Just bought a 1990 240SX with blown head gasket, here are my choices, what you think?

[Jays90240SX]

OK, I just bought a 1990 240SX and the dealer told me it needed a Head gasket. The previous owner put in a new rad, all new rad hoses and such, and it still overheats, so he figures it's the head gasket.

It's at my friends shop now, he is looking at it today. From all the reading that I have done, and yes, I searched, and read that nice 14 page thread on the "SR vs. KA"

And I have a couple questions.

1. No one mentions the SOHC vs DOHC KA engines in that thread, is it because they would make the same power? Or is it because the SOHC is junk and we are to assume to use the DOHC?

2. Looking at the costs, and the fact that I would need to remove the head anyways on the KA, should I just get some rods and pistons in there at the same time? The only problem I have with this, is it seems to be custom ordered pistons, which will take a longer time. Unless someone has some more insight on where I can get some good pistons that someone has in stock.

3. I could go with a SR20DET, but since I don't have a shop, I have to get the engine installed, with the cost of the swap, plus labour, I could have a pretty darn sweet KA, WITH a custom turbo manifold and Downpipe.

4. Even with the SR, I would still need a new manifold, and downpipe and such, when upgrading the turbo.

SO, from what it looks, if the SOHC KA is good to go with, I would be building this up. Just need to source the parts needed, more importantly the pistons and the rods and I will be on my way to a SWEET setup on my 240!

any insight.....comments?

[ADAMHU]

imo the improved flow of the DOHC vs sohc head can be compensated by properly porting the sohc head ..

adam

[WDRacing]

Replace the thermostat and flush the block and head with fresh water for about 15 minutes. Install a turbo and you'll be happy. If you want big numbers you might as well swap out the pistons and rods. But your head might not be the problem at all.

WD

[1LoSX]

Stay with the SOHC - if you pick up the DOHC for lets say 400 then you still have labor costs and what not when you could be putting it into then SOHC - go under raceeng and they have rods and pistons

[jrc90240sx]

I have just gone though rebuilding my engine because of the same thing. I was dumb and let the machine shop worry about it (my bigest mistake on my rebuild) the only place that i have found that sells both pistons and rods (for trubo) for the KA24e, is realnissan.com witch happens to sell one of the only turbo manifold i know of. they quoted me 1200 for rods, pistons, rod bolts, and metal head gasket. they are more then likely other places, but JE took 2 months to get me my pistons (personaly feel it was the machine shops fault again, well really my fault for not doing it myself) but whatever, should have the oilpan (machine shop messed up, but wouldnt confess to) and new fuel injectors (3 of them had bad coils) but so i should have it up and running shortly, well hoping to anyway.

also my rods where about 700 something, and pistons where like 550 or somthing like that. so its not a bad deal from realnissan

[bruinbear714]

1. No one mentions the SOHC vs DOHC KA engines in that thread, is it because they would make the same power? Or is it because the SOHC is junk and we are to assume to use the DOHC?

A lot of people just assume that just because the engine has two cams, it is better. In my opinion, both engines have the same potential capabilities. No one likes to work on the SOHC because everyone else is using the DOHC as the platform to build their engine. If I were you and had access to machinery, some money and extra time, I would pick the SOHC over the DOHC for a few reasons:

1) Simplicity.2) Costs.3) Availibility of OEM parts.

Quote »2. Looking at the costs, and the fact that I would need to remove the head anyways on the KA, should I just get some rods and pistons in there at the same time? The only problem I have with this, is it seems to be custom ordered pistons, which will take a longer time. Unless someone has some more insight on where I can get some good pistons that someone has in stock.[/quote]Sure, toss in rods and pistons if you plan to go turbo. Don't forget new rings and rod bearings while you're at it.

Quote »3. I could go with a SR20DET, but since I don't have a shop, I have to get the engine installed, with the cost of the swap, plus labour, I could have a pretty darn sweet KA, WITH a custom turbo manifold and Downpipe.[/quote]SR swap will give you a downtime of about a week. After that, you get 200hp stock.

KA buildup will give you room to expand later down the road if need be but at the expense of longer downtime and more work.

Quote »SO, from what it looks, if the SOHC KA is good to go with, I would be building this up. Just need to source the parts needed, more importantly the pistons and the rods and I will be on my way to a SWEET setup on my 240! any insight.....comments? [/quote]

If I were in your situation, I'd build up the SOHC only if I had another car to get to work and around town.

[kysard]

A shortblock for a ka23e is much cheaper than DE, you can get a shortblock assembly w/ forged pistons for $800, with the DE your looking at $1200.

But from what Ive heard the DE will pay for itself in gas savings on a daily driver, the SOHC is a pig on gas?

[TrunkMonkey]

A shortblock for a ka23e is much cheaper than DE, you can get a shortblock assembly w/ forged pistons for $800, with the DE your looking at $1200.

what do you mean by shortblock assembly? aftermarket pistons and rods cost about the same for both engines.

But from what Ive heard the DE will pay for itself in gas savings on a daily driver, the SOHC is a pig on gas?

they both get pretty much the same mpg.

-demetrius

[kysard]

I'm talking the about real nissan short block, complete assembled for $800 with forged pistons, find a price like that for th DE!

I believe you may be right about gas milage if you have it tuned right

[jrc90240sx]

both blocks use the same rods, so the only difrence would be pistons. witch would only really have a problem if you where to up the CR, but for a dished piston you should be ok either way. that 800 is alot less then when i frist emailed them about it, but that was over 3 months ago. my car is about done, so i will see if i am about to be happy or greatly disaponited in what i have done. looking back i wish i would have gone with either a newer rps13 sr20det blacktop, or rb25det for the time it has taken with my KA, and the money i have spent, i would have more HP.

[syka24et]

yeah man i just got my pistons from them last week, they are je with upgraded pins, stock compression. They only cost me 450 and they actually brought them to me in person. I meet Luis he has like a 10 sec or so datsun running a sohc ka. I also spoke in length with Anthony from there, and he was extremly patient and answered all my questions. Give them a call the number is on the site.