JMortensen

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

Doug, Every coilover and camber plate is different. Given that Mike only wants to go down 2 inches, and my plates don't use the stock hat so they already lower the car over an inch, if he used similar plates he would not be able to section the strut and only go 2 inches below stock unless he made a spacer to sit on top of the strut assy. If you section 2 inches, and the plate gives an inch and a half, that puts you well below where Mike wanted to be. I also have a 240 and I am running 200# and 250# springs. I would think that sag should be at least 1/3 of the travel, if not a little more. Sorry, I don't have anything to back this up, just my previous years of tuning suspensions on motorcycles and cars. To be honest, even when I was prepping Porsches (just the local Porsche shop, but great experience aligning, corner weighting, modifying) no one ever asked for a specific sag setting. But those cars all ran really low and there was no point. I agree that sectioning the struts is a VERY GOOD IDEA when your car is being run at a significantly low ride height. Tom Holt has a picture of his car with sectioned struts in the full droop position http://www.ccsi.com/~tholt/shocks.htm. In the rear full droop is with the control arms only very slightly pointing down. This is not enough droop for a road car IMO, and apparently not enough for him either. He also states that he has 1 1/2" of sag. I would argue that a little more than that would be preferable for the road. In a race car (especially road race) you don't need 12 inches of travel. A smaller amount of travel with extreme control over its movement is the goal. Plus if you go past horizontal with the control arms your camber changes positively when you load the suspension. From what I have been taught it is also easier for G forces to compress the suspension with the arm pointing up than when it points down. I don't think that sectioning the struts is as necessary as some. I've never heard of people buying Euro springs or Eibach progressives then sectioning the struts to regain travel. I don't know why this would be more necessary on a coilover setup that is being used to lower a Z 2 inches. My $.02, Jon Mortensen

Find a 60's to 80's Nissan truck with L series motor. Take the shifter from that, bend if necessary in a hydraulic press, cut to length, thread for shift knob. Cheap and not so easy $5 short shifter. Jon Mortensen

I just installed some header wrap on my MSA header. I did this because I thought it would keep the 3x Mikunis cooler, and because I hate the header with a passion (had to weld on it just to get it to seal to the head, tubes are really crushed down inside coming out of the head, etc.). I want it to burn up so I can justify something better to the wife. My engine has NEVER had any problems overheating, even during track days at 100+. When I test drove the car I found that the wrap made quite a difference in noise, but seemingly little difference with regard to the heat, and the car suddenly seems to be creeping up in temp when sitting at stoplights. It used to be that my electric fan would RARELY come on. Now its on the perma-fan setting, and it can't bring the temp back down. Sitting in traffic when its 90 with the heat going SUCKS Is it possible that the wrap is the problem? Anyone experienced this before?

For brake fittings: Get a cheap flare nut wrench. Cut the end off. Grind notches along the outside. Slide the end onto the brake fitting. Clamp flare nut wrench end in a Vise Grip. Crank away. Most flare nut wrenches will open up when you put a lot of pressure on them. Craftsman are especially bad IMO. This is just basically using the Vise Grip to hold the flare nut wrench closed. Then you can put quite a bit more force on the end without it spreading open. I don't remember where I heard this, but it works! Jon Mortensen

My understanding is that the same calipers are used from 79-81. They are pretty easily recognizable. They have deep hats, like 3 inches deep. The caliper is huge also. The 82-83 calipers are much smaller, and the rotors have a much shallower hat. This is the one that uses the Maxima bracket. If you have the deep hats and the big caliper, then you cannot use the Maxima bracket. A company called ZQuip used to make a bracket. I have a set on my car right now. I used these because I was told that the smaller calipers are more prone to failure, specifically relating to the e brake mechanism. In my experience, this is true. I have seen at least 10 later style calipers frozen. Never have I seen the early style frozen. The downside to the early setup is that it has a smaller pad, and the calipers are very heavy. When I did mine some 5 years ago I was able to mount a 87 240SX e brake cable fairly easily, I took out the second bell crank in the ebrake system and it all works pretty well. Were I to do it over again (and I will) I am going to go with something that can handle a little more heat. I have cooked the pads to the point where they start breaking apart in chunks. I am thinking vented rotor, possibly like Terry Oxendale has done (no ebrake then). If you are street driving and autoxing the early setup like I have should work fine. Mine only has problems after a long day at the track. Jon Mortensen

The Ground Control hats are shorter than the stock rubber hat by over an inch (at least on mine--I have the "roadrace" version". So you will drop the car an inch or an inch and a half just by eliminating the stock rubber hats. If you only want to go down 2 inches from stock, run the stock length struts. If you section the struts and then run the adjuster all the way at the top, you will have very little sag in the suspension and it will top out over bumps (this is more of a problem in the rear, since most of us seem to like a little rake). Topping out is bad, especially if you hit a big bump in the middle of a turn and you're near the limit of traction. I figured my heights on the perches this way: set the coilover so that at the top of the threaded adjuster the spring is touching the perch and the hat. I figured that would be as close to stock height as I could get. That turned out to be a bit high in the front with the adjusters all the way up. I wanted to go DOWN but with so much adjustment you should be able to find a happy place in there somewhere. Good luck, Jon Mortensen

Do you know what kind of flares are on the green Z on your website? Are those MSA's IMSA flares? Seems to me the problem there is that they look a little less finished when they are not glassed into the body. Jon Mortensen

I am running a 10 inch wide slick on an 8 inch rim because I have stock fenders. I would like to run these tires on a 10 inch rim with a different offset to make track width wider. I like the idea of the ZG because if I bash one up on a cone I can just buy a new one and bolt it on. How wide are those things. Some pics looks like 3 inches, some looks like 1.5. Thanks, Jon Mortensen