Took the block off the stand and positioned it on the work bench to install the rear main seal and rear oil galley plug. The rear main seal is a full circumference seal that slips over the end of the crank, unlike old V8's that use a 2-piece seal.

Used a block of wood to gently tap the seal in and flush with the housing. Mating surfaces were cleaned with brake clean. Oil seal lip was lubricated with engine oil as was the crank seal area. Applied Right Stuff to the housing flange and around all of the bolt holes. Positioned the housing into place while aligning the dowels and then tapped it to seat. Tightened bolts.

I decided to install the rear main seal at this point after the crank for 2 reasons. I could lift the block with crank off the stand without a crane, and ultimately the seal needs to be installed so as to install the oil pan.

I used FelPro BS40660 rear main seal. I did not use the mangled gasket that came in the box but rather the Right Stuff as the original seal assembly did not have a gasket rather it used sealant and the manual specifies use of sealant.

 

I used the plastigage method to check the rod bearing clearances. The rod big ends were cleaned with brake clean and lint free cloth. Bearing shells inserted dry (my upper and lower shells are the same, there is a oil hole in the lower shell that is not used). I used a Sharpie to label the pan rail and head surfaces with the cylinder number.

I used a piece of wood, a head bolt, and a 2.75" long piece of pipe to hold the piston from falling out. The process was install rubber fuel line on rod bolts to protect journal, rod installed with block upright and crank at TDC, arrow on piston towards front of engine, piston holder wood piece rotated to cover bore once upper shell seated on journal, rotate block on stand to put crank upright, place plastigage, install cap and torque to spec, remove cap and measure. Note I did not have the rings installed at this point.

Edit 7/10/16 - the cylinder numbering shown in the first picture is not correct. I used it only to ensure that all parts went back to their original location. The correct cylinder labeling is shown in the last picture I have added.

 

The Nippon Piston Rings literature says that the ring end gaps are sized properly from the factory and no adjustment necessary nor recommended as will violate warranty. As such, I did not bother checking.

I placed the piston/rod assembly on a tall cardboard box that was slit to let the rod big end thru. This held the piston stable while I installed the rings. I used the ring end gap orientation from the Mitusbishi Manual and for convenience labeled the box with the gap positions.

Order of assembly is oil ring expander, upper oil ring side rail, lower oil ring side rail, second compression ring, and finally upper compression ring. The oil side rails are spiraled into positioned while the compression rings need a ring expander.

After the rings were installed, I generously coated the piston rings and skirt with 30w engine oil, installed the ring compressor, applied assembly lube to the bearing shells, installed the rubber fuel line on the bolts to protect the journal, cleaned the journal one last time and rotated it to TDC, installed the piston into the bore gently tapping the piston with a wood hammer handle, rotated piston holder into position, spun the engine block over on the stand, installed the cap, and torqued bolts to specifications.

 

Anyone installed new pistons and wrist pins?

There is a interference fit between pin and piston. Measured pin at 21.97 mm and bores at 21.75 mm for an inference fit of 0.22 mm (0.0086"). Pin floats in rod small end.

Manual shows heating piston in a bath of 158F fluid (water/oil?). Currently I have pins in the deep freeze pondering the heating method. Wife would not be happy with me doing this in the kitchen. Maybe side burner on gas grille. No hot plate in garage.

 

It is purely a guess, but I'd think you should use an oil bath. Water seem to be a wrong liquid for this. Having cylinder in hot bath and pins in freezer should do the trick.
I truly enjoy following your adventure with the engine rebuild. I bet you are exited to see it all starting to go back together. Best of luck.

 

Thanks Hunter. Thank god I don't need the vehicle in a hurry as this is a slow weekend type project.

I've been leaning towards the oil bath to heat the piston as well. That way the pin bores are fully lubricated when its time to insert the frozen pin.

 

The piston pin has an interference fit to the piston and a clearance fit to the rod small end bushing.

The new OEM rods are coated in Cosmoline. This had to be removed via brake clean before the lubricated wrist pin would fit.

New OEM pistons come with a new pin, but not new circlips which is odd. Having no choice, I removed the clips from old scored pistons to reuse after cleaning. I installed one clip on the REAR side of the piston.

I put the wrist pins in the deep freeze for a week. The deep freeze was at -12F. The new rods were at room temperature.

I used MIG wire thru oil groove holes so as to suspend the piston in a coffee can filled with 30W non detergent engine oil. 2 quarts of oil worked well. I then put the coffee can on the side burner of the BBQ grille and heated it until the oil was starting to pop and the unsubmerged rim of the can was about 220F.

Using gloves, I brought the coffee can inside and quickly proceeded to align the cleaned rod bushing with the hot piston and inserted the chilled pin until it bottomed against the circlip. The "74" on the rod beam points toward the front. I then installed the remaining circlip.

 

With the wrist pins finally installed on the two new pistons and rods, I installed the rings as before and assembled them into the block and crank and also confirmed the rod bearing clearances.

I also installed the front oil galley plug with Loctite

Short block is finally assembled.

 

Next I disassembled the passenger cylinder head so as to be able to replace the valve stem seals, cam seals, and thoroughly clean the head, valve lash adjusters (VLA's), ports, oil passages, and valves. I decided to do one head at a time to avoid potential for mixing up the parts.

The Craftsman valve spring compressor I had purchased turned out to not be ideal for the job. The retainers for all of the intake valve keepers and some of the exhaust valve keepers sit very low relative to the valve cover gasket surface. As a result, the compressor frame would hit the gasket surface before compressing the spring. I made an extension for the compressor from a 2" long piece of 3/4" black pipe and cut the opening with a sawzall and bimetal blade. A 3" piece would have been better. The Craftsman compressor has a nice ratcheting mechanism which holds the compression achieved.

I used a pair of pliers to extract the valve stem seals.

Anyone have pictures/dimensions of the tool used to install the new valve stem seals? Seams most use a socket and light mallet tap to install. I don't want to screw this up.

 

I used an impact wrench and socket to remove the cam pulley.

Gradually loosened all bolts on the exhaust rocker shaft to relieve the spring pressure, and then carefully removed the exhaust rocker shaft assembly. I did not have the special tool MD998443 to hold the VLA's to the rocker arms and only 2 fell out and I returned them to their position without mix up.

I then repeated the above for the intake rocker shaft assembly. This time I used masking tape to hold the VLA's in position once all the bolts where loose.

At the rear of the head, I removed the camshaft thrust case (flanged piece that has o-ring seal). This lets the cam slide out the rear of the head.

My front seal was found to be flush with the head. Post 68 of this thread https://mitsubishiforum.com/forum/mi...t-31214/page7/ says to seat the new seal flush with the head and then insert it an additional 1/4". Searching the part numbers for tools MD998713 and MD998777 which are suppoosed to be used to install the seals, it appears that the seals are only slightly recessed. So - which is it?