Alright, I have a bit of a delema, and I need some advice from the s2000 owners out there (I know i will probally get flamed so I have my nomex suit already on).

I have decided to build my F20C motor. It is currently sitting at the shop all disasembeld and I am having 2nd and 3rd thoughts about everything. What was meant to be was: j's header & exhaust & intake, skunk2 stage 3 cams, milled head for 12.5:1, j's jdm pistons +.25mm (just to refresh the block with new rings since it has 130,000 kms on it), blueprint, and knife edge crank, comptech diff with 4.57 gears, lightweight flywheel and aem ems (and a whole ton of suspension mods).

now I am wondering if I should sleeve the block (dart sleeves) and use aftermarket pistons without going stroker (i am running out of budget) and add the cams with the valve terrain and then fully port the head. What do you guys think? I am not looking for peak numbers at all, rather useable power off and on the track (and I am not talking about drag strips). I am also concered about the tuning process since I am unfamiliar with this and I just like to get in and go and hate to fiddle around with the tuning here and there to get things running properly.

 

What is wrong with the engine that caused you to tear it down?
Is the block damaged at all? (Scoring?)


From your post, it looks like you want to play with the car and don't really need to build a motor? Did I read that right?

(No flames, just trying to figure why so I can anwser a few of your questions)

 

Sounds like some fun mods. Personally, I would put some more money away and go for the stroker + sleeves + 90mm pistons. You are already going to have the engine apart anyway...no better time to make that addition. I say go for it all if you are going 90% of the way there.

Oh...AEM tuning is definitely something best left to an expert who has done that work before. Check in the Toronto forum for a recommended tuner.

 

I have had some highly recommended tuners, but they definatly tune on the aggressive side. The whole idea is to build an extremly reliable motor with decent power rather than ultimate hp numbers.

Stratocaster, absolutly nothing is wrong with the block. It isnt even burning a drop of oil. What sparked the tear down was a snowball effect of mods. Clutch needed to be replaced, changed flywheel, gears, and then decided I might as well take out the engine & do engine mounts and then decided might as well "rebuild" the motor while it was out (seeing how it has already 130,000 kms on it and it is a daily driver). You read it right, just looking to play around.

I am very skeptic on using 90mm pistons and its reliabilty especially for a track scenario, and long track sessions at that.

 

If reliability is your concern, then you should put the bottom end rebuild money towards something else...some head work (port/polish head & intake manifold) or more suspension mods perhaps (the best Mouton coilovers should suck that money away immediately). Any time you crack open the engine you are taking a risk...and it sounds like you may be risk averse in that regard.

Oversize pistons have been a performance mod since the '50s...you're talking about half a century of hot rodders and import tuners using this method. So long as the sleeves are good and there is room in the block, it will put less stress on the engine compared to a stroke kit, which significantly increases piston speed.

The same goes for the AEM tune. If you do not plan on taking full advantage of the timing and A/F changes, then perhaps that money is better spent on a J's or Mugen ECU that does not require the cost of tuning or run the risk of being too aggressive.

 

With the J's or Mugen ECU, how do they work? and in comparison to the Aem ems?

Port/polish and im are planed in this build. I was going to work on the bottom end as well as replace the bearings and any other item which might need to be replaced.

Suspension is kw variant 3's with bushings all over, bsk and other items as well.

If I sleeve the block, what type/style of sleeve works best with the F20C and what would be a safe overbore to go with which will allow for the car to remain at high rpm for a long period of time on a stock rod. or should the stock con rods be replaced?

 

^AnDre^

Since the block is currently in good shape, I would not sleeve it. I would put it back together and ware it out first.

Next I would find a used block that needed to be sleeved (I have several so that are not hard to find). This will give you a car you can drive while the motor is being built.

Then I would build the engine however you want. There is a number of good custom piston manufactures here in the US, so no need to go JDM. For 5K inlinePro will build you a 2.4L stroker at 12.5:1. There is a few other builders that have delivered proven results boring and sleeving the F20C block.

 

how much of an added gain would there be from re-sleeving and boring to say 86-87mm with 12.5:1 ?

I am not set on going stroker for some reason, the idea does not apeal to me. I know the best idea would be to pick up a second engine and build it, but at the moment the budget wasn't planed for it and there is no room for it. Majority of the parts I need I have so the idea was to make use of them or sell them. The sleeves I can get pretty easily and same with the pistons. If the gain isnt that much maby the best idea would be just to mill the head and leave everything else be until she really needs it. which is starting to sound like what I should do, do very minimal, forget the cams and just go with a j's ecu or something of that sort.

 

A used, damaged block sells for next to nothing (100-300).

The JDM ECUs were tuned with higher octane gas that is availble here in the states. That is one reason for the higher compression ratio on their engines. AEM EMS would be your best bet. The cost is about the same as the JDM ECU and it is completely tuneable. Where the JDM ECUs are not. They have a fixed tune.

As for rasing the compression ratio on a stock motor, I am not sure there is enough clearance for the valves. You may need a custom piston for that reason.

If it was me, I would sleeve and bore the block and build it with custom pistons and rasise the displacement and compression. Basicly stroking it. There is a post in S2000 Talk where someone stroked the motor using all stock Honda parts. So for parts that would be a cheap route.

 

Im not sure that I would use a local AEM tuner.

If it were my car, Id be bringing it to Devin in Michigan. No one else.

He's mainly an NSX guy, but I know he has tuned a ton of S2000 engines also.

Id also ask yourself what kind of gain youll get from a NA S2000. What, 40 or 50hp? You can get double that with a supercharger for less money and probably with a more reliable package. Once you start using a tuner, you cant assume that you will have reliablility in all conditions (you PROBABLY will, but you cant assume so). Basically a built S2000 engine is probably a lot of money spent for an outcome that, while cool, may not be what you had in mind. Id put a SC on it in one second if it were my car. CTSCd S2000s are fast and reliable.