cnwayland

RIP indeed.

PM'd

As title reads, looking for 280zx 79-81 Distributor Mounting Bracket. Thank you HybridZ!

I messaged this exact question to Edan yesterday. He says, "They are brand-new unit made because demand was very high and rebuilds are no longer available". I assumed Japan.

Madkaw, Those are tapped for your brake booster vacuum and what else?

Looking for a good condition 15/16" Master Cylinder to power dual-piston 4x4 Toyota brakes up front and don't want to go the Wilwood route. Would prefer to not rebuild but not a big deal for the right price. Thanks HybridZ!

@madkaw - based on how I had described my current driving feedback, Rebello - as with what I've always heard from l-series advice - started at the valve lash adjust, followed by moving the cam chain sprocket from the 2nd to 3rd timing mark before ever touching the carburetion. I still haven't found a good explanation as to exactly how much each timing mark retards/advances timing but moving from 2 to 3 definitely brought where I 'felt' the cam 'come on' so-to-speak lower in the RPM range by 500-1000. When I was building up the motor I put the new chain on the number 2 mark because to me #1 felt extra loose, and #3 way too tight on the chain. Again, I'm still looking for a better explanation on the cam sprocket settings for future reference. Anyway, most of us know to start with valve adjust and cam timing/distributor timing check before adjusting our carburetors. The venturi discussion happened after I was asking about running the 40s with NO venturi. Apparently an older Mikuni PHH model has a slight shelf in each chamber which would allow you run them without venturi, but mine (R Type - later model) do not - it's a smooth chamber. So the largest the 32mm venturi can safely be lathed is up to 35mm. In other words, PHH 40s are slightly under-carbureted for an L28 with a high compression ratio like mine. Ryant67, I would say that also based on Leon's post, you're changing the amount of vacuum or draw achievable by the motor ~ maybe this is obvious but wasn't to me. The larger amounts of air you're able to let it will allow the motor to run more power at high end because you aren't restricting airflow as much. But alternately, like with a pure race motor, low RPM idling will be more difficult because of the lower vacuum draw and less friendly on the day to day street condition.

@madkaw, thanks. Corrected that info. Also, forgot to mention moving from the 2nd to 3rd mark on the cam sprocket.

Was at Rebello Friday. Here's my quick update and download of what I learned. But upping the pilot jet size (I'd gotten up to 80) I was masking the issue I was having with what were essentially under-active accelerator pumps. I had 40 pump nozzles all the way across and the 80 pilot jet was pouring fuel through the motor, so on my 1 1/2 hour drive down to Antioch I literally watched the gas gauge fall. Rebello used a lathe to open the 32 venturis up to 35, bent a retaining spring inside the 280ZX distributor to manually recurve/allow less advance, twisted one of the throttle shafts that was causing the Mikunis to go out-of-sync, and then went back to a 65 PILOT (mostly for fuel mileage on the way home - this being on the leanest side of tuning), 150 main jet and retained the 190 main air. All in all, I think the most useful part of the day was getting to test-drive a few jet settings with Dave (who is just as nice as can be and a wealth of great insight) who in just a few words was able to summarize what was happening. I also have a great kinesthetic reference for what in-sync carbs feels like, versus going just off of the syncrometer. Highly recommend Rebello to anyone, anywhere.

An update: I found a vacuum leak. Small, but detectible with brake cleaner from the spark-plug side of the motor. The culprit was the aforementioned o-ring insulators. On my Harada intake, the o-ring slips just BARELY outside the intake mounting surface, creating a small leak which I am presume at WOT would cause serious difficulties. It just never ceases to amaze me how quickly I turn to the most complex issues when the solution is stupid-simple (i.e. thinking my 5-speed transmission was crap when I had the 4-speed shift lever installed... ). In the process of removing the carburetors yet again I replaced my Taylor plug wires with the blue NGKs I used to run. They just seemed to be something funky about the Taylor wires and she feels more steady after swapping them out. As tuning continues I've come across a few questions/statements I'd like to ask/pose to you folks: 1) Recurving distributors: the 280zx distributor swap was probably the first major upgrade I performed on my motor. Even at 16 degrees I get light pinging under WOT. I backed it down to around 14 but apparently with my compression and cam I'm supposed to be up around 18 degrees. To me, this sounds like a curve issue, yes? What distributors have been successful with your Mikuni setups? 2) After discussing with Dave Rebello the fact that my venturis are significantly undersized for my motor (32s), I'm curious if I could potentially run an open throated (without large venturi) 40's. I've heard of people with race motors doing this and wanted to know if anyone has direct experience doing so. Leon, you'd mentioned that they'd be easier to tune with undersized venturis. What is the reasoning behind that? I've found a local who says he has "bundles and tons" of Mikuni PHH jets. I'm hoping to pick them up this evening to have on hand for a serious tuning session.

If only you were in Cali!

Still hunting... open to purchasing full Mikuni 40 PHH Type R carb also.

After going back into my bag of Mikuni leftovers.. I found the old pilots. 55's. Trying to buy 60's, 62.5's, and 65's (up from 57.5's) ~ At this rate I'll just buy a few more 40s for parts...

Okay, so I tore down the #1 carburetor and found that the pump body had disintegrated, leaving the check ball floating in the bottom of the float chamber. When I ultra-sonic'd the ass'y, the brass bushings fell apart, so I had to JB weld the small brass peened fitting back in. I didn't however, JB weld the brass bushing seen below. More work! For anyone wondering what the internal pump body ass'y looks like (the small washer is part of the accelerator pump plunger/rod). However/unfortunately, I'm still pretty sure that this wasn't the cause of major hesitation (although it certainly wasn't helping at all. @JMortensen ~ Smaller than 40's on the pump nozzle? Pilots up from 57.5 to 60 ~ I believe the jetting parts list notates that they increase in increments of 5... not sure if that's .5 Cylinder 1 plug = wet... Regarding the Wats being sweet... They are. Trying to not worry about damaging my newly built motor with all of this rich-running carb-tuning. ~C

So jumping back in here, I got all of the accel pumps operating as they should. Beautiful streams of fuel out of all throats. But I still nearly drown the motor every time I apply over 15-20% throttle. I emailed back and forth with Todd@Wolf about the issue and I ended up reverting to my 40 pump nozzle and adjusting the cotter-pin to the last hole on the accel pump plunger. No major conclusive feedback. I was beginning to think tonight after putting the project away that I may have fouled my plugs, but my idle is solid and that wouldn't make sense at all. I think I have stop resisting the urge to get an AFR after all of this guessing which is just exhausting. Watanabe's are supposed to be here tomorrow so it's going to be a shame if I can only drive up to 2k RPM in all gears.