JMortensen

I've told this story before, but one of my Z buddies had a friend who built a motor and then fired it up and just let it idle for something ridiculous like two hours. Thing was smoking like crazy. He calls my friend complaining that something is really wrong, etc. My buddy goes over and has a look and asks what he's done and is told about the long period of idling. So goes out for a drive and just beats the piss out of it. Up to redline and then back down, back up to redline, back down over and over. Comes back about 15 minutes later, pulls up, no smoke. I think before you pull the pistons and look at the oil rings, you might as well go drive the thing and do the same revving up and down bit. It's not going to hurt the motor in the long run, but it might save you some hours pulling the engine and the crank, etc.

When you turn the side gears in opposite directions, you're forcing them through the viscous fluid which is what makes the LSD work. It should feel difficult to turn. If you turn the pinion and it is hard to turn, then you may have a problem. You could pull the main caps off and remove the carrier and look at the bearings, but make sure you mark left and right and top and bottom and put the shims back in correctly. If the pinion moves smoothly I'd just install it and go for a test drive and see what it feels/sounds like.

If you look at pictures of Paul Ruschman's yellow autox car on 13's and compare to any Z that has 17's or 18's on it, you can see that Paul's car is lower to the ground, and the rear control arms are actually still pointing down from the center to the wheel, so the geometry isn't all F'ed up and he still has plenty of travel. At some point you do have to consider the possibility of smacking the chassis on the ground before the suspension bottoms, and some real low autoxers have skid plates for that reason. Terry Oxandale actually modded the struts to get his roll center back above ground in the rear of his extremely low Z with 17s, he's the only one that I've seen that has done it.

Sounds yucky.

E31's aren't a dime a dozen, but they're not hyper-expensive either. If the head is straight and the other issues fixed, I would be inclined to just run some cam tower shims and drive it. If it's going to cost hundreds of dollars to fix it and then you need a valve job etc on top of that, I'd go find another one. I wouldn't to the thick head gasket, as it moves the head out of the quench zone and so it might be more ping prone with the thick headgasket than without.

Stupid thought popped into my head just now... I'm sure that we've all seen the leaf blower superchargers on youtube and been surprised at how well they worked. If one wanted to test this theory that helping to evacuate the exhaust would help, why not put a leaf blower intake on the exhaust pipe and see what happens. Might at least help to prove the concept (might also suck a lot of gas into the exhaust if you have a lot of overlap). Googled "exhaust scavenge pumps" and spent just a few minutes. I did find that there are apparently systems out there for pusher motorhomes (makes sense as they might have 30' of exhaust to get out the back), and a lot of people think they're scams.

IIRC my buddy's 510 wheels fit my 240 with just a teeny bit of grinding on the stock calipers. Tube80Z has run 13s on a 240, as has BRAAP, and I've seen them on an ITS 280, so it is definitely possible.

Uhh... OK. Here's another post from me on the same subject which I think is a little more descriptive: I don't think there is a law against fuel cells, certainly a lot of drag racers use them on cars that get driven on the street. Personally I would avoid a cell at all costs unless it was necessary with the body you're racing with. My cell is 20 something lbs heavier than the stock tank, so just installing the cell will make my car slower. If you don't have a firewall between you can the cell, then you run the risk of spraying fuel into the passenger compartment if you get rear ended or have a rollover. Not to mention the stink in the car when you dribble a little gas filling it up. If you do the remote filler to the stock location, that makes the cell a lot more liveable day to day, but it becomes much harder to separate the cell from the passenger compartment. Then there is the cost of the cell and plumbing it. The only upside to a cell is that you can run larger fuel lines. Aside from that, there is no other benefit except the crash worthiness of the cell itself. Having been in a 72 Z that was rear ended at 50+ mph and seen that the tiny amount of fuel that leaked went outside the car, I just don't think it's a smart way to spend money. I'm sure others will disagree, but that's my $.02.

There's a bit of room for discussion here. Just because you can put a 315 on a 9.5" rim doesn't mean that you should. Ideally the rim width would be a little larger than the tread width (315 is the section width [widest part of the tire], not the tread width). On the other hand, sometimes putting more tire under the car will make it handle better just by virtue of having more rubber available, even if the tire would perform better on a wider rim. If you want the car to turn, putting a tire that is too wide on the rim will make transitions feel sloppy. I ran a 250mm wide slick width on an 8" rim, and you could really feel the tire flopping over before the car took a set. It was a lot faster than a 205 on a 7" rim that fit perfectly though. That 250mm tire should have been on a 10" rim according to the manufacturer. If you really want to run a 315, ideally you would get a rim that fit a 315 best. If you have to run that rim, then you can figure out how much tire floppiness you want to deal with and take it from there. If you want a suggestion for how to get the most out of the tire that you want to run, I'd say find the tire you want, look up the tread width, and buy it .5" narrower than the rim.

I gotta disagree on the LSD. The traction difference coming out of corners is way more important than understeer on a street car, and if you're carving canyons and that sort of thing, you can tune around it with suspension. A 2 way LSD, like the Nissan CLSD, limits slip under power and decel, and has spring preload when feathering the throttle, the amount of lockup changes as a function of the torque sent to it, but it doesn't unlock under decel.

I don't like the Schneider cams because it seems to me that I have seen about 10x as many posts about Schneiders than about all other types of cams combined. No technical reason not to like them, just a gut thing from seeing so many with a lobe wiped.

Yes, and don't listen to people who tell you that you can't swap cam towers. Just number the towers before you remove them, install them in the correct order and make sure the cam spins freely after they're torqued. I would regrind a stock cam. If you don't have one, email my bro-in-law at mat m AT m2differentials.com. He has probably 10 cams loose in his shed.

Most 30 or 40 year old Datsun gauges provide nothing more than a vague suggestion as to what is happening. The right size tire helps of course, but even when you have the right size tire, you might still be off, and don't trust the tach either. If your tach is as accurate as mine was, it's only real function is to provide a very dim green light so that you don't have to be afraid of the dark when you drive at night...

Wasn't www.zccjdm.com having them made?

Delta, Web, and Isky offer regrinds, among others. No doubt you could get something that would spin up to 7K.

.460 is about the limit on the stock springs, kinda depends on how far the valves and seats are cut and installed heights after that. Schneider makes nice springs that aren't super stiff and will handle a lot more lift. There is a common Ford 2.9L V6 valve stem seal that works, it is Fel-Pro #SS72686. With those parts you can run .600 + lift without any binding issues. Losing a lobe does seem to be a pretty common issue with the Schneider cams for whatever reason. I would go with a regrind, and maybe add a spraybar as well. Not sold on the ZDDP, but a bunch of others are.

Yes, that is a bad assumption. You can read on harmonic dampers and look at cars with broken cranks and try and decide where you want your rpm limit. I wouldn't hesitate to turn any of them to 7K, and I would hesitate to turn any of them too much higher, but you can take a look and see what kind of risks you're willing to take, and what kind of rebuild intervals you would like to have. The subject has been discussed many times before. Search for things like rod/stroke ratio, valvetrain stability, crank harmonics, etc.

A couple hundred rpm on a less powerful motor is probably a worse compromise than a taller gear on a more powerful engine. The functional rpm limit of an L series doesn't change very much from L24 to L28 or stroker. I would suggest you go for the bigger motor and gear it to where you want it.

No need to double post. Take your shims to a local gear shop and see if there is something close. The shims are just a placeholder and they don't need to be exactly the right size.

Still need the MM adapter.

I am told I'll have my CV's in 2 weeks. Definitely feeling better about this company.

I think having it angled will improve the reliability of the pickup too. In my case it really is just a tube in the corner of the cell.

My pickup was at the right rear, so I flipped it backwards.

Tilt the fuel cell.This is a 12 gallon. I expect I might only get 10 in it now...

I've basically written off the original CV that I sent out. I expect that I won't get it back and that I'll never get the parts ordered. I did find another company that will make CV's and they are more expensive. I have a set on order and they received my 2nd CV shaft yesterday. Hopefully this one doesn't disappear, otherwise expect a WTB ad for Z31T CV shafts. If this all works out, I'll sell the LH shaft for about $325 (you swap the stock LH to the RH) and the set for $575. I have to see what the shipping charges and all that are going to be before I finalize the prices, but so far this company is much more responsive.