Piston Help

[trulyphly710]

I took my whole motor apart finally this weekend. Decided to do the lower timing chain... And while doing so. basically everything is just about apart so might as well do the pistons and rings sooo.... I was wondering what a good place to get some pistons and rings at? or what kind?

I found a piston / ring set on "Summitracing.com" for $124.00.. If im just doing a regular rebuild??

Thanks!-WoO

[Chezedik]

No need to change your pistons if your engine did not undergo catastrophic failure, or the ring end gap is excessive. Just put new rings in, and maybe put some bearings in, if the engine is out (at least new rod bearings). The only reason you should put in new pistons would be to replace them with forged parts.

[trulyphly710]

thanks! should i go ahead and get my Rods Shot Peened at least? or could it be left alone? i have a 92 240sx with 220,000 miles. and i think its all original internals.

[Chezedik]

My machinist told me that I shouldn't worry about it, because the rods were not significantly stronger after doing so. Plus, then you have to bore the rod ends again, after you are done.

Polishing rods is supposed to do some good. But in the end, I would look at the AMS Sportsman Rods or the Eagles. They are fairly inexpensive. If you get them with pistons you will spend about 800 bux. And that will help. But I would not Shotpeen.

[trulyphly710]

The stock rods are forged right? 240sx dont have much rod problems do they?

[Chezedik]

No, the stock rods are cast. They typically do not have much of a rod problem, until you get some boost on them, and sometimes they give. It depends on a lot of different things, but sometimes they give.

[trulyphly710]

I was wondering. what is the difference between a Main bearing set vs. a Rod Bearing set? i was hoping to know which i needed cuz it seems the Main bearing set costs like $10.00 more vs the Rod Bearings.. ALso which one would i need?

Thanks.

[Chezedik]

I am sorry, this is the part where you really should be flamed for not searching. This is a very elementary question.

Here is the deal, the rod bearings are the bearings that bolt to the big end of the rod, and so it is the bearings that the rods turn on. The Main bearings are there for the main journals, or the ones that support the crankshaft. So, they are the ones the crank turns on. You probably do not have the facilities to remove the crank to put in Main bearings, do you? But you can change the rod bearings without removing the crank, and so change what you can, but don't sweat the rest.

[trulyphly710]

nope i sure dont. The crank is still in place only the rods were removed

Thanks for the info. It was just that when i went to Napa online. i couldnt find any Rod bearing and only found Main bearings. on top of that. autozone and every where else had the price difference. but the info helps Thanks a bunch man

[Chezedik]

Yeah, when I rebuilt mine, the rod bearings were cheaper, too.

[trulyphly710]

I am just really thrilled bout putting the motor back together now kind of scared also since its my first time. but learn as you go right ?

[Chezedik]

You will not be able to do the TQ'ing the right way, so you can TQ them to 35lbs/ft and it will be alright.

[trulyphly710]

are you talking about tq'ing the head bolts or the rods?

[Chezedik]

the Rods.

[trulyphly710]

thanks man!

[Chezedik]

No problem, good luck.

[s13ka-t]

What about replacing pistons? I am also doing a rebuild and would like to go with forged pistons. I found pistons for an s14 motor but I have an s13, should these pistons still work?

[Chezedik]

Oh yes, the combustion chamber volume is identical. I don't know why they would only market them to the S14 since they should work in any 240sx KA24DE for the same compression (may be different compression for Frontier KA24DE)