What's involved in switching to type-s pistons? - Honda Prelude Forum

Vapor · 03-04-2003, 08:46 AM

First off, I've never tried to do a piston swap on an engine I wasn't rebuilding on a stand, so whats involved in just swapping the pistons? I can get away with these pistons without sleeves and not screw up the walls, correct?

Also, tuning wise, do I need to make any changes or is it something the ECU can handle? Is a V-AFC and dyno time enough to handle the pistons and some stage 2 cams?

I want to stay N/A, but I'd like it to be decently quick without spending an absolute assload of money, so the Type-S pistons seemed like a good option. Any info would be helpful. And yes, I trie searching, but the computer here at work is having issues, it craps out every time it tries to forward me to the results.

71dsp · 03-04-2003, 09:35 AM

The ECU should be able to handle it. It won't cause a problem.

Ideally, you would pull the block, pull the pistons, have the block honed, and intsall the new pistons. This take a lot of time, and it can be quite expensive, as you are basically doing a rebuild on the block.

You can do an in-frame cylinder bore hone, but it is critical that none of the debris from the honing process get into the engine internals.

Cost varies, depending on what you do. Some replace the rod bearings (which is recommended) when you pull the rods (which you have to do to replace pistons), head gasket, rings, etc. etc.

Honing is not terribly necessary, especially on a low mileage engine, but if your engine has a few miles on it, I would worry about the rings not sealing. That being said, James Chan had excellent results with his Type S pistons and no cylinder honing.

If you want to do it quick and dirty (which I wouldn't do myself), you would have to:

1. pull the head.
2. drop the oil pan.
3. remove the pistons and rods.
4. replace the pistons and install new rings (be sure to check piston to cylinder wall clearance and ring end gap)
5. install the pistons and rods.
6. check clearance on rod bearings.
7. install oil pan.
8. install head.

This is a basic outline. There's more to it, but you get the idea.\

Keep in mind, it will cost you $250+ in parts just to replace the pistons (head gasket, rings, timing belt, tensioner, valve cover gasket, etc. etc.)

Vapor · 03-04-2003, 09:45 AM

Christ, what a PITA. Well then what's the point? If I have to pull the damn thing anyway, seems silly to just do type S pistons, may as wel go whole hog while you have it out.

Anyone had a shop do it in car? Costs and timeframes?

Sorry, I'm a little bitter that my "That seems easy enough" idea just went down the toilet.

Vapor · 03-04-2003, 09:53 AM

Would it be easier to mill the head a bit to bump up the compression? That just seems like a more drastic, no turning back solution. But now it seems like it'd be easier and I could always trade someone for the stock head I guess...

Opinions wanted...

mcgill · 03-04-2003, 01:59 PM

yeah i was also thinking about dropping some new pistons and stage 2 cams in my car.. didn't know it was such a *****

yohan420 · 03-04-2003, 02:59 PM

Me 3 with a h23 --> h22 upgrade.
What about octane on even a stock type-s engine?

71dsp · 03-04-2003, 07:53 PM

Milling the head is an option, but keep in mind that it retards the cam timing, so in order to restore the cam timing, you would have to install cam gears. It's also a modification that cannot be un-done, so once it's done, it's done.

19924ws · 03-05-2003, 11:32 AM

Not to mention that it won't raise your compression to a type-s piston level. You'll be able to get .1-.2 increase.

ar5enal · 03-05-2003, 12:14 PM

There's also the type A/B cylinder stamp problem. From what I know, cylinders may have come from the factory bored out a little (less than overbore) to make up for casting inconsistencies in the block.

You won't know what the situation is with your block until you lift the head. The cylinders should be stamped nearby with an A or B. If you have any B cylinders, you would need the appropriate type B piston.

Here's the problem: "B" type-S pistons are extremely rare, and you usually need some combination of them (A,B,A,A). If you have any B cylinders, you may as well get a whole set of oversize type S pistons and bore your cylinders out a little

HTH

71dsp · 03-05-2003, 02:42 PM

Also keep in mind to bore the cylinder, you have to stip the block BARE. You CANNOT bore the block with the engine in the car. Everything has to be stripped off the block, the cylinders are then bored, then everything is cleaned up. By the time you are through replacing bearings and seals, you will have essentially a brand new engine.

schwett · 03-06-2003, 02:09 PM

Quote:

Originally posted by 71dsp
Also keep in mind to bore the cylinder, you have to stip the block BARE...

and for those of you considering this route, don't understimate that amount of time (and parts!!!) it takes to get your engine to this state :

and back again.

yohan420 · 03-07-2003, 11:59 AM

any answers about running octane on a stock type-s ? will 90/91 work? or is 92 preferred or .. ?

Ritteri · 03-08-2003, 11:45 AM

ANother thing too, the JDM type S piston valve reliefs are at a slightly different angle than the US counterparts. So clearance is vital. The best route to go would be to get a JDM head to go with the pistons. Otherwise I personally think its a waste of time. Since the valve reliefs angle is off, so is the potential for detonation greater since they werent designed for the US head. If your going to go to this much trouble, better off getting a forged set of pistons and resleeving the block. Just swapping out pistons for a slightly greater CR is a waste of time and effort. If you want a higher CR, then just get a set of S2 HC valves which will raise the CR up about .5 . Reworking the had can also afford you another .5 of CR for that 11:1 you are looking at possibly. And its a much better route than breaking down the bottom of the motor. If your going to go to the trouble of redoing the block, then wait until you can get sleeves,rods and pistons.

Forbidden · 03-09-2003, 05:59 PM

Do all JDM head have a different valve angle or just the Type S?

TimeRacer · 03-09-2003, 06:58 PM

I forget what the USDM valve angle is but the JDM valve angle is 60 degrees. I don't think that there truly would be a clearance issue unless you're running oversized valves or a very high lift cams.

bb6flier · 03-10-2003, 09:09 AM

Well before you get worked up about "A" and "B" pistons you will want to measure your block. I had a "B" piston in #4 cylinder but the bore was the same as the others. Suposedly the difference is only 0.01mm smaller for the "B" pistons, the over bore pistons are 0.2mm larger than standard by comparison. So just because you have a B piston doesn't rule out the possibility of a good rebuild.

Forbidden · 03-10-2003, 05:14 PM

Or you could always get all A pistons and overbore the B cylinders a bit.

precisionelite · 06-26-2004, 09:49 PM

Quote:

Since the valve reliefs angle is off, so is the potential for detonation greater since they werent designed for the US head.

What does the valve relief angle have to do with detonation?
-Greg P

bb6flier · 06-27-2004, 11:59 AM

The valve angle they are referring to is one of the seat angles, not the entire valve it's self. The JDM heads are pretty much the same casting as the USDM heads.

Mike95lude · 06-27-2004, 08:04 PM

Here's a page that highlights the differences between the Type-S Prelude vs. all other models:

http://asia.vtec.net/beystock/honda/preludes/

Quote:

The valve seat was re-adjusted from 60 to 45 degrees.

Also, in response to Ritteri's comments about using a JDM head to avoid this problem: that won't do anything, because this article is saying that ONLY the JDM Type-S head has the 45 degree angle valve seats. Meaning all USDM H22's and JDM H22A's (excluding Type-S) have 60 degree valve-seats.

So my question is, is there a way we can change the valve seats to be 45 degrees just like the Type-S head on all other H22 engines? If not, is this really going to be a problem/drawback when using Type-S pistons?