Engine internals, and other questions

[91TSiAWD]

I wasn't going to post, I was actually trying to find it somewhere on the forums, however, after 3 days of looking, I've given up.

I'm a DSMer. :ylsuper Take me out back and shoot me if you must, but please answer first.

What is the difference in the ka24de made up to '94, and the '95-98? S13 vs S14(?)

The reason I ask follows. A friend from work has a '91. More miles than he cares to admit( >200k MILES), but it runs well. His plan was an rb25det swap, but, due to various reasons, he has shelved the idea. He seems to think I'm the resident turbo expert, as well as engine builder, and has asked for my help.

First off, I asked if he had considered boosting his stock KA. He hadn't. Then I asked the big one - what about an SR swap? Nope, not his thing. Cool, I agree there. Back to my first question - why not boost the KA?

I've got him pretty much convinced to go with a boosted KA, and then my digging started. Stock compression is a little high, but I'd turbo it. His engine is tired, and is probably not going to last too long boosted, so I suggested a rebuild. I've been looking for forged pistons and rods(I now know that stock rods are fine) and while reading through the wiseco catalog, I came up with the question. There is a piston listed for the '95-98 KA, but nothing for pre '95. If they were the same, why the destinction, and if not, what is the difference?

I've had very good luck using wiseco pistons in the 4g63's that I've built, and am about to put a set in a 2.4L hybrid(DSM). And I can get them for a decent price.

Scroll to the second page.http://www.wiseco.com/PDFcatalogs/sc-mits.pdf If you try to go to the Nissan section directly, it gives a broken link, I've already emailed them about it.

I'm pretty sure we're going to boost the stock KA, and pick up a rebuildable core and have it ready when his is ready to retire.

[stillmatic]

The S13 DOHC and S14 internals should be interchangeable.

Check ka24de.com and realnissan.com. They sell internal parts for the KA24DE. Nismoparts.com or any Nisssan motorsports store should have some internal parts as well.

[Naro182]

i know very little( im still learning) but between the s13 and the s14 ka, i know the maf and the valve cover are different as far as internals are concerned, im pretty sure they're the same. oh the s13 ka's have better cams...

[kpark129]

Forged Pistons for the s13 and s14 should be interchangeable. I know the Ross Forged Pistons 8:5:1 CR can be used on 91-98 KA's. In my opinion I think the stock compression is fine (9:5:1CR) on a KA, that is if he is also going to do a lot of daily driving. If he is strictly going to go all out performance then 8:5:1 CR is ideal.

-K

[91TSiAWD]

Kpark - I agree, for a daily driver 9.5:1 boosted is fine, better off boost power, and a bit better throttle response, however, since all the off the shelf forged pistons are 9.0:1 or lower, it'll likely end up with those. I figure if its going to need a rebuild, it may as well be built to take some abuse.

Checkered-member brings up an interesting idea in this threadhttp://www.nissaninfiniticlub....47235I may consider suggesting going with the Frontier pistons as a cheaper alternative. Perhaps. In the end it will be his choice to make.

A Stock 1st gen DSM has 7.8:1 cast pistons, too low in my opinion, and a comon upgrade is to use the pistons from a 2nd gen and get the small end of the rods machined to fit. They're supposed to be 8.5:1, however they actually end up being closer to 9.0:1. That was the setup of the first engine I ever built, and it was nice. Too bad I lost an oil filter gasket at 7500 rpm...

Many thanks for the serious, and constructive answers. I'm not used to getting useful answers so quickly. Perhaps I should stay away from the Honda boards.

[91TSiAWD]

Oh, right, I have more questions.

Since it is going to need to be overbored for the forged pistons, and I don't have a factory manual, is a torque plate needed, or is the block rigid enough to go without?

Again, falling back on my DSM experience, it is not needed. However, I had one made anyway. Can't possibly hurt. Since I don't plan on building many KA's, I don't need one for myself, it'd be a shame to have one made and only use it once.

That said, is there a certain order recomended for boring? I'm thinking thermal reasons. 4g63 overbore/hone order is 2-4-1-3, makes sure that there is time to cool and not stress the block unevenly. Is this suggested on the KA, or should I not bother?

Sorry for all the n00b questions.