ansonowicz Posted October 3, 2016 Report Share Posted October 3, 2016 I've been lurking this forum for quite some time now. After many many years, the ol' 521 is getting some attention. After disassembling the L16, I've discovered some major piston damage (walls look okay until I remove the rotating assembly). This is an original L16 with matching 210 head. I'm open to getting another block & head in there (limited funds for this project) but availability seems limited. 1) Not knowing the history of this block, if this gets resurfaced, how far is too far? Based on the scratches around the cylinder, it looks like it was poorly resurfaced with a belt sander or something (after I removed the gasket) Any markings or reference points to see how much room is left for another resurface? 2) Any somewhat modern pistons still around for this L16 with matching overbore rings available? 1 Quote Link to comment
Draker Posted October 3, 2016 Report Share Posted October 3, 2016 Get those pistons out of there and lets see those walls! 2 Quote Link to comment
Draker Posted October 3, 2016 Report Share Posted October 3, 2016 You can still get pistons and for this. Just depends on how the walls look. If they are not scratched up.. the block might be find to reuse. 2 Quote Link to comment
ansonowicz Posted October 3, 2016 Author Report Share Posted October 3, 2016 You can still get pistons and for this. Just depends on how the walls look. If they are not scratched up.. the block might be find to reuse. Thanks Draker! Even if they are mildly scratched, they'll be bored out and fresh again. I hope to get the pistons out in the next day or two. I'm mostly concerned about resurfacing too much and it causing issues with the head/valves 1 Quote Link to comment
datzenmike Posted October 3, 2016 Report Share Posted October 3, 2016 First of all this is not an L16 it's an L20b. Look behind the dip stick handle for the stamp at top of block just below the head. Detonation will do this damage. L20B with tiny 210 head is 9.23 compression. This would ping like hell and no wonder the piston is punched The walls I see look too smooth, probably been rebuilt. Measure the diameter of the bore across the top. It will be at least 85mm but if over bored could be 85.5mm 2 Quote Link to comment
Draker Posted October 3, 2016 Report Share Posted October 3, 2016 Good catch Mike, block vent is the give away. 3 Quote Link to comment
ansonowicz Posted October 3, 2016 Author Report Share Posted October 3, 2016 Welllll SHOOOOOT, thanks guys. Had to clean up lots of grime to find the stamp. It's an L18. 2 Quote Link to comment
Draker Posted October 3, 2016 Report Share Posted October 3, 2016 Well look at that.. both wrong. lol 1 Quote Link to comment
datzenmike Posted October 3, 2016 Report Share Posted October 3, 2016 Odd never seen the top vent on anything but the L20B and up. Maybe this is a much later import engine???? How many bolts on the flywheel????? Picture of the oil filter boss with the oil filter off? 1 Quote Link to comment
ansonowicz Posted October 3, 2016 Author Report Share Posted October 3, 2016 5 bolts on the flywheel. I don't have a bore gauge on me, but rough ruler measurements are 86mm maybe even 86.5mm. That's only from the top deck so not that accurate 1 Quote Link to comment
datzenmike Posted October 3, 2016 Report Share Posted October 3, 2016 The top is the best as this is not scrubbed by the rings and is the original bore. L18s are the same bore as the L20B.... 85mm This raised boss is not common to the L18 and is, I think, a much later casting. The L18 was used into the 80 on 720 in Australia and other parts of the world. 1 Quote Link to comment
Draker Posted October 4, 2016 Report Share Posted October 4, 2016 Are you talking about decking the block surface? Or the head? Or both? 1 Quote Link to comment
flatcat19 Posted October 4, 2016 Report Share Posted October 4, 2016 Those aren't L18 pistons. Too deep. Head gasket was really bad on that one too. 2-3 being worse than 1-2. 1 Quote Link to comment
flatcat19 Posted October 4, 2016 Report Share Posted October 4, 2016 Get them pistons out and survey damage. I'm wondering if the crank is scarred from the detonation. 1 Quote Link to comment
datsunaholic Posted October 4, 2016 Report Share Posted October 4, 2016 That's a Z18 casting machined as an L18. I've seen L16s the same way (and in fact have one- late style PCV vent and bosses for putting the serial number on both sides of the block). Typically a crate engine, or a used import engine, but definitely 1979 or newer. 2 Quote Link to comment
ansonowicz Posted October 4, 2016 Author Report Share Posted October 4, 2016 Update: Cylinder walls feel smooth and no major damage. Rod bearings look great, no visible damage to the crank (as far as connecting rods go). Haven't been able to remove crank yet for further inspection because flywheel bolts are stuck. Like stuck stuck stuck, will need to soak in some PB blaster and figure out a way to hold down the block & crank while getting breaker bar on that thing. Pistons and rings, all sorts of carnage! can't believe the broken bits didn't score the walls. All of the pistons measure 85mm, and the rods have datsun/nissan markings stamped on them. 1 Quote Link to comment
flatcat19 Posted October 4, 2016 Report Share Posted October 4, 2016 L18, ZX flattops in next size up, U67 head. Bueno! 4 Quote Link to comment
ansonowicz Posted October 4, 2016 Author Report Share Posted October 4, 2016 L18, ZX flattops in next size up, U67 head. Bueno You guys are all great. Thanks for the advice and direction! 1 Quote Link to comment
flatcat19 Posted October 4, 2016 Report Share Posted October 4, 2016 Hold on. My post was a bit misdirecting. ZX flattops are already 86mm. 2 Quote Link to comment
G-Duax Posted October 4, 2016 Report Share Posted October 4, 2016 That's OK...... As we get older, everything shrinks. 2 Quote Link to comment
ansonowicz Posted October 4, 2016 Author Report Share Posted October 4, 2016 Hold on. My post was a bit misdirecting. ZX flattops are already 86mm. Based on this statement, I'm guessing the existing rods and wrist pins will fit the flattops? 1 Quote Link to comment
Doctor510 Posted October 4, 2016 Report Share Posted October 4, 2016 Update: Cylinder walls feel smooth and no major damage. Rod bearings look great, no visible damage to the crank (as far as connecting rods go). Haven't been able to remove crank yet for further inspection because flywheel bolts are stuck. Like stuck stuck stuck, will need to soak in some PB blaster and figure out a way to hold down the block & crank while getting breaker bar on that thing. Stick a hammer handle in the block, rotate the crank over until it wedges and the crank won't turn, Use the right socket on a 1/2' breaker bar and use a floor jack handle or a long piece of pipe for more leverage. If you have an impact wrench it may or may not work. Pistons and rings, all sorts of carnage! can't believe the broken bits didn't score the walls. All of the pistons measure 85mm, and the rods have datsun/nissan markings stamped on them. Bore it .040" over, as mentioned the late Z/ZX are 86mm STD. 2 Quote Link to comment
ansonowicz Posted October 4, 2016 Author Report Share Posted October 4, 2016 Stick a hammer handle in the block, rotate the crank over until it wedges and the crank won't turn, Use the right socket on a 1/2' breaker bar and use a floor jack handle or a long piece of pipe for more leverage. If you have an impact wrench it may or may not work. Never thought about wedging a handle inside the block! My impact definitely did not work. I have a 24" breaker bar that should do the trick. Bore it .040" over, as mentioned the late Z/ZX are 86mm STD. Got it. 1 Quote Link to comment
datzenmike Posted October 4, 2016 Report Share Posted October 4, 2016 Flywheel bolts are not stuck they are torqued from 100 to 120 ft lbs. Put ratchet on and kick down on the handle... HARD. 2 Quote Link to comment
banzai510(hainz) Posted October 4, 2016 Report Share Posted October 4, 2016 Danielor wayno Made a bar using the clutch bolt holes. and used them to hold the flywheel. then one can remove the bolts. some one has a photo 1 Quote Link to comment
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