ezzzzzzz

Probably its a stock crank. Those holes are found in every crankshaft from factory balancing.

I just received the sonic testing results. On the thin side it measured .165" wall thickness. I want a second rebuild option so a .020" bore is where I'm heading. Tops would be a .040" bore. Abacus Racing and I both agree that a .120" wall thickness is minimal for durability and longivity. .040" converts to 1.02mm. Stock LD bore is 84.5mm. Max overbore would be 1.5mm for 86mm IMHO. I'm happier with the .5mm overbore for a 85mm. That just exceeds the stock 2.8 displacement but with a much nicer bore/stroke ratio. Using the L20b rods and custom slugs allows for a perfect fit. It would make for a nice NA although I'm still pushing towards the SC conversion.

True about the stock LD timing cover usage. I may still have one buried in the garage somewhere.

I don't see how you'll get 87mm out of the LD block. From rough measurements I've taken the upper limit should be 86mm. Beyond that the walls become too thin and require sleeving. My sonic testing results will tell the tale.

BlueovalZ, I jumped ahead of all the other posts to state I'm in agreement with your observation. Any helical cut gear is going to try to walk away from it's mated gear under load. The pinion is no exception. In this case, the pinion bearings do experience axial (side) loads of some sort.

I do but you're far far away. There has to be someone on the left coast or nearer to you.

The LD block looks the same as the L block at a glance. The block is about 19mm taller and requires a L20B timing cover. The oil pickup is located in a forward location. The passages can be drilled to relocate that pickup to the center or lengthen the pickup tube. I chose to drill/tap the block. There's also a couple of small oil passages that need to be tapped and plugged. I've heard rumours that the oil filter pad has some differences as to ports but I suspect that just isn't the case. No matter, it will be addressed as required. My LD block is at the machine block getting sonic testing to determine how much I can punch it out and still have material for a future rebuild. I'm looking at a 2.9 or 3.0 (at the most) and slapping on a Eaton M62 4th gen SC to boost. I'm using L20B rods and custom forged slugs (not ordered yet). I have a P90a (mechanical) head getting rebuilt and drilled to accept 12mm head bolts. I'm waiting on Justin's intake flange to complete the porting.

The only way anyone here could start to help is to get viable information from you regarding the 3.1 build. We would need specifications for all components used. It could any number of problems.

I'm assuming that removing this material ( as shown in that post) does not measurably weaken the valve guide and/or risk a bent valve in the process? I'm getting ready to port my P90 for my SC'd street engine. I'm looking at a balance of performance and longivity while leaning towards the later.

Great news! I'm sure everyone is elated to here of the progress. The wait will have been well worth it after all is said and done. Thanks!

How much is your time to swap trannies worth? How many of these old boxes have you actually gone through? I have rebuilt several of these boxes. Only once did I open a 240SX transmission and find it in impeccable condition. In all others, the consummables were worn out (bearings/baulk rings/seals).A rebuilt 5 speed is durable unless you're just slamming gears and dropping the clutch with total disregard. The two obvious upgrades are the 240SX and Z32 5 speeds. Both will cost a bit to install though. Both are covered extensively in this forum.

Comp trannys are hard to come by and expensive. They are not substantially stronger. The bigger benefit is the direct drive 5th gear. Depending on your driving habits a stock 5 speed (has overdrive) will hold up. Some have updated to a 240SX tranny with the early bellhousing or later Z box. Both of these provide a wider margin of strength.

It may not apply here but I believe the two pcms are physically the same assuming both had either an auto (for pinout to the auto tranny) or manual transmission (some have the wiring for an auto tranny anyhow). In such a case, I have approached a dealer with PCM and a good VIN is hand. The VIN must be from a vehicle with the proper engine/transmission combo. They would flash it for a few dollars if I would not hold them responsible for functionality afterwards. Once done, the pcm can be flashed with applicable software to meet your other demands. The dealer would NEVER touch my non-chevy vehicle to scan or flash even if the driveline and electronics were stock GM. They actually appeared to be totally baffled that such a conversion could be done. Sadly, I have found that the mass of GM techs are clueless unless they are following the FSM line by line.

DCZ, Thanks for taking the time to climb under your car too. With this info I can continue the companion flange fabrications.

Pull the hose for the vacuum booster to the intake manifold. If it's wet inside (brake fluid) then your MC is leaking at the rear and fliud is being pulled into the booster. It ultimately ends up in the intake through the hose. I'd bet good money that's where your problem is. Replacement of the MC is the fix.

http://roav.org/ That's me in my 71 Land Rover 88" Hybrid on the front of the calender. We also do a bit of beach running. I've got the best of both worlds, high/slow or low/fast.

Raami, there are numerous posts regarding engine configuration, deck height, etc., etc. First thing you want to do is a lot of searching and reading. You'll want to investigate much more before coming to a choice of components and a final build plan. Plan to invest several hours reading and pen down lots of notes to yourself. Once you've done this your questions will become more specific and the assistance will be there for you. Your ideal clearance was mentioned above, between .016 and .025 will provide ample quench to reduce detonation.

Thanks, Nullbound! That's a start. Now I only need the 280ZXT measurement.

For anyone running the 280ZXT or 300ZX conversion flanges on their S30 I need a quick measurement. Can you please provide the thickness of the machined flange that is tig welded to the stock stub axle flange? The 280ZXT should be about 1" to 1.5" thick and the 300ZX should be about .5" thick. These are the only measurements I need. It should take all of a couple of minutes to do this. Any assistance would be greatly appreciated.

With a Kzillion cars out there running 4x100mm I don't think they give a rat's a** about a few early cars running the 4 x 4.5 pattern. It sucks but it is the reality.

It might bend in a severe impact but it isn't likely going to break. If it does you're probably heading to the morgue anyhow. I won't worry about the gussets for now. As stated, it does add some bling but probably little else.

Good question about the gussets. I don't know. Maybe they were trying to rush the kits out and shortchanged me. I'm not real happy with the spray can finish. It will probably get pulled out for blasting and powder coating in the near future. At that time I'll likely add more gusseting too.

I just finished the installation of both front and rear strut braces from PDK Fabrication. Overall, I am satisfied with the end results. I'd like to point out a few observations and stumbling blocks. The quality of the product is good enough although I'd rather have chromoly over mild steel. If it had been so the cost would surely have be more substantial. As with any car as old as ours there is bound to be twist and turns accounting for misalignments. Mine was no exception. I chose to perform the install out of sync with the online instructions. I also want to note that the online instructions show the install in a bare engine bay. I had to do this with a complete drivetrain, all wiring and wheelwell-mounted parts. Tight working conditions come to mind! First, I loosely bolted on the front strut brackets. Then the cross brace was fitted in place using the supplied 7/16" socket head bolt. A nut is also provided and instructions state to use a screwdriver inside the down tube to hold this nut to tighten. That's because the tube diameter won't allow for a socket. That was ridiculous so I purchased threaded rod couplers to use instead. These extend about 1/2" outside the tube so a proper wrench can be used. The rear triangular pieces were fitted up only to find the passenger side left a gap of about 1/8" from the strut brace. I ignored it and continued on. The hood bump stops were removed and the braces pulled into position. I used a small C-clamp to hold this tight. I suitable drill was used to drill through the captured nut using it a guide. A tap was used to cut threads into the brace using the captured nut as a guide. The hood stop was reinstalled and the C-clamp removed. The next step was to drill down through the cowl lip into the brace and fit with a supplied nut and bolt. I chose a different option. The inner brace leg was clamped and drilled through into the firewall with a 1/4" bit. The braces were removed and the firewall hole opened up to install nutserts. Once done, the braces were reinstalled. The down tubes were next on the list. I jacked up the frontend and placed jackstands under the framerails behind the tires. The anti-sway bar links were disconnected from the LCA's as were the frame brackets (this isn't mentioned but it will become readily apparent that it is required). I drilled out the fixed frame nuts to 1/2" as directed. There is a spot-welded bracket on the passengerside framerail topside where the down tube brace fits. The instructions say to beat this flat. I chose to drill out the spot-welds and remove it correctly. The fuel feed and return lines also needed to be reshaped to clear the down tube. The down tubes were loosely fitted and the brace holes marked. These were drilled out to 5/16". The supplied crush tubes and lower support plates were cleaned and painted (they come as bare metal). The crush tubes were tapped into the frame rails. The anti-sway bar, brackets, and plates were installed with the supplied 5/16" bolts. At this point I'd like to state that this proved to be a PITA! I was working alone and stuff just didn't want to line up. The holes from top to bottom were misaligned. I managed to get everything bolted up despite the difficulties. If you undertake this then be sure to find a second set of hands to assist if only to hold the anti-sway bar in place! It would have been a big help! After all the efforts I was able to snug all the bits up tight using a hex bit, extension, ratchet, and wrench....yippee! The strut braces were finally tighten down. Next came the rear brace. It was much easier. Again, the strut brackets were loosely installed and the cross brace fitted. The lower legs were drilled from either side and the chips vacuumed up. The supplied bolts/nuts were installed and everything tightened down. I cleaned up my mess and took the Z for a brisk spin. The local interstate seemed the logical choice with several exit and entry route banking left and right. We all like to think that time and money invested proves positive. I tried to remain objective. There are several ramps that I've taken in the past at comfortable limits with a bit of tire squeal. These same ramps seem to be much more pliable...truly and with no tire squeal although I pushed the car much harder. The car did hold tighter to the road without the harsh banging on expansions joints as felt in the past. Even the straight aways felt smoother. I believe the suspension is actually working harder instead of the car being twisted and bounced around. Of course, I must admit the bracketing does look formidable and very functional. If you're looking to stiffen up your car I believe this is a viable solution for the budget-minded.

Sounds like you chipped a gear tooth. You could pull the drain plug and see if there is any large chunks to indicate this. When you're slowing down the gears run on the coast side which is also where you have likely would have damaged the gear on the downshift.

What does fresh rebuild mean, all new bearings and syncros? How many miles on this new tranny? Are the shifter bushings new? What gear oil are you using? The 2-3 shift happens between two different shift rods. loose bushings will cause mis-shifting. The first 4 syncros (baulk rings) are the same in the 280 to 280ZX trannies. Unless there is a major problem, only those rings wear. The hub and sleeve are steel. Breaking down the transmission is not too difficult but you will have to remove the countershaft (partially remove the mainshaft), and input shaft to get to this syncro. The seals can be reused. The front cover gasket will need to be replaced.