not even going to try. I guess for making the distinction between NA engines and supercharged engines more pronounced, I used the term 'sucked' to emphasise the increase in torque from having more than ~1 atmosphere of pressure difference (ignoring harmonics) pushing the air & petrol mix into the cylinders. * Obviously, with EFI the amount of petrol added to the air flow is determined by the ECU and the parameters set by the tuner/manufacturer. In the case of direct injection the petrol goes straight into the cylinder and not via the inlet port and past the valve. And for carburettors, the venturi affect determines the amount of petrol added to the air flow (subject to jet sizes).

Torque = Moment or Turning Force – is a function of the perpendicular force around the point of rotation and the distance to the point of rotation. In the case of an internal combustion engine, the force is a function of the pressure in the cylinder during the burning of the fuel (petrol & air mix) AND the area of the piston (as Lurch was alluding to). The higher the pressure or the larger the piston area (or both), the greater the force creating torque. Additionally, the ‘stroke’ or the offset of the crankshaft journals from the axis of rotation, is the distance over which the Turning Force is acting. Hence, a longer stroke will increase torque. So this brings us to the next problem, the pressure in the cylinders is dynamic not constant. And more in relation to your question, how do you increase the average pressure applied to the piston during combustion? Firstly, because there will be a time in the combustion process when the pressure will be at its highest, we want to time the piston travel (crank to conrod angle) such that this pressure peak generates the most torque (this is why ignition timing is so important and why programmable ignition is worth its weight in unobtainium). Factors that can affect the pressure profile in the cylinder include (but are not limited to) the amount of fuel sucked or pushed (if supercharged*) into the cylinders, the chemical properties of the fuel, the amount the fuel is compressed before ignition (although I believe this changes the burn rate rather than the actual thermal energy output), the shape of the combustion chamber, etc. The biggest influence here is the amount of fuel in the cylinder before combustion. Remembering an engine is basically just a big reciprocating air pump, meaning this is all about a combination of mechanical factors (valve opening & closing times, valve sizes, valve durations, port flow characteristics) and fluid dynamics. Plenty of people on here have knowledge about getting an L-series to be a good air pump. To summarise, your options include: Increase Piston Size Increase Engine Stroke Ensure optimal ignition timing for all rev ranges (programmable ignition required) Increase the amount of fuel in the combustion chamber (messing with cams, valves, ports, inlet and exhaust manifolds, etc) * Turbo is short for Turbine driven supercharger. NOTE: I reserve the right to be proved wrong about any or all of this by someone much smarter than myself.

Chris, I should be able to make it in the Zed (assuming it is in one piece at the time). Otherwise i'll be in a Manga...

Got some tyres. A big thanks to dat2kman for taking the time out of his long trip from QLD to VIC to meet me at Yass with some tyres!

Hi guys, I'm chasing a set of 4 second hand 14" semi-slick tyres in reasonable condition - so not worn down to the wear indicators. The street legal ones, so I believe tyres like the Toyo Proxes R888, or the Dunlop DZ03G, Bridgestone RE55s, Yokohama A048, etc. Preferably from the ACT area so I can pick them up (postage to Canberra would just about make it cheaper to buy new ones). If anyone can help me out, please send me a PM.

Sorry if this has been covered before, I did a search and couldn’t really find any answers to my question. Does anyone know of any seats (from another car or brand new) that give better lateral support (shoulders, ribs, legs, etc – similar to that of a race seat) which either fit the 240Z seat rails or the rails from the donor seat fit the mounting points on the 240Z chassis, therefore removing the need to make custom mounting brackets? If there aren't, I'll make some brackets up I guess...

Fair enough. Probably not my finest literary work. The first coil (either the top or bottom) sits in the spring seat and is generally an inactive coil, yeah? Right, so at ride height (when the spring is under compression by the vehicles mass) some part of the second coil usually ends up in contact with the first coil (coil bound). This continues the more the spring is compressed. Ultimately the spring would become fully coil bound, if the spring was in isolation and comprssed to its limit. My question was whether the tie-wire holding the first coil in place (for non-captive springs), gets squashed (and therefore damaged) by the second coil under large amounts of spring compression? Does that make more sense? Having said all that, you guys all seem pretty convinced that this works and that you have been doing it for years. So I’ll give it a go...

As I should have done back when I first joined, here is a quick introduction. Name: Bede Location: Canberra Occupation: NOT a public servant Datsun Collection: I have owned 8 or more Datsuns (much to the annoyance of my wife I’m sure). Currently I own 5, all in various stages of completeness. The two that count are a ’73 240Z road car and a ’74 180B rally car. The Zed: I purchased the car about 18 months ago and have been in love ever since. Every time I walk into the shed and see the Zed it puts a smile on my face. I never thought a car would have that kind of effect on me. The short-term plan for Zed is to improve the handling (springs, dampers, anti-roll bars, bushes, geometry, etc), of which I’m most of the way through doing. The long term plans are to put a 20B rotary engine or a more modern equivalent of the S20 engine (NA Toyota 1G engine – 2L straight 6 with a twin cam, cross-flow head).

Chris, as Dazzed alluded to, it means the spring is loose at full droop (full shock extension). Normally there is still some tension on the spring (which is why you usually use spring clamps to remove them) even at full droop. Thanks for the offer of standard springs, but I have a set. I might do some measuring tonight. Thanks for the suggestion Dat2kman, I was thinking something along those lines. My question then is, usually the first half a coil or so ends up coil bound, does that mean the spring is clamping/riding/hitting on the wire you used to hold the springs in? Whittie? Dat2kman? All this talk of 'full droop', maybe we need some Viagra for this thread...

As long as the bolts have never exceeded their Yield Strength (i.e. over-torqued), and have no signs of mechanical damage (corrosion, scratches, etc), they should be okay to re-use. Obviously without crack testing them, no-one can say for sure.

Fellow Zed enthusiasts, I fitted some Tokico Illuminas to my 240Z recently and while reassembling the rear struts I discovered that the rear springs are no longer captive. Has anyone else had this issue with the Tokico Illuminas? The rear springs were captive with the previous dampers (some old Pedders Comfort Gas apparently)...

An Ford RS200 like this; Or did you mean an Ford Escort RS2000?

Sinisha, Are you trying to reduce the distance between the CoG and Roll Axis (by raising the rear RC), or are you trying the bring it to a similar height compared to the front RC (assuming the front RC is higher than the rear RC)?

I met up with Chris and a few of the other guys from Canberra just as they were filling up and checking their tyre pressures at the Chisholm BP Service Station this morning. It was fantastic to finally meet a couple of the people off the forums. Have a safe trip guys, and I hope it doesn't rain too much.

Damn, that is the Melbourne F1 GP weekend.

My apologies if this sounds like a silly questions, but can you just enter the track day section or do you have to enter the event (concourse, presentation dinner, etc) and then enter the track day section as well? The entry form doesn't make this clear.

Dat2kman, I guess my connection to rotary engines started when I bought my first rallycar, a Mazda RX-2. It was fitted with an EFI, Bridgeported 12A. Also as an engineer I can appreciate the elegance of the mechanical efficiency (three moving parts, less amplitude on the intake and exhaust flow pulses, the potential to make a lot of power, etc). There is a certain appeal about the inlet air flow not having to slam into a closed inlet valve all the time, but maybe that is just me. Can you please tell me more about your rotary powered historic sports sedan (if you are happy to share)? At this stage my DAZDA projects are still just that, projects (Time and Money and all that). I plan to put a NA 13B into my 1600 (I agree with you Gav240z) and am considering putting a 20B into an HS30 (as much as others may view this as sacrilege)... Gav240z, The FD RX-7s are a beautiful car (almost as good looking as Zed! ) great choice! I forgot to add, I'll try and get some pictures of my Zed up here soon.

I guess my question has been answered. Thanks to all for their responses. P.S. Thanks Lurch