DAW

I'm putting Z32 rear brakes (calipers and rotors) on the rear of my 280Z and thinking about a cheap but effective mechanical parking brake). I haven't built this yet but here's the idea: The cables may have a fairly short, direct route to the actuating lever on the caliper. The caliper is a self-aligning unit and is originally

Norm, I love junkyards and a good one is a great find. I've used a lot of pistons harvested from the core engine pile and you can also see weak points in the engines, like L24 rods with 8mm bolts break, even if they are ARP bolts. If you've got the Nissan SUs, have you considered cutting the stock airhorns out of the aircleaner housing base? I think your exhaust idea is good. The header should have equal length primaries grouping 1-2-3 then 4-5-6 into separate collectors, as the firing order (1-5-3-6-2-4) is then split into equal volumes and by ignition interval. From what I've read the way to make the optimal balance in the secondary pipes is to make the exhaust all the way back as your dual system then put an "H" pipe between the two by painting the pipes on the sides that face each other, drive the car, then look at the pipes: the hottest spots where the paint is burned is what needs to be bridged with thw H-pipe. Actually, I think a two-into-three one's-into-one type exhaust would be better for flow balance and low-end torque: 1-6, 2-5, 3-4, but the 3:2 is more practical. Oh BTW, of the dished L28 pistons I think the turbo pistons are drilled under the oil ring rather than slotted which adds strength, and the top rings and lands are different on the turbo pistons which may make them a better choice for a high compression n/a engine. DAW

Thanks, Racer X. I was also considering putting the box flare on across the ZX door, then measure and cut the Conquest panel where the ZX door edge lies under it. In other words, split the flare panel and incorporate the front section onto the ZX door panel, then close off the cut ends so they don't show when the door's opened. Know if anyone's done the fronts? DAW

Get rid of the 195 thermostat and change to 180 degree. 160 is too cool for aluminum head engine from what I've read. DAW

I've been thinking of a design that I believe would resemble the Maranello or some Aston Marton styles, but haven't gotten a damaged hood yet to practice on. Basically, cut out a section of the stock hood at the front of the bulge starting at the leading edge of the buldge point where it meets the flat plane of the hood, and including only about 1/8-1/4" of flat metal around the buldge. Carry the cut rearward symmetrically on both sides of the buldge/flat-hood junction to where it turns from angling toward the fenders to angling toward the rear of the car. Then cut across perpendicular to the centerline of the bulge axis to join the ends of the side cuts. The cut-out piece is pointed at one end, square on the other, and has curved sides. It is about 8-9" long and roughly 10" wide. Flip it over and weld it back into the hood cutout and finish. I would probably substitute a thin plastic door-edge guard material along the free edges of the metal of the scoop that will show, rather than try to roll or fold the edges. The scoop falls well forward of the L6 valve cover end. Anyone tried this? DAW

The water temp sensor on the N47 head should work as a substitute for the CHT sensor on the P79. Canadian spec '81s had the same setup as what you're doing. The N47 head you put on might have been from a car with a temp warning light instead of a gauge like your car has. Take the old sensor out of the P79 and exchange it into the N47, it should be a yellow single wire. You are going to have to deal with some mixture-enrichenning factors now that you increased c.r. from 8.8:1 to over 10:1. First off, make sure that the thermostat you're running is 180 and not 195. Second, you can adjust the baseline mixture throughout the rpm range by adding resistance to the engine temp sensing circuit (water or cyl head sensor types). One way is to add a fixed value resistor (650-700 ohms, Radio Shack) in line with one of the leads to your sensor. I did a little finer tuning on mine by adding a second temp sensor (CHT or WT) in line (series) with the first, but placing it externally, outside of the water jacket, tucked under the intake manifold and in contact with the top of the exhaust manifold heat shield. That has worked very well for over a year and I just fine tuned it even more (leaned it back) by placing a 980 ohm resistor in parallel, not series, across the leads of the secondary temp sensor. I get over 20mpg with no pings on this 10.0:1 engine, and it pulls strong through a wide powerband. Further tuning would include adjusting the spring tension (small adjustment) in the AFM, but do the temp sensor first. DAW

I've been watching this thread with interest, as I'm wondering what to do with my ZX that's almost ready for paint. My ultra-cheap approach would be to fit plastic flares from a VW Jetta. These line up pretty close and look no worse than...a Jetta. The Porsche 944 box flares sounded interesting and it dawned on me that I've got an '87 Conquest TSI (boxed flares) parts car that I could harvest for flare panels. Has anyone tried this or seen this done? The biggest problem I see is the leading edge of the rear flare/quarter panel of the Conquest extending farther forward than the rear edge of the 280ZXT door would permit. I was thinking of cutting the box-flare off square at the ZX door edge, letting that creat a "scoop" opening in which I'd put a mesh grille (like the JCR 240Z big flares). DAW

I guess it's too late now, but are you using octane booster too? I autocross with a F54 flat top/N42 which always wants to ping on 93 octane so I'd been using 108+ brand booster which helps some. Over the winter I've discovered one that works really well: Outlaw brand. I've got an old Datsun 720 King Cab with an L20B, 10.2:1, headers, and twin 240Z SUs. It wanted to ping, even with SM needles. I followed the tuning method in the book "How to Build & Power Tune SU Carburettors" by Des Hammill, where you identify the lean-ping rpm/needle position and turn down the needle on a drillpress, pinching it with fine sandpaper at the specific needle/jet level where it was lean. The improvement in performance and decrease in ping were like night and day vs before this tuning. Back to the octane booster. The truck no longer pings unless I get a marginal tank of gas. This happened recently while on my way to pick up a full load of bricks and it was pinging even unloaded. I filled the truck with bricks and put in one vial of Outlaw, and I drove it the 65 miles home at highway speeds and rarely had a ping (and got 20mpg). Huge improvement. My L20B has a closed-chamber head, my L28 has an open-chamber (N42) head. If the Z still pings using Outlaw booster, then I'm going to try the P90 big shave/shim/longer valves approach ala Bobby (search for P79). DAW

A leakdown test is a good test and is what's used on aircraft engines. However, you've already done a compression test and you said it was fine. With an intact compression test, any findings on a leakdown test would be subtle and not significant enough to make the car undriveable. DAW

Man, I'm not paying attention...I thought I read "SK" carbs, forget the tri-power reference. Start with simple things first before you start tearing into your SUs. Reach in with your finger into the SU airhorn and lift each piston in turn. If they feel about the same and return to down position when you let go, then rule out other things before going further with them. What about the quality of the gas? Has the car been sitting? Each SU fuel bowl has a little drain plug. You could drain these, top off with a full tank of fresh gas and use some gas treatment to get rid of water which may have collected with condensation. DAW

Sorry, I missed compression test on your list but you shouldn't be still concerned re a bad/bent valve; your compression test ruled it out. DAW

Last time I raced autocross, my Zcar sputtered and backfired and performance was poor and erratic. Turns out the linkage to the front of the three carbs was intermittantly slipping where it clamps to the linkage rod. DAW

note the A/T 280zxt cars with the oil cooler also use a higher volume oil pump than the M/T zxt cars. DAW

Run a compression test. DAW

Bang for the buck in performance gain, increase your compression. The question facing you is how to do it. Put on your old N47 head onto the F54 shortblock and you'll have about 10:1 cr and a big boost in performance. The problem is that this combination tends to ping. A lot. You can add octane boosters, etc but that's kind of a pain. One way to go would be to get an N47 head from an L24 Maxima, install the intake valves from your N47 L28 head (44 vs 42mm), this head will boost cr even higher than the L28 N47 head would, but it has the benefit of the high-quench closed (peanut-shaped) combustion chambers and you may get around the ping problem. You might have to run two head gaskets to pull this off. If that didn't work, then the P79 shave/shim/N47 valve trick is what's left. DAW

Thanks! What a great site. I searched it though , and didn't find the exact spec, except an article transplanting VG30DE rods & pistons into an SR20DE, where the rod ends had to be narrowed slightly...so I guess I'm looking for rod cap width of VG30DE also. DAW

I can get a couple of SR20DEs with externally damaged blocks. Does anyone have the spec for the connecting rod cap width? I know the rod length is 136.3 mm and the journal is 0.080" smaller than the L28. DAW

slicks and I'd like to know if there's any way these would work and issues with tech inspection, etc. DAW

Katman is right re measuring the head to know how much is gone. The dimension is from the head surface to the valve cover mounting surface. The chain tensioner can't take up slack between the crank gear and cam gear because that side is always pulling the cam gear. Rotating the gear through adjustment won't increase the lost distance in length (i.e. raise the cam) and the change in geometry between the two gear centers. It's not the same as a stretched chain. So if it's a big cut, you'll need to use shims..but take a close look and make sure that shims aren't already installed. Calculate the c.r. before you but a $100 2mm head gasket that's for a 90mm bore (stock L28 is 86mm). If you determine how big a shave the head's had, people on this site can help calculate the change in combustion chamber volume. DAW

Racing engines see severe loads/heat, need to ensure higher oil pressures, and often have clearances toward the larger end of the ranges and these factors demand higher viscosity oil. This is my opinion, so engine-builders correct me if I'm wrong. You haven't said how many miles are on the engine. I usually run 15W-40 Castrol semi-synthetic until the engine has 75K miles, then go to 20W-50. The lower number, 10W, 20W, etc is important regarding what climate you live in and what temp the cold starts are going to occur at. In Southern CA you could run 20W- all year; a bad idea in Fargo, N.D. in the winter. DAW

If the Amsol choices are the only ones you're selecting from, 10W-40 would be the best, if the engine has high miles then 20W-50 in Southern CA may be better. DAW

Recommendations would depend on some specific factors: what is the serial # of the L24 engine? Mid-'72 the rod bolts were changed from 8mm to 9mm and it matters re what kind of use it will see. What year ZX is the L28 from? Early ones had dished pistons; later ones, flat-tops. Later ones had shorter valves that you can't transplant into the E31 head. DAW

Jeff, there are probably plenty of sources for "Y" fittings, but one I noticed that would work well is the heater hose metal "Y" from a '73 240Z. It is about a 5/8" tube about 5" long with a 1/2" tube feeding into the other in a "Y" configuration. Use the larger, straight section to vent BOV into large air intake hose, and connect the PCV intake hose to the smaller tube and aiming toward the large air intake hose. This should do it. A check-valve effect is created both by the difference in hose diameters (BOV vs PCV) and the direction of the "Y". DAW

A "Y" fitting aiming at the air intake hose and close to it would be better than a "T" fitting. DAW

You're letting in unmetered air by creating a new air intake into the PCV system (valve cover). I guess this ultimately lead to an overly lean conditon. If you tee-in to the PCV hose, do it very close to the air intake large hose rather than near the valve cover to prevent spikes in crankcase pressure so that the BOV is dumping into a larger volume of air. DAW