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Hey, I understand skirting the law and getting around stuff, but older now and head covered with bumps.  :lol:  The pick up may be closer to the front but still on the right side to feed into the oil pump gallery, but be sure to support it to a main bearing cap. The 720 engine oil pick up has a support strut that uses the main bearing bolt to hold it.


That compression fitting doesn't have a nylon seal does it?

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Ya i scratched the copper pipe idea...just welded up a steel one, also had to snip out a small section of a baffle in the pan..got it on and all filled up with no leaks...but..... Now my dip stick wont work..lol dear got what will become of me without a dip stick! It should be in the car today...then just throwing on all my smog stuff..or, wait.....

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  • 2 weeks later...

So owning an old car is really a pain in the ass...I have been fucking with this thing for so long...it's nothing but a headache..I'm trying really hard to be a Datsun fan but damn its a struggle..I commend those of you who continue fixing up these fixer uppers...I have been struggling with this blow-by issue...so the 240 smoked like crazy... With new rings in it... Smoked like crazy... Now the 280 in it...smokes like crazy.....but here's the catch...why the fuck does all of this smoke come out my block and valve breathers (that is supposedly pushed past the rings) but not a single puff of smoke comes out of my tail pipe? Even with the exhaust taken off down to straight headers still I don't see any smoke...yet it billows out the breathers... Hope someone can answer me that... Cause I can't wrap my mind around it...

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OK, after thinking a bit more I've theoried up this scenario...it's not smoke from the burning gasoline in the cylinder. It's smoke from the hot combustion gasses kissing the oil in the bottom end..and I'm not seeing any smoke out the exhaust because by the time the valve opens and piston is on its way back up, all of the would be exhaust smoke has long since made its way through and around the rings..it sounds OK in my head...but maybe someone else can clear things up..and what would the peak pressure upon detonation get up to in the cylinder..cause it still seems like even 100psi would never get around even a worn out ring in the amount of time it takes the cylinder to reach bottom and the exhaust port to open.... anyway I took the rings that I put in the 240 motor to check if I had maybe cracked them or installed them funny and everything looked tight as a drum...this blowby shit makes me crazy...

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The things in common between the L24 and the L28 is the oil pan and the pickup tube. Using the L24 dipstick??????


Drain the oil and refill with exactly 4 quarts or whatever is recommended. Check the dipstick. Is it on the full line or below? If below you are over filling it.  

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I got the pan, pickup tube situated. It's the pan on the z cars and the blocks on the z cars are different then our 810. But with a rerouted oil pickup and slightly modded pan, and cutting about 1 inch off the dipstick it works...motor is in the car and running, I also know how to change my oil. But what I don't know is how to get rid of blowby...I'm going to re-ring this engine and see where that gets me...my neighbor thinks I'm a lunatic pulling the motor every other weekend...this will be the 4th time in 3 months...

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I know that you know how to change oil.  My concern is that it's over full. Because of the L24 pan on an L28 and the two possible dipsticks the mark on the stick being used may be wrong. Only way to check or be positive is to drain and refill with a known correct amount. Then confirm or mark a new full line on the dipstick.


All engines have some blow-by. If your crankshaft is spinning in the oil, it will splash up onto a fog of oil droplets and simply over power the screens on the block vent or the valve cover.


This is an easy check that costs nothing to do.

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I see. I didn't even think of that. I assumed they both would take the same amount of oil since they were the same casting, or are they not?. Is it more displacement because the piston is bigger or because stroke is longer? I did like you said though when I installed it I drained completely and refilled with 6 quarts as in my manual for the l24 then I just trimmed the dip stick till the rubber plug seated and the oil marking was still right in the crosshatch. It only needed about an inch taken off. and could you explain a bit more about this oil fog? Cause it's not actually dripping out of the breathers and it doesn't seem to be a condensed oil vapor..it seems to be burned oil smoke that is coming out..and is the test you mentioned a leak down test? It seems that it could only be blowby if it's smoking out the crankcase. What other possibilities would cause that?

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  • 3 weeks later...

Just an update...motor is back in the car and running tits with zero blowby....yay for me..after teardown it was obvious why it was smoking. Two pistons had broke right between the two compression rings it just tore the entire step right off about a third of the piston...so I got some new to me ones off eBay for 125. New rings and new tires for the hell of it...back on the road!

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