L20 rebuild questions

[datzenmike]

In all cases the piston should be supplied to the person doing the over bore so he can measure it and bore accordingly to get the perfect clearance.

[screamer510]

I'm calling a machine shop here soon. It comes recommended by another machine shop who specializes in factory machining and maintenance. I may go that route, just to be sure!

$75 for boring, $21 for Beck/Arnley pistons and rings puts me out the door for less than $100. Will the wife approve?

 

Thanks, Datzen

[docbainey]

I'm calling a machine shop here soon. It comes recommended by another machine shop who specializes in factory machining and maintenance. I may go that route, just to be sure!

$75 for boring, $21 for Beck/Arnley pistons and rings puts me out the door for less than $100. Will the wife approve?

 

Thanks, Datzen

 

$21 for a set of 4 & rings? Where at?

[screamer510]

If (when) I have the engine bored 0.020" oversize, do I have to worry about the compression ratio dropping? When my state tax returns hit, I'm taking the block to a well-regarded machinist in the next county over for boring.

 

Thanks for all the tips, expecially with the persuasion of going with oversize pistons and boring.

 

pistons and rings

 

EDIT:

I ordered the new pistons this morning while waiting in the McDonald's drive-thru. When I get them, they and the block will go to the machinist's to get bored properly.

I'm working on removing pistons and crank this week. How feasible is R & R pins and rods from pistons at home? Is heating the small pivot end all that's necessary or do I need to do that and have a shop press?

 

I need to install the main bearing caps in order for boring to be precise, correct? Do I torque them to specs for the boring process, or just tighten them by hand? I think that's what I've heard at least...

 

Been reading that an increase in bore size would increase compression ratio a few tenths?

[screamer510]

I am running into a problem. I ordered a set of pistons, but the set only meant that it was one piston and rings and a pin.

So, I called to (complain) order some more, and was told that there were 3 more, so I ordered them (for a total of 4). Now I get a call saying that there were actually only 2, for a total of 3 (which is obviously 1 less than I need).

 

Are there any internal differences between L20s from a truck, a 200SX (like mine), a 710, or whatever else they came in? My question is because I see RockAuto has pistons for an L20 from a truck, but the problem mentioned above for pistons from a 200SX L20b.

 

Q: Can I order oversized pistons for an L20b regardless of the vehicle it came in????

Help please before my wife kiiiiiiilllllllllllllllllls me!!!!

[screamer510]

Could I buy pistons for a 1976 Datsun 610 L20b instead of my 1977 Datsun 200SX L20b?

[banzai510(hainz)]

L20b should be the same part number,trying again here

 

http://www.kb-silvolite.com/silv-o-lite/spistons.php?action=Mfg4l&mfg=Nissan&Div=Nissan&l=1952

 

early 610s like 1973 should be the L18

 

 

with your listed proplem above ,maybe its a different manufacture.

I have seen slightly different styles with valve reliefs or what not.

 

Rockauto has been good that with what I buy. But since Ratsun and the 510realm alot of people have been buying up the stuff and its running out of stuff.Down to the point of the crappier stuff is left. esp the hydralic brake clutch parts but that all is avail unless we know where more to get stuff.

The 2 places I used to get stuff from when out of bussiness but had the best Jap made stuff at the lowest price.

 

 

I like Carquest stuff from what I seen so far but most is old stock(made in Japan) Its a hard bussiness and cheaper is always going to win ,meaning even they might be getting the cheap stuff

[Guest kamakazi620]

Shoulda just taken the block in and Let the machinist Deal with getting the pistons... :rolleyes:

[screamer510]

Do I need to adjust the ring gaps if I'm using 0.020" pistons and rings in a bored out block? Should they be gapped to the same dimensions as a standard bore/block? I have the FSM for the L20b engine.

Thanks Ratsun

Dan

[datzenmike]

Stock top ring end gap is about.............. 0.010" to 0.015"

Stock second ring end gap is about....... 0.30" to 0.050"

Stock oil ring end gap is about............... 0.30" to 0.90"

 

On a .5mm oversize I would run closer to the right hand side numbers. Usually it's 0.004" per inch of bore. An 85.5mm bore top ring should need 0.0085" MINIMUM end gap, so this fits..

[screamer510]

Thanks everyone. Ready to drop in tomorrow!

 

[banzai510(hainz)]

makesure the oil pump is primed

[screamer510]

Filled it with assembly lube/oil mixture before putting it in. Is that good enough?

[ddrum]

silvolite website

hard to seach they cahnged it around. call them for a vendor that sells as they dont sell direct

I got a set for 76 $ shipped about 5 years ago.

http://www.kb-silvol...v=Nissan&l=1952

 

9048 is what you want

 

what is the difference between 9048 and the 9071, my engine is out of a 1980 720 L20b, and my pistons look like the 9071, can i get 9048 instead? :confused:

[datzenmike]

Nissan part numbers show the pistons the same. Sil-vo-lite shows the only difference is the shape of the dish in the top. Their chart is wrong '75-'80 for L20B pistons.

[ddrum]

so it doesnt matter? and i caught that also on silvolite. On summit the 9048s are cheaper, so i guess ill be buying those.

[datzenmike]

It shouldn't mater. The dish is the same just different shape... or that's what I get out of it. I checked and the rings are the same.