JMortensen

I wish I knew about those control arms before I had a set made. Having them made cost me more than his would have, and I have to disconnect mine before I can adjust them since they are only threaded on the end. Depending on what you want to do, you may need both the camber plates and the control arms. I think I maxed out the camber plates at about 2.5 degrees neg, so I needed the control arms to get to 3 degrees. You need a lot of thread to safely go that far with the control arms, it is entirely possible that his have enough. They also really reduce suspension bind in the front especially if you get the TC rod kit as well (another part I had made for too much $$$). Not sure, but I think the ZFRS ones still use poly bushings in back. His site mentions GMachine, maybe he's using the delrin/aluminum bushings. It looks like a lot of fabrication to get a rod end or monoball setup into the back. All of this stuff is loud on the road, BTW. Jon Mortensen

Should be an 8 inch. Jon Mortensen

Toyota uses a crush sleeve in the 8 inch, V6, and T100/Tacoma diffs. A lot of guys replace with the solid spacer. Maybe yours was one of them. Regardless, like you said, looks like you got away with it. Jon Mortensen

Oh, and I should apologize to seeker for the bad info Jon Mortensen

That is excellent news! I had a diff built ~6 years ago, and I specifically remember the bastards charged me for a crush sleeve. Later I learned more about diffs and built quite a few, but no Nissan diffs, while working for Randy's. Hence my comments on crush sleeves. If that is the case, forget the crush sleeve stuff and go for it! Very happy to know I was misinformed! Jon Mortensen

Pull old seals with a screwdriver or a seal puller. Put a very thin layer of silicone on the outside of the new seals. Put a little grease on the inside of the seal, tap them in with a hammer and socket. Easy job. Jon Mortensen

You also asked what the best way to remove them is. Lots of people use a slide hammer, I think this is the hard way. The easy way is with an air hammer. If you don't have access to air tools I think this is a job for a mechanic, because you'll need to cut the peened area on the nuts off with a cutoff wheel and its gonna be way harder to get the new nuts back on tight enough. The nuts on the inside are peened (hammered against the flat section of the axle so they can't back off), so you need to cut away the peened area with a cut off wheel. Some mechanics peen only one side, some peen both. Make sure you cut it all off before turning the nut or you will waste the threads on the stub axle. Once this is done take your air hammer with the pointy bit, and stick that bit right in the dimple in the center of the axle shaft. The air hammer doesn't beat the crap out of the bearings like I think the slide hammer does. It will actually just vibrate the shaft a lot (wow that could be taken the wrong way) . Then you just put some pressure behind it and the stub shafts will slide right out. Make sure you have a friend standing on the other side to catch them. Have fun... Jon Mortensen

YEP... Jon Mortensen

My understanding of the rotary installation problems is that the eccentric (would be the crank in a piston motor) sits so high in relation to the transmission tunnel. Heightwise it would be equivalent to the flywheel bolting onto the back of the camshaft in a V8 from what I understand. The tunnel has to be cut out and fabricated to allow clearance for the high position needed for the transmission. Also raises cg. I would assume that this causes driveshaft alignment probs also, requiring alteration of the diff angle or repositioning the diff to fix. Mazda trannies are not the most sturdy, according to a guy I worked with who is on a GT2 RX7 crew. He says they have lots of synchro issues, which is a bummer because the lure of the rotary is super high rpms, and the synchros can't handle that. I don't know of a fix for the weak trannies, I think he said they just rebuild them a lot. If you get serious a call to Tri-Point or someone like that may be in order. I used to work near Tri-Point about 10 years ago and they were always putting rotaries in something weird, Bugeye Sprites, MG's, Lotus's, etc. If memory serves I think I saw a Datsun 1600 roadster in there once. Also the exhaust is REALLY HOT. I wonder if you might be able to insulate or jet hot the whole system. I certainly wouldn't want rotary exhaust routed in the same place I've got my L6 exhaust run! Jon Mortensen

I believe that is Zbarn. http://www.zbarn.com My understanding is that Tweeks sold their Z business to Zbarn, but I'm not absolutely sure on that. Jon Mortensen

I used to do it on an alignment rack. I've seen my ITSS Firebird racing ex boss lift his car on the hoist, set it down on 4 upside down 50 gal drums to give himself a place to work. If you don't have a flat space it makes things pretty tough. I suppose you could make blocks that are level and pull the car onto the blocks. I don't know exactly what kind of ROI you would be getting at that point... Jon Mortensen

Hey 260DET, I've had the same problem with my admittedly inferior Z Quip late 280ZX setup on my 240. I was running the stock rotor with 4x4 calipers in front, and ended up taking the prop valve completely out, and still could not lock the rears in water! I suggest you install the prop valve in the front system. As for me, I'm saving for some bigger brakes front and back. Still looking at options, but I'd like to keep in a 15 inch rim, so I think that means 12 inch rotor max. Just wanted to share my experience... Jon Mortensen

Here's the response I got from the zhome mailing list to my "Does header wrap cause overheating" question: "When I crewed for a Z car that was racing SCCA nationals in the 1970's in the NE, we started to wrap the headers and immediately experienced blown head gaskets. Consulting with the header manufacture, they indicated that wrapping headers does what the product is designed to do, reduce heat in the engine bay. However, as an unwanted byproduct, the the wrap also backs heat up into the head. Too much heat and the head warps blowing the head gasket. To correct, remove the header wrapper. If you need to keep heat from the carbs, build a heat shield between the headers and the carbs." Thought this might be of interest for anyone else considering a bad purchase... Jon Mortensen

Sounds like a bad master cylinder. Its been a while since auto shop, but I believe the primary cup (?) is the name of the seal that actually pushes the fluid. If the front primary cup goes bad, the fluid can pass the secondary cup and return to the reservoir, without actually exiting the system. If the rear primary cup blows it will usually leak brake fluid into the booster. You can look for a leak at the back of the master and see if there is fluid there (usually seeps). Put light pressure on the pedal, hold it there. If the pedal slowly sinks to floor, then the master is bad. Its not a bad idea to check for other leaks like wheel cylinders and calipers, but you said the level was the same, so I'm thinking the master is the culprit... Jon Mortensen

If you want to take the preload out of the swaybars you can drive around as planned then loosen both ends. Sit in the car, and have someone else do the work because your weight is important here. One end of the sway bar end will touch the end link, the other will be probably 3/8 to 1/2 inch from touching. Put a stack of flat washers on the side that is higher so that both bar ends touch the end links at the same time. Then tighten as usual. If you don't do this then the bar is constantly preloaded, which is not noticeable by most but will tend to make the car feel different when turning left vs right. Jon Mortensen

You have a 240, but you didn't list what engine you have. Assuming you've got a 2.4, I'd say 40's are OK. Anything bigger and I'd go 44 Mikunis or 45 Webers. Don't do it if you cannot tune a carb or don't want to spend money on jets. They're a big PITA if you are unfamiliar. Get the How to Modify book, it goes through all the circuits on the carbs, and get a one wire O2 sensor mounted in the exhaust manifold/header. With the O2 sensor you know exactly what the air/fuel ratio is. Just hook up a volt meter to the O2 sensor. You want voltage to equal about .85 - .9 volts for best power. Also make sure you have enough cam to take advantage of the carbs. I've got a friend running a basically stock L20B on a 510 with dual 44's. He can't rev over 6K, because of the cam. But the velocity of the incoming air is so slow at low rpms that he really doesn't have much low end either. So he has the worst of both worlds. No bottom end and flattens out really bad on top end. On the plus side I've got 3 x 44's and a fairly big cam and a light flywheel and I can drive in stop and go all day long (except for my new overheating prob--totally unrelated). People often warned me not to do the triples because I would hate driving in traffic. Same thing with the cam. Same with the light flywheel. And the ACT pressure plate. People generally just told me not to do to my car what I've done to it. My experience has been that the L6 has enough low end torque to offset the all of these potential problems, and I love the way my car drives! Jon Mortensen

I cc'd my head and polished the combustion chambers and did a little port work myself. It is not that hard. And the How to Modify book helped me A LOT. First thing I did was lay the head gasket down on the head and trace out the pattern. Then I unshrouded the valves to the fire ring line. When I had all of these done, I took a piece of Lexan and cut it so that it fit over one combustion chamber. I drilled a hole in the Lexan, then filled the chamber with water from a graduated cylinder. I did have to drill some vent holes with a pin drill to get the air out of the chambers. I kept grinding away on the chambers one by one until I got all of the chambers within .5 cc. I even went further and notched the block to match the head so that there was as much open space around the side of the valve for air/fuel to get by as possible. As far as ports are concerned, I did a lot of smoothing on the short side radius with my finger and a piece of sandpaper, but the bowls and the runners were already pretty good, since they had been worked on previously, so I cant give you too much there. So you're not flow testing. At least you know that the chambers are the right size and shape, and that you've removed all of the sharp edges in there. Datsun ports are pretty good anyhow. I would match the gasket to the head and the manifolds, clean up the big errors in the casting of the runners, then work on the chambers. Jon Mortensen

The reason we use pressurized cooling systems is to keep the water from boiling. We mix antifreeze and water because water transfers heat a lot better than antifreeze, and antifreeze has a higher boiling point and provides corrosion protection. If you use a liquid that doesn't boil until 370 degrees, then you don't need a pressurized cap to keep it a liquid (pressure raises the boiling point in a conventional system). I question the cost ($25/gallon) and the heat transfer effectiveness of that fluid. I'm not saying it isn't better than what we normally use, but I saw nothing on their site about the heat transfer properties vs. water, only the size of vapor bubbles comparison. I suppose you could just buy 5 gallons or so ($$$) and have some on hand, but it would be expensive when you spring a leak and need to fill the system, or need to remove the radiator for some reason. I also don't know where to get a 4 lb. radiator cap for my Z to take advantage of the longer hose life they offer. Hoses aren't that expensive either, so you could replace a few of them before you actually saved money by spending 10 times the price for coolant - since you don't mix 50/50 you gotta fill the WHOLE SYSTEM at $25/gallon. One thing they say that kinda bugs is that your engine can get up to 250 degrees without the coolant boiling. WOW! Never mind that warped head, I'm gonna run at 250! Now I know that newer Vettes have a 245 degree thermostat, and that increases fuel economy, but I don't think our Datsun equipment is designed for that kind of heat, and I think we can all agree that you don't make the best power at that temp. The whole thing reminds me of the synthetic oil commercials: "Look how regular oil gets all crusty at 450 degrees." Hello??? If your oil is 450 degrees you have some other problems!!! Always a skeptic, Jon Mortensen

14" puller. Got rid of clutch fan a while ago. Triggered by Nissan temp switch in lower rad hose from 240SX. The weird thing now is that it cools fine under hard usage. It gets hot when idling. I think I'm going to take the wrap off and see what happens. The one thing that always gets my panties in a wad is wasting money on $*&! that doesn't work. If nothing else I suppose this has been a nice commercial for Jet Hot. I don't think a coated header would pass nearly that amount of heat to the head. Thanks all, I'll update you on the situation when I get that crap off. Jon

What again is this supposed to be for? You want me to take a reading of the plugs at cruise (like plug color), or the radiator temps? I know that the way the air/fuel isn't the issue. The O2 sensor read about .85 to .9 volts at 65, so thats about 13:1 to 12:1 air/fuel ratio. Since I've switched to the AVGAS I would have to pull plugs and check color to get air/fuel, but I'm no plug reading expert, so I think the O2 is going to be WAY more accurate in this instance. The only difference in the cooling of the car occurs when I am stopped. When I'm moving the car never gets hot. That's why its so confusing. You would think that with my foot in the gas the thing would get hot because I would be putting a lot more heat out at that point. But it seems to be only when I'm idling that I have a problem. I would be happy to check a plug, but I wanna know what you're looking for... Jon Mortensen

With relation to fuel I forgot to say that I've been mixing 92 octane alternately with Tolulene and AV Gas to get around 95 octane. Tolulene when I was tuning the carbs, AV Gas after the tuning was done. And yes, I know that AV Gas runs a little leaner than regular fuel... Jon Mortensen

I just caught your question as to where I'm from. Grew up in SoCal, lived in San Luis Obispo for 6 years, then just moved to Seattle area. Why I chose that thermostat: Prior to this the car would barely ever see 195 degrees. According to "How to Hotrod" the L series makes power there, and if I put in a 175 thermostat, the engine would see 180 maybe 5% of its life. You could watch the thermostat open and close on the temp gauge. I haven't yet found a thermostat that opens at the temp on the box. Even this 195 that I just put in opened at about 187. But that is the reason. Maybe a cooler thermostat wouldn't be a bad idea, although I don't know if it will prevent me from having to take the wrap off. I think the wrap experiment has been an expensive waste of time.

The only thing I did other than the header wrap is to rebuild the distributor. That's all. I just replaced the thermostat as well, with a 195 degree thermostat. I chose this thermostat based on the "How to Hotrod" book. Apparently the L6 makes max power about there. I would be curious to see what other members are getting down the radiator at idle. Thanks again, Jon Mortensen

Thanks for the welcome. I've been on the zhome list for years, but I always thought this was strictly V8 conversions, so I never checked this place out. VERRRRRRRRRRY COOL. Shoulda been here years ago. As to the state of tune, I guess I could have provided more info. No detonation at this time. I tuned the Mikunis with an O2 sensor, so I know they're pretty close to right. I was always taught that if you made a change and had a problem, than that last change is your likely suspect, but since header wrap is such a weird thing to cause overheating (and I thought that the gasket would insulate the heat to some degree), so I was just going to run it by everyone to get some opinions. Seems like you agree with me on the last change bit, but I am still having a hard time imagining that wrap is the issue. Here's the gist of the motor: 280ZX flattop block E31 head 11:1 compression .490 / 280 cam newly rebuilt electronic dizzy D6K8 from 280ZX 15 degrees static advance, no vacuum 3x 44 Mikunis (didn't change any jetting while I was working on the car) MSA header MSD Mechanical Autometer gauge (pretty confident that its not a gauge problem) 240SX fan switch in lower rad hose comes on at 100 degrees C, gauge agrees that that is what it is doing The radiator is a 3 core 280 I got it 2 years ago in a parts car, and it was brand spankin at that time. Does that help? Thanks everyone, Jon Mortensen

I recently installed header wrap on my Z and when I put it back together the water temps have been really high. This car used to very rarely use the fan at all, now the fan is on all the time. I was thinking about this some more and figured that it is highly unlikely that the wrap was the culprit, so I did a little more investigating. I took my infrared pyrometer and got the car warmed up, then took some readings on the radiator while it was idling. I found that it seemed to be able to hold about 205-210 degrees steady. When using the pyrometer, I found that I had about 205 all across the top of the radiator, and about 195-200 at the bottom. This was on both sides of the radiator. When the fan came on the area directly hit by it was 205 top and about 150 where the fan was sucking. I was looking for a cold spot, somewhere where the radiator was blocked possibly. Did not find it. It seems to me that the other part of the radiator (where the fan isn't) should do more than 5-10 degrees worth of cooling, even if there is no airflow. Is this right? Is the radiator just partially clogged and not capable of doing its job? Anyone suggest any other checks or tests I can do? Thanks in advance, Jon Mortensen