Howdy

Arrrrr just get out your angle grinder and cut them to the length which suits you. Thats what I always do. Just make sure you don't hold them between your knees and your overalls aren't impregnated with oil because it gets a bit hot in the nether region.

Agree with Dat2kman, Clive is good and has the Wade grinds plus some old racing grinds which cover most situations. Usually you can have the choice of grinding your cam which will probably require thicker lash pads or welding up your cam then grinding. I can't tell you how good welded cams are because I have never used one but the ground cams I have used have been good. Need to make sure you run any cam in properly. If it was me I'd use the 72 with your combo. I have used a 663 grind on a stock standard 240K motor with twin SUs and extractors only and it worked great. Also built a few other higher spec motors with big porting, high comp and 45 DCOEs and it also worked great for the street. I thought it was a good all rounder. Please someone correct me if I'm wrong but from memory I think the 663 is a 72 deg cam so was 288 duration and 0.335" lift at the lobe. I thought it was a grind used in some Datrally motors but might be wrong. I may even still have it somewhere because that motor died at Winton after being thrashed to within an inch of it's life then just one more inch. The 240K was a one make series but there was only one 240K and lots of Drivers. It spat the lash pads a couple of times so I'd definitely run some new heavier valve springs.

When you are talking about the porting required. Are you talking about cleaning up the ports and matching them to the manifold, or are do you mean I have to really get bigger valves? It depends on what your final specs on the motor are but if it is higher comp, 72 or 74 deg cam and 45 webers then a high flowing inlet port will enhance that extra breathing in the medium to upper RPM range. Bigger valves would help in a higher spec motor but probably are not necessary for this build and the money could be better spent. If you do your own porting, take the time to learn the basics about port flow as first timers would be more likely to make them flow less than more. Pay particular attention to NOT ruining the port's shorter radius which is the usual number one mistake, and don't highly polish the inlet ports (exhaust yes so carbon doesn't stick but inlets need to be kept reasonably rough to aid flow and keep the fuel mixed with the air) and there are areas on the L series heads where you can hit water if you go too Gung-Ho. If you are at all unsure about doing it, just clean up any casting irregularities, match the ports to the manifold & gasket and carefully smooth the port to seat to chamber transition, lap the valves, polish the chambers and leave it at that. Bleedin obvious stuff is measure your comp ratio (need a piece of perspex, bit of grease and a burette) balance all the chambers and do your piston to valve clearances from 30 deg BTDC to 30 deg ATDC on the exhaust stroke but I reckon you already know that. (Can weld a piece of hardened steel to an old valve to cut the valve reliefs if you need them). Not so bleedin obvious stuff is if you get the cam ground, you may need taller lash pads so the rocker wipe pattern remains centralized. You may also need heavier valve springs depending on the profile and intended revs. IMHO I don't trust even the best machine shops as I have picked up major faults in machining so many times, from the most highly regarded workshops, things that would wreck a new engine in minutes but may not be picked up by an assembler who does not double check the measurements and clearances. So my advice is even if you farm out work to a machine shop you will still need to check it carefully anyway. I too prefer to do everything myself and only farm out machining I can't do at home because I don't have the equipment.

G'Day Jeff, What you have in mind sounds good. What ever way you can get higher compression is OK but need to try to keep the port size reasonable and they do respond very well to a good port job on the inlet ports. Not sure which pistons are in your motor but if they are dished, it might be cheapest to find some flat top pistons and keep that head. I'd find another good rocker from somewhere, should be plenty around. The triples might get a bit fat in traffic and not like idling for too long, especially with a cam. Plugs tend to foul easily especially if you go with BP-7s which are a suitable heat range for higher comp and triples. They might need a reasonable tuning effort to get good enough for Sydney traffic. Trouble is the air flow velocity is a lot lower with decent size triples and a longer duration cam. Personally I don't think anything under 44mm carbs is worth the trouble and expense as they just use extra fuel. But man they do sound good. I found twin 2" SUs work very well for a city car and are a cheaper alternative but you need to stuff around with the linkages a bit, port out the manifold and modify the air box which are all easy jobs. 240Z carbs are a common straight swap also. If it was me I'd go with 45mm triples, a decent set of headers, 2.5" exhaust, 9.5 to 10.5:1 comp - max you can get with that head (98 oct fuel) 72 deg cam, nice port job, recurved dizzy to suit, BP7ES plugs and keep it to 7000RPM / 7500 max - she will like to go higher but don't. Any higher you will need a good harmonic balancer, rod bolts and a good full engine balance including clutch. Optional extras would be a proper engine balance, lightened flywheel and HD clutch. And limit the heavy city traffic as she will be for the open road - old school with soul and character mate. One option you may not have considered is fuel injected individual throttle bodies which would be a bit easier to tune, more suitable for dual purpose driving and still sound awesome.

I really think the rotor button is running off the post in the cap when you retard it. That's why it runs crap. The small 8mm bolt at the bottom of the dizzy might have enough adjustment to re-align the rotor button with the dizzy shaft but you may need to move the shaft one tooth retard.

OK that's good. Have you made sure that No1 lead lines up with the rotor button while at TDC and they aren't out by one hole? I mark the dizzy body with a texta where No 1 lead goes so I can see when the cap is off at TDC. The rotor button must cover the post in the cap for all the timing range say between 0 and about 40 deg. If the metal part of the rotor button runs past the edge of the post then it may spark to the adjacent post and fire in the wrong cylinder. If you whack the timing light on No one lead and give it a rev, what happens? It should be a relatively smooth and uninterrupted move around the pulley to about 30 deg and back. Do that for all leads and see if they move the same roughly. It shouldn't make big jumps around the other side of the pulley. If it does you are getting cross firing which could be dirty or damaged leads or tracking in the dizzy cap due to dirt or a crack. If it doesn't move from your 10 deg at idle then the mechanical and vacuum advances are seized up. Did it do this before you replaced he leads and cap? What you have, to me, sounds like it is firing way out at the wrong time while inlet and exhaust valves are open or less likely extremely lean. Also grab the rotor button and give it a gentle wiggle to make sure it is solidly mounted. There should be a slight springy feel to it and it should always move back to the same spot. Give the vacuum advance a suck and see the plate rotate then return. Make sure the inside of the dizzy cap is in good condition, pins are clean and the carbon brush is located in the center and springs in and out. The last thing I can think of is the star wheel thing (6 points) sitting under the rotor button where each point should be lined up with the corresponding point on the center shaft. This triggers the spark so with zero timing and TDC they should exactly line up. The top part (rotor button) needs to be aligned with the bottom part holding those points on the shaft. I can't remember if the top part is on a spline or not - been a while since I stuffed around with one of those. If all that lines up then maybe have a look at the carbs. If it only misfires when you raise the revs quickly but runs fine while holding the revs up then it could be running lean plus insufficient dampening in the pistons making it extremely lean under acceleration. Check the valve is on the end of the dampening rods and there is an amount of resistance when you push them into the oil. I'm assuming the springs are in the top of the carbs pushing the pistons down? Don't laugh I've done that before.

Sorry for the dumb question but have you checked the leads for correct firing order?

G'Day Aircobra, It's probably the carbies causing the bad idle. With the timing - set your points gap (assuming here that they are not burnt - if so replace them and the condenser). Then work backwards - disconnect the vacuum advance then set your maximum timing which means revving it to about 4000 RPM to ensure all advance is in. I'd try about 32 to 36 deg total if you are using (98 octane with 9.5:1 comp). Once that is done, connect the vacuum advance and check the idle. Should be about 10 to 15 deg. The vacuum advance can seize up with crap so you can check it is working by giving it a good suck. and see the points plate turn then bounce back. With the carbies, I always checked the jet heights first by removing the tops and pistons then use the back end of a vernier to check the depth of the jet, set both exactly the same then you can use No turns to adjust from there onwards to adjust the mixtures. While you have the tops off make sure both needles are identical part Nos, not worn on one side and set to exactly the same height. Check the springs are identical. Also give the inside of the tops (suction chambers) a good clean and make sure the piston slides in and out smoothly with no rubbing. Empty the dampener oil out of the top of the pistons. Then adjust each carb's idle screw back until the throttle plate is just closed completely then turn them in the exactly same amount (around what they were before so your idle will be in the ball park). Then adjust the balance screw between the carbies so that when you open the throttle, they both start moving at exactly the same time. Just one thing left now - Check the dampener pistons are clean and look the same then wack in some oil. The weight of oil will determine your acceleration enrichment so light oil will lean it out and heavy oil will richen it up. I nearly always used engine oil 20w50. Light oil tends to leak out faster. See how you go with that. You really should check your tappets. One other thing not normally checked which will cause rough idle is the front pulley - make sure the bolt is tight and screwed all the way in. They can unwind then seize in the crank thread.

The suspicious thing here is loosing power at the track which is likely water in the combustion. When it looses power like you mentioned at the track, stop and pull the plugs. Check for a really clean or wet plug and that will be the cylinder with a leak. One likely culprit might be the inlet manifold gasket leaking water into the inlet port. I am assuming here that when you say they tested the head, they tested flatness and porosity. Also most torque wrenches are way out so it might be worth using another one.

G'Day Jeff, the L series is about 10 X easier than the Porsche motor you pulled apart. Rip it apart Mate, not worth whacking back in now you have it out. Even if it's good, get a full gasket set, give it a quick hone by hand, new rings and bearings, maybe a cam chain and lap the valves in. It's very cheap and easy and any questions I'm sure we can answer them for you. If the motor is bad, you'll be glad you didn't whack it back in. Also I don't think anyone can get compression by hand, except maybe Arny Swarthisnickers. One option is to do a leak down test if you can get hold of a tester as you can do this on an engine stand. Or put each cylinder at EXACTLY TDC and put 100PSI into it, maybe using your compression tester hose, then see where it leaks out (rocker cover breather, exhaust or intake). You will soon see where the compression is going. You should just get a little leakage out the rocker cover breather - similar amount for each cylinder, which is leakage past the rings and none past the valves. The rusty cam might be an insight into what the bores are like. The cam should just be brownish colour on the base circle.

Greg, make sure you plan out any suspension & brake changes before settling on the size, especially if you are going to 8" width because there is not much clearance on the front with standard guards. For example, I can't run 8" x 15" on the front due to camber take on blocks under the strut and modified tie rod ends to get rid of bump steer. The outer steering rod end sits too low and fouls the inner rim. Consider camber, camber take on, ride height, caster (which will cause the wheel to hit the front of the guard) and position of the disc (over or under the hub). Also make a firm decision about which tires you are going to use, or at least narrow the choice right down. Then look at the size range and recommended camber settings. Smaller diameter tires are getting less common with several brands starting at 17" now and some just having narrow sizes in the 15". The A050 is a very good track tire, as is the Z214.

Nice, looks like a lot of rubber there - will be interesting to see how they go. One thing re-GPS I found is the position in the car of the aerial and the frequency. I just installed a 10mhz GPS (so detects 10 times per second) with my Motec dash and it is extremely accurate and close to my wheel speed sensor. It was picking up 19 satellites at Winton. I placed it right at the front & center of the windscreen inside the car on a small piece of thin sheet steel. Motec recommend you mount it center of the roof (on top) away from metal pillars & edges, cage etc which can deflect the signals. Also to mount it on a metal sheet so signals don't come from underneath (as they will be reflected signals). I imagine this would be the same for any GPS sensor like phone or other.

Took a day off to spend tuning at Winton, Lambda probe packed it in and I nearly burned the car up after a fuel line split (the only piece I didn't replace about 2 years ago literally 50mm long) but got the boost control sorted and managed a PB of 1:33.79 which is about 2 seconds better than way back in 2003. Was on the way into 32's when we got red lighted. I need better brakes, g forces are pathetic under brakes, though I didn't bleed them before I started. https://www.youtube.com/watch?v=3FSFoZBfu0g

RB30 NA, RB20, RB20DET, SR20, SR20DET - pretty well all the same strength (gear widths wider so stronger than 280zx, 260 etc boxes) but differences in ratios and syncro arrangements). RB30ET, VG30DET & RB25DET = truck boxes - big and heavy, virtually unbreakable gears, bigger input & output shafts, crap 1st gear ratio except for pulling stumps, about the best box for the price for big HP. Can't put a L series belhousing on these boxes due to the physical size.

Hey Andrew, black deposit is normal in a long service box and some small fine metal flakes like small hairs on the magnetic drain plug but not lots of metal shavings on the inside of the bell-housing. Work out if the shavings are alloy, brass, or magnetic - will give you and idea where they came from. Best to pull it apart and check the needle roller bearings and inner races which each gear rides on. The box may have been sitting for some time and surfaces have rusted. That box will break the countershaft drive gear, 3rd gear or 5th with a turbo L28 @ 220 RWKW if you use the power a bit. An SR box in very good condition might last for a while but may eventually break 3rd or 5th gears after a bit of abuse. You can beef them up a bit by adding a heavy duty 11 ball bearing on the input shaft (std is 9 from memory) and a HD needle roller bearing (the contained type so it holds thrust) on the rear of the counter shaft and limit oil flow through the sandwich plate - late model SR boxes have a 1 way trap door to block flow towards the rear under acceleration which causes starvation of oil to 3rd. The bearings are available at most bearing suppliers.

G'Day Andrew, if the countershaft is pushed all the way back, 5th shouldn't be hitting reverse but this sometimes happens after pulling the housings off and the countershaft slides forward. I can't see any countershaft thread out the back of the nut but is hard to see from the side view, normally there is a little shaft showing or it is flush with the nut. If the nut is overhanging the countershaft, maybe there is something not quite right. You can check alignment by bolting only the front bell-housing up and front cover with the countershaft shim (or no shim) installed (leave the extension housing off) tap forward both shafts and check there is clearance between 5th and reverse. If not you may have incorrectly installed spacers somewhere. There shouldn't be any grinding when you turn the main shaft. I reckon it will look right when you bolt the front up. Make sure you get measurement "A" right by using the correct countershaft shim and allow for any gasket you use on the front cover. As the others said, if it is a quiet whiring sound, probably OK but if it is a whine and there are no chips, rust etc on the teeth, probably input shaft bearing. It is always important to put new, good quality bearings in while it is apart, especially if you have reasonable power because these boxes are not very strong. Worn bearings allow too much gear spread under load, especially 3rd gear, and is the reason for a lot of failures in my experience.

Ahoysandy, what is your comp ratio, what plugs are you running and what gap? 2, 3 & 4 black - what colour are the others? Did you check, with a timing light, what the stability looks like when you rev it up? Is it all over the place and does the balancer look true? Also not sure how your fuel lines are set up, when they removed the manifold if they disconnected the lines did they reconnect the return line to the inlet? I don't suppose you are running a restrictor in your return line like the 260z has standard? Wait and measure your leads before lashing out on new ones, if they look OK, ends are good, no sharp kinks or damage and are clean - they are probably OK. Did you check the float chambers after the power pull?

G'Day Ahoysandy. Do a full throttle pull to where it cuts, hold it there for a second or two, foot on clutch and shut it down immediately (don't lock your steering ) and roll to a stop with the engine off in neutral. Pull the plugs out and have a look, that will tell you if your too lean or which cylinder has a vacuum leak. They should all be roughly the same colour. If they are black after this it is probably due to the misfire and this is likely due to a weak or bad ignition system. If you changed the plugs the gap might be wider than before. If you have high compression, low coil output, crappy leads, or very lean mixtures you may have previously closed the gap to compensate - check your old plugs to compare the gaps. If you changed the fuel filter, are you getting enough fuel flow through the new filter? After the full throttle pull and shut down you could check each float chamber - all should be at the right level and not empty or very low. You can check the resistance of the coil - high and low side and compare to specs. Also the lead resistance, including your coil to dizzy lead. While you have the multimeter, check your earth resistances. I imagine you have already checked the timing and stability at idle and revved up? Sounds a little too coincidental that you replaced the headers (I'm assuming better system than before so engine will run a little leaner) and the plugs then suddenly have this issue. So my first guess would be leaner mixtures has tipped the possibly weak ignition system over the edge. Wider gapped plugs would make it even worse. Usually ignition modules just crap themselves so either working or not working. You mentioned a fuel regulator so I'm assuming you are using an electric pump so it might be worth checking the pressure which could be either high or low (maybe higher due to the new filter's extra flow and the return not flowing enough and flooding the float chambers). Also assuming you are running a return to the tank? Oh yep and I'm also assuming the exhaust shop didn't take your car on a joy ride AKA Ferris Bueller Day off and over revved it. If it is a possibility, check the harmonic balancer and bolt. A loose balancer can cause misfires.

Yep was good to catch up Sinisha, been a while. Those times are very impressive, can't believe how quiet your car is now. Doesn't seem right that such a fast car is so whisper quiet. Well done.

Coilovers: I’ve avoided them on my cars in the past simply because they cost money and take a little time which might have been better spent on other things. In this case, however, I needed to get heavier rate springs for my car and no matter how many times I sorted through the pile of bits strewn around my joint, I just didn’t have the bits to make it work. Besides, next set of tires I plan to go to bigger wheels and 8 inches wide so I need more room at the front. Back in the day I would just take the standard springs out to Thomastown where O’l Mate would shuffle to the window of a dirty old spring works and I’d hand over the carefully cut springs plus a piece of paper with the free length required (calculated using the tried and proven formula lifted from Fred Someone’s book “How to make your car handle”, Pouhn maybe)? Then a few weeks later I’d get back the new heavier springs with proper ends, not the sharp cut off ones that don’t quite fit right, not that there’s anything wrong with them as long as you don’t jack up or jump the car. [i wish I could remember the old Bloke’s name from the spring works – about 120 years old, took 20 minutes to get to the window and used to do all the touring car springs so I had to wait my turn but he’d get them done eventually and was so cheap because he still thought it was 1947. I’m talking $10 per spring. He would lend me lengths of spring steel rod of varying sizes so I could make up new sway bars then take them back for annealing and I’d have to remind him to charge me for the bar. Don’t see many Characters like that these days]. Anyway, after Winton and Sandown last year and from the meticulous data captured over the years (old 1997 diary with 10000 loose bits of oil soaked paper, cardboard, ripped up 6 pack cardboards stamped with my greasy finger prints) I calculated I would need to go from 211 lb to 336 lb (6kg/mm) in the back and from 162 lb to 280lb (5kg) in the front. This would give me the ideal ratio front to rear going by my fuzzy logic. [i call it fuzzy because it all starts out dead straight in my head then after a few beers towards the end of Fred Whatshisname’s formula, which you need either a photographic memory to recall the denominator or 2 memories on your calculator, both I don’t have, I end up going in continuous circles of “yep W to the power of 4 times G, got that one, just remember it and type in the value of N times D to the power of 3 times 8, OK, Ahhhhh forgotten the Numerator or is it the Denominator, damn should have done it the other way around and what on earth makes me think I can remember it to the 10th decimal place? I decided on the MRC weld on coil over kits. Had a good look at them, the quality and dimensions looked very good, have helper springs and the springs are not a bad price at $120 per pair (when I find out that I should have multiplied Fred’s numbers instead of divided). I ordered the 2 sets for the 55mm 260Z struts and 5 and 6K springs. The kits took a while but I wasn’t in a hurry and MRC were great to deal with, plus are local to me. The 5K springs were very hard to get so I ended up getting 2 pairs of 6K and a pair of 7K (392 lb) springs so I could run at Sandown and have something to play with. As it turned out, the 5s would have been too soft except during torrential rain so I am happy I didn’t get them. The kits were easy to install, I already had sectioned struts front and rear, which is absolutely critical in order to get the bump travel, and my home made strut tops which just required grinding the spot welds off to separate them from the standard spring perch. The top spring perch in the kit comes drilled small so just requires drilling out to suit the inserts. The hardest part was buffing down the strut tube so the sleeve fitted over it as they are exactly 55mm ID which is the exact OD of the strut without paint. I used a length of emery paper for that. Again out came the calculator and several beers later I had the exact position on the strut tube in which to place the sleeve. “250Kg per corner = X compression minus ride height by the power of the wheel rate divided by the square root of the …..ahhhhh! Ha, Amazingly at ride height my calculations were within 3mm on all four corners but that could be my garage floor. Suck on that Pouhboy. Tuned out pretty damn nice if you must know. I did Sandown on the 7K rears and 6K fronts and these are definitely not too hard. The car is still very predictable, the springs are well dampened even on the softest shock settings and it is not skatey or bouncy at all. It doesn’t dive as much under brakes, squat so much under acceleration, and hits the curbs more solidly without the splitter rubbing like before. Previously the rear always used 100% compression travel even with 50mm out of the strut. And best of all it seemed very neutral in balance. I did, however, have to carry out one further important mathematical calculation prior to Sandown. This too was lifted from good O’l Fred Whathisname’s book and it’s the one for sway bars. Not even going to mention that one but Pouhboy really knew his stuff because it worked out perfectly. As I couldn’t get the 5K front springs in time and the ratio front to rear using the 7R/6F compared to the 6R/5F springs is slightly different, skewing it towards understeer and I hate understeer, I made a new front sway bar out of one of those lengths of bar from the spring works. Its 2mm smaller than the previous bar. I only got 2 sessions in and no time to play with the suspension due to the alternator failing (ended up being the wire to one brush broke) but I’m not sure I would have changed spring or bar rates anyway. All up I changed tires from the Toyo RRRs to Hankook Z214s plus the springs and picked up 5 seconds a lap. It was dry compared to damp patches previously though but very happy with the results.

“You don't put a car on the track unless your prepared to crash it.” Really? Here’s a little pearl for you. No one in this class racing is prepared for that level of carnage unless they or their sponsors have bottomless pockets and don’t care about their car….Probably none!! This is different to Hyundai racing where the car is just a vehicle to get the Driver to the podium and further their career. Sure they might accumulate some old parts and panels and it’s in the back of their minds but that’s about it, mentally no one is prepared. Most of these Guys are just as passionate as all of us on this forum about old metal, maybe more because they go that extra step and put their car on the track. They will be devastated. I for one absolutely love to see these cars on the track as they were back in the day and not hidden away in a man cave next to a fancy coffee machine, leather bar stools and automotive memorabilia. I know some of these Guys, sure some might have plenty of coin but the passion is there just the same. My heart sunk seeing this and I felt for these Guys. It’s like saying “well if you drive your Z on the road you gotta be prepared to have it written off by some crap Driver in a Camry”. Comments like this, to me, just read “I told you so“. Damn soapbox just broke, now I got to find another one.

Bahahah. That man has WHITiddlydoodley. Is there any such thing as a Virgin rat?

If you have decent power it will get hot during a 15 or 20 minute track session, but so far (touch wood) I have never had issues with diffs except the spider gear pin drifting out and seals leaking which I guess could possibly be heat related.

Yep it really gets hot inside my car like a sauna, having no insulation probably doesn't help. Will definitely go to the Synthetic but higher viscosity this time. Great info thanks Dat2kman, I too run the breathers up high and use a fuel filters to separate the oil and filter the incoming air when it cools down. So you returned the oil to the top filler hole in the front of the box? One of my concerns was returning to the front might starve the back but I suppose it is coming from the front anyway. I'll have to look into that Jabsco pump. I was considering returning the oil to the top over 3rd & 4th gears. The diff does get incredibly hot and I have avoided measuring the temperature because I'd need to do something about it then. It's a CIG locker so none of those issues with the plates slipping but I know what you mean as I used to run one.

Thanks Richard. I have used several good brands in the past but seemed to blow more boxes (Z, SR, FJ, RB-na), mostly the counter shaft drive gear, and 3rd gear. I think part of the issue is that if it is too thin it pools at the back end too easily even using center plates with the one way trap door. It would also blow out the breather when hot. I have been using this oil for some time now with much (and I mean a huge MUCH) better results, especially trying to keep the std syncros from snatching when the oil is hot and revs are high. In saying that, I might try the Motule competition 75w140 as synthetic might be happier at the higher temps. Do you think lighter oil would not get so hot?