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Everything posted by JMortensen
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Electronic ignition distributor. I like the one from the 280ZX. Plugs right in, 2 wires and your done. You can bypass the ballast resistor too. Upgrade the coil if you have the $$$ too, you'll get more accurate hotter spark and not have to mess with the points all the time. Your 260 has points, right??? Jon
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Guidelines for tire inflation pressures?
JMortensen replied to strotter's topic in Brakes, Wheels, Suspension and Chassis
I don't think a pyrometer is going to help much in this situation. Like you said Drax, he's gonna do some 8's or something then check tire temps, but this problem occurs when he's on the street, where he's going straight 95% of the time. Of course it might help to know what the problem is too. Twitchy is a little vague. Does it follow ruts in the road? does the front end blow all over the freeway? Does it get sideways when you floor it around a 15 mph turn? I'd say don't underinflate the tires trying to make the car feel better. You have a much shorter sidewall now than the original tires did. The tire should have a max pressure on it, and I would be very surprised if it was only 32 psi. If you underinflate you will probably bend a rim if nothing else, but you can also debead a tire or overheat a tire that way too. Take the car to an alignment shop, and if not twitchy is really what you want have them do an alignment and put it as close to factory spec as possible, assuming there is anything to adjust. If nothing else you could post the numbers here and we can all help you analyze what is going on in your suspension. 327 on 205's is gonna be a handful in certain situations anyway, and you may just have to deal with it. Jon -
While you guys are researching this, I want to ask a question that's been nagging me for some time, because I simply don't know if this was worthwhile or not. My friend with the 510 and the steer knuckles modded for Ackerman also did something else that was interesting. He moved the TC pivot up the same amount as he moved the control arms. He said this would counter dive under braking and restore the geometry of the original design. He already had rod ends on the TC's, so he made a new bracket with 1/8" plate, boxed it all in, cut the original TC mounts off the frame, and welded his new ones on. He then made a hole to mount the rod end at the original height, and a new one that was higher by the same amount that he had raised the control arm pivots (which was about 1.5 inches I seem to recall. Any thoughts on that??? Jon
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BIG THANKS To Ross Corrigan and Mike Gibson
JMortensen replied to Mikelly's topic in Brakes, Wheels, Suspension and Chassis
Does this mean we'll see Ross making your adjustable control arms soon? Jon -
Relocating Front Top Strut Insulator Mounts?
JMortensen replied to 260DET's topic in Brakes, Wheels, Suspension and Chassis
That was me. I've seen it before, can't remember where. I have camber plates myself, so I've never actually done this. I want to say Dan Baldwin has slotted the holes... just not sure. The limiting factor would be the size of the strut top insulator. Its pretty big, so it would limit the movement when it hits the inside of the strut tower. Also, if you moved them back for more caster you might put some suspension bind into the control arms and TC rods. Maybe not, as the top insulator might flex enough... Jon -
Those spring rates aren't bad, but why progressives in front and not in back??? I suppose it would work, but I wouldn't want to be in a bumpy turn at 100 mph with those springs... I am anti-progressive spring, because it just means you will have more body roll until you get to the "real" spring rate. If you are serious about the track, you don't want that. For a street driver they might be more comfortable. I'll be interested to see what others say... Jon
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FWIW- I have a .490/280 cam with a decent amount of overlap. Jon
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What distributor are you running Dan? The 280ZX EI dizzy has about 17 degrees mechanical advance. I've got mine running 18 degrees BTDC with stock springs and I JB Welded the breaker plate to keep it from moving, but did not close up the advance slots. Check this site out: http://home.att.net/~jason510/dizzy_specs.htm Degrees advance and rpm are distributor degrees, so double for crank degrees and rpms. I know this is a cheesy half @$$ thing to do, but when I found this site I just set my initial advance and ass-umed that the page was correct. Perhaps I should double check my total advance... Jon
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Ceramic brake pads, what's the deal?
JMortensen replied to JMortensen's topic in Brakes, Wheels, Suspension and Chassis
Hmm, now that you mention that they last forever, I did see a sign outside a parts store the other day "Ask us about our new 100,000 mile brake pads." The consensus is that these are not performance pads. Guess I'll stick to my Porterfields. Really I was just curious as to what they were. I'm not in the automotive loop anymore, and the idea of ceramic pad lining sounded interesting. Thanks for all the replies. Jon -
Every post and every book Ive read about max power and timing says something like 34-36 degrees. If you went 34 you'd be right in there. Disconnect the vacuum advance and alter the breaker plate inside the dizzy so it can't move. The diaphragm is probably broken anyway so it is just a vacuum leak, and it only advances the timing under cruise or idle. Nice for mileage, but not nice for performance. You can play around with spring weights to have the advance come in earlier if you want. I think Dan actually lessened the total advance from the mechanical by JB Welding or brazing the advance slots so that they are shorter, and ran more static timing. Isn't that right Dan? Did you change the springs too? How did that all work out for you? Jon
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Switch to rear steer????? Jon
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I recall trying to find a piece of linkage that slid back and forth off of a 280ZX when I was trying to make the linkage work. I was using the Mikuni linkage on a Cannon manifold, and nothing was lining up, so I just gave up and went cable. I ran a cable from a mid 80's Nissan truck. I drilled out the peened ball for the linkage on the gas pedal, then welded a small tab to the side of the pedal and used the plastic bushing that comes on the truck cable. On the other end I just used a piece of angle aluminum to hold the cable, and moved the actuator arm to the center of the linkage and hooked it all up. Smooth and easy. Jon
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I have that combo with flat top pistons. My block is standard size, so theoretically I should have 10.2:1 compression. In actuality I think it is higher, because I've done some testing (mixing race gas with pump gas) and it seems like I need about 95 octane to run a decent amount of advance and not ping. I also took quite a bit of metal out of my combustion chambers unshrouding the valves and polishing the chambers. I did have the current motor running on 92 and not pinging, but I had to retard the timing so far that it wouldn't rev and I was worried about burning up exhaust valves. When I originally built my first Z motor I had the same head with dished pistons. It ran great, and had decent power, but nothing like what I've got now. If I had it to do over again I'd probably get a P90 and mill it to get the compression and use cam tower shims to fix the timing chain. Jon
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My experience with Ackerman has been positive, although it was not in a Z. I have a friend with a 510 that has modified steer knuckles for more Ackerman. You just can't get his car to push and it turns in REALLY hard. Of course he also has 7 degrees of caster and 2 degrees neg camber, and cantilevered Hoosiers. I'm wondering how you would get it in a Z, though, since the steer knuckle would have to be bent out instead of in like the 510. I seem to remember the rule of thumb is you want the theoretical lines from the tie rod to the ball joint to cross at the middle right where the diff is (not an expert here, so don't quote me on that). That would require a pretty crazy offset on the front wheels to clear the tie rods. Also, would that be legal for Prepared??? Jon
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David, that was my post. I put header wrap on my L6 not a V8 (which is why I didn't respond to this post) and immediately the motor got hot, especially when sitting. This still seems sort of backwards, because you are putting a lot more heat in the exhaust when at WOT, but that's what happened. I asked on the IZCC list, and got a response from an old ITS racer who said that since the flange was not insulated it puts lots of heat into the head and that his race team had warped a bunch of heads in the early '70s when they tried wrap. I don't think you would have any of those probs with a coated header. Jon
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Ceramic brake pads, what's the deal?
JMortensen replied to JMortensen's topic in Brakes, Wheels, Suspension and Chassis
OK, so I would assume that they are selling these pads for light trucks so that they don't overheat the brakes when towing. Sounds like that could be very useful in performance brake pads. I wonder when we'll start seeing them... Jon -
Try Courtesy Nissan. Very Z owner friendly. I know they have a discount for IZCC members, not sure if they have one for HybridZ members. They have a good website, and have been very helpful and knowledgeable even when I was ordering parts for Mikunis and other oddball stuff. Jon
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I was at the auto parts store and the guy behind the counter was trying to sell some ceramic brake pads to a customer with a new Chevy truck. He was saying the ceramic was in the pad lining itself. I've heard of a ceramic insulator between the back of the pad and the lining to limit heat transfer, but never ceramic in the lining itself. Is this some new thing? Was the parts guy wrong? Jon
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The Euro model has amber for the turn signals, you can get them from MSA or Nissan for about $150 each. Other than that lots of people have adapted other taillights from other vehicles. I met one guy who had made his own rear panel. It was totally flat, and had glassed it in so that there was no possibility of exhaust coming in through there. Looked pretty good. He kept the original plastic light fixture and wiring, and had bought some red reflector material that he glassed in. If memory serves he got the reflector stuff from a trailer shop. I think he made little access panels so that you could change the bulbs when needed. I've thought about doing the same, not so much for the look but to eliminate the exhaust smell. Jon
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Scarab vs Setback? The true test.
JMortensen replied to SportZ2's topic in Gen I & II Chevy V8 Tech Board
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what is the difference for california and federal emmisions?
JMortensen replied to a topic in Miscellaneous Tech
I thought that cars coming from other states had a pretty serious tax on them when they came into CA, and that they then had to acquire all the CA smog BS and get certified by a smog "referee". I've never done all of that, but you should probably go to a smog referee and ask. A guy I know swapped a 280Z motor into a '72 and took it to the ref, got it registered as a '78, then about 2 weeks later they passed the exemption law. DOH!!! :malebitchslap: This was about a month after I bought a brand new air rail and spent hours tweaking my SU's so that I could pass smog. Double DOH!!! :malebitchslap: Jon -
Wet weather scariness? Anyone else, just me?
JMortensen replied to jeromio's topic in Brakes, Wheels, Suspension and Chassis
That is hilarious johnc. I've got a similar story: I had just done an alignment on my Z. When I zeroed the alignment machine, something went wrong. I ended up with about a degree (!!!) of rear toe in, I was shooting for .35 total. Somehow I didn't notice how much adjustment I was making. About a week later my rear tires were BALD, and it started to rain. I was driving home from a friends house with a big line of cars behind me, probably wondering why I was going 25 mph. As soon as I hit the 1st puddle the back end stepped out about 2 feet, and the car behind me went from riding my butt to about 20 car lengths back. My car would swing the back end over every puddle either way depending on the slope of the road. This is on a winding road, and every corner was cambered slightly. It's an interesting sensation to have the back end swinging towards the apex of a turn when your going 25! By the end of my 5 mile drive home I was laughing hysterically! After that experience, and one more similar one on a Porsche 928 that ate up its tires after a week, we tape measured every toe setting just to make sure that the machine had correctly zeroed. Jon -
What is your dream suspension?
JMortensen replied to a topic in Brakes, Wheels, Suspension and Chassis
Nic, A strut is load bearing, and determines how the suspension moves through it's travel. So if you take a strut out, the suspension doesn't work. Usually, but not always, a strut has the coil over the shock. A shock absorber is not load bearing. It just dampens the spring and usually limits the travel as well. Usually, but not always, a shock does not have a coil spring over it. That's probably not the best explaination ever, but I think you'll probably get the idea. Tune to Win, How to Make Your Car Handle, there's a bunch of other books that will help... Jon -
MSA camber Adjuster
JMortensen replied to Nismo280zEd's topic in Brakes, Wheels, Suspension and Chassis
Don't people just slot the holes on the strut tower? Jon -
I'll never forget that clutch adjustment again. I just remember how frustrated I was at the track that day. I was glad someone was there with enough knowledge to help me out, and I'm happy that I was able to pass it along. Jon