A Project Is Brewing...

[rossiz]

been quiet for a while - parts starting to trickle in and finally ready to dig into this.

with the new rings, gasket set & bearings in hand i pulled the rest of the block apart and took it into autosport for tank/surface/hone and while they're at it they will balance the crank & rods, lighten the flywheel and deck for optimum quench. i'll be bringing in the head for a little shave as well - they'll cc it and shave to hit 9.75:1 so i can run regular pump gas w/out drama. i'd rather have full advance and more gas selection than the higher c/r because it's my DD. 

 

they tell me a week or so, which is exciting as i'd love to get this thing ready to swap in june if possible.

 

in the meantime, i've been rebuilding the carbs and picked up a fuel pump for them. also picked up some POR engine paint for the block and will be cleaning up the 5sp tranny and replacing seals in preparation for the swap.

 

gasket set from MSA - plus the upgraded pan gasket. came w/a nice stone head gasket too.

 

main caps were easy except the center and end ones that have the side flanges - needed to rig up a makeshift puller from a piece of angle and some wood blocks but they popped off with little drama.

 

new stuff

 

will be cleaning these puppies up

[rossiz]

$3 ring pliers from harbor freight made a pita job into a breeze. old rings were nasty, stuck & worn

 

new set from MSA - they said they were nissan rings, my shop tells me that npr made rings for nissan - anyone know about these?

[siteunseen]

Looks real close to Hastings packaging.

[Jeff G 78]

My pistons and rods looked about like that.  I couldn't find anything that would clean them, so I let the machine shop clean them when I took the block in  for cleaning and honing.  They came back looking like new.  They cleaned the front cover too and that came out even better.

 

 

[rossiz]

i gave them the pistons & rods + front cover to tank along with the block - hoping it'll get 'em clean. i expect to have to scrape out the ring grooves, but i'll be further along...

[charliekwin]

Don't have a whole lot to contribute, but just wanted to say that I love looking at stuff like this if for no other reason than it's that much beyond anything I've ever tried to do in any of my cars.  I was happy enough having mine start after re-doing the fuel tank.  I hope to get to do even half of this kind of thing one day!

[rossiz]

the block is honed, decked & surfaced, the crank is balanced and i just got the pistons cleaned up so they can be balanced as well. the zx motor came with a 3-row pulley (a/c, power steering) and i unbolted the front pulley and had an idea to cut off the next one. put it in the lathe and sliced it off, leaving a slight gap up front to let me mount a crank trigger wheel to the leftover threaded lugs. those who know are probably chuckling right about now... turns out the rear pulley (the one that drives the alternator) is actually not attached to the harmonic balancer, but cantilevered off the middle pulley, which is attached to the center of the assembly. so as soon as the middle pulley was cut through, the rear one fell off in my hands. nice. oh well... a new single-row harmonic dampener pulley is on its way. while i was at it, i ordered a new clutch kit - went w/a 240mm one that comes with a flywheel so i should be good to go there - will turn off 10 lbs or so to get things a little snappier then balance it with the new pressure plate attached.

next i've got to tear down the p79 head so it can be cc'd and shaved - just enough to hit ~9.75:1 c/r so i can happily run regular pump gas (it's my dd & i'm a cheap bastid).

re-build kit is on its way from ztherapy so i'll be finishing up the carbies while the head is in the shop. i've already cleaned 'em out, beveled the bottom of the pistons and polished the bottoms/sides to get every bit of flow they have to offer. once the head comes back i'll port match the intakes as well. i'm thinking of keeping my k&n cold air intake from my efi setup and ducting it to the oem filter can and running it w/out the internal element to give a little better flow and cooler air - anyone done this?

i've got a slick little 2-sensor wideband setup on the way, will run a 6-2-1 header and weld bungs into the y-pipe to measure front vs. rear carbs for tuning. not sure if i'll mount the gauge permanently or just leave the leads tucked under the dash after she's running well.

for ignition i'm gonna get her running with the stock '81zx dizzy but once i scrape up some $$ the goal is to do crank-fired ignition run off a megajolt lite with coil-near-plug setup, using 6 coils mounted on the block below the heater hose and short plug wires. i don't expect blinding performance gains from this, but i'm interested in tuning my ignition advance map and getting rid of as much spaghetti as possible up top.

but of course that's all future talk - gotta get the lump put back together first...

[Zed Head]

You have a lathe?  Niiiccceeee.....

[Zed Head]

the block is honed, decked & surfaced, the crank is balanced 

Curious - who's doing the work?  I looked back but didn't find anything.  Is there a Seattle shop that knows how to work on these old engines?

 

Of course, what you had done isn't super-complicated, but still, some knowledge required.  

[rossiz]

no lathe - drill press. wrapped the top of the carb pistons in some tape and got 'em in the chuck, then used a file to slowly bevel off the bottom edge and then scotchbrite down to 1500 grit to clean up and hit 'em w/the buffing wheel on my bench grinder. works, but i'm wanting a lathe (so i can be like cap'n O when i grow up).

the machine work is being done by autosport here in seattle - right in ballard, 5 min. from my house. i'm lucky to live so close to them. they specialize in vintage stuff - jags, triumphs, etc. and know the L6 very well. really nice, old-school guys.

[Patcon]

On the O2 sensors. When you are done tuning you may want to pull the sensors and put the bung plugs back in. I ran an Innovate on my truck for a year or so until the O2 sensor went bad. At $54 for the replacement that starts to add up. I have read that depending on the location and heat as well as moisture in the exhaust system they can have a short life

[Captain Obvious]

Well since you brought up pulley stuff. I don't think I've posted these before... A while ago a local Z buddy of mine had a chipped pulley he gave me to mess around with. Chucked up in the lathe:

 

 

Cutting from the inside. Using carbide on the cast iron pulley:

 

Converting a two row pulley into a single row:

 

I'm sure there are different designs of pulleys, but I was able to work this one and still have the main pulley still attached to the harmonic rubber. This pulley originally came off a 74 260.

 

Haha!! Am I really grown up??? That would be too bad!