Could someone explain this for me? For a week, I've been to various boards and people all say the same thing, that you cannot use forged pistons with the stock (nikasil) sleeves. But no one gives an answer why. I just can't be satisfied with people saying, it won't work when no one can give me a reason why.

Here's the reasons people have given me so far:

Calling various companies, machine shops, and asking at disc boards like this, here's what I've gotten:
1 - JE Forged pistons have too much clearance and nikasil sleeves are too tempermental
2 - Nikasil sleeves that come in the h22's are only 0.07mm in width so unless the piston is a perfect fit, you'll have to hone and then you won't have any sleeve left
3 - Going turbo with forged pistons will warp the cylinders. (ok, but this has nothing to do with the sleeves...this is more a problem with how you cool the engine...as long as you can keep the engine cool, the cylinders will be fine)
4 - The two metals (forged pistons' aluminum and the nikasil sleeves) are incompatable (and what does that mean?!?! do they corode?)

So as you can see, I got so many conflicting answers and I don't see any hard evidence to WHY you can't use the two together. I just want a real life example of why it doesn't work and good reasoning to back it up.

 

...in 1997 Honda decided to use FRM [Fiber Reinforced sleeves which are a combination of Carbon Fiber and Aluminum Oxide, which is a very cleaver component b/c of its resistance to oxidation and higher wear resistance vs. cast iron liners/sleeves]sleeves instead of cast iron sleeves like they do in all the other motors. The reason they did this was to make the motor lighter and to add cooling capacity to the block; as heat transfers b/w the FRM sleeves and the surrounding water jackets w/ greater efficency than the corresponding cast iron sleeves do. However, b/c the FRM sleeves do not have the same lubricative or oil retaining properties as cast iron sleeves, Honda added a layer of Nikasil coating onto the FRM sleeves which provided greater lubrication and reduced friction w/ the cylinders by a great deal. So, to summarize, '97+ h22 sleeves are FRM sleeves or Fiber Reinforced Sleeves made of Carbon Fiber and Aluminum Oxide, plus others, that is later coated w/ Nikasil to reduce friction!

Now, forged pistons are in fact too hard to properly seal against the FRM sleeves, and will ruin the Nikasil lining and overtime the FRM sleeve as well. As far as Nikasil being too tempermental, I would ask them to explain that to you. Also, call the shop I told you about, they have a lot of h22 info.




[Modified by bb6h22a, 3:47 PM 1/30/2002]

 

That's what I've "heard" also. And I used to be a strong believer in this to the fullest extent. However, member sgT and I had this conversation yestreday actually.... what we came up with was inconclusive. Has anyone SEEN the long term effects of a forged piston in an H series block? I know I havne't personally, so how can I say for sure one way or the other? Its all logics, but where is the hard proof?

Also, another thing we discussed is: What are the differences in the sleeves and composite of the sleeves between an H22A1 and an H22A4?

A good question that again, I haven't seen hard proven evidence about.

 

Wow, didn't know you're on this board too. Well, I actually just read your post in hybrid forums right after I posted that. Thanks again for your help.

 

Looks like in '97 the NSX also got these FRM sleeves and this explains why and how the sleeves, work and states that why forged aluminum pistons are not reccomended:

To increase the displacement of the 1997 NSX to 3.2 liters, the bore was increased from 90 to 93 mm.

Despite increases in horsepower and displacement, engine weight was reduced by 2.4 kilograms. To achieve both light weight and durability, the block is made of aluminum alloy. The cylinders on the new 3.2-liter V-6 are now made using an advanced metallurgical technique called Fiber Reinforced Metal (FRM), in which an alumina-carbon fiber is cast into the traditional aluminum alloy for enhanced rigidity. This process not only allows displacement to be increased without increasing bore centers, it also provides outstanding cooling characteristics.

The NSX's block has cylinder bore surfaces consisting of an 0.5-mm-thick layer with fibers of carbon and alumina (aluminum oxide, or Al2O2) in the aluminum alloy. In production, the cylinder block's aluminum alloy is poured around cylinder cores composed of these two fibers. The cores absorb the molten aluminum during the casting. After casting, the cylinders are bored to a slightly smaller diameter than the cores, leaving a tough, wear resistant, composite cylinder wall integral with the block but reinforced by the fibers. The process allows larger bores within the same external block dimensions and bore spacing, and makes open-deck block construction possible. In turn, this is appropriate for the new NSX engine's higher performance level. And with the elimination of iron cylinder liners, the reduction in engine weight by 2.4 kilograms was made possible.

In engines with steel cylinders, conventional aluminum pistons are normally used. Because aluminum-on-aluminum is not a satisfactory combination for durability with a piston sliding in a cylinder, the NSX's aluminum pistons are given an iron coating.
The information above was taken straight word for word out of the 1997 Honda published NSX tech update!!!

There you have it, the FRM sleeves have as an integral part, Aluminum which will not provide proper sealing when combined w/ a forged aluminum pistons, hence the comment about the piston sliding in the cylinders! That's why the pistons are coated w/ IRON!!

Also, this is very important, the Nikasil that everyone talks about is only a coating that is placed onto the surface of the FRM sleeves that come into contact w/ the pistons to reduce friction. The Nikasil is not, not what the sleeves are made out of, everyone please remember that!


[Modified by bb6h22a, 4:13 PM 1/30/2002]


[Modified by bb6h22a, 4:32 PM 1/30/2002]

 

Good answer, like I said, in logic it has always made sense... I'm looking for proof. I'll always sleeve an H series block before I put in forged pistons, but if I'm going to tell anyone that they HAVE to sleeve it, then I want to be able to pull out a fact, not a Honda theory. Does that make sense?

Also, about the differences between the A1 and the A4........................... ?

 

I meant in sleeves, like we've been talking about.

 

Well we'll see how it affects it because I will be using JE forged pistons on my stock sleeves.

 

All dohc 92+ preludes have FRM sleeves.

 

..then the information applies uniformally. But, why are the FRM sleeves only mentioned in the newer generation of h22's?

 

The Helm's mentions FRM in pre 97 cars.

 

..regardless, then the explenation above still holds true. How about the Nikasil, and do you own a pre-97 Helms?

 

Backing that up, helms does mention it!

 

Well, then all 92+ h22's are covered and I'm guessing the h23's as well?
Anyway, so is everyone satisifed w/ my explanation(s) above?

 

Yes, I have a '95 Helms.

Nikasil is not mentioned.

It says in the engine description "The cylinder block is made of aluminum alloy using FRM".




[Modified by Inlinefour, 7:18 PM 1/30/2002]

 

Yes, the H23 has FRM sleeves as well. It mentions it in the honing/boring part of the Helms.

Satisfied with your explanation? Not really. I have heard SO many different things about the stock sleeves, many of which you went over.

I don't want to speculate on the subject.

 

https://honda-tech.com/zerothread?id...=847019#847019

I think that we've all come to the conclusion that we would like to see some long term 50k miles plus test results.

Nikasil and FRM are two different technologies for cylinder lining. They don't work together.

 

I have not seen the long term effects of it, but I have seen the short term effects. A newly rebuilt motor with JE Pistons and stock sleeves locked up after a couple of minutes of running. The cooling and oiling sytems were working fine. The rings scored (sp?) into the cylinder walls and locked up. All the cylinders were damaged.

I spoke with JE and Wiseco about this. Wiseco told me that with their pistons, you did not need to resleeve. When I called JE and aksed them why I needed to resleeve with their pistons, and not Wiseco, the JE rep replied "Well buy the damn Wiseco then". That is what I plan on doing, however, I would still resleeve even with Wiseco.

 

All I can dig up in the 1993 Helms are the H22a1 sleeves are FRM, but I don't know if they are nikasial coated.. It says Says nothing of nikasial?> I wonder why.. But because it is aluminum/alumina fiber mix, you cannot put forged aluminum piston's, they will just eat into each other...

 

You will need to re-sleeve the motor. Here is why. ALL H-series motors have a nikasil coating on the sleeves. When you want to put in different pistons, you would normally want to hone the motor out to get a good surface to have the new pistons slide and seal on. When you hone an H-series motor though, you will loose the nikasil coating, hence exposing the FRM. The FRM by itself is not a good surface to try to get the new rigns to seal on. It will wear excessively fast and can very eaisily gall up on the new piston's skirts. However, if you do not hone the motor out and you just want to install new pistons, almost all of the aftermarket piston manufacture's rings are NOT compatable with the nikasil cylinder wall. They just won't seal like they are supposed to. Here is a good rule of thunb:
Hard cylinder wall ( nikasil ) , soft ring set!
Soft cylinder wall ( standard ductile iron ) , hard ring set.( the standard of almost all piston manufacturers )
This is the rule that I have learned talking to the experts at JE, ARIAS and ROSS. This way one of the surfaces can wear into place and keep the combustion contained on top of the piston instead of having massive amounts of blow-by that can ruin rings, cylinder walls, and shorten the life and performance of your motor. Just a rule of thumb. If you want to try it though, please by all means do so! I wouldn't recommend it, but keep us up to date on what happens.

 

One point I would like to make.
The B20B/Z uses an FRM 1 piece sleeve. So many people are boring/honing
these blocks and using aftermarket pistons of all makes and sizes.
Why are there no problems with those since the sleeves are the same material?

 

...and we're back to where we started again. anyone?
Do the b20's also have nikasil sleeves? What about pistons? Do the h22/3's have different pistons compared to other common honda pistons? (if we follow the rule of keeping the combination of hard with soft)

 

this is interesting ****....but we're not getting to any conclusions

 

The Question in my mind is how much would both solutions cost?

First: Get the H22A block sleeved and go with forged, which i would like to see some pics on, if anyone can supply.

Second: Go with iB Spec Weisco Pistons with the slip skirt design that wont damage the nikasil and FRM design. But unforetunetly this design is not proven over long periods of time.

If am i missin anything plz let me know.

 

Then why does a magnet stick to the cylinder walls on a b20 engine and not on a h22a???