Everything posted by steve91tt
- Customizing my MSA flanged exhaust
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Does your idle change with temperature?
I tried two different heat shield extensions before I found one that worked. The first was only a few inches bigger than the stock shield and that had little effect. The second one extended all the way to the inner fender and entirely separated the intake from the exhaust. I got the idea from Dave Rebello who told me a story of a guy who picked up 1 second per lap on the track by using this sort of heat shield. I'm not sure it helped my lap time but I do think it helped drivability. YMMV.
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Does your idle change with temperature?
I ended up hooking a wideband up to the car and finding that the reason that I had poor idle when hot was that the car would become progressively more rich as it got hot. When heat soaked my air to fuel ratio was down in the high 9's at idle. The car does not seem to like anything less than mid 10's to be happy. If I adjusted the mixture nuts on the bottom of the SU's to lean it up a little at idle I found that I was overly lean on the highway which caused a surging issue. I assumed the rich idle condition is due to the boiling of fuel out of the nozzles so I extended the heat shield with some reflective insulation. I can't find the exact one that I used but it is similar to the following... http://www.amazon.com/Thermo-Tec-14100-24-Cool-Mat/dp/B00029KCW0/ref=sr_1_1?ie=UTF8&s=automotive&qid=1302036108&sr=1-1 except with finished edges and meant for underhood use. Addition of the extra heat shield solved the problem. No more idle issues even in the Texas heat. I hope this helps.
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Help with rear end noise diagnosis
Swapped diff's with my street car. Noise is gone now. I guess I'm looking for a new diff. I'm thinking an LSD on the track car would be the way to go. Anyone got one for sale?
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Help with rear end noise diagnosis
I decided to start with the transmission. I dropped the stock 4 speed out of my 1973 and swapped it for the one in the 1971 that I have been working on. The swap went without issue. I'm getting good at this, I completed everything before noon! Bad news, nothing changed. Next up...diff swap.
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Totally confused about primer!
Not all self etching primers are the same. The cheap ones are single pack alkyds. These are great for getting adhesion on bare metal that cannot be perfectly cleaned. However, if it were me and I had to choose between a 2 pack epoxy and a 1 pack self etching primer on clean body panels I would go with the epoxy. I don't see the advantage of the extra adhesion provided by the self etching feature on clean, sanded steel. When you take adhesion out of it, the epoxy will give better corrosion protetion than the alkyd binder used in many self etching systems. In the end it's going to be up to you. Both will likely protect well enough for a car that won't be used much in a corrosive environment. However, if you were planning to drive it on salted roads then I'd definately go with the long term protection afforded by the epoxy. Just my $0.02
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New 240Z build
I got the wideband working tonight. I let the car warm up and found the following AFR's: Idle =12 cruise = 12.5 WOT = 13.5 Transition from cruise to WOT = 20ish I think part of the high AFR at transition is due to the fact that the car misses so badly. This causes plenty of unused O2 in the exhaust which causes a very lean reading. I moved to the upper hole on the linkage on the accelerator pump arm and transition is 80% fixed. Still a little lean (15ish) but most of the stumble is gone. There is still some adjustment left in the pump rod so I'm going to try that next. Looks like good numbers to me. What do you think?
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Help with rear end noise diagnosis
I put a few more miles on the car tonight. Arne, I'm thinking you may be right. It could be the transmission as I was unable to get it to make noise in 1st gear. 2nd, 3rd and 4th but not 1st. Does that make sense?
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Help with rear end noise diagnosis
4.11 gears may be an issue with my current setup. I have a 4 speed and smaller rolling radius track tires. When I use this setup on my other car I'm close to running out of RPM's on the long straights. I suspect that going with 4.11's will make this a bigger issue. I might be able to get away with it with the stock motor but eventually I will move my 3.0 liter motor to the track car. In other words, I'd rather stick with the 3.54 gear ratio for now. Anyone got an R180 they want to sell?
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Help with rear end noise diagnosis
The noise occurs in all gears and seems to be more related to speed than RPM. I would say the frequency of the noise changes with speed but not as much as I have heard in the past with parts rubbing on other parts for example. I guess that still does not tell me if I am looking at a transmission or diff issue. Any ideas on how to diagnose which it is? I would rather gather as much data as possible before throwing money at it.
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Help with rear end noise diagnosis
I am trying to diagnose a rear end noise in a 1971 240Z that I am putting back on the road / track after sitting since 1989. Here are the facts... 1. There is a significant noise coming from the back end. It seems to change pitch slightly with speed. It only occurs when accelerating and decelerating but nothing while coasting. 2. The noise does not occur with the clutch in when the engine is rev'ed. 3. I can't feel or hear anything wrong when I jack up the back end and spin either tire. 4. Rear brakes are freshly rebuilt. 5. I pulled the differential, opened the cover, replaced the oil. No excessive metal shavings, nothing looked out of place. 6. The driiver's side rear wheel bearing was bad. I replaced it. 7. Stock R180 with new Wolf Creek CV joints. CV joints feel very smooth and have little play. The noise it fairly loud so I want to make sure I fix what ever is wrong before something let's go and leaves me stranded on the side of the road. Any ideas of where to start or what to test?
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New 240Z build
I confirmed with Todd at Wolfe Creek that 1.5 turns out on the pilot screws is the correct setting for these carbs (not 2.5 as stated above). Todd believes that the accelerator pump system has some air in it and needs to be primed. I'll work on that tonight. He also shipped me a new part to hopefully cure my idle screw / throttle linkage issue. Great customer service!
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New 240Z build
I've been playing with the pilot screws. At 2.5 turns out (starting point) the car backfires and idles rough. By about 1.5 turns out everything smooths out nicely. Nothing I have been able to do with the pilot screws have had any impact on the hesitation. Do you think I may need new pilot jets?
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New 240Z build
I took a rest from wrenching and took my son fishing in the car we have been working on. Good fishing...a little on the small side though. Anyways...I found that when I got out on the highway and the car runs great with light throttle but still stumbles badly at tip in. However, if I keep my foot in it the car clears itself and pulls smoothly to red line. Basically the car runs normally except on transition from light throttle to medium or heavy throttle. Once I get past the stumble it will pull happily through the gears. Any ideas?
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New 240Z build
More data this morning...I plumbed a temporary fuel pressure gauge so I can watch the fuel pressure while I drive. Good news, the fuel pressure holds rock solid at 3.0 psi. Not sure what the problem is but I'm starting to figure out what it isn't! Back to the drawing board.
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New 240Z build
I've got a friend that will weld a wide band bung in for me next weekend but I'm pretty sure that it's running rich. The plugs look like charcoal brickets. I'm working with Todd at Wolfe Creek. He knows these carbs inside and out. I'm confident we'll get it dialed in soon.
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New 240Z build
Update: The plugs were jet black so I went down from a set of 150 main jets to a set of 140's. It may be a little better at part throttle but definitely not dialed in yet. I found that the car will rev smoothly above 5000rpm with light throttle but go beyond 20% at any RPM and it starts to cut out.
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New 240Z build
The triples are here! Todd at Wolfe Creek came through with a set of beautiful mikuni's. I installed the carbs this morning. All went fairly smoothly. I had to trim the flange on my header about 1/16" to get the manifold to fit but easily done. I love the sound! Here's a quick video... Couple of issues... 1. The idle screw on the middle carb is frozen. I can't get it to budge even with vice grips. If I put any more torque on it the idle armature will bend. Because of this I can't get the idle lower than about 1500 rpm and still be in reasonable sync with the other two carbs. To get to 1500rpm I have the screw on the front carb all the way off and the rear carb similar. 2. The idle hangs at about 4000rpms at times. I took apart the linkage, lubed it up and de-stressed it as much as I could but it still hangs some times. Related to #1? 3. The car starts great but under more than 20% throttle it dies. I don't have an O2 bung yet for my wideband and I don't think I could make it to the muffler shop with it the way it is so I'm going to have to trouble shoot it the old fashioned way.
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Rear bumper back from Denver Bumper
I POR'ed everything that wasn't chromed. I taped it up before applying. No issues.
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anyone in winnipeg?
I have to agree. I drive my 240Z almost every day 365 days a year here. I'm not sure that would be possible in Winnipeg. Nice city though especially if you like fishing. Some really great spots north of the city.
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Rear bumper back from Denver Bumper
I had mine done by Denver Bumper last year. Don't make the mistake that I did and forget to paint the backs. The backs may not look like it but they are bare steel and will rust . I removed mine after a few months of use and POR15'ed the backs. Good as new.
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anyone in winnipeg?
No, sorry. I didn't.
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Relocating to Winnipeg
I lived in Winnipeg for 3 years before moving to Texas but I don't know any Z owners living there. Good luck with the move.
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L28 stock exhaust replacement. What is the power gain?
I love data! Especially data that correlates a butt dyno to a real dyno. Very cool. Keep it coming!
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Electronic ignition - Revisited after I gave up!
Did you try the voltage measurement as a function of RPM? Maybe my logic is incorrect but I'm thinking more RPM means more current and therefore the potential for voltage drop as the components could become resistive with higher current draw. You might also jump straight from the battery to the resistor with a fresh wire, temporarily, for testing purposes.