Rob

Thanks!

Hi everyone. I ordered one of those really deep dish air filter bottom plates which came on '67 Camaros which allowed room for a 4" tall filter on top of my ZZ4 with a Holley 650 double pumper. I was delighted with how tough it looked and figured it would only help it run better. However, whenever I open up the secondaries it bogs momentarily and then wakes up, every single time. When I put the edelbrock bottom filter plate back on with 3" filter, it is a silky smooth transition when the secondaries are opened, every single time. Is the engine running so much more lean with one extra inch of filter that I need to rejet or change the squirter or something like that? Its hard for me to believe. When I went from paper to K&N I didn't notice anything like that. I've never heard of a filter change requiring rejetting. Curious if anyone else has experienced this, and how it was fixed. If it really did lean out due to that filter that must mean there's more power waiting if I get the carb dialed in for it. For now, I'm just running it with the 3" filter. Thanks!

I've got to put in my .02. The Porsche wheels are pure art. Can't think of a nicer looking design. Are those the ones with hollow spokes??? Wish they fit on a Z, I would tell you they suck and offer to take those hideous things off your hands!! He he he.

Thanks as always for the information Grumpy. Reading your posts is an education. I'm curious what your opinion is on gapless rings. They seem like the best thing since sliced bread but are there any problems or compromises with them? Seems like if they really have 1/10th the leakdown of conventional rings (2% vs 20% according to Total Seal) then everyone would use them including oems. Sorry if the answer is in the info, I read some but not all of it.

Be careful when designing the tranny mount, if you go that way. That mount is not only holding up the weight of the tranny and engine, shared with the motor mounts. It is constantly experiencing shock loading as you drive over bumps. (Ever notice your shift lever bouncing a little over bumps, on any RWD car?) I'm guessing the g loading of going up a hill suddenly at high speed could be quite significant as well, basically making everything heavier. So I am trying to make two points here. 1. Fatigue strength is important for the tranny mount and engine set back plates and steel is much better in this area. 2. If you do design one out of aluminum (I'm not saying its impossible) keep 1. in mind and overdesign the hell out of it to account for shock loading and hills. My guess is that if you do properly design an aluminum mount the weight savings will be less than you think. FYI, I had my fabricated steel mount fail on me due to a bad weld that finally fatigued. I probably spent about as much labor fixing my unibody that literally tore apart due the mount failure than the rest of my conversion. Believe me you don't want this to happen to you! The JTR mount has no welds which is a big plus. My car now has the JTR mount. I did increase the bolt sizes to 5/16, and I recommend reinforcing your floor by welding a sheet metal patch to it to distribute the load between the frame rail and tunnel better. Good luck, whatever you do, and if it helps any I am also a weight freak. When you think about it the thing that makes V8Zs so incredible is the power to weight ratio so we all are to some extent!

I really like my 3" single exhaust and Edelbrock (I think its called) 304 series muffler. It sounds very cool, I get lots of compliments on it. Not too loud, but you can definitely hear it. It fits nicely in the stock location. I also have the ZZ4 crate motor. For under 400 HP I think you are OK with single 3" if the system is designed correctly. I would recommend buying a good flowing Y connector from flowmaster or similar rather than relying on the skill of the muffler shop in this critical area. One other thought, the dual exhausts really hurt the sleeper look. Nothing wrong with that, but it could be a consideration. I love surprising people. Any gear head can tell I have a V-8 from the sound of my exhaust though.

I have Prelude seats in my Z but I think mine are older than the ones you have. They don't have all those cool adjustments- just lumbar. Can't remember for sure but I think they are out of a 91. They are wider than the original, and crush ever so slightly when you shut the door. Adapting them to the current seat bracket was pretty easy. They do sit you up higher, which I actually preferred. I'm 5'10" and I still have plenty of head room with a helmet on.

Unfortunately, I can't go to larger rotors. It is a spec class and you can't change much at all besides suspension and cage, and for that they tell you exactly what is allowed, brand, model number, everything. Guess I'll just have to get really fast about changing pads. Since you seem to know something about brake pads, I've got a question for you about pads for my Z with Wilwoods. What do you think of Polymatrix "C" compound? Its a lower friction race pad. I'm wanting to use that one as an all around do all pad. However I'm learning that a do all pad really doesn't exist. Curently I have polymatrix "cold stoppers" and I have two issues: fade and too much grab before they start to fade. Its way too easy to lock a front tire up. I just found out that the guy that sold me the brake kit put cold stoppers in it, and its no wonder I don't like them, they are pretty much a drag car pad, and Polymatrix refers to them as "sticky".

Mainly I will be using it for road racing. However since I can't afford a trailer this year I will be driving it to the track. I've done some more research on these pads, and they will turn the rotors down like a lathe until they warm up. The Hawk rep told me I should swap the race pads for stock pads just to drive to the event, or to autocross. Gee, that's convenient!

Yes I did wash the rotors thoroughly. I installed the pads correctly. The bearing play I set according to Haynes for Zs. It consists of tightening to 22 ft lbs and backing off 60 degrees, all the while rotating the hub. I didn't feel comfortable with the Mazda procedure which said to tighten the nut until the hub binds and then backing off 1/6 turn. Seems kind of subjective. Funny you should mention the pads. That's the first thing the guy asked was what pads I was using. I admitted that they were Hawk pads. He asked if they are racing pads and I answered with "well they are performance pads". I think I learned that one from Clinton. The 100% honest answer would have been "hell yes they are racing pads, and I still want you to replace those rotors, please". His stance was that if they were metallic he wouldn't warranty the rotors because his information stated that this car should only have organic pads. Well I brought one in and we agreed that they were probably carbon metallic, which I actually wasn't sure about. Makes sense now I think about it since Hawk calls it Ferro Carbon. Ferro for ferus or iron I guess. I stood around for a while, and next thing you know he said that he would replace them for me this one time. I will be calling Hawk to see what they have to say about this. If they hadn't have put those instructions in with the pads I would have never put that much heat into the rotors right off the bat. By the way if you are interested the Hawk procedure is as follows: (no I am not recommending this!!) If using new or used rotors you must follow the steps listed below to achieve maximum brake performance. 1. slowly engage brakes 6-8 times at medium speeds. Don't drag brakes or come to a complete stop. 2. Increase speeds to simulate race conditions. I used 75 mph which should be very conservative I thought. Allow 6-8 Very Hard stops at racing speeds. 3. Allow brakes to cool for 15 minutes or more by parking the car. I actually heard them pop on stop number 6. The right was within one second of the left which was amazing to me. That would take very identical rotor characteristics and very balanced heat being generated on each side. Or, perhaps very balanced bad luck. Thanks for all your inputs. Be careful if you get new rotors and or race pads! Drewz procedure would have worked fine I'm sure.

No, they are not cross drilled or anything. They are Raybestes brand which I thought was supposed to be a good brand. The temp was about 45 probably. The wheels were torqued to 55 lbs, and on this car the hub and rotor are all one casting. (which makes changing them much more fun, all that grease and press fit bearing races and all!) The rotors were probably not from the same batch. I've been having too much fun with this project. The first pair I received had the bore for the inner race out of tolerance so I returned that one and they had to special order the replacement. Thanks for the comments. [This message has been edited by Rob (edited February 18, 2001).]

Does anyone know the proper way to break in new rotors? No punn intended! I know I don't, cuz I followed the procedure on the Hawk brake pad burnishing procedure, which states specifically that it applies to new and used rotors, and I cracked both rotors!!!! I guess its possible there was a casting problem but I think I put too much heat into them too fast. Not good! Be careful out there people! Hope I don't get in trouble here- my problem was not on my Z car but my RX-7. This is the best car tech site I've ever found and I think my concern applies to all cars. Thank God my new rotors didn't crack on the Z when I installed them with the wilwoods! Yep, I still have the V8 Z and don't plan to get rid of it! Too much fun! Thanks!

Thanks a ton for the information John.

Way to persevere Danno!! You are going to end up with the best rear brake setup for an early Z I've ever even heard of. Well done.

Yes, I think there is a demand for a better suspension and brake kit. I would check it out if you sent me the information.

Actually the original stock distributors, with points, have small caps so they are not computerized. What I did was buy a rebuilt early 70s points distributor, which is extremely cheap by the way, and converted it to electronic with a pertronix ignitor kit which you can get from summit. There is no black box to mount with this setup- it's all in the distributor. I have not touched it for two years, after I put the recurve kit and adjustable vacuum advance on. I like the stock distributors because the centrifucal weights are right on top so changing the curve is incredibly easy. With this setup, you can just throw a $3 points kit in the glove box and if the pertronix system fails just put that on and you are on your way. By the way I am told the pertronix is very reliable, and has been for me so far.

Its a Holley 390 vacuum secondary. Not a Ford symbol on it! With the blower the 650 would be better, but I think you said you had to mill the choke horn and install plastic floats to do that. According to Holley your 4.3 is best suited to a 413 CFM carb rating at this altitude and 85% volumetric, at 7000 RPMs normally aspirated, not far from 390. I think you can also sense that I don't want to tear down my 650 after my 3 months or so of getting it set up, shipping it back and forth to the factory because they forgot to drill the bleeds, a wheezing gasket, carb fire, broken stud and a whole lot of cussing. Those double pumpers are touchy little buggers and the odds of bolting mine on your 4.3 and it working without problems seem quite remote. So if its OK with you I will unbolt the non-brand loyal Holley 390 for you.

John, if you want to try my carb, let me know. Since you are working in Niwot, you are very close to the south end of Longmont, where I work. I could drop it by if you give me directions to your work site. I think the 390 will be just fine for you to try on the v6 without the blower, and I can get the thing off the Bronco in a hurry. Give me a call at home or email at work if you want to do this.

No Pete, I don't remember that induction system. The cool thing about Smokey is that he wasn't afraid to try anything. A lot of the stuff didn't actually work I think, but enough did to make him a legend.

I think you are definitely on to something Mike. I bought a book by Smokey Yunik, race tuning guru from way back, and he talks about cooling temps. Below is some plagarism from his book Power Secrets: Keeping the engine cooler than is necessary puts energy that could be used for power in the radiator. "Running an engine at 180 will drop overall horsepower 2-3%. For max power the coolant temperature should be at least 200, and you should have at least 25 psi in the system. Actually a racing engine like the small block chevy will produce more power as the operating temp is increased to a maximum limit of 220. This can be confirmed with dyno testing, but I would not unconditionally recommend that any engine be raced at 220. This leaves very little leeway for variations in the operating environment." Back to your original comment, you mentioned a huge difference. Smokey mentioned 2-3%. It could be that your mixture is richening a little due to a hotter manifold, and perhaps you were a tad bit lean at the 170-180 coolant temp.

In the rear I am using them more for toe adjustment. The camber was about 1 degree negative before eccentric bushing installation which was the target. In the front, even with the bushings adjusted all the way out I can only get 1 degree negative on the right and 1 1/4 degree on the left. I'd like to try 2 degrees in the front for autocrossing, so I'm still looking for more! I'm using the Motorsport Auto lowering springs. I think they are supposed to be 2" lower. I had a knocking sound in my rear suspension for a while, but I found that it was the gland nut that holds the strut cartridge down. It had come loose. Something to look for, if anyone has a mysterious clunk. I kept looking at the exhaust system for the longest time thinking that was it. I'm not trying to say that you didn't have a problem with your bushings here scca, you just reminded me of a problem that I solved that others may be struggling with. Anyway, I wish you the best of luck in your search for suspension adjustability Morgan.

On the rear suspension, there are two inner eccentric bushings for each rear suspension arm located maybe 18" apart. The center of these bushings run parallel to the length of the car as well as the wheel mounting surface. If you adjust one of these eccentric bushings differently than the other you change the toe of the wheel. Most people want negative camber to make a car handle well around the corners. These bushings push the bottom of the wheel out to create negative camber. So the track, as you would measure it at the road surface, would actually increase. I respect your opinion, but my experience is that the plastic bushing inside the aluminum was the wear/durability issue, not the aluminum itself. Time will tell how the bronze holds up. I bonded the bronze bushings in the aluminum to keep the friction areas restricted to bronze against steel. So I don't consider them JUNK. Given an unlimited budget I'd have someone build me a fully custom adjustable titanium arm with heim joints specified by NASA for the space shuttle. But that not being the case I'm getting by OK with the bushings for now.

I have adjustable bushings front and back. If you didn't know already, they are good for only 1 degree camber. Better than nothing, that's for sure. I like the fronts a lot because they are very easy to adjust and have a grease zerk even. The rears are not as much fun to adjust, and are more prone to wear. The thin plastic bushings that fit inside the rear aluminum eccentric bushings wore out over 4 years and estimated 30,000 miles. I have replaced the plastic bushings with Bronze ones. I think they should last very long. I had to buy some bronze flanged bushings and have them modified to fit by a machine shop. I think the rear bushings, even though they are not as nice to work with and have wear problems, are very important because they allow you to adjust away any rear toe you may have, and I had a lot. Regarding loss of adjustment over time, I have not had a problem with that at all.

Hey Rick. We are getting quite a showing here in Colorado. There's one more- Danno from Berthoud who has a 260Z which is getting a LT1, T56 and coilovers. Danno actually works with me. There's even another guy who works for this company who is building one. He hasn't posted anything yet I don't think. I've also got a early 74 260Z. Its up and running, has been for a couple of years now I think. ZZ4 Chevy 350 crate motor, T-56, open 3.7 diff and 280ZX half shafts, and single 3" exhaust. Tokikos, Panasports, adjustable bushings, a big front sway bar and no sway bar in back is my suspension set-up. Front brakes are upgraded to Wilwood and vented rotors from Arizona Z. Very much a sleeper, no flares or air damns. You've got the blown 350, right? I think John showed me a picture of your engine. Very nice. Catch you on the road some day. Well, maybe with your powerplant you will catch me. What color is it, and ever get up this way? Later!

I don't think it's too tough. Just unbolt the shaft from the differential, 4 hard to get to bolts, and slide the shaft out from the transmission. Mark the flange before removing the shaft so it is reinstalled in the same orientation. Then remove the snap rings and support one half of the joint with a open vise and tap the other half with a hammer until you push the cap out. Repeat until all the caps are out. Check the play in the splined joint. If it feels pretty sloppy, it should be replaced at this time. Alternatively if you don't replace it and still have a mysterious vibration suspect that spline as the culprit. Another source of vibration can be the infamous front differential mount. You can tie the front of the diff down with steel cable to keep the mount from breaking, a very good idea. I'm assuming you don't have a V8 swap. If you do, I suggest converting to a shortened chevy shaft or custom shaft. The JTR manual spells all that out for you. The small u-joints used on the datsun shaft are fine for the original engine but inadequate for the torque of a V8.