USDM crank in JDM

[azreark1]

So my JDM SR20 crank was hosed on #3 due to a spun rod bearing, mic'd the crank and it needs to be taken to a machine shop so i picked up a USDM SR20 for dirt cheap so that i could just use the crank out of it and get it back together quick.
My first question is about the balancing of the crank, i know both the JDM and USDM cranks have the same number, but are they balanced differently due to the fact that the USDM rod is smaller than the JDM rod?

Second question is how much does it matter if the connecting rod is out of round? As long as the crank is perfect and the rod is BARELY out of round, will the bearing still ride the crank good? I'm not trying to cut corners here, because my wife would KILL me if i got this back together only to have to tear it back down again in a month due to a failed rod bearing...i'm just curious about the clearances and how bad it would have to be to make it fail again.

GOOD connecting rod measurements are about 2.001 - 2.003 all the way around, bad connecting rod is 2.001 where the halves meet and 2.010 from the bottom of the rod to the top (perpendicular to the connecting faces), Looks like a huge difference to me but i will admit I'm illiterate when it comes to oil clearances.

[Sileighty_85]

Only "V'" series cranks are balanced with rods and pistons.

Inline cranks are balanced to themselves.


I would not run that rod. in sure you can find another used SR rod cheap.

[azreark1]

For rod bearings, getting standard size, saw ACL race bearings for the same price as regular bearings...any idea what the difference is?

[Sileighty_85]

No idea about ACL. Ive only ever used Nismo and Tomei bearings.

[m-drift]

No idea about ACL. Ive only ever used Nismo and Tomei bearings.

do you think the oem bearings last longer then race bearings?

[m-drift]

So my JDM SR20 crank was hosed on #3 due to a spun rod bearing, mic'd the crank and it needs to be taken to a machine shop so i picked up a USDM SR20 for dirt cheap so that i could just use the crank out of it and get it back together quick.
My first question is about the balancing of the crank, i know both the JDM and USDM cranks have the same number, but are they balanced differently due to the fact that the USDM rod is smaller than the JDM rod?

Second question is how much does it matter if the connecting rod is out of round? As long as the crank is perfect and the rod is BARELY out of round, will the bearing still ride the crank good? I'm not trying to cut corners here, because my wife would KILL me if i got this back together only to have to tear it back down again in a month due to a failed rod bearing...i'm just curious about the clearances and how bad it would have to be to make it fail again.

GOOD connecting rod measurements are about 2.001 - 2.003 all the way around, bad connecting rod is 2.001 where the halves meet and 2.010 from the bottom of the rod to the top (perpendicular to the connecting faces), Looks like a huge difference to me but i will admit I'm illiterate when it comes to oil clearances.

im doing the same with my sr. did u get the usdm crank for a older nissan sentra?

[azreark1]

You know, I have no idea what year car the engine came out of, bought it off a guy that had it sitting in his garage.

[TheRealSy90]

sr20de/det cranks should all be the same with the exception of the GTIR sr20 and the sr16ve obviously.

[azreark1]

Correct, that's been clarified a few times around the internet, that's why I picked up the motor...now I have a bunch of other parts I don't need from the donor motor...scrap yard here I come lol

[azreark1]

So i'm getting the motor put back together and here's what I've come across with the middle (#3) main bearing housing...seems there is a small nick where the bearing notch sits and there is a 'groove' between where the bearing sits and the sidewall...not sure if this will make a difference in the longevity or performance of the main bearing...
http://imagizer.imageshack.us/v2/640x480q90/673/7EyCFQ.jpg
http://imagizer.imageshack.us/v2/640x480q90/673/CU6cXd.jpg
http://imagizer.imageshack.us/v2/640x480q90/540/sZxCXd.jpg
http://imagizer.imageshack.us/v2/320x240q90/537/nD2L0P.jpg

[azreark1]

...Since i can't post in the For Sale section yet...I also have USDM parts for sale, everything off a SR20 long block except the crank, need it GONE! lol

[azreark1]

So got my block problem figured out...now the freakin thrust washers don't fit!! I mean WTF. I've only seen them in STD size, they measure exactly like BOTH old sets i have, but now they don't fit, i just don't get it.