Zmanco

FWIW, I just had the exhaust guides replaced on my new-to-me P90 head at $15 each (10 labor, 5 guide). The intakes were ok.

When I had the P90 head shaved I gave the shop 2 sets of springs etc so they could use the best ones. I also gave them a set of the longer valves from an N47 head hoping that when I move my cam over that I'll be able to use the same lash pads. They felt they needed to use a second washer under the springs in order to get the proper fit. Given the valves are longer than the P90 valves and there is only 1 spring part number used for all the L6 heads, I think this makes sense. But to be sure before I put it all together and onto the car, I wanted to check that this is indeed the right way to go. I've seen a few write ups on using a P90 on a NA engine, but I don't remember this being mentioned.

FWIW, the resets I experienced due to EMI from plug wires never occurred when the engine was cold although I wasn't able to isolate the conditions with the same degree of repeatability that you have. I can say that it usually occurred under hard acceleration. If you have a spare set of known-good plug wires it might be worth doing a test with them and seeing if/how the symptoms change.

I agree with Cozy Z Cole, get someone experienced with wiring to help you evaluate it. You could easily make it worse, not to mention reduce the value of the car for resale. If I was looking at a car and the seller told me he had rewired it, I'd likely run away from it unless he could demonstrate that he really knew what he was doing. And even then it would have to be a great deal or something I just had to have. Trouble shooting someone else's wiring mess is just not fun. Wiring isn't rocket science, but there are only a few right ways, and a whole lot of wrong ways to get it done. And unlike some other skills where people can write a book or give a quick set of instructions in a post like this, wiring doesn't lend itself to that.

It sounds like you feel you need to scrap the existing wiring harness and start over. But why do you want to "hook everything up to the battery"? If you are going to bypass the existing harness for some of the accessories, the proper source for +12V is the output of the alternator, not the positive terminal of the battery. If you use the battery as your source, then the load from the accessories will show up on your ammeter as if the battery is being charged. And make sure you use a proper sized fuse placed close to the alternator. Choose the fuse based on the size of the wire - that's what it's protecting.

http://denver.craigslist.org/car/781851850.html

You didn't say what engine and how it's controlled, but as cygnusx1 said, it's quite possible if you have FI that the controller is always keeping some of the warmup enrichment active and so you're running too rich all the time. I'd still be curious to discuss the general question further, for example, how would mileage be affected between running with 180 and 190 thermostats? In theory the higher temp should be more efficient, but I'm wondering if anyone has any experience or data to support that?

When I still had the L24 I pulled a bone-head move and damaged my stock E88 head. I found a stock recently refreshed E31 for a good deal so just bolted it on. The L24 was completely stock. I could not feel any difference at all. We all know the E31 has more performance potential, but on the stock motor I couldn't feeel whatever differences there were. As for paying your mechanic to rebuild your head vs. buying one, if your head isn't trashed and you trust your mechanic, I'd suggest you have him give you an estimate on the rebuild. My guess is that until he tears it apart he won't know if/how many valve guides need replacing which would be the biggest unknown cost. But I'd guess that he could do it for no more than buying one off ebay, and quite possibly for less. I always prefer to give more business to the local guy to help ensure he's around the next time I need his services as long as there isn't an excessive price penalty.

So does anyone have one that they'd be willing to part with? I have a resonance between 55 and 65 mph that this might help cure.

In theory, a hotter engine, all else being equal, will absorb less of the energy from combustion which should mean more of the energy is used to move the pistons up and down. However, I have never seen any testing to verify if this is significant enough in the real world to be measurable and/or if there are other compensating factors at work.

The schematic Noddle posted shows that pin 26 is the +5V reference for the TPS. Using your terms, that is what "pos" connects to.

Do you find that this helps reduce the oozing of coolant around the HG when driven hard? Also, the next time you change the HG, how do you clean off the copper spray? Any trick to it?

http://cgi.ebay.com/ebaymotors/Datsun-240Z-260Z-280Z-4-PISTON-CALIPER-BRACKETS-NR_W0QQcmdZViewItemQQcategoryZ33564QQihZ021QQitemZ310070696273QQrdZ1QQsspagenameZWDVW I'm guessing this goes between the caliper and strut and would allow the rotor to be mounted directly to the hub instead of requiring a spacer. But it doesn't look thick enough given the hub spacer is usually 0.5". And notice the packaging - it looks like a genuine Nissan part. Anyone know anything about this?

Indexing spark plugs is new to me. For those of you like me here are 2 links: http://www.fordmuscle.com/archives/2000/07/indexplugs/ http://www.advanceautoparts.com/english/youcan/asp/pht/pht20001001sp.asp# On our L series heads, what is the ideal position? Straight down (position of the ground electrode), or angled slightly towards the exhaust valve as mentioned in the article above? And what's the tolerance? The Ford article suggests that being within 20 - 30 degrees is good enough.

Hmmm, this might be an effective way to reduce some of the noise from my R180. Anyone have one of these kits that they don't want any more? Please PM me, or email me: daniel at bailin dot org

I had occasional resets (not 120 per minute!) that I thought were noise related and tried most of the electrical filtering and wiring solutions with no success. Then I read about someone who had found that their spark plug wires had degraded and were emitting more EMI. Apparently the best wires for minimizing EMI are from Magnecor and so I tried a set. I haven't had a single reset since. I can't say this is the source of your customer's problem, but failing wires would explain how it's getting worse and might explain why it happens when heat builds up under the hood. FWIW, I went with their racing set which has the best suppression - their part number 6524. They weren't cheap, but they're supposed to last longer as well. So far I have 5k miles, too soon to tell...

You want to use the connector that has a pigtail connected in your picture. I don't remember the colors of the wires, but if you have a DVM, set it to measure resistance and then measure across 2 contacts at a time while moving the throttle. 1. When you find 2 where the measurement doesn't change while moving the throttle, those are the two to which you attach power and ground. 2. The remaining connector is the one that goes to the TPS input on the MS board. 3. If you want to have the TPS values increase as you open the throttle, then measure the resistance between the TPS signal from #2 above and each of the other two wires. The one that has the lowest resistance should be grounded, the other goes to +.

The built in search tool does not understand quotes. As Jon suggested, use the Google search. BTW, you can do it from google's page too by adding the term site:hybridz.org.

Daeron, on the airflow issue you bring up, I think you are going back to the discussion elsewhere regarding managing airflow at the front of the car. I realize there is overlap in this and cooling, but in my situation, I have an MSA spook with the brake ducts covered. I've also put Al tape over the remaining holes into the engine compartment and have the factory rubber seal between the hood and the top of the radiator support. All gaps between the radiator and the support have been closed. In other words, all the air that enters the mouth goes either through the radiator, or through the 2 openings shown in this picture between the turn signal lenses and the bumper gaurd: http://forums.hybridz.org/attachment.php?attachmentid=8266&d=1217219012 which then flows around the front suspension under the fenders. The splash guard was on for this last session, but not the one about which I started this thread. I realize that there are benefits to be had with regard to overall aerodynamic efficiency, but as for cooling, which was the focus of this discussion, the airflow into the engine compartment has already been controlled and by itself did not solve the engine temp issue. The lesson learned here for me is that when running the engine at its peak outputs (WOT on a track for extended periods), the water cooling system should not be the sole method for dissipating heat.

Look at the pictures in my post #25. It's mounted towards the upper left (passenger side) corner. My water temps were about 10 degrees cooler on a track with much longer straights (0.5 miles of WOT). I was at 6100 rpm at 110 mph before braking. I remember reading somewhere that although everyone focuses on the water temps, in fact nearly 40% of the engine's heat is dissipated by the oil system. Like John said, the extra cooling of the oil more than offset whatever impact the warmer air had on the water radiator.

In the end I went with an Earl's (EAR-41010ERL) mainly due to cost and my confidence that I would get it the next day from Summit. It's a flat style like the Setrab and Mocal.

With the vented toyota 4x4 calipers and the 300zx rotors the spacer is required so that the rotor lines up properly with the caliper. It doesn't have anything to do with the wheels. I used that combination and don't remember there being any others that didn't involve some level of customization (such as machining the rotors to fit instead) unless you wanted to stay with the stock solid rotors. If you haven't already done so you should read the sticky on brake combinations for S30 cars. It's pretty comprehensive.

Last Friday I put on an oil cooler as JohnC suggested and had a track day on Saturday in Pueblo. It was probably only a few degrees cooler than the previous weekend (low 90s) but a longer track with a lot more WOT time. The oil cooler did the trick. The highest water temp I saw from megasquirt logs was 206. Also, I noticed that the heat soak was greatly reduced. I found that when I would back off a little (such as when I was making mistakes and decided to focus on my line instead of speed) that the water temp would come down very quickly, often it would be a few degrees down within 2-3 corners. Unfortunately I don't have an oil temp gauge so don't know how much that was reduced, but I'm guessing it was significant. By the time I exited the track after a cool down lap, the water temp was nearly normal. The fan shut off within a minute of parking the car and opening the hood. Before it could take 5 or more minutes. Thanks John for the good advice!

Friday the UPS guy dropped off my new set of Dunlop Direzzas from Tirerack. I had a good track day on Saturday and the balance is now far enough off the old tires that they are no good for the street, yet too worn to be legally rebalanced. They were Kumho MX 225/50-16 and the best tire I've yet run on the Z. The SCCA forums are raving about the Direzza for autocross and pan the MX for soft sidewalls, so my hopes are up that I'll like these new tires even better. Not sure how well it shows up in the picture, but the Direzzas are even wider than the Kumhos which were wider (by a lot) than the Yokohama ES100 they replaced. Unfortunately I don't have any more track days available until September so won't know how they do for a while.

That's what I understand as well. Perhaps someone before you replaced them with NA injectors?