ozconnection

Hi Guy Could be a diesel block, they had L24 sized bores but its the crank that made capacity to 2.8 litres. Notched block in those? Maybe. But the stamped engine number is L24 right? Hmmmmm. Have you looked down at the bottom of the block, where N42, F54, P30 etc lives to see what yours is? Post a few close up pics if you get time. Don't throw it out man....seal it up in a plastic bag or sell what you don't need. Perhaps not as desirable as an L28, sure, still good to have though. Cheers. :classic:

You'll find that I'm in Australia, that much you're right. The add for what you need is in the USA.....all I did was to pass on HIS ad to you.

Wow, I don't think I agree with any of this! In a perfect world, where every engine was the same, there was no such thing as two stroke, all grades of gasoline were the same and all engines were efi or carbed, we all lived with the same temperatures all year round then what you've said may be more accurate. (I'm sure there are even more variables.....I'm only listing what comes to mind quickly) Even the plugs themseves will look somewhat different due to their designs, ie heat range, fine wire, projected tip and manufacturer etc. "Maximum power and minimum emissions" are two opposite ends of the performance spectrum and biasing your tuning efforts towards one or the other will dramatically alter the way the plug will colour. If carb cars ran "safer" then it would be in the best interests of auto manufacturers to continue using carbs. However, we don't. Carbs can be surprisingly accurate at metering fuel. It's the fact that the intake manifold is a wet flow design that has to warm up sufficiently in colder weather to help vaporize the fuel that requires the mixtures to be richer. A good manifold design with sufficient heating will work very well indeed. EFI doesn't have this design 'limitation' and can reduce emissions immediately after start up. Also, carbs don't measure inlet air temp directly, so no recalibration can be made with reference to this variable. So can plugs colour differently on hot and cold days?.....or.....does the air/fuel ratio change on hot and cold days? The thermostat used in the engine will vary the operating temperature of the engine and will effect the air/fuel mixtures entering the engine too. I recently tested my Holley 4 barrel equiped L28 with several thermostats, all different temperatures and found that my fuel ratios were changing based on what thermostat I had in the car. A colder one required slightly richer jetting, which allowed for a degree or two more timing which can also have an effect on the temperature of the burn in the cylinders. A P90 head will burn the fuel differently to an N42 which will burn differently to an E31. Can you see the problem here? Back to the original poster, there was an article I read some years ago that suggested you rev the engine in 3rd or 4th and cut the ignition and declutch the transmission, pull over and pull the plug to read it. Pulling a plug from a hot engine is not recommended as it can strip the softer aluminium threads in the head, but it's dangerous to do this anywhere in suburbia too. If you let it idle at all, you don't get an accurate reading of the mixtures at WOT. My solution: I got myself a wide band oxy sensor and never had to touch my plugs again until its time to change them.

olie05 from Hybridz is selling this right now........ I just went and looked. It's a 3n71b. I'll drop the price by $10 since there is no overdrive. $40+shipping takes it. Cheers

I can tell you, it's really not that hard to leave the chock in there! :stupid: I've made my own, very short so I can take the cam bolt out and drop the sprocket, pull the chain over the teeth to find a new timing position, all done in seconds. When I want mine to come out after doing work, I just turn the engine slightly via the crank bolt and the wedge instantly pops out.... As for that block of wood, someone had no freaking idea what they were doing.....or needing to do the job properly. OMG.

Here's something a little different for you Guy Why don't you just remove the inhibitor switch from the transmission and keep it plugged into the harness? No cutting/splicing of wires and your harness remains original. You could be tricky and place the switch in the cabin and devise a way to make into a kill switch!! :bulb: Just a thought.

That's true and that's an accepted tradeoff when we decide to instal a performance cam, isn't it?

An aluminium flywheel has a friction surface on it so that the clutch plate doesn't actually run directly on the aluminium. Look at the aluminium unit built for our engines by Fidanza. I have one and its design is sound in this regard. As for your bolts ripping out, I would perhaps suggest that there were some fundamental problems with your installation. The bolts were perhaps too long, bottomed out and whilst torquing the bolts the softer aluminium threads were stripped. There should be locating dowels installed in the flywheel so that the pressure plate can be suitably located on the flywheel (to ensure correct balance during machining) and take the sheer loading forces that the clutch and flywheel experience. Without the locating dowels and/or the correct instal of the bolts, this could have potentially led to your experiences with aluminium flywheels. As for more torque, the engine provides the torque. A lighter flyweel will allow faster engine acceleration due to less inertia. A drag race engine may benefit from a heavier flywheel, to keep the wheels turning as the clutch is dumped on the start line, preventing the engine from bogging. In most other situations, a lightened flywheel should see some benefit, allowing the engine to accelerate more quickly. If your own testing has proven the heavier flywheel to work best (for you) then go with that and be happy with your choice. Cheers.

Anytime you start playing around with cranks rods and pistons, you're bound to change the characteristics of the engine compared to what it was like before. Compare an L24 with an L28. Different bore, rods and crank mean the same thing here too, the characteristics of that engine are different. Throw in things like rod/stroke ratios, cylinder heads, camshafts, induction systems and exhaust setups and you'll quickly see that the answer you seek is not easily obtained from just a few lines written here. Go over and read the stroker stuff on Hybridz...there is some solid info written by some very talented people. This discussion falls heavily into the modified engine section. Good luck with your project.

I bet you it's your horn relay. They're an old electro-mechanical relay that can go 'off' because of dirty contact points in the relay itself. When you press your horn and your surroundings are quiet, you should be able to hear the 'click' from the relay in your engine bay. To open the relay you just bend back the little fingers, one each end, that holds the relay mechanism captive in the housing. Remove the wiring to the relay and unscrew the mounting screw so the thing ends up in your hand. Much easier if in your hand to work with. Don't get too aggressive with the 'fingers' as they can break off easily! Once exposed, plug the harness back in and press the horn again. You may see some sparks at the relay. Clean those contact points with an emery board of some fine wet and dry paper. Then try the horn again. If it works

Be careful with information like this. The L26 engine has a bore size of 83mm's The L28 has a bore size of 86mm's. A 120 thou or 3 mm rebore is too much. I have an L26 engine in my shed that's been bored to 85.5mm's, so it's almost L28 capacity. The problem with such a large overbore is that the cylinder walls are very very thin. Risky business. As already suggested to you, an L28 may be the better option to begin with.

"A plane that never lands, and a boat that never comes to shore" was a quote from David Vizard about the only times not to run an air cleaner of some sort. I think we all know what happens to our engines internals without some form of filtration. We wouldnt run a fuel line without a filter. Same logic here. I use K&N filters in my car. I did a lot of dyno testing myself to dispel the BS on these things. When I replaced the paper element with a K&N, there was no power increase. Changed the filter box and power rose. It was the filter box that was restrictive, irrespective of the filter I used. I still believe that the K&N is a good product and the variety of styles they have for custom applications is impressive. The dirty throat on that image you posted Pomorza is from the phenomenon called "intake reversion" and not from the K&N. I have seen this many times on carbed engines, especially on those where the owner likes to 'tune' their carbs themselves. They often set them up a little rich to smooth out any flat spots from lean mixtures and because of reversion, fuel residue is left staining the throat of the carb like in your picture. Another term for this phenomenon is 'standoff'. Its created by the firing order of the engine and the type of intake manifold used ie dual plane. I saw a cloud of air/fuel mix sit 6 inches above the throat of my Holley using an Arizona manifold once and thought "WTF is that?" I did some investigating and that is what I learned. Adjusted the jets to take into consideration this event and my power and torque rose substancially. Leave it stock to play safe. But to modify is to investigate and learn. That's the part I love. Cheers.

Cool! :classic:

You'll enjoy the swap over, it transforms the car. I did it once to one of my Cedrics and it was like driving a different car and I wanted to burn off everyone at the lights. Have fun with it Guy All the best.

Hey Guy, it's not a 4 speed auto is it, ie L4N71B. If it is, the shafts are very different. BTW, if its a manual (stick) transmission, why only a 4 speeder? Cheers

Try tuning them at the same time. There is a balance tube for this reason, so make 'em both rich and then progressively lean them out together...at the same time. Don't finish with one and go to the next one...as you know, that doesn't work well. Good luck mate.

I worry about your compression ratio with that head Two things that will help though....a better Rod to Stroke ratio using the 240 rods and a 'big' camshaft profile. If you have to use less than stock timing with the fuel of your choice, then you'll know that your compression is too high. Solutions to this are, use more octane, use a bigger cam or rip the head of and open the chambers by unshrouding. Thicker HG's cripple the quench, so I don't advocate that, since the N42 chamber is not exactly what I'd call high quench anyway (unlike the P79 or P90 heads that have been mentioned to you by others here already). Good luck with it though. Cheers.

Hey mate, Those rods look fine...and the price is very good. By the time you factor in all the work you may want to perform on your 'stock' rods, including new ARP rod bolts, I think there would be very little in it. Save yourself the time you'd spend on your rods and get these mate. Good luck with your project. Cheers!

I'll second this absolutely.

With all this modern internet technology around............ I know, why don't you post a high quality video/audio of your noise? Diagnosis can be easier if we can see/hear the 'patient' Just a thought. Good luck with it.

Those plugs look like they're Bosch ones......nothing inherently wrong with them but many punters out there who own L series engines swear by NGK's. I would buy a new set of plugs. Get plugs that are hotter than the ones you're using. Hotter plugs will stay alive longer in your engine if it's too rich or burning some oil. Standard NGK's are 6's so get some 5's. Check their gaps before you put them in, too. The photos have poor resolution, so it's hard to see if they are really oil fouled or fouled from over rich mixtures. Good luck mate, cheers

Did you attempt to increase your compression ratio by doing the head? How were your oil/compression rings? I have a turbo pump in my 'stock' engine......no blue smoke. Could be the pump, sure....do as Nissanman suggests and swap the old one back in for argument sake. As far as the head goes, it 'should' be good, yes? Good luck man!

Not owning a Z, I can't comment on the specifics of coolant system purge for your cars but I'm reading a lot of stuff here that seems like a lot of effort, at least more than seems necessary. Whenever I do a coolant change or the system gets opened up (that even means taking the radiator cap off), the way I purge the cooling system is by taking the car for a drive with the heater on. The fluctuating revs and added vibrations from driving for 15-30 minutes will get the air pockets to the radiator header tank. I then park the car and let my engine cool completely. At this point I used to take the cap off and fill the radiator with extra coolant. Now, and I always had this on my Datsun, is a coolant recovery system. I make sure that the tank is filled with coolant to the full mark and as the engine cools, it draws in coolant into the radiator via the radiator cap. Two or three cycles of this and the cooling system is completely purged of all air. Don't take the radiator cap off to check the coolant level, at least I don't anymore. I don't have to, the coolant level in the recovery tank is now my coolant level measure. :bulb: Air under the thermostat can happen by using a thermostat without the little bypass that some thermostats come with. I always use the bypass type to avoid the 'air under the thermostat' malady. Like mentioned by Zsondabrain, water wetter is a good thing! Cheers

I had absolutely no warning when my failed. :disappoin Replace it now if it worries you. It's only money and your baby

You're not having much luck with this one hey? A leak in the radiator is just that .....a leak. The cooling system must be completely sealed for it to work properly. It must be able to contain pressures of up to 30 psi in the water passages in the block and prevent air entry after shutdown. Air in the cooling system is compressable. Water is not. Air in the system, entered into via the small radiator leak will prevent pressure from building in your cooling system and thus allow nucleate boiling, the water boils in the hot spot areas, the engine gurgles as the air pockets move around and your engine will overheat. Water pump cavitation is also a problem with reduced coolant pressure, so less water moves through your engine, and what does, overheats and perpetuates the problem with runaway overheating. Fix all leaks. Don't discount a faulty headgasket even though your oil isn't milky. How old is it? Do you have a coolant recovery system on your radiator? Try a higher pressure radiator cap. I'm using a 20 psi one (up from the 14 psi one I had originally) and I swear that I've had zip problems with overheating. You'll beat this, just keep at it. Cheers.