THSCC Forums

My experience has been with L16s and L18s in 510s. With a 510 it was very very hard to get the pan out with the motor in the engine bay. I would go ahead and pull the motor. If it has eaten a bearing I would go ahead and pull the crank so you can have it checked for diameter and polished or turned. If the bearing has spun in the rod then I would pull that piston out and have the rod checked and reconditioned as needed. If youa re careful you can leave the pistons in the bores. When you put the crank back in slide some tubing over the rod-end bolts so to avoid having a bolt scar your crank. It is hard to remove the front cover with the head still in place but it can be done. The front cover off will make it much easier to get the timing chain back in place and time the cam. While you are at it use the number 3 hole on the sprocket. This advances the cam about 4 degrees which wakes up the mid-range on a L16. I assume it will do the same for an L28. If you decide to replace the oil pump get the pump for the turbo L28. It is a bolt on and has higher volume and was the same price the last time I had to buy one.

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George Bright Member # 141
One of the youngest of the old farts.
Yes I voted against you joining the club.

Building on George's input:

My friend purchased a tired Datsun pickup with the L16 to literally serve as practice for someday rebuilding his Z's engine. We got the pickup finished and shortly thereafter he dropped a valve in the Z (apparently the tach read low) at an autocross almost 150 miles from home. Once we figured out what the tapping noise was (a valve that would not adjust) he simply removed the rocker or backed off the adjuster (I don't recall . . . this was about 1978). The drove home slightly below the speed limit on freeways mostly. I was the "chase vehicle" in my 260Z. The only damage other that the keeper being broken off the valve stem was a "slight" mark on the piston top. He rebuilt it anyway but there was literally no need to do so. Nothing was even close to the wear limit. I don't recall the miles, probably less than 100K.

Anyway, the two engines were almost identical except for number of cylinders.

Dick

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Dick Rasmussen

FS 50 2018 Mustang GT

Thinking of a stroker of your own Steven?

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'07, '08, '11 Autocross VP
'06, '10 Mike Dishman Cup
'21 MX5, '13 Corvette GS, '92 Corvette 383 c.i. 413whp/390wtq, '03 Expedition

The thought crosses my mind, since I have a spare set of the correct late 73 9mm connecting rods... 3mm overbore + 240sx pistons + diesel crank gets 3.1liter displacement and 225-240hp. Not bad in my 2600lb car.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

Or you can put a stockish, reliable engine in it and have beaucoup de $$ to drop in your STR mobile........Motons........hint hint.

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2011/2012 Autox VP
2013/2014.5 President
2013 Top Gun

2015 Fit

22R-EC => 4G63 => D16Y7 + D16Y8 => EJ255 + K24Z2 => K20Z3 + K24Z2 => K24Z2 + M54 => L15B

trust me, James....I've been doing the mental math gymnastics ever since the incident. Too bad triple Webers and a Cannon intake are $1800+. Sigh.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

LSX swap!!!!

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[color=#FFFFFF][/color]http://www.usedmiatapartsonline.com for all your used miata parts needs
http://www.wagnersauto.com for your salvage needs
2000 miata se Estreet,going to rally
2004 mazdaspeed miata bsp #77
shifter kart also(someone buy this $1500)

No, that sounds pretty good. Does doing this require any clearance machining of the block?

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'07, '08, '11 Autocross VP
'06, '10 Mike Dishman Cup
'21 MX5, '13 Corvette GS, '92 Corvette 383 c.i. 413whp/390wtq, '03 Expedition

The math is pretty accepted by most of the folks in the Z world that the piston/rod/crank combo clears the deck of the block by something on the order of 0.6mm. So, you can go with a 2mm headgasket and keep the CR around 9.5, depending on chamber volume and cylinder head variety. (P-series heads from 280ZX have better quench characteristics than earlier N and E series, but to get to 10ish CR, most go with the N42 head from a 280Z.) Other combinations may work, but require shaving the piston (thus putting oil control rings too close to combustion resulting in premature failure) or shaving the cylinder head, introducing slack in the timing chain and the inherent potential problems there.

Honestly, if I could find 0.080 over pistons for a 280ZX, I'd just go that route with the OEM crank-- but the only ones available are $1000+ custom built Ross or Wiseco setups that are likely beyond my budget.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

A friend of mine has a double-downdraft weber setup from a 260z, with cannon manifolds for a direct bolt on.

I know, not as cool as triple sidedrafts, but LMK if you might be interested- he's trying to sell.

quick follow-up...finally got some time to check into things. Drained the oil, no metallic debris or shavings. Dropped the pan, no fragments there either. All connecting rods were tight, no play as far as I could tell by using just my hands. I expected there to be more free play in the connecting rod if the bearing was the problem. Crankshaft had no end-play or other signs the main bearings were the issue, but I guess it's hard to be certain with the engine in the car. I Double checked the torque on the rod and main bearing caps. {shrug} A couple of the rod bearing cap nuts were a little off, by ~5 lb ft, on the low end of specs, but other than that everything *seems* OK. I retorqued to the middle of the acceptable 33-40 lbft range just to be consistent. I'm going to double check top-end stuff, thinking maybe it was in fact a cylinder head issue, then maybe call Rex at Happy Japs for advice. For fun I may try to start it to see if I can better localize the noise. It may be better use of money to rebuild the original engine than put a lot of effort into this 2.8....

Commentary and wisecracks always welcome!

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

I am not sure about the L24 and L28 but L16 and L18s very seldom spun rod bearings. I did on a L16 motor that was was put together with the late rod bolts but were torqued to early rod bolts specs. The motor was also spinning about 7300 rpm at the time.

The L16 also had a stock oil pump with stock pressure relief springs. The L16 that I auto-xed was built with the turbo oil pump and oil pressure adjusted to about 90 psi. That motor saw 8400 with out any ill effects. I made the 2nd to 1st money shift by mistake.



I miss my 510.

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George Bright Member # 141
One of the youngest of the old farts.
Yes I voted against you joining the club.

Yeah...in my "How to" book about OHC Datsun engine rebuilding, the author lists 20-24 lbft for the 8mm rod bolts and 33-40 for the 9mm bolts. Makes me wonder if something similar to your experience happened here? The engine had been worked on/over a bit before I got it, seeing as it was in a track car, so I wouldn't be surprised. Also wouldn't be surprised if it had always been that way, as it was a "remanufactured" engine from Nissan.

Good 510s are still around! Seems most are in SoCal, though.

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86

Why not just pull a cap or 2 to check the bearings? Silver = good, copper = bad.

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

Hi Mike,
I just re-read my post and left that out--whoops. I pulled off the #5 and #6 bearing cap, both were silver and the crank journal was smooth. Is it worth pulling a main bearing cap as well?

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Steve Carter
1972 Datsun 240Z-- resto pics at http://picasaweb.google.com/srcartermd
2007 GPW Honda S2000-- STR 86