mustard-z

Braap, The springs were part of the cam/rocker/lashpad/retainer package. It would seem that the springs should be capable of controlling it if they came all from the same place. The intresting thing is that the intake valve DID have the failure that you speak of. One piece looks laminated. I will take a picture of it. I do live in bend. I don't go to EESCC as I think they kinda suck. They have always been a pain to work with. I am usually in Medford or Redmond though. I was hoping to go to Bremerton or Packwood this year but. Alas, not this year. Cary, The failure occured at about 4500 rpm at the end of a 6 cone slolom. The throttle was wide open (excelerating). BOOM! Let off the throttle and it felt wierd, disengaged clutch and rpms started to climb, engaged clutch and shut the car down. Pulled the carb and found 6 dime size pieces of the intake valve. We never solved the compression issue. We were told that 2-3hrs of running in the garage will not seat the rings and that we needed more time on the motor. So we put time on the motor. Never again will I do that! John, I don't think that I overrev'd it. We don't have a limiter but the car wasn't revving freely above 6500. I can't be sure, but I really don't think that the valve only hit once cause every valve has a clean spot that corresponds to a clean spot on the piston. I think that they were touching much more frequently. But what do I know, this is the first motor we have built and the first one that I have trashed.

My father and I co-drive and mod our '78 FP autox car. We decided to build a new motor last winter, but unfortunately started too late and just finished installing everything back into the car 2 weeks ago. We decided to build the motor ourselves as our machinist didn't see any problems with it. We have done all the work on our car and are what most people would say "competent" at modifications/fabrications and whatever else. This is our first motor from the ground up. Anyways to the problem; The motor: -77 N42 block overbored 1mm -stock crank balanced and polished -stock 240 rods cleaned up and balanced -stock main bearings -87mm forged alum. pistons w/ deves rings -stock balancer -stock timing chain w/ new guides -adjustable timing chain sprocket -N47 head w/ liners removed and ported by us on exhaust side only, port matched. combustion chambers lightly smoothed out -stainless valves stock sizes -stiffer valve springs w/ new keepers/ retainers/ lashpads/ rockers -550/300 regrind cam -ARP head studs/main studs/flywheel bolts -1mm steel headgasket -13lb flywheel -dual friction clutch This motor was pre-assembled to check for valve-piston clearance and cam lobe wipe pattern. Cam wipe pattern checked out OK. Piston/valve clearance was between .065/.075 on all intake and exhaust valves. Estimated Compression ratio: 10.2:1 This engine has about a total of 6hrs of run time and 13 autox runs before these pictures. We need help figuring out what happened. It seems to us that the intake valves ended up touching the pistons and eventually one valve failed and broke into 6 pcs and ended up wedged in the brand new DCOE 45's we bought for this motor. It seems odd that this would be the case unless things in the combustion chamber expand and move this much. However, in the "How to Modify your OHC datsun engine" Frank says that something like .060-.070 on the intake valve is adequete clearance.

I design aircraft structure/systems for a company called Epic Aircraft and we offer an experimental kit airplane that the entire structure is carbon-fiber. Although we haven't made a part that looks anything like what bjhines has done, that doesn't mean that what he has done is wrong. Weight is critical in aircraft but strength and practicality is the primary goal. Every part we design that is flight critical has a computer analysis for it as well practical test data to back it up. Further, all flight critical loads are calculated for SPECIFIC cases in aircraft flight and and are designed to maximize strength for THESE cases. The point that the sub-structure in the rear for the fuel cell is a big point. Design for the loads that it will see......realistically. If you want parts to be the lightest they can be, they WILL be weak in ways that they are not intended to be used. Such as jumping on a sub-frame for a fuel tank. This is where I work http://www.epicaircraft.com

Trevor, The bushings are the standard tranny bushings, they have the funny rubber washer-cap things on either end of the main bushing. I re-used the bushing sleeves from the previous mount and used them to fab this new-improved one.

I *think* that I installed the medium collar but now am unsure. I need to double check. Eric Neyerlin from zpart.com has a pretty good page that is in process. http://www.zparts.com/zptech/articles/trans_swap%20parts/4tobear_specs1.html The collar I measured in a previous post is for sure the type "A" collar from the 4-speed, that I previously had in my car. Thanks to everyone helping me out.

I bought this tranny from a guy in CA. He said it came from an 83 280zx. I am not entirely sure. It bolts up OK to the car the rear mount move back by about 1.5" and the shifter moved forward by about 3". We just tried to start the car tonight so I don't know if my throw-out collar and fork are correct.

Made a T5 mount for my new installation: It's out of 1.5" .120 wall mild square steel tube and some .25" plate. I think it will hold OK.

I talked with motorsport and they measured a clutch fork that they had for the T5 and it measured 1/8" longer than the forks that I have that came from early 4 & 5 speeds. Motorsport lists the same part number for the slave cylinder as for all years from 70-83. I don't know if that information is 100% correct but that is what I am going on at this point, unless I find out different. ----------------------------------- Speeder, I have attached a few pictures of one of the collars that I have. Could you measue a known T5 collar for me so that I have some comparable numbers to check my installation? I posted the measurements in one my previous post for the dimensions of the fork that I have. Could you also measure a known T5 fork and post the sizes?

I compared this clutch fork to a few others that I have and it seems to be the same as other 70-78 forks. Did the clutch forks change in 79-83? The flywheel doesn't have any stampings/markings for a manufacturer so I really don't have a clue. I did measure the contact area and it measures 225mm. If someone could take measurement to ease my mind that would be awesome. I uploaded pix but am not sure they will come in the post.

I found the flywheel on ebay from some guy, I may be a bit screwed if I ever need to replace the steel insert. I'll go home at lunch and get a few pictures. Things just don't seem quite right with the assy.

I installed the following; 280zx T-5 225mm aluminum flywheel Centerforce DF Centerforce release bearing roller pilot bearing mystery clutch fork mystery collar 4-speed 280z slave cylinder 1. My mystery clutch fork seems too short by 1/4"-3/8". The slave cylinder is pushing at an angle on the clutch fork. Is there a different fork I should be using? 2. My mystery collar seems to be the same size as my 280z collar. I just don't know if it will be OK for my installation. I haven't driven the car yet so I don't know how it works but it seems that the slave cylinder should be pushing approx. 90° to clutch for for proper operation. Can anyone help me confirm the sizing of my clutch fork and collar? I appologize if this is covered but I couldn't find anything that was clearly stated in my searches.

Thanks Jon. I guess I will just get them and try them. They look like they are OK though.

John, Did the 203-2801 ARP kit work out OK for you? Thanks, Aren

We've been having problems with our charging system in our 280z FP autox car. Seems the alternator gave out and we looked for a replacement. We ended up using a GM 1 wire alternator. I worked out great...we ended up using the stock lower mount and cutting the front half off and addind a plate that bolts to the front of the engine and installing a 4" bolt to thru bolt the whole thing together. It is the same size as the stocker only needs one wire connected to the battery for charging and mild mods to fit it in. Its rated to 60amps too. I can take pix if anyone is interested. Aren

Does anyone know the thread size and pitch of this plug for the early 240's...I have an early '70 240 that has stripped oil pan drain plug threads and am going to make another bung and want it the same size. I think that it is a 16mm x 1.25 can someone confirm this? Thanks, Aren

Thanks for the help and specs on some other setups. I didn't mean to get bent outta shape but when I ask a question I am looking for an answer to that question not input on what I should do. Maybe I was unclear in my first post but it is all water under the bridge now. Thanks again to all.

WOW! All these tips are great, I asked for how to calculate MC sizes or places to find the info and all I get back is "Fix you're booster and learn how to brake properly" A simple "no, I don't know would suffice, or better yet don't bother even responding." HybridZ is turning into Zcar.com as evidence of this thread, useless responses that don't help. johnc, the reason I want to do this sounds like the same reason you wanted to do it on you're car. jmortenson/mark, thanks for the info

the problem that I am running into is that it is too easy to apply too much pressure on the brakes. I do have the SS lines on all four corners and with good grippy pads if you breath wrong the tires are being locked up. my thought was that if I replace the booster I will still have to adjust the modulation, and therefore probably have to buy a new pedal and MC. If i just yank the booster out, and replace the pedal and MC I have saved money ( ie. no new booster)

My brake booster in my auto-x z is bleeding vacuum, and I am thinking that instead of replacing it I may remove it and run the brake system without it. I am pretty sure that I will need to increase the master cylinder bore to accommodate more pressure on the calipers/drums as well as possibly have to change the pivot on the pedal too. The goal is to create a bit stiffer pedal pressure than with the booster, which should make modulation more linear and allow for better at-limit braking. If anyone has elimiated the booster and gone back to manual brakes on a 78z with stock rotors/calipers and drums. I've got Hawk HP plus pads on the front and will have Nissan Comp Rear shoes the next time run the car next year. Maybe some tips or ideas for calculating the master cyl. size or those sort of things? Where to go to find this info? Thanks, Aren

haha. That dash is actually 1/8" ply wood with a .025" thick brushed aluminum laminate over the top. It's mounted so far forward that it is actually pretty tough to touch it. I guess I will see the good/bad/ugly at the first race in Medford in a few weeks. Just about everyone that i've shown the pix/car to is gaga over the dash. I think the carbon stuff is TOTALLY cool. Thanks for the nice comments. Aren

Finally got the parts trimed and mounted. I just need to add a few stiffeners into the hood and fenders. Since the parts are about .060" oversize the fit isn't perfect but it is good enough for my auto-x car. http://f1.pg.photos.yahoo.com/ph/shank4ever/album?.dir=/3c06 Finally the car is seeming to come together. 8)

Well, install should be by next weekend, the parts are curing this weekend, as I sprayed some clear over them. As far as what I have in materials, it is somewhat hard to tell. My buddy gave me 1gallon of resin and hardner and the glass/carbon to do the hood. However, I decided to do the fenders too while I was there. The hood and each fender took 6 yards of glass and 2 yards of carbon to do 1 ply carbon and 3 plies of glass and took 1/4 gallon of resin/hardener. The carbon costs something like $30/yard The glass costs something like $15/yard The resin&hardener costs something like $70/gallon So for my two fenders and hood I have 150 bux in it with leftover carbon and resin for small projects. The hood/fenders are definately too lite for street use, the hood weighs like 5-6lbs and isn't tremendously sturdy. There is no structure for using hinges either, just pins. The finish is kind of up to you, and how well the lay-ups are. If there are a ton of bubbles then you will see small bumps. The one dissapointing thing is that we changed the orientation of the 3rd glass ply in the hood and had to make some joints and unfortunately those can be seen through the carbon. If i did it over I wouldn't have changed the orientation and just run 3 plies of glass in the same orientation. The finish is somewhat unique on mine. I didn't build up the clear coat so the texture of the carbon weave is still evident, but it's got the shine of the clear coat. I will have to get some pictures to show it. The effect is absolutely stunning.....I think.

I'm not too worried. the ply thickness is .015" x 4plies = .06 You could double that and still have a gap between all the surrounding parts. I guess I will see when we install the part.

Yeah, i could do a write up. Basicly the steps that you see there are exactly how you do it. Wax the part untill it is a slippery nipple(for me that was 4 coats) then we used this stuff called PVA witch is also a mold release agent. Then you spread a light coat of resin on the part, then lay the first ply down, work the bubbles out and add more resin to completely wet the cloth, work the cloth into the corners and such. Then add more resin to the cloth and work around, then add the next ply of cloth. Just repeat for the number of plies you want, for me that was 3. Then to finish we did the same operation with the resin, just added carbon cloth to the top. Now, this isn't a true carbon hood, being 100% carbon but it will be fine. The cost of carbon cloth is extremely expensive, somewhere close to 30 bux a yard, and you would need maybe 6 yards to do a somewhat flimsy hood. Mine is only for racing and therefore wouldn't be suitable for street use, so an additional 2 plies would be good. just FYI carbon is about 3x stronger than glass.

A buddy is helping me build a carbon hood for the Z. Click the Carbon Hood link. Enjoy. http://home.bendbroadband.com/mustardz/zmain.html