Ok, thanks Will. I have more M12 c/w 16mm socket nuts on the way. I look forward to your update!
By the way, what M12 washers did you have before? My kit from quadstar came with 19.1 mm OD washers, and 301-8400 has a 20.7 mm collar diameter.
Retoactive update.. last month when I got my block back and started plastigauging, everything I checked was within spec. Main bearings were all 0.0025" on the green, so I lubed up the main mearings and installed the crankshaft but noticed binding on cap #3. I followed the GM manual with exception of the outer studs, which I had inserted without nuts at the same time that I inserted the inner 12mm studs with nuts. When the #3 was in place and the 12mm studs torqued to 10 ft-lbs the crank would bind on the front upper / rear lower thrust bearings and I could not fit a 0.004 feeler gauge, even after tamping the crank to align the thrust bearing surfaces. I removed the 10mm studs and reseated the cap, then the crank was no longer binding but the 10mm studs would not thread in.
I pulled the cap and looked closely at the alignment of the new splayed main holes and discovered they were out of alignment, enough that the 10mm studs were pushing the cap alignment out of spec for thrust bearing clearances.
I took an airphoto of the webs, skeched up lines and approximate dimensions in CAD, and sent the above picture to the machinist who originally did the work. They indicated the drilling and tapping was outsourced to a subcontractor who were not engine specialists, and they must not have understood the importance of hole alignment forward/backward on an engine block. They took the block back with the main bearings, caps, and crankshaft, and returned them to me the same day with the issue fixed and the crank re-polished free of charge. They fixed the #3 alignment issue by offset reaming the outer holes on the #3 cap, similarly to the below sketch.
Once I got back home, I installed the crankshaft again and aligned the thrust bearing caps, the upper and lower thrust surfaces aligned perfectly. With the crank forced forward, the 0.004" feeler gauge would fit but the 0.010" would not, on both the upper and lower thrust surfaces. Same withe the rear upper and lower thrust bearing surfaces with the crank forced backward. I removed the caps, cleaned the 10 mm splayed holes with an ARP thread chaser, swabbed with q-tips, and applied Permatex Maximum Temperature Thread Sealant to the M10 studs and bolt holes (since they penetrate into thewater jacket) , then re-seated the caps again.
With the crankshaft caps and studs installed, I torqued the nuts in the following torque sequence for ARP studs on splayed mains:
I re-checked the crank for binding and the thrust clearances, was easily turnable with one hand on the nose.
I then went on to installing the pistons and connecting rods. The new pins and small ends of the rods were measured by the machinist to be within spec, same with the big ends - they measured and told me that my standard size upper and lower bearings would work just fine. I plastigauged the rod bearings and like the main bearings were all close to 0.0025" on the green. Side clearances checked out as well with the feeler gauge.
Piston rings were measured and gapped by a machinst, but I re-checked in the cylinder with a feeler gauge before installing on the pistons. I used mahle bearing guard on the bearings, lithium on the cam, pins, and gears, and 2-stroke oil on the pistons. I ensured the dot stamped on the top ring was facing up and the gapless #2 ring was on the bottom.
Timing gear installed (lubed with white lithium grease after photo).
I picked up new old stock 5234530 valve lifters. Submurged in diesel overnight, primed in the morning, submurged in lucas, then installed. I coated the lifter guides and retainers in lithium grease and installed.
I also installed the timing cover, 251603 water pump, and DS4-5288 injection pump, using mahle gaskets and thinly brushed Parmatex Hi-Tack gasket sealant onto all contacting surfaces. Thankfully I marked my old IP and timing cover with a cold chisel prior to teardown, so I just re-aligned the marks. Time shet should go smoothly, but I have OTC-6087 wrenches, J-29872 and an Auto-Enginuity scanner just in case.
Tomorrow if I have time I will clean the mating surfaces and install the heads and studs. I already chased and swabbed the block threads and will use Permatex Maxumim Temperature thread sealant on the coarse stud threads.
Today I checked the block and heads with a machinists straight edge, cleaned the block and head surfaces, and cleaned the injector thrust washer mating surfaces. I also installed the right head and injectors.
Once the surfaces were confirmed to be within spec, I swabbed the block threads with a Q-tip and Permatex Maximum Temperature thread sealant. I previously chased the threads with ARP chasers and swabbed them clean earlier in the week. I coated the coarse threads of the studs with sealant as well and screwed them in hand tight, wiped away the excess from the block surface, then again ensured the rest of the block surface was clean.
Since my heads were decked once before, I installed a 0.010" thicker gasket. Mahle 4021T .
ARP fastener lube was applied to all contacting surfaces.
I referred to the 1998 C/K Truck Manual and the ARP instructions, and proceeded with the following torque and sequence:
Once the head was installed, I installed the injectors with high-temp anti-seize compound and new crush washers. The injector housings are Bosch and were rebuilt with Bosch nozzles by Vimy Diesel injection in May for ~$700CAD.
Tomorrow I will prepare the other side, and possibly fabricate a jig for drilling aircraft safety wire through the main nuts.
Thanks Will! Good eye. Yes I will be running a single block off thermostat from a '96, GM #12551519.
Followed Heath's article for cooling upgrades and purchased from RockAuto a new 190°F ACDelco thermostat, balanced w.pump, '00 fan clutch, and an LB7 Fan. I replaced the motor mounts with polyurethane and will trim the fan shrouds to fit the larger diameter fan.
My 16mm head 12-point ARP nuts came in today. I also ordered another rear main seal, since I jumped the gun and installed it and probably should remove it to facilitate removal and replacement of the #5 cap fasteners.
If I am replacing all 20 nuts, I have to unload and reload the clamping of all the caps and I'm not sure how the rear main seal would affect loading of the cap 5, or if unloading and reloading cap 5 with the seal in place would cause the rear main seal to fail prematurely.
To remove the rear main seal without damaging it I would have to pull cap 5 at minimum. I'd rather not touch the caps because the pistons, timing, and valvetrain are installed meaning I can't easily spin the crank to determine if the bearings re-seated correctly or are binding.
My plan is to cut and pry out the rear main seal, replace the 12 and 14mm head ARP nuts with the 16mm ones, torque to spec, then install another rear main seal.
@Will L. I've been wondering in 3D how the safety wire will work. With elevation difference between the inner and outer bolts.
I'm considering using the wire on a second nut so the angle isn't too extreme. If the angle between the nuts is too extreme, the wire would roll over the head of the nut instead of wrapping around it.
The angle issue is particularly noticeable with the splayed outer studs.
Maybe in my case it's safest to just drill a hole through the center of the M10 nut and stud, and thread it through and buy new nuts/studs on the following rebuild
If you don’t mind drilling through the stud with the engine assembled, it is better to through wire. You could then pre drill nuts.
If willing to drill through the stud after final torque, (then don’t really need the thicker nuts).
I just haven’t brought myself to drilling there on an engine assembled to that point. I am the guy that freaks out if someone uses lint bearing rags during assembly, so metal shavings is like torture. Some N52 magnets and physical shields maybe? Obviously engine stand rotated for all precautions available. Air compressor blower on during drilling?
If you do a chisel mark on the end of the studs indicating hole placement, you could drill new nut each replacement during rebuild and not need to redrill studs.
I expected a bit of an angle between the two, but didn’t think about the more severe angle you have with the splayed.