JMortensen

That's the first time I've ever heard low r/s ratio goes with high rpms. In fact I've always heard the opposite, basically that ~1.8 is what we should be shooting for in an L series engine. That's why your usual high rpm forged piston NA L28 uses L24 rods. Also Mack, have you checked the weight of the LD28 rod? I don't know about the LD in particular, but most diesels have HEAVY rods and pistons. Really heavy. Like putting a heavy flywheel on heavy.

This link should work: http://cgi.ebay.ca/Racing-Dual-Coil-over-Coilover-DATSUN-240Z-260Z-280Z_W0QQitemZ8014559397QQcategoryZ33586QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Look at the spring rates he's selling John. That may explain the "jumping noises". It's more like the car skipping off the top of the bumps in the road. Dorifto retardedness... http://forums.hybridz.org/showthread.php?t=105676

The install of the Power Brute/Nissan LSD is easy easy easy. I haven't yet seen someone put one in that had to mess with the backlash. Everyone (including me, my backlash opened up .0005 when I installed the carrier into another diff) seems to agree that it is not really an issue. It is a good idea to CHECK the backlash before and after, but the actual installation of the LSD is not something to be afraid of if you have a torque wrench and some loctite.

What I'm getting in the text is that they either tested stock against stock or modified against modified, hence the sentence: "However, this isn't a major loss because the crossflow head will give 'only' a 4-6% horsepower increase over a comparable two-valve, non-crossflow head." Comparable doesn't mean a modified head vs a stock head, at least not the way I read it. Frankly sounds like Honsowetz didn't do any testing, but he just took someone else's word for it, who may or may not have tested the heads against each other. The whole bit about the LY is only 2 paragraphs long, just like the 2 paragraph section on the OS Giken. Compared to his pages and pages on the "normal" L heads, I'd say he either consciously chose not to discuss the crossflow heads, or he just didn't know much about them. Regardless, as Tim240z and Alan have pointed out this has been discussed ad infinitum here, and now we have another thread that just muddies the waters even more. One more useless thread with useless speculative answers to screw over the next guy attempting to use the search function.

This thread sucks. So much misinformation here it should be shut down. Here's a better thread about OS Giken heads, crossflow heads, etc: http://forums.hybridz.org/showthread.php?t=76847

From How to Modify: So it isn't the fully race prepped OS Giken they were talking about. There was another 2 valve crossflow L head that was released, and it made 4-6% more than a normal head. OS Giken would be worth a lot more than 4-6% IMO.

With SU's I'd say 1 5/8" primaries.

I don't know how much power they'll give over a modified SU, but IME it was a HUGE power gain over stock SU's.

I had my pickup in reverse at the top of a steep driveway and it rolled down into the street just like cyrus's car. Very similar situation, actually. I didn't think it would roll because it was at the top so it wasn't nearly as steep there. Came home from work for lunch, parked and jumped out of the truck and locked it. About 15 minutes later I hear all these car horns blaring, look out the window and my truck was in the middle of the street blocking both lanes. Putting a car in gear doesn't always work...

I was saying he would need that if he wanted to shim underneath the bearing as Mongo510 suggested, which is not the way the carrier is usually shimmed by the sounds of it.

I saw the same guy on 80 Eastbound kinda in between Napa and Sacto when I was down there about a month ago. Looked like ZG flares, nice looking car!

Kinda tough to pull the carrier bearings to shim underneath them without a puller tool like the one pictured on this page: http://www.ringpinion.com/default.asp?pid=6&pageid=80. That tool costs a couple hundred bucks. A "cheater" method would be to buy new carrier bearings, pull your old ones and hog out the center with a die grinder so that you could slip them on by hand. Then you can test, pull the bearing back off and change the shims, retest, etc and when you figure out the exact shim needed then press the new bearing on. That's the way Dana diffs are commonly done. Also the shim that would fit underneath the cone would be a different size than the one that fits outside of the cup, so you'd still need to find appropriately sized shims. Cyrus, I still think you should grab a shim and a race and take it down to a gear shop and see if they can't match it up to some other diff. It's a shim, so it doesn't have to be the exact same size. If that is just out of the question you could probably get a machinist to make you a shim out of shim stock. Also, I didn't understand exactly what you meant by this statement but it doesn't sound good: "The only other issue is the right bearing only is in contact with 2/3 rds of the machined case. This leaves 1/3 of it to float in air. I am not sure if this is significant" Crush sleeves set the pinion bearing preload. Not sure what "front lash" is. Nissan doesn't use crush sleeves in the R180 or R200, so I would imagine preload is set with shims in the R230 as well. Pinion depth is the other thing to worry about. IIRC the pinion depth on the R200 is set by shimming under the bearing that sits on the pinion head. This might help you out. It's a set of generic "how to set up your diff" instructions: http://www.ringpinion.com/downloads/yukoninstman.pdf

If you don't have adjustable control arm bushings then the only adjustment available is front toe. Do it with a tape measure. It's easy.

Still need to wash it out, especially when they ported the head IIRC.

Then why bother with SU's?

So apparently you didn't wash the head and the block when they came back from the machinist... is that right? You need to THOROUGHLY wash any part that goes to the machinist with soap and hot water. Sorry to hear about your problems though. Hopefully you can still use what you've got. I'm with Dr Hunt when he suggests a full tear down.

I thought we had figured out that the 280Z chassis was wider, so the halfshaft issue was a non-issue on the 280.

I've done two rounds of auctions recently. With the first one I did GREAT. The second was CRAPPY. The difference is that I closed the second auction at Friday at about 6:00PM. I think that nobody was in front of their computer at that time of day, and my bidders got some painfully good deals that day. I'll do it again and I'm smarter for the experience. I was absolutely SHOCKED at how well the first round went. Sold a nice set of roundtop SU's on the manifold for $180, brand new smog rail for $170, it was pretty cool all in all. The key is to host your own pictures, don't do reserves, etc. My auctions usually cost less than $1 to list.

Rubbing is racing... Rubbing is not HPDEs.

I used to freak out the other kids in high school auto shop by washing my face with Boraxo... hard. I will tell you this much though guys. The General Manager at my last job went in for a physical and they thought he had Hepatitis because his liver function was so bad!!! Turns out it was from using brake cleaner to wash his hands for the last 20 years. The doc advised him to take flax seed oil pills, and avoid getting the brake cleaner on his hands. Eventually after about a year his liver function was pretty much back to normal. Getting dirty is fun, but since he told me that story I've been wearing the gloves pretty religiously. Washing with acetone, brake cleaner, carb cleaner, tolulene, xylene, etc is NOT GOOD FOR YOU. And if you want to get your hands clean, do a big sink full of dishes. Works every time...

Halfshafts are all the same from the 510 right up through the 280ZX. Same length same size same everything. The R200 came in all manual 280Z's, so I don't know if the R180 would be legal, rulebook should tell you. You can buy a Nissan clutch LSD for ~$500 for the R180 or the R200 sold under the name Power Brute from http://www.differentials.com, or you can buy a Quaife for ~$1500. Personally I don't think the Quaife is worth the extra $1000, but I know lots of people disagree with me on that one. Lots of ITS guys just weld em up too. Swapping a LSD or Quaife is pretty easy and usually doesn't require changing the backlash or anything of that nature. Changing ratios in a diff is a PITA. Much easier to have multiple diffs in the ratios you want. You can get 4.11s and 4.38s R180s out of mid 80's 4x4 Nissan 720 trucks. If you could run a real low gear ratio than the 5 speed might be worth it, but I think you'd have to run the 280Z 5 speed and not the ZX 5 speed with the closer gears IIRC, which is kind of a bummer.

Same thing happened on my 22RE, then one of those plastic bits got between the crank gear and the chain and broke it and bent the valves. Luckily I was starting the car when it happened and I only managed to bend 2 exhaust valves. Single row chains and plastic chain guides SUCK!

My uncle was the president of Freedom Arms in the mid 80s. Got to shoot his "Oh ****" gun. .454 with 5" barrel, with 340 grain handloaded ammo. He said it was the second most powerful load ever made for the gun, second only to a 400 grain bullet they loaded for a safari. Needless to say, the 340 grain bullet was BRUTAL. But it was fun to shoot the thing and then watch EVERYONE elses' head swivel around like "WTF was THAT?!?!" Nothing like a 4' wide 6' long fireball out the end of your gun to attract attention...

Damn... Dan tells a good story!

On my 2 R200s I pulled apart there were only 3 shims in each. So I don't think you'll find a shim pack like you will for a GM 12 bolt. You'll have to either guess at what you need and order the correct thickness shim from Nissan (I think that is how that worked) or you can try to find another shim from another diff that will work. Shouldn't be too hard to find something similar that works from an American diff.