2nd Chance 323GTX

I'm terrible at this, but I'm going to attempt to document my current build here. 

I picked up a pair of 1988 323GTX rollers a couple of years ago for a really sweet price.  Included was a couple of non-running B6T motors, 3-1/2 GTX transaxles in various states of bustedness, and a bunch of other spares.  I sold one of the shells along with a few BP parts, and I'm planning to assemble the 2nd one and sell it complete.  This was a parts car with a seized engine, and my rescue prevented it from going to the scrapyard.

Please bear with me as I learn to use this type of forum.  Starting with how to share pictures...

Nice...

I started with "Engine 1", which was the seized engine from the silver car.  It didn't look too bad until I cracked the head off.

There had obviously been water sitting in the cylinders.  The block was too pitted to use and the crank rusted.  So I disassembled it and set aside anything that might be useful.  I even knocked out the pistons, which was a very difficult task.

I moved on to Engine 2, which turned over pretty easily.  I did a leakdown test and it was excellent.  I'll spare the details, but I dove into assembling it without taking the head off.  Bottom end looked great.  I got this far before asking about something that was bothering me...

When I turned the engine over, I could feel a slight little "catch" at TDC and a smaller one at BDC.  I consulted my people at the 323gtx yahoogroup, and they convinced me to take the head off and check it out.  Needless to say...

So back to square one.  Blew the whole thing apart down to the bare block.  Then I remembered those pistons from Engine 1.

I cleaned them up and took a caliper to them, only to discover they were much too BIG!  Not as big as BP pistons, but a full 1mm oversize.  Hmmmm.  After some intensive Googling, I came to realize these are a set of Wiseco forged 79mm 8.5:1 badass pistons.  Had to send them to the machine shop to dig the rings out of the grooves, but they are fully intact and within .001" of their original spec.  The coating has worn off on the skirts, otherwise they would have been instantly recognizable.

I'm going to use them.  Sticking with the 79mm bore will give me a little extra clearance (~.004").  Picked up some (upgraded) pins and rings for them, which just came in today.  I'm going to try to get the block to the machine shop as soon as I get my hands on a torque plate.  It was out of spec anyway.

I wanted one of these real hard when iw as 16-17 after seeing the SCC articles on their GTX. Then I actually read the articles and the comments on how hard parts where to find and how fragile they could be. Good luck on your trip.

BTW, you're pictures are set to private or some other authentication is blocking them from showing.

Meanwhile, since I was at a stopping point, I moved on to the transaxle.  The "1/2" transaxle I mentioned was a box of guts removed from a JY trans that was dropped on the floor and had its case cracked open.  The trans from my original GTX was still sitting in the corner of the shed, in timeout for the past 17 years.  I knew it stripped first gear but the case was perfect.  Light bulb.  So I disassembled it.

I didn't remember that big chunk missing from the center diff's ring gear.  That may have been what took out first.  The center diff assembly makes nasty grindy noises, so I disassembled everything and set aside any usable parts.

Next on the operating room table was the trans labeled "BAD 2nd gear syncros shifts fine other than that."  My old trans had the 2nd & 3rd syncros replaced shortly before it grenaded on me (during a non-aggressive start from a red light with my kids in the car, I swear).  Light bulb.

So this unit looks pretty good inside.  I cleared enough junk off my bench to get to my 3 ton arbor press and dove into disassembling the secondary shaft.  Good thing I haven't lost too much weight so far, cuz it took all 250-something pounds hanging on the arm to press it apart.

Sure enough, the 2nd gear syncros were totaled.  I pressed my old secondary shaft apart and discovered it still had the original syncros from the factory.  This is why I do all my own work these days.  "He'll never know." The originals had some kind of brass-based friction pads, whereas the new ones I ordered many years ago are solid brass with ridges.  From back to front: New style, old style, burnt-up old style.

I decided to go ahead and use my old syncros rather than ordering new ones, since my trans had low miles and I generally took it easy on the shifts.  After a couple of false starts, I got the assembly back together.  No extra parts!

This is where the trans operation stands.  The case is pressure-washed and ready for reassembly.

Next up:  Disassemble the head from Engine 1 and make sure it is serviceable.  If not, I have that old MX-3 head...

In reply to t25torx :

Thanks.  I thought DropBox would work.

I've had a couple of these, should've kept my last one...

In reply to docwyte :

Did I mention this car will be for sale?  

Southern car - no rust.

This thread is relevant to my interests and I would like to subscribe to your newsletter

Ordered ARP studs, Redline MTL, and a torque plate (rental) from Flyin' Miata.  Ready for progress.

Wow.  Has it really been over 7 months?  Sorry if any of you were holding your breath.  Gotta teach myself how to do this again...

Had some distractions.

Distraction (for sale)

OK let's catch up.  Got the block cleaned up.  Made my own thread chaser for the head studs to save money.

Thread Chaser

Block is now bored using a Boring/Honing Plate to 79mm.  Flushed the rust out with some stuff.  Ready to go.

Block done

Fully disassembled the head.  It was worrisome because some of the valves were kinda stuck in the guides.  Turned out this was due to the water issue.  Bought a full set of new valves.  The guides cleaned up and measured within spec.

New Valves

I had the head surfaced.  The machine shop told me they had to take quite a bit off as the head was pretty warped.  Great.  At least this explains the water in the cylinders.  The picture emerges of a blown head gasket. 

I decided since I had some extra clearance with the 79mm bore, I'd do some unshrouding in the combustion chambers.  While doing so, I noticed the chambers weren't just dark from age or oil or whatever.  They were obviously ceramic coated.  Hope my few bare spots don't mess it up.

Combustion Chamber

Despite some minor pitting, the valve seats looked pretty good.  I lapped the valves the old-fashioned way, looking for uneven patterns that would indicate major warpage.  Everything looks good.  Tried several YouTube tricks to get the keepers back on and gave up.  Recently bought the proper tool and will resume assembling the head soon.

Meanwhile...  I finished up the transmission (almost).  I definitely took way too long between disassembly and assembly.  Finally got everything in place.  There were a couple of bearing races that spun in the housing, so I used Loctite 630 to glue them in.  I installed a complete set of new seals.  Forgot to order the locking nuts, so it's waiting on those to come in before final assembly.

Seals

Discovered TascaParts.com has the best prices I could find, but they recently lost some sections of their search engine.  Get the part number elsewhere and order from them.  Someone named Matt who works there is also a fan of AWD Mazdas.

Almost Done

Back to the head.  Everybody has their preferences, but I really love this tool from Lisle.  For this head, you want the smaller "metric" size.  The installer is p/n 36440 and the hammer is 36740.  Inserted the new valves with assembly lube, measured the installed height and shimmed as needed, stuck the keepers in the retainers with grease, then WHACK.  Done.

Valves Installed

Next, I turned my attention to the HLA's (hydraulic lash adjusters, lifters, tappets, etc.).  I had two heads worth to choose from, so I picked out the best feeling 16.  Ended up rejecting 3 of them.  There's instructions all over the internet about how to disassemble and reassemble them.  The bucket of carb cleaner is definitely helpful in getting the varnish off.  A brass brush and lots of brake cleaner finishes the tedious job.  I've got them soaking until it's time for them to go in the head.

Cleaning HLA's  

Ready to Lift

I'm going to attempt to polish the cam lobes and journals, assemble the head, then start on the bottom end.  Progress feels good!

Cams done.  They tell me I may have gone a bit overboard with the polishing.  Started with 2500 grit wet and finished with a buffing wheel.  So the head is done, in a bag, waiting on the floor.

I moved on to the crank.  Measured everything with a micrometer and found all journals in spec with no measurable taper or oval.  There were no grooves or scratches visible, but I went ahead and polished it anyway.  This time I started with 1000 grit and finished with the 2500.  Came out real nice.  One journal has a couple of little dings where I probably hit it with a rod bolt.  I don't even think my camera would pick it up.

Spent some time tonight with the PlastiGage.  Installed the ACL Race bearings and torqued the ARP main studs down to find everything nicely within spec.

Checking Journals

Scoreboard

Pretty sure #1 was uneven due to that being my first try, and I stretched the gage by pinching it off instead of cutting it.  I'll go back and do it again another night.  I did redo #2 and it read the same.  Not sure what's going on there, but it's still well below the max.  Spec is .001 to .0017 with a max of .003.

Looking ahead...  The turbo I have is toast and the manifold (like most) is cracked.  This could potentially be a budget-buster.  So I got to looking at the little DSM 2G T25 I have sitting on the shelf.  If the compressor maps I'm looking at are correct, it looks pretty good at 20lbs/min at a 2.0 pressure ratio, which is what the calculators say the 1.6 will need at 14psi.  Feeling a bit reckless, I ordered some weld fittings, pipe, and a flat bar in 304ss.  I really don't have the time for this, but that's offset by my obhorrence for spending money.  We'll see how it works out.

Wow.  Has it really been almost a year?  Time for an update, I suppose...

I was ready to bolt the head on when a sharp-eyed reader of the 323 GTX facebook group noticed my block wasn't smooth enough for a MLS gasket.  He was right.  Took everything apart again and sent the block off to be decked.  So the head is now firmly bolted down over the Cometic MLS gasket with ARP studs torqued to 60 lb/ft.  Not an easy decision on the torque, believe it or not.  Read all about it on the Turbo Miata forums.

During reassembly, it was bothering me that I was assuming the pretty oil pump I had selected was good.  I took it apart and was glad I did, because it was scored up inside.  So I took apart the ugly one and it was much nicer.  While I had it open, I did some porting on the inlet and outlet areas.  Not sure how to reclaim the video I posted on FB.  Sorry.

So the motor is mostly back together now.

Current State

I found a good alternator on the shelf, had it tested, and bought a new bearing for it.  So that's good to go.

Also took apart the two distributors I have.  One was bad news.

Bad Dizzy

These have centrifugal advance weights at the bottom.  As the weights fly out, there is a rotating motion of the pins to which the springs are attached.  This eventually wears through the springs and they break.  With no spring, the weight is free to fly unhindered, and actually starts cutting away at the body of the distributor.  You can see the groove it has cut.  It would eventually cut the housing in half.  Not good, but the worst part is you get unbridled timing advance even when you're lugging the engine under boost.  This might explain the set of cracked pistons.  So I went back to Tasca Parts and ordered a replacement set of springs & weights.  It took a while, but they finally came in - despite reports of them being NLA.

Dizzy Springs

Note how there is a nylon bushing where the spring wraps around the pin.  So all I need now is a new cap, rotor, and wires, and we're set for ignition.

More to come soon, I hope!