240hoke

Well thanks for the replies again. I will report on the other skirts and bearings in a few, I am about to go tear the rest down. JeffP Thanks for the advice. The pistons however were coated on the sides from JE, a teflon like coating. Thats why they are dark and the scratches actually look alot worse then they really are. I kinda got stuck with these pistons, I didnt pay any extra for the ceramic but I was disspointed to see that it only lasted a couple thousand miles non the less. Right now I just cant justify spending the money on rebuilding this motor (nor do I have the money right now) So more then likely ill be sanding the ridges off the piston and head and installing some new bearings.... and turning the boost up screw it.

This pretty basic for most of you I would assume. But I thought I would post up a step by step guide on rebuilding the clutch packs in the z31 R200 LSD. First off here there are a couple great threads about this diffy floating around. Here is the main one: http://forums.hybridz.org/showthread.php?t=112921 In summary a large problem with the nissan CLSD was that from the factory, presumably to save money, they only installed two clutches and filled the extra space in the clutch pack with two spacers. This, along with wear over time, makes many of these LSD's very weak with almost no breakaway torque. These spacers can be removed and replaced with extra clutches, to make the unit have a total of 6 clutches, how it should have come from the factory. Shims are then added to adjust the breakaway torque. The differential can also just be shimmed without the addition of clutchs for a quick fix. Phyxius was kind enough to design and have new clutches cut from spring steel and offered them as a group buy here on hybrid. The stock units are now NLA. I used his clutches for my rebuild. Cant thank him enough for taking the time to draw these and have them made! __________ Start by removing the rear diffy cover and the main bearing caps. This will alow the LSD unit to be pulled out. Its take a good bit of wiggling and working but will eventually come free, I used a wooden dowel and taped it easily through the axles holes to get it started. KEEP TRACK OF THE SPACERS, the LSD unit is aligned in the case with spacers on both side. Take pictures and/or mark which side they go on. Here is the LSD unit and the spacers laid out on the bench: Next remove the ring gear, once hte bolts are removed It should slide off fairly easy with a few taps from a rubber mallet. I marked the position of mine relative to the LSD housing for safe measures. Once the ring gear is removed you will gain access to the four phillips screws that hold the unit together. These can be a pain to get out as the unit is loaded. Grab a couple spare bolts and nuts and put them through the ring gear holes to take pressure off the screws. Once you get the screws out you can open the LSD housing and take out the internals. You will see: spacer (which will be removed) spring disc spring disc plate clutch plate center section plate clutch plate spring disc spring disc spacer (which will be removed) Heres a picture of the contents laid out on the work bench (sans spacers): The discs with internal tabs are the clutches. The discs on the ends that look like plates are springs they are dished (kinda hard to see in the picture) With the new clutches the unit will be assymbled as follows: spring disc spring disc clutch plate clutch plate clutch center section clutch plate clutch plate clutch spring disc spring disc This is just the beginning thoug heh. You must test the brekaway torque for the differential and shim it to your liking Here is an excellent site which has alot of information on the R200 LSD and specific information on testing: http://www.gordon-glasgow.org/lsd1.asp I bought .004 SS shim stock from Mcmaster. I use the spacer as a template and cut the stock using a good pair of scissors. The shim will look like this: Here is a picture of my testing apparatus using r200 stub axles: I used a cheap ($10) beam style torque wrench from autozone to make the measurements. It was placed on the bar at the welded nut you see in the picture. All differentials are going be give slightly different results bases on the wear of the clutches and the thickness of the new clutches along with the co ef of friction provided by the type of oil you use, however here are my results which may help as a baseline, I used Mobil 1 sythetic gear lube (75w-90) and Tran X LSD additive. I mixed up approximatly the amount that you would have in the differential to get the right ratio for testing. A base line test without shims netted me 45 lb/ft for breakaway... (.004 SS shims) 4 Shims - 60 ft-lbs 5 Shims - 75 ft-lbs 6 Shims - 90 ft-lbs From research on this board and other sites, it seem that 60-75 ft-lbs is best suited for a street/autocross car perhaps you may want a little tighter for the track, its all your preference. Putting it back together is the same as disasymbly, make sure the case marking on the LSD unit align and you get your bolts torque down to spec. Its a good idea to replace the axle seals as well while youve got the unit apart. Torque specs for the rear main caps are 65-72 ft-lbs. Hope this helps some of you get started I wasnt sure what I was doing and thanks to JMortensen and others I got it figured out.

Thanks for all the replies guys. Blairjj there is literally one single dimple on #5. Bearing damage is to the top as well. I have only pulled the #6 piston so far, I will check all the other bearings and scoring in the morning.

I agree with warren and have a hard time believing its detonation. Note especially the raised lip around the dimples and the dimples on the edge of the dish. looks more like a "cold" deformation I guess you could say. But i dunno, I was running some pretty crazy advance at SEZ so umm perhaps it was detonation Heres a picture of detonation I found on gooogle: The bearings were in the same motor just the motor was put in a different car with different pistons. There was no shotpeening done, right now im thinking perhaps MIG slag from the I/C pipes. I blew rings lands on #1 before I did anything else on my last rebuilds with stock pistons, seems like 1 and 6 are the quickest to go due to intake design and as you said cooling on 6

Nope, just a regular ol t3 center section. Perhaps it got demolished in the combustion chamber or the damage occured at idle while the turbine speed was slow enough to not be damaged. i dunno if this is what was causing my motor is miss a little, it could have been like this since day one for all I know. Those bearing have a good many miles on them, they were in the motor since Ive had the old 260. But I inspected and reinstalled then when i put the new forged pistons in last year and they were perfect. Its been just a couple thousand miles since then. My guess is the pressure from the object caused extra stress on the bearings. I wasnt tearing the motor down because I thought something was wrong i was just double checking stuff really. This surprised me. heres what that coating used to look like LOL:

So today I took out my engine and tore it down. The reason I was tearing it down was to find and mark exact TDC for more accurate tuning and to install some ARP rod bolts. I was also wanting to double check my cam timing as my car had always been kinda hard to start and lately had seemed to be missing a little at idle. Turns out my timing was dead on, but I found something much worse: piston damage mainly concentrated on #6 with a little on #5. It looks like something got inside my motor and bounced around for a little while. Whatever it was it was big enough to damage the motor but small enough to not do any damage whatsoever to the turbo. These are Forged and ceramic coated JE pistons that are less then a year old (Notice the ceramic coating!! .... perfect for turbo/nitrous applications my ASS). Piston Damage: Head Damage: The dimples were enough to pinch the top compression ring so much so I cant remove it with any resonable force. Scoring on the sides: Scoring on hte main bearings So thats where im at right now, I honestly dont know how it happened, but it did. Not exactly sure what to do at this point either. There is no crank or block damage that i can see at all. Another thing wierd I noticed is i can wiggle the pistons a bit in there bores Your thoughts and suggestions please, if yall think this is bad enough to warrant a rebuild i may just be junking the L28 all together.

WOW this is an old thread hehe

You can talk to Quoc here, 240Z_Master. He can get you a new set.

Im jealous That looks like it will work great, I gotta toss my plastic cell soon. You can get an aluminum trap door from Jegs, that what I have on my fuel cell cover. Also on mounting it at an angle, im sure you dont really care, but your not going to be able to put as much fuel in it and any kind of sender if going to be off.

nice choice.

Toyoter Spectra Blue, its actually a celica and rav 4 color, heh.

Oh man, i cant wait to see some more pictures!!

mamba - yea mail boxes are painted in rustoleum, and they also arent shiney and purdy Most everything Ive seen turns a satin color after a while. And on the wetsanding thing just make sure to clean it up before it drys and youll be fine! other wise its pretty damn difficult to get up. Kellhammer - I did mine in a make shift booth in my garage, first time painting anything. Im pretty happy with my results. But again not knocking, more power to you guys. I cant wait to see the finished product. Didnt big Phil spray his car in rustoleum, I coudl be wrong but i seem to recall it looking purdy good. maybe he has some input to how its holding up Btw my wetsading supplies were more then 100 bucks I would say, Different stages of sandpaper, squeegees, buffing compound, and buffer sure do addup. I have 1000 dollars in my Dupont Base/clear job, inlucluding guns and supplies. But i wont go that route again, 300 pr/gallon is a little much for clear Oh and that BMW art car is kickass.

Very Cool work! Finished product should be quite nice.

EvilC - Not Much... I go to college 2.5 hours away from my house, and the Z stays at home since its not exactly a daily driver, nor do I feel comfortable leaving it out at the apartment Sooo... Im limited to the weekends when I come home... and even then Im usually modifying someting on it heh.

Yup the key to building one of these cars is doing all the work yourself. Like OTM said, you gain tools, and knowledge, and still get out alot cheaper. There isnt a shop anywhere that will pay attention to detail like you will on your own car. And I will say on the rust issue I cant agree more. Personally if i was going to do it over again i would have paid the extra money to find a car that is as rust free as I could get. I bought my car for 1500 bucks, looking back it would have been much smarter to find a really nice 240z for 5-7K and start from there. That way you have a solid car to start with. After building a car from the ground up, again looking back I would have rather done a few mods here and there and enjoyed the car inbetween.

i must say I admire you guys effort here. I wetsanded my car once and that was enough! I personally would save the extra 30 bucks required to get a gallon of single stage and a spray gun is only 50 bucks if you dont already have one. But anyway looks like you are having some good results and getting a work out as well. Id be curious to see how well this stuff actually holds up to UV rays, car washing etc. -Austin

Thanks alot! I definitly used youre car as an insipration for a couple things, such as the frames rail and subframe connectors!

Hahaha Thansk for tipping me off to the auction guys. As much as it pisses me off its kinda amusing too lol.

chrome - classic, black - agressive. Fiberglass bumpers are light, and cheap, and can be fitted easier to your car. I have a thing from chrome euros though. RacerX i think most carbon hoods these days are jsut overlays, mine is. Beta Motorsports has a super nice all carbon hood, however you get what you pay for and its expensive!

Yuppo no flexing at all. Heheh just dont leave hte stock hood springs on lol. They will break the hood in half

if you have some time and space on your hands you can do the job yourself with 100 bucks worth of sheetmetal. I literally used a nibbler a hammer and a welder... My floor boards arent the greatest but heres a link to what I did... http://www.geocities.com/projectzt/floorpans.html it was my first real weldin job so i didnt know what i was doing. If i did it again it would be stich welded and i would pay alot more attention to keeping it from warping.

Hey guys, Thanks for posting pics of my car, and RacerX thanks for the compliments! As for the carbon hood I think they look awesome on Z's. A great color combination I think also is Alex's car.... s2k gunmetal with stain black and carbon accents. Alex's car One thing i think about the carbon hood is you need something else to kinda make it flow, other carbon or black accents are needed to tie it in to the car. I think my car looked kinda funny when I has silver panasports and and otherwise stock body. With the black zg's splitter and gunmetal wheels i think it flows better. Gunmetal or black wheels I think really tie a carbon hood in. But Ive found black wheels are a love hate thing... Here is a shot of mine I think shows off the hood, alot of people told me blue and black wouldnt work... well i love it.

Wow motorhead those pictures are awesome. I love the vents in from of the rear wheel. I have thought about doing something similar.

Very Nice!! I love it, I vote for a writeup and a sticky!