ozconnection

I stuffed the 'nipple' with a small piece of rag and used an angle grinder with a cutting wheel to make two shallow cuts about 2mm's wide,180 degrees away from each other, ie either side. Then I used a piece of steel to bridge them. Multigrips on the steel piece should get it off. The threads are not wrecked on the nipple this way. You're able to tighten it now when you put it into your other block..... Suffice to say, clean the area well and remove the rag to rid of cuttings. Two nuts tightened against each other will work, but you'll have to find them etc. The first idea worked for me great without having to leave my workshop! Cheers!

I've heard that 75-80% rule before: the reason (I thought "excuse") that my brother spend so much time and money on slicing up the exhaust side of '70 Ford Cleveland 4 barrel heads and then bolting an aluminum plate on to raise the exhaust port roof and straighten the flow of the exhaust ports. Only clean up work on the intake ports. It worked, but those heads are infamous for huge direct short intake ports and a sharp turn down in the exhaust ports. For a while it seemed that every third Cleveland had an exhaust plate to balance the flow between intake/exhaust. The percentage to shoot for seemed to be an exhaust that flowed 75% of the intake port. Cleveland 4V heads were overkill for a street driven car. They were designed for the racing cars of the '70's. It's not so much the problem with the exhaust being a poor flower, it was more of a case of the intake valves and ports being too big, poor low speed flow was the result. Guys tried to correct this problem by using aluminium tongues in their intake ports to make them substancially smaller and flow better. Eventually the 75% thingy returned and the engine woke up at lower speeds. Power at the top end wasn't adversely effected by the tongues either. And the story continues but lets not bore the Datsun guys with Ford stuff. Lets move on from this shall we.....?

If my high school physics serves me correctly, a descending piston in an engine doesn't suck in air, it is the difference in atmospheric pressure caused by the descending piston that allows the air to be PUSHED in. The intake system therefore has a maximum potential flow into the cylinders of 14.7 psi (1 atmosphere at sea level) at WOT. At part throttle, the volumetric efficiency is less, so less air /fuel enters the engine. Therefore, at part throttle, you're not using the full airflow potential of the intake port/manifold etc. Less air flows into and out of the engine as a result. The exhaust side is different. Camshaft timing of the exhaust valve influences cylinder blow down, so almost all the exhaust gas is blasted out of the cylinder the moment the exhaust valve opens after the power stroke. Like the inlet side of things, it is the differences in air pressure, heaps this time especially as the exhaust valve opens (much more than 14.7psi!!!) and the gasses are very hot and 'excited' that allows the exhaust to work as it should with these 'apparent' shortcomings. Then, as the piston rises on the exhaust stroke pumping losses are reduced. It has also been found through years of experimentation that the exhaust valve needs only be 75% or so of the intake valve size because of the above mentioned. Larger exhaust valves than this didn't gain any more horsepower. I think your confusing the idea that after combustion takes place that there's more 'substance' to get out of the cylinders. No, this is wrong. After the air and fuel is ignited in the cylinder, energy is released, the temperature goes up dramatically and the gasses expand enormously, and it's the expanding gasses that is the element of power production (and also the major force behind the expulsion of exhaust gasses from the cylinder after combustion like I've already said). There is a lot more to this discussion and with my limited high school physics knowledge (It was a long time ago!) I might be cutting some corners. Finally, I do have to say that there may be some use in improving the exhaust port flow but I don't thing you need to lose too much sleep over it, it does a pretty good job of it all by itself. Having said that, there's always room for a well designed exhaust system.

What else do you need to know? Why don't you speak to Stewart Wilkins? He has a vast knowledge base and you can pick his brains about your project if you're still unsure of the details. He has supported teams that have competed in the East African Safari with great success and I have personally seen some of his L24's and L28's that he had shipped over to Africa for competition. Personally, you're not shooting for the sky as far as power expectations are concerned. Therefore, you should be able to achieve this much power without extremes in any one area of your build up. Many people have done what you're trying to do and got as good or better power figures using many of the original engine components. Like I have aready said, if you're going to spend some cash, talk to Stuart and spend it there. You could do a lot worse than him.

I have been down this path myself. Stewart Wilkins will recommend you use an E88 from the L24E R30 Skyline. A 'closed chamber' head, you will have more chance at achieving your high compression ratios using this head milled a 'little' bit and the chamber shape is better suited for high comp, being more detonation resistant than the N42. Needs L28 inlet valves though 'cause the E88 uses 42 mm valves, not the L28 44's. There are different headgasket thicknesses that can be used to adjust comp. ratios as well. A compression calculator is a good idea from this point onwards. Are you running carbs or programmable injection? That's still a high comp ratio for Optimax or Shell Ultra, which is 98 octane, I think. Dunno mate, I would drop the comp a little to move away from potential disaster. Nothing worse than a high comp. engine backed down so far in the ignition, it just kills power. Rather, go for a slightly lower comp, 10-10.5 and use the full 32-36 total advance. Good power is made with full ignition advance, not the other way around. Cheers mate.

I keep playing with the idea of trying to get one of you Ozzies to ship me an L20A crank to build a DE-stroked L6... I just have to convince myself that I really don't mind poor low end power on a streetcar that could run up to 8000 RPM... You want, I have. PM me.

I too have an 05L head from an "M" block L20 turbo six cylinder engine. I also have a Y70 head from an E30 L20 turbo six cylinder engine. The O5L head has 28 mm intake ports and square exhaust ports. They are smaller than the Y70 intake ports which measure 30mm's. Both heads have 38 mm intake valves and 33 mm exhaust valves. The Y70 has round exhaust ports with liners like the MN47 and P79 heads. The bottom end of the "M" engine has the smaller rods and journal size, like the US Maxima L24E engine. The E30 version has the larger, stronger bottom end setup like the rest of the L Series six cylinder family. Why did Nissan make these two versions of the same engine....who knows??? I can get some pictures of the Y70 on here if anyone is interested!

I don't know how detailed you need your diagrams to be but there are some pictures and descriptions of where the vacuum hoses go in Chiltons Repair Manual Datsun/Nissan Z and ZX 1970-88 models Chapter 4 pages 157-188. Good luck.

Shame that the actual pictures of the ports are blurry. This head will need a lot of work (welding) if your ever going to consider using it...check the water ports! Never seen a round exhaust port N42. I'm a little suspicious that someone has reworked them for some reason and attempted to make them round but it's hard to really tell. Post some better pictures please so we can all have a better look. Cheers.

I bought some of these for my P90 head. They are found on ebay under 'Nissan L28' Find them here, http://www.ferrea.com/sportcomp05.html Cheers.

I think it was the RX-7 that used two turbos, a small one for maximum low rpm torque and a bigger one for top end power. Has anyone built an L series like this?

I have done just this type of thing myself a number of years ago. The only difference was that it was onto an L28 instead of an L24. I agree that the sump may be a bit of an issue as it was on my car. I had to drill a hole through the rear dipstick boss on the block and plug up the old one, modify the sump for the turbo oil return and modify the oil pickup too. The rest was a piece of cake really. The L20 turbo should work well with the L24. For an L28, it was too small, but had full boost at a little over 2000 rpm....what a torque monster that was!!. Get a bigger exhaust..I used a 3 incher and that was plenty! Cheers.

I too personally prefer the stock setup with the tempcoupling hub/fan and fan shroud. Keep an eye out for the larger 8 bladed version. The fan itself is slightly larger in diameter and has a slightly more aggresive pitch. It fits where the original one does no problemo. You might find one on an air conditioned Maxima with the L24? You are running a thermostat in your car right?? Cheers.

A few years ago I had this really strange thing happen to my tacho...similar to what you're describing. The problem was found to be a poor electrical connection between the battery post and the clamp...sure nice and tight but a poor electrical connection. Solution: Take off the clamps and give them a good clean. Baking soda and a post/clamp cleaning tool will do the job very nicely. Should only take you a few minutes. As far as your cooling system is concerned...make sure it's in perfect order before deciding you need to add water sprays etc. Do you have a fan shroud? When was your radiator/engine flushed out and new fresh coolant added, condition and tightness of fan belt, water pump age/condition, water leaks, collapsing hoses...stuff like that. Good luck.

Does this help?? I think Trust in Japan made these. Dunno if they still do? Cheers.

What other mods have you done to your engine? Have you got a performance exhaust or are you still working with the original setup. Head work? Port work? Upped compression? And to slap a "big" cam into a stockish engine is a mistake IMO. Do the cam thing last, and don't forget your ignition timing curve may need regraphing, to get the most out of your new combo. I was shocked at how much power I was able to get from a stock L28S camshaft, which is smaller than what you guys in the States run on your twin carbied and injected L series sixes. Throttle response was terrific and torque at lower engine speeds didn't fall off the face of the planet. Weren't these things important to you as mentioned in your initial posting? Street work mostly with good fuel economy? Don't waste your money on a cam....yet. Do all the other stuff first and if your still lusting for more grunt, do it then. At that point, you'll get the most "bang for your bucks" from the bigger cam profile too. Good luck.

Kameari make 'em Try this. http://www.zccjdm.com/catalog.php/azcarbum/dt43033/pd858322/KAMEARI_L6__3.1L__SPL__ENGINE_KITS_

Hi, If one were to use a stage two turbo grind camshaft from MSA on a normally aspirated L28 with stock compression, what would be the effect? Smooth idle? Great low speed torque/throttle response? Mid range and top end performance? Just wondering what a boost in compression might be like from say 8.3 to 9.0:1 or a little more. Would I have to run premium fuel all the time because of the higher cylinder pressures due to the cam's minimal overlap? I had a look around in the forums and didn't really find anything that looked specifically into this, but I could be wrong. I have a heavy car (1978 Nissan Cedric with an L28, 1500kgs, auto, air etc) and would like to keep low to mid range torque and improve the top end power production without actually going to turbocharging. I have another Datsun that will be built with a turbo L28 in it. What do you guys think? Dumb idea or does it hold some value for my application? From my perspective, bigger cams always seem to rob so much from what I like about stock cams, low speed torque. Can the bigger turbo grind camshaft be an adequate if not optimal compromise? Give me your thoughts please. Cheers!!

Oh dear! What does your gut tell you about this situation? You've already answered your own question. Good luck.

Thanks Braap! How much friction is there with the standard setup compared to one of these? I mean, can the power difference be measured by an engine or even a chassis dyno? After starting this thread, I did what i should have done, a little digging. Found some older threads that talked about this setup and I'm wanting to see what those who have them have to say about throttle response and the noise that they make, good or bad! How about idler sprocket wear and no automatic tension adjustment of the timing chain? How often would you have to check on this situation to make sure that all is well? Does any advice about this come with the installation instructions? Just curious, thanks for your advice!

I recently found a website that advertises a timing set made by a Japanese company called Kameari. They produce a variety of go fast parts for the L4 and L6 engines. Of particular interest was their Timing set. Have a look at this: http://www.zccjdm.com/catalog.php/azcarbum/dt/pd858282#IMAGES Has anyone used this setup?? What are your thoughts on this and is it worth the money?

DatsunD DatsunD, try putting a small piece of bread into a food processor and see what happens to the bread when you turn it on! The compressor wheel of a turbo will keep the fuel in suspension with the air so there will be no "build up" of fuel here. (Consider the processor spins at say 1000rpm and the turbo spins at more than 100,000 rpm) What may happen over a long time is the erosion of the leading edges of the compressor wheel. The wheel isn't pushing just air but air and fuel.

The L4n71B ia s hydraulically operated trans. The E4n71B is a later version that is controlled by a dedicated ECU. I personally like the idea of running a purely hydraulic trans because of its simplicity. For the street, I run an adjustable vacuum modulator valve that lets me determine the shift points somewhat in relation to engine vacuum. You might be able to source a US Nissan/Datsun L series that came with a 4 speed trans. In Oz, the R30 Skyline had the L24E engine and the last run of those in 1984-5 had the L4n71B. From then, when the R31 came to Oz, they had changed over to the RB series so the belhousing was changed and the trans was upgraded(?) to electronic control. Also, as mentioned, these transmissions came in GM VL Commodores. If you can find one for the L series, get the flexplate as it is different to the one for the 3n71b. The other changes include building a new crossmember to suit the different style of mounting. Not really hard to adapt if you can weld, so grab the crossmember if you can. The output shaft is larger so you'll need the first part of the tailshaft (prop shaft) to have it adapted to yours. (I had to do all of this to make it fit into my machine!! Not particularly cheap, but I'm very happy with my conversion.) There is a company here in Australia that is currently working on a transbrake for these transmissions and 3n71b's Almost ready for release so they say. Their website is: http://www.automatictransmission.com.au/release.asp?NewsId=8295 Hope this helps mate, cheers:wink:

grab a small mirror for those cam id's.....wifey might have one for her makeup....dont forget to clean the greasy fingermarks or you'll be toast man!!!!!

What is the conversion for, and extra gear (overdrive) or for serious track (drag) work?? I'm using an L4n71B behind my L28 with great success. On the highway, it substancially drops the revs down with an 0.686:1 O/D ratio. Compared to the L3n71B, 1st and 2nd gears are a little lower for more torque. For me in my heavy street car, this is a bonus. In Australia, VL Commodore Turbos (a GM/H car) used the RB30ET Nissan engine. The L4n71B boxes in those could handle extreme power ups with suitable modifications. I consider these Jatco's to be pretty tough. Something to consider perhaps. Cheers.