[ReyKe]

Well I recently did a trade with a friend and come to find out he dropped off with me a low mileage b21 block, so I do what any other inquisitive individual would do and decide to tear it down and see what makes this so different, the biggest thing I notice right off the back are the cylinder walls, I have torn down, rebuilt, or at least seen the internals of every honda engine, and this version of the FRM sleeves are the most interesting and unique of the bunch. I can honestly say that this is the only block I have seen with the sleeves like this. The honest and only good thing I can see of this block is that it will have fast ring seal and break in period. In all honesty if I was aiming to build an engine that would only last 50k at the most under a life heavy abuse and pushed to its maximum performance this would be the block bar none and I wouldn't touch the sleeves. Also I have some jdm B20A piston and rod combos, I'm taking one of them along with the b21's to get a weight comparo to see if the necessity for the lowered rev-limit on the b21 is really that necessary, or did Honda just freak out. Also I noticed that the block is stamped as a PK1, and the rods are stamped PK2, only the pistons and the IM are stamped PK3, the head may have PK3 as well but I didn't notice nor did I look into it. Also I will be dynoing this setup to see what I can pull out of it, and then I'll be doing the same port and wolish work to the b21 head so if anyone would beinterested keep your eyes on Ebay, becuase I know you bastards would just dance around the issue of actually buying it, lmao JK.

 

[car_boy_16]

Alrighty! That's good youre doing so research on it....

As you already know, the reason that honda chose to use Fiber reinforced metal sleeves is because they wanted to keep the b20a block design. In order to bore the b20a block out to 2.1L's Honda felt that iron sleeves that thin would not do too well, it might crack or simply allow a piston to break through. They could have just enlarged the bore and kept pushing the outter diameter of the sleeve into the water jackets more, this would obviously bring the cylinder sleeve strength up to par but it would also risk cooling ability, or lack thereof.
So in order to retain the same cooling jacket capacity around the cylinder sleeves they decided to go with the then-exotic material we know as FRM (More generic name: Metal Matrix Composite, manufactered by Saffil).

Recap: Honda used FRM sleeves to retain the ability to use the b20a block design while enlarging the bore from 81mm to 83mm. It was most likely an engineering decision brought on in order to 1.) keep the block the same design 2.) to not make the engine bay more cramped due to total redesign (if they chose that route). 3.)not have to redesign the block they most likely have the redesign the crank, head, intake and exhaust manifolds....and that would cost a hell of a lot.

This is just my take on the thinking behind Honda when it comes to applying FRM sleeves to our b21's.
What do you think?

 

[Ghetto...]

Hmm, so it is a tradeoff. Better sleeves for oil burning engine. I love it. I still got my b21, probably will for a long time to come too. Is there any real way to stop the oil from burning up so fast or what? Its a good sturdy engine, thats all I know.

 

[ReyKe]

yeah there is a way to stop it from burning oil open it up get new rings and take a course grit cylinder hone and rough up the walls and you got another 100k on it before it starts burning again, also as long as you have them out you might as well swain coat your piston skirts

 

[Ghetto...]

Another 100k? It only has 78k right now. And I always heard that when you hone our cars everything gets fucked and then you need to get everything redone agian.

 

[Kalm_Traveler]

PK1 is stuff that was made for the dual-carbureted B20A(3). I didn't know that B21A1 blocks were still stamped that way.

PK2 is stuff that was made for the FI B20A's.

PK3 (of course) is stuff that was made for the B21A(1).

I do know that all of our B20A's have the same block casting, but this is definitely news to me that a B21A1 has "PK1" stamped anywhere on it. Now I'm kinda curious, maybe I'll go pick one up to play with hehe :twisted:

 

[ReyKe]

umm who said that, look when you hone the cylinders you do it with a fine/course grit so you dont put too deep of a cut becuase if you do then it'll take longer, and afterall the frm sleeves are soft enough that they break in quicker as it is. I'm not going to sit here and profess to be the one all knowing but I have worked with these particular cars and engines for awhile and have a good understanding of them, just on this trust me. I can tell you this a machine shop would say the same thing.

 

[car_boy_16]

If I remember right the honing stone has to be of a special material.

 

[88hondapreludesi]

yes car_boy thats right. are you sure your right on this reyke this has been a very killed topic on here many ppl have fucked up there cylinder walls (on the b21 of course) by honing it. honda says if you wanna hone it you need some special hone (and its very expensive from what ive heard) everyone thats opened theres up has said that the FRM walls have held up good and didnt need to be honed just new rings. The real problem is that we need stronger rings to keep up with the strong walls cus the walls are so much stronger then the rings that it eats them up.

 

[Ghetto...]

^^
Yeah that i what I ment. I knew I remembered people ocmming on here saying they just rebuilt the whole thing and it burnt oil just as bad/worse now. Something that hasent really been tlaked about to much either :?

 

[dano]

I doubt that the reason for using FRM for the B21 cylinder walls had anything to do with adding a few, very few, cc's to the displacement. I'm pretty sure the B21 was a test platform for future Honda blocks. Who better to use for "beta testers" than universally hated merkins.

:lol: :lol:

 

[mouchyn]

the stone required to hone the b21 shouldn't be any different than the stone required to hone any other FRM Honda block. The only difference is the sleeve material between the b20 and b21 as far as machine work is concerned. People who try to bore/hone the b21 as if it was a solid metal sleeve like the b20 and older "normal" engines, just destroyed the b21 sleeves. They will flake, chip and crack. I've seen it with my own eyes.

 

[SSkater]

he he he... i love the frm discussions.... do you guys realize how far 3genners have come over the last several years? for years it was said: you can't rebuild it... yada yada yada... yet it says right in the manual how to bore/hone...

he he he... ReyKe, i love ya man... can i have your beer?!

i have two b21s i use for mock ups... we have bore gauged both... i have never seen cylinders with so 'little' egg shaping... i love frm sleeves... we measure, keep in spec, hone the cylinders, and re-ring... good for another 100k is absolutely correct... i got 200K out of the originals...

and i have to say, i am glad someone else is singing the swain coating praises... after we get these other heads extrude honed, we are shipping them off to be swain coated.... having the pistons done as well (dome treatment and side skirts).... this is a great tool for managing heat in the turbo applications...

he he he...

m

 

[88hondapreludesi]

ya mouchyn thats what im saying I didnt mean special to the b21 just special to the FRM walls thats all

 

[buck19]

honda never freaked out about our 7100 rev limit. the reasoning is very legit. 99% of the domestic engines out there have a far better R/S ratio than that of the b21, but they peg out before 7100 in some cases. i have it saved some where, but theres an article that explains the importances of rod to cylinder angles and how you modify you motor according to them, with certain types of intake manifolds, plenums, TBs and even exhaust systems... it also inadvertantly explains how shitty our platform is for making high rpm power. not that it wont make it, but it just wont last with certain stress points as your rods, crank shaft, piston skirts (a big variable in long stroke motors) and cylinder walls with all of the side loading. you also have to take into concideration dwell times when dealing with modifications and timing issues.

sorry if i rambled but i am learning a lot from old timer engine builders.

 

[Kalm_Traveler]

be carefull what you hear from "old engine builders"... they know their stuff when it comes to small block Chevys or 351 Fords but in my experience most of them don't know much at all when it comes to aluminum 4-cylinder Japanese engines :roll:

 

[buck19]

um actually most of his business comes from 4 cyl toyota motors. i believe its the 22r or something like that. and those motors take one hell of a beating. he also builds the DART honda blocks from time to time.

 

[buck19]

his personal car is a 700hp all aluminum v8. your principals are the same when engine building when either it be a v8 or an inline 4.

i know youve heard of endyn before. that man, "the old one", knows how to build motors. he retired as a nascar tech a few years ago, and is a thermal and fluid dynamic genious. hes the one that built a now 1.5 litr SOHC VTEC crx that pushes 450whp on C16 with 11.5:1 compression while running 27psi on a modified jackson racing super charger. and to be quite honest i choose to trust him. and his car makes 350whp on pump gas. plus its his engine and parts hauler. it was showcased in muscle car magazine. thats right a wee little sohc crx made it into muscle car magazine.

 

[Kalm_Traveler]

um actually most of his business comes from 4 cyl toyota motors. i believe its the 22r or something like that. and those motors take one hell of a beating. he also builds the DART honda blocks from time to time.

I didn't say don't listen to any particular guy, so chill out.

The 20R, 22R (RE, RET) are all cast iron blocks. Dealing with an aluminum block necessitates different building techniques than those of an iron block.

And no, building a big iron pushrod V8 is absolutely nothing like building a little 2 liter aluminum OHC motor so don't even try to spout that kind of garbage. I have met more than enough engine builders who are great at one or the other, but if you learn engine building on an American V8, you will still have alot to learn about building a B18C5 and vice versa.

Once again, please take a chill pill and don't get all down my throat about some guy you don't even know having more knowledge about engine building than me. I have not said ANYTHING about me knowing anything more/less than anyone.

 

[88hondapreludesi]

Im pretty sure the toyota 22r is a aluminum block kalm. I use to have a toyota with one in the back yard till I ran the truck over with mine.