I am beginning a rebuild on another Isuzu 4BD2 engine I bought a couple of years ago. The plan is to install it in my 60 as a replacement for my current 4BD2.
The engine I have works fine, but I do not know the history of it, and I found this 99% complete motor with a bad piston for $275!
I'm using factory Isuzu pistons, rings and liners, as they are graded and matched in size, the rings are the correct material, and each set comes with a new wrist pin, clips and rod bearing - Nice! The gasket set and seals are Isuzu OEM also, as I've heard and seen the stories of aftermarket.
So far I have stripped the engine, pulled the liners and inspected the parts. The cam is worn and I sent it to Delta Cam in WA today, along with the lifters, push rods and rocker assembly. Delta will inspect, weld if needed and regrind the parts for a very reasonable price.
I am placing an order for a other OEM parts, just because - oil pump gears, oil by pass, a few nuts and bolts, etc. I'm getting the OEM parts from Way Scarf Isuzu in Auburn, WA, as they came recommended from another Mud'r and they have good prices.
I spent a few hours prepping the block before it goes to the machine shop for hot tanking and cam bearings. I deburred the block, cleaned up the water passages for better flow, smoothed any casting slag and matched the oil passages and pump to help with flow.
I have a new head, complete with valves and springs which I will lap the valves into. I have just started to match the head and manifolds to the gaskets to help the flow. This is not really porting, just match the shapes.
These are good engines, cranks are titanium nitride coated, so no grinding, just polish and new bearings, and rods are huge.
The IP and injectors were overhauled and I had them turn the fuel up 10-15%. I'm going to keep the same turbo I'm running now - stock 4BD2 with waste gate which gives a max boost of 18-20 psi. I;m swapping in the larger inter cooler from the newer Isuzu NPR the motor came from. The IC is about 50% larger overall and has 2.75" inlet/outlet vs. 2.25" on the one I have now.
I am making a couple of changes this time to the flywheel. My set up runs 2 flywheels to allow the use of the H55 and keep all the driveline stock and in the stock location. It uses a Downey "Chevota" bell housing mated to an IDS adapter ring on the back of the Isuzu to make it a Chevy bolt pattern.
What I have now is the manual Isuzu flywheel with ring gear that the stock 4BD2 starter turns to start. To this is an aluminum adapter (IDS) that bolts to the flywheel that the second flywheel is bolted to. This second flywheel is what the clutch operates on. It all works well, but I have discovered that these engines like more flywheel weight, and for the second flywheel, I had used an aluminum flywheel. Did not know at the time that extra weight was a good thing!
This time, I am using the cast iron Isuzu automatic transmission flywheel, a new steel adapter that locates on and bolts directly to the crank. Then I have a forged steel Hayes 33 pound flywheel. This will add about 28 pounds to the rotating mass, which is very good.
I have a new 12" Chevota pressure plate and disc, plus a new stock throw out bearing.
The machine shop is going to balance the crank, piston assy's, rods, both flywheel's and adapter, plus the clutch as one unit. These are pretty smooth engines to start, so I'll see what happens when its all balanced.
I'm not in too much of a hurry to get this done, as my current engine runs well, plus we are going on vacation and we flat tow the 60 behind our motor home. Unlike when I first did the swap...finish it and leave on a 3 week vacation a week with only 200 test miles, I will wait until my return to install the rebuilt engine.
I'll post some pictures soon.