'93 S10-Blazer long block swap

Out with the old.

Old and new sitting next to each other. All I need to do is swap over the sensors, and intake manifold, right?

Got the old intake off the '85. Everything looks good. Little carbon build up. Had to oil the pistons to free the rings, engine spins over great. Nice and tight.

Time to deal with the oil pan and remote oil filter, cooler lines.

Problem with swapping the oil pan from the '93 to the '85. Not in pic the '93 is on the left. The '85 on the right has the oil pan gasket from the '93 on it. Won’t fit. There is a difference between the size where the 2 piece rear main seal and 1 piece rear main seal mate up to the oil pan.

'85 oil pan on top, '93 4x4 oil pan on bottom. Note the bottoms of the oil pans. Now way the '85 is going to fit around the front diff.

Since the 4.3L V6 with a 2 piece rear main seal was never offered in a S10 truck, I had to fabricate my own.

This is what I cut off.

I had to add 1/2" to the bottom to clear the crank journals. Note the oil pan is bolted to that board. I wasn't taking any chances on warping the pan.

Pan completed and ready to be installed.

Little trouble. To get the oil pump pick up tube to clear the new side of the oil pan I had to tilt it like so. However that leads to other problems. I need another solution.

After some searching I came up with a Moroso high flow oil pump pick up tube. The high flow oil pump is 1/4" taller then a stock oil pump. To get a pick up tube to fit, it needs to be 1/4" shorter. Plus this pick up tube locates the screen directly below the pump. I needed that 1/4" to provide the proper clearance between the screen and pan.

Oil pan fits.

Alright, cruising right along.
Attached the rest of the accessories. Nice thing about the '93, it has 2 accessory brackets that hold everything

Time to deal with the flexplate.
Remember the 1 piece, 2 piece rear main seal issue with the oil pan. Guess what, it affects the flexplate as well. Take a look at the next two pics. Top one is a 1 piece, and second one is a 2 piece. Notice the difference in the crank ends. See the counter balance on the two piece design. This is why you cannot replace a two piece rear main seal with the oil pan on, or while the engine is in the truck. With the one piece rear main seal it slides over the crank.

So you’re saying to yourself, what does that have to do with the flexplate. The hole for a 1 piece crank is smaller then the hole in the flexplate for a 2 piece rear main seal. Yep, that meant I had to buy a new flexplate. Dealer cost, #218.00, AZ cost, $30

Alrighty, the engine is finally ready to be dropped in.

And in she went.

Finished hooking everything up, and fired up the engine.
You know how you’re nervous just before you turn the key. Not sure if that used engine will work, not sure if you did everything right, hoping, praying it will fire and run.
I left the coil wire off for the first crank. I wanted to make sure the oil circulated some, also wanted to make sure the fuel circulated, and wanted to hear it before it attempted to fire. Just in case it made some funky noises.
I put the coil wire on, and gave me son the go ahead. It fired and died. I told him to pump the peddle, he cranked it again and she roared to life. Checked for leaks, checked a few other things. Revd her up and she went, no stumbles. Awesome. Pulled the oil dipstick, problem. Milkshake.
Radiator fluid disappearing. Not good, shut her down.
This is what I drained out of the oil pan.

Not good. Quest to find the problem.
Head gasket, I didn't take them off, and the old oil filter and old oil didn't show any signs of coolant in the them. Must have been something I did.
Intake gasket? Could it be that accessory hole I drilled? Maybe I went too deep and put a hole in the water jacket?
Pulled the intake manifold off.

Found the problem. I did get a little to aggressive when drilling that hole. I pierced the water jacket in the corner and never saw it.
Notice the screwdriver blade, that’s as far as it will go into the hole.

I used JB Weld to plug the hole. I drilled about 1/2" too deep. I figure the JB Weld should hold. I have used it before on other projects without trouble. It is rated to like 800 degrees, and I serious doubt my water temp will reach anything over 260 degrees. More like 180 degrees.
Put everything back together. Put on a new oil filter, ran 2 quarts of oil through the engine. Fired her up, and the leak is fixed. Let if idle for a couple minutes. Drained the oil, replaced the oil filter, and ran another 2 quarts through the engine. Filled her up with fresh oil again.
Cleaned the front brakes, replaced the rear brakes, installed a glasspack and new tailpipe, added fuel injector cleaner to the gas tank. The 1/4 tank of gas is 2 years old, topped the tank off with 89 octane with 10% ethanol.

Took it for a trip around the block, topped off all fluids. Another trip around the block. All fluids still look great. Ran some errands and put about 100 miles on her. Checked everything again. Looks great.

Saturday we got the title transferred, transferred the plates, and got it insured. My son has been driving it since with no problems.

I love it when a plan comes together.

Well it’s Been almost a month now.

Update.
Other then a lose hose clamp on the upper radiator hose, she works great.

She has one hell of a cam in it. Add the glass pack and she sounds good too.

I figure I have less then a grand into this truck and that includes the new tires. Not bad for a '93.