"FRM sleeves are bad." Why? Someone please explain this.

[deevergote]

For years now, I've been told that FRM sleeves are bad... and for a number of impressively false reasons!

I'm hoping to get a discussion going as to why this is. I'd like to see some intelligent responses here. I'd like to compile a list of any genuine downfalls of FRM sleeves (there are some that aren't total BS.)

Please research and know what you're talking about before you reply.

[Jarrett]

I don't think there are many points at all as to why an FRM sleeve is bad. If so, they wouldn't be used by some of the most expensive cars that people purchase to drive daily. They can simply handle some abuse!

The gripe against FRM cylinders is not a fair one. You hear it the most with H22A guys. They want to turbocharge their engines but the pistons are weak and need to be replaced. This creates a separate issue because any piston that they could buy, with the exception of one still largely unproven option, is not going to be compatible with their FRM sleeves from a metallurgical standpoint.

So, since FRM sleeves are not compatible with trying to get by doing things the cheap way, they take the brunt of the bitching. Thus the popularity with putting an F22A/B or F23A block underneath an H22A head.

One factory piston that could be an option is the piston from an F22C. The F20C piston would work as well but it has a slightly larger dome to get the same 11.0:1 compression ratio from a much shorter stroke. Anyway, the F22C piston is FRM-compatible, it has a 30mm compression height(1mm shorter than the H22A), it's an 87mm bore and it's factory forged. The downfall to this piston is that it uses a 23mm wrist pin as opposed to a 22mm pin used by all other F/H/K-series pistons.

[Stoner51]

I don't think they are bad.

From my reading it has to do with the rings and pistons. I believe the frm sleeves are basically too hard of a metal and causes the other components, piston rings to wear prematurely causing oil burning and lower compression.

Everybody knows I am no expert. But I do know that from working in orthopaedic for 20 years that harder metals will cause softer metals to wear.

That's just from the research that I have done and the reading on the net

Steve

[sonikaccord]

Well what does "bad" mean? Are they fragile, brittle, weak? Are they not malleable? I think it's more along the lines of what Jarrett said. People don't like them because they have to work around their "weaknesses."

What type of fiber is used in the metal? I'm assuming some sort of carbon based material.

EDIT: It is a carbon fiber matrix:
http://honda-tech.com/showthread.php?t=2196081

EDIT:EDIT: Good reading here:
http://books.google.com/books?id=sfs...istons&f=false

[Raf99]

Ya, have to agree with the above statements. You don't hear people who do turbo builds properly (or expensive) complaining about their sleeves. Its always guys saying they tried X piston and it didn't work, blaming the sleeve.

I guess more people express their complaints online, meanwhile the people having zero issues because they build their build proper and reliable are cruising down the drag strip worry free. So in the end all you see are people complaining about sleeves messing up their cheap pistons.

I am no expert, but I do have Darton sleeves in my block with Aeries pistons.

[thumping_accord]

FRM sleeves are rather good sleeves, like Jarret said if they were bad why would some higher end cars use them, like porsche?
One downfall that I've come across is that to bore them its a whole completely different proccess from standard boring which then limits the amount of shops that can actually bore these motors. But as I stated thats just a downfall, I wouldn't calssify the sleeve as bad just because of that.

[Ralphie]

There are no bad FRM sleeves, just bad tuners.

[JDMDriver]

Its a new concept largely misunderstood causing grief to some that judge based on the normal expectations and they in turn vent their pain in anguish in the process of understanding and coming to terms with this new design.

Much like the oldies complaining about fuel injection and how carburettors were better because their knowledge base is more so on the familiar rather than new which gives them grief from learning curve and reshuffling of approaches methodologies supplier contacts etc etc to deal with the new set of problems of this new concept of FRM.

It is a relatively new concept and it being "Bad" is dependent on standpoint. As with all things new If you know what you are dealing with, know how to overcome the problems then its not hard. But I can see why it can be the case for many people and then form their negative opinion bout it.

[CyborgGT]

FRM sleeves are rather good sleeves, like Jarret said if they were bad why would some higher end cars use them, like porsche?
One downfall that I've come across is that to bore them its a whole completely different proccess from standard boring which then limits the amount of shops that can actually bore these motors. But as I stated thats just a downfall, I wouldn't calssify the sleeve as bad just because of that.

Not only is the process different, but there's quite a fine limit on how much can be machined off when you're replacing piston rings. Personally, I've always believed in the strength of FRM; I'm re-sleeving mine, but only because one of the cylinders is scratched.

HondaTuning, R.I.P., ran an article a while back

[deevergote]

I wouldn't really say it's a new design... FRM sleeves were being used by Honda in 1990! It's only one year newer than VTEC (which has been largely embraced by most Honda enthusiasts.)

This thread has turned out to be less interesting than I had hoped. I really wanted to see if there was any actual technical argument against FRM sleeves! You guys are doing a great job of defending FRM (in some ways that i haven't even thought of myself.)

The inspiration for this thread was a Facebook discussion that I stumbled across. A number of people made the usual idiotic "I read it on the internet so it has to be true" arguments, such as the sleeves being weak. There were a few that posed the "FRM causes oil consumption" argument... which I normally argue with the concept of engine health and maintenance (I've never noticed any significant oil consumption in my H22A).
One person did mention an interesting point, though... in regards to the H22A specifically. He said that the H22A's FRM sleeve material is thinner than the material found in other "better" FRM-equipped engines, such as the engines found in the NSX and S2000. I'm not sure how much merit there is to that, seeing as I've never even attempted to hone or bore an FRM sleeve... but it's interesting nonetheless. I'm curious to see if anyone can actually confirm that, and if the thickness actually does present a weakness in the design. To my knowledge, FRM can't really be bored, and it can only be honed very lightly... but it is also not supposed to become worn out with proper use like iron sleeves do. If it doesn't wear down like iron, then I'd have to argue that the thickness isn't an issue.


CyborgGT touched on the only TRUE weakness that I recognize in FRM sleeves... the fact that if they get damaged, they're pretty much shot. Score up a sleeve with a damaged piston, and there's no bringing it back.

[cb7 calling]

Iron sleeve honda 4 cylinder motors burning oil beyond a quart every 1500-2000 miles are the exception.
Fact:h22's and especially b21a1 motors burning oil are the norm. I don't think we have enough examples of high milage nsx and s2000 to really judge the piston rings in those, but I know the s2000 has forged pistons so it's a slightly different scenario.

[Domesticated]

In regards to the oil burning. I changed my oil back in December. I've driven 6000 miles since then including my 2200 mile move last week and my oil level didn't noticeably change.

[Flip-Eye]

Only experience I've had with FRM sleeves were those in my 91 Prelude SE.

If I'm not mistaken, the B21A1 (90-91 Prelude) was the first north american honda engine to use FRM.

Granted, when I got the car it had already 200-250k mms, but the thing consumed ungodly amounts of oil, I'm talking like a quart per tank of fuel.

I never was able to pull the motor and open it up, so I can't say what condition the components were in.

Thinking back, I wish I had kept the thing.

Anyways, this is an interesting thread, and I'm interested in hearing people's reasonings and knowledge on the subject.

[NTYPE]

I probably wont add much new to the conversation other than my own thoughts..
I believe that the oil burning issue is more due to piston skirt & ring wear than wear of the FRM sleeves themselves. Remember most of the 1st gen H22's are getting on 20 years old now and getting up around 130k mi on the clock and as its a sports engine, in most cases will have been thrashed to some extent in its lifetime.
As stated in the Helms manual FRM sleeves Can be bored out but only 20thou over - thats why you can only buy H22 pistons from honda in standard size or 0.5mm over . The boring and honing process is different to that of a standard bore job and requires a particular set of tools which not all "John Smith engine rebuilders" will have in their inventory. - I suspect this contributes to why people are anti FRM, because its just not that simple. It's also possible that some of these shops arent following the proper procedure for FRM and doing a substandard job which ends up in engine failure further down the track, this is only speculation however.
Also the procedure for re-sleeving is different to that of a normal motor, its not just a case of heat up the block, press them out and press in the new sleeves. I believe the original sleeves need to be machined/milled out before the new set can be installed. This adds to the cost and difficulty of the job.

Basically I think it all boils down to the same recurring theme which we see daily on cb7tuner "Do it once, do it right","Buy quality, dont buy cheap shit"etc etc, FRM sleeves are great if the time/money is spent to do the job right. However some people cheap out, or just dont do their research, and slap together their engines and run in to problems down the line.

I guess this can be seen as a good argument as to why FRM IS BAD, not because its unreliable but because its harder to work with and more expensive, and theres just not enough engine shops out there with the experience and tools to work with this technology. Not to mention poor compatibility with regards to forged pistons..

[evil_demon_01]

FRM was designed as an OEM feature (but still designed knowing that Friction is inevitable)

We all know modifying things creates problems, Classic case is Stock F22+Boost leads to cracked ringlands . . . Eventually.

However in its factory state (keep in mind engines DO actually have a calculated lifespan) doing 250K+ miles is impressive without any form of rebuild and still maintain impressive HP figures.



Inevitably though -
We are talking about few thou (of wear) for a piston ring that does approximately 50 cycles in a single second at 3000rpm (Average cruise speed)


IMO most H22s, B16s and B18s I see are well above the 250k mark nowadays.
Reality is, Yes they burn oil, Yes the rings are likely worn, And I have genuinely told customers the engine needs a rebuild.


BUT - that doesn't make FRM sleeves bad. Its simply a general wear and tear, No different than a clutch, or valve guides.

Think of this:
3000rpm cruising speed = about 50 piston cycles per second.

@3000rpm & 100km/h = takes ABOUT 1hour.

So 250,000km (odometer) worth of driving is about 2500 hours.
That works out to 104 days of constant driving.


There is 86400 seconds in a day;
And a piston goes up and down 50Xper second @ 3000rpm

That makes . . . . 4,320,000 piston cycles in 24hours.
Hmmm and 250k = 2500hours.

((I'll round it off (plus 1 hour because its easier)

If I calculated it right, That makes 450 million strokes . . . .And THEN it starts to show wear . . .
OF ONLY A FEW THOU
Pretty impressive if you ask me . . .






And after all of that - Who says the sleeve is bad . . . Not that the rings are worn . . . .