Need to rebuild L20 in fairlady

[jpgoodenough]

ive got a 72 datsun fairlady z with the original 2.0l inline 6. However i cannot find pistons/rings/bearings for this thing for my life. Can I use l24 pistons and rings in this motor? or will they not work with the rods? what about bearings? Also I wanna rebuild both carbs however I have gotten three kits and none of them seem to match the carbs i have. This car has been in the family since day 1 from japan, so i know all this stuff is original. Thanks guys

John

[Arne]

As I understand it, the L20 is a smaller bore and stroke than the L24, so pistons and rods are not interchangeable.

[jpgoodenough]

i realize l24 pistons AND rods would not work due to the stroke, the block can be bored all day though. What im getting at is if the piston pin diameter is the same on both pistons and if the piston height above the pin is the same(so compression would stay the same). thanks

[sakijo]

ive got a 72 datsun fairlady z with the original 2.0l inline 6. However i cannot find pistons/rings/bearings for this thing for my life. Can I use l24 pistons and rings in this motor? or will they not work with the rods? what about bearings? Also I wanna rebuild both carbs however I have gotten three kits and none of them seem to match the carbs i have. This car has been in the family since day 1 from japan, so i know all this stuff is original. Thanks guys

John

Z Therapy can rebuild your carbs. They didi mine . The carbs are different from the ones found on 240/260/280 Zs, having a diamond shaped back side versus the Z's square one. PM me and I'll check on the part numbers.

[Arne]

Seems to me I recall the L20 pin height spec listed separately in my factory manual (has both L24 and L20 in the engine section). I'll try to remember to look that up when I get home this evening.

[rztmartini]

does Z therapy have a website? where are they located?

:edit: nevermind...google answered my noob question

[HS30-H]

Seems to me I recall the L20 pin height spec listed separately in my factory manual (has both L24 and L20 in the engine section). I'll try to remember to look that up when I get home this evening.

Arne,

Bear in mind that the English-language factory engine manuals that covered the L20A and L24 ( green cover ) usually only listed specs pertinent to the sedan, van and pickup versions of the L20A. These were almost exclusively single carb and low compression versions of the L20A.

John's car will more than likely be the high ( 9:1 ) compression version - but it is worth checking and making sure.

John,

Here's a scan of a page from a Nissan factory parts manual for your reference. A good Nissan dealer in the USA ought to be able to follow up on these numbers and find the superseding numbers ( where applicable ). Watch out for 'high' and 'low' compression pistons ( I marked them accordingly ) - but I'd go for 'high' anyway, although be careful that you have a matching distributor.

Seeing as the car has been in the family from day 1, my personal bias would be toward keeping the engine close to original wherever possible. If you want more pep you can always put a different ( bigger ) engine in there and keep the L20A on ice. You could pick up a good used complete L24 / L26 / L28 and match it up with your transmission for not much money surely?

Please tell us more about the car. Got any interesting stories / documents / photos? Was it a 'G.I. Bride'?

Alan T.

[MikeW]

My 1972 FSM lists the L20A in addition to the L24. It shows a compression ratio for the L20A of 8.6:1. The models given are the (L)230Q(U) "Datsun 200C" and the L230QT "Deluxe". It does later show the L20A as having a single carb. The standard piston diameter for the L20A is listed as 77.92-77.97mm versus 82.99-83.04mm for the L24.

[jpgoodenough]

thanks for the scan alan, however my nissan dealer wasnt able to show anything. How thick are the cylinder walls on the l20a block? Can this block be bored to 83mm(l24 pistons) without the need to put sleeves in it? I have searched all over the net for l20a pistons and rings and they are not to be found. I know this would bump my compression up some, however couldn't i add a thicker headgasket to lower it some? Also, what are the differences in distributors? I know with this motor(already did a headgasket and had cracks in the exhaust port welded back together) that installing the distributor is different than in a US 240z, as i had to pretty much walk the distributor tooth by tooth over until it ran again. How much compression can i get away with on 93 octane fuel? And yes alan, i want to keep this as factory as possible, or factory looking at least. Yes, the car is a "G.I. Bride" in a sense. My grandfather flew for the US Air Force and was stationed in Japan for almost two years with his family(my dad was 15 when my grandfather bought the car, so you can imagine how he felt coming back to the states with a brand new Fairlady). It saw lots of daily use throughout the 70s and 80s, until about 1992 when my grandfather passed. It sat in the garage rarely being started or driven until 1996 when it underwent restoration(my grandmother lining everything up), however the restoration was not very thorough. Not alot of rust on the car when they did it, but whoever painted it did a QUICK job, and it shows small runs in the paint and air bubbles all over. Then right back in the garage it went until this past march(2005) when i recieved it after my grandmother passed. I trailered it to my house, parked it until i got it running. I aired up the tires to spec, and then drove it to school. Only on the way back the left rear tire blew out and did is shown in one of the pics. Well, thats her story guys.

[sblake01]

Why would you even have driven it on tires that old?

[montoya_fan01]

Why would you even have driven it on tires that old?

well, the tires were inflated with "new" air!

[jpgoodenough]

Well, i guess i just didnt see that coming. And ive never had a tire blowout that actually did body damage. Lesson learned eh?