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I RULE YOU!!
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Discussion Starter · #1 ·
So I just completed replacing my blown B21 block with a B20a3 block. I used everything off the B21 setup except for the block, crank, pistons, fly, etc.

It started right up on the first try and purrs like a kitten. Makes it's owner very happy, too! But my question is....

A few months ago I replaced a B20a5 with a ceased block to a B20a5 head with a B20a3 block. Worked great for about a month with no problems at all then all of a sudden one day a rod went flying through the block. No warning signs, no overheating, fresh oil... just straight out of the blue. Now, is this going to happen with my B21 head and PK1 block or was that just a fat stroke of luck? I think I remember somebody saying way back when that the PK1 internals are inferior to the PK2/PK3 internals, but aren't the PK1/PK2 blocks pretty much the same?
 

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New title is new
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The internals (excluding piston size and wall material) of the PK2 and PK3 are identicle, the PK1 has smaller diameter wristpins and rod journals (crank too? i don't remember).

The rod going flying was straight up bad luck, the PK1 bottem end should be able to deal with stock power levels just fine, it'd take a turbo or serious n/a nonsense to get beyond it's abilities.
 

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I RULE YOU!!
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Discussion Starter · #3 ·
Thanks bobnova... glad to hear that. This will just be a temporary engine until I have the funds to back a nastey H22.
 

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I'll punch in and agree with Bob, here. While the Rod bores are smaller, they don't seem to be any MORE succeptable to the standard B20Ax rod throwing problem. Oh, and the crankshaft main bearing bores are the same as the B20A, B21A1, and B20A5. Let us know how it goes, though. That compression is going to suck though, with the larger bore of the PK3 head meant to match the larger bore of the B21 block. Hope you remembered to use the PK3 headgasket too!
 

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I would've at least plastic gaug*sp the bearings to see if the need replace while it was torn down. That should go without saying on b20a's.
 

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I RULE YOU!!
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Discussion Starter · #6 ·
Well so far so good. I've put about 200 miles on the engine and given it a 2nd oil change. It feels very smooth but it isn't quite as powerful as I'd like it to be. Still could walk my 2nd gen. Last night my radiator decided to start leaking however so I get to replace that this morning! And I'm really wishing that I would've replaced the rings and honed the cylinders because it's burning some oil. And yes, I did use the PK3 head gasket.
 

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Rep me if you hate my ass
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At 200 miles on a fresh engine, it might be normal for it to be burning a negligible volume of oil, but what kind of bum doesn't take the bottom end apart and put new rings in!? The money you spend on oil might outweigh the money you would have spent on rings, you silly goose.

--J
 

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I RULE YOU!!
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1,750 Posts
Discussion Starter · #8 ·
yeah yeah yeah... well maybe I just didn't have the money to front some new rings :p

Plus this is a temp engine. In a couple weeks I'm going to start gathering H22 stuff when I sell my truck and my 240sx.
 

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穏やかな旅行&#
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fcukwithmeprelude said:
yeah yeah yeah... well maybe I just didn't have the money to front some new rings :p
:|
For the price of a few cases of oil you could have bought some rings.... probably even less than that off eBay:Rock:
 
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