Advice on 2.0ltr DOHC VTEC (F20B)

[joewalsh86]

Hey Guys,

Firstly, sorry for the long post, but i felt it was necessary.

Been a member for a while now but this is pretty much my first post. As a bit of background, I've spent the past few years saving for a b-series transplant into my ek civic (tough thing to do when at uni). My original plans were to stick a b16 in there, then build up a b20 block on the side. This, in my opinion, seemed the most cost effective way of hitting my 135-140kw n/a (at the wheels) goal. For reference, this is my current, all motor aim.

Whilst talking to a local mechanic about the advantages and disadvantages of the b20 block, he suggested looking into the F20B accord sir-T engine (of which he knows little about).

After doing some research, it appears like the F20B is a competent platform to build from. Iron sleeves, 85mm bore 88mm stroke (good r/s ratio), high compression (11:1 i think), type-s h22 cams, stock 3-angle valve job, well built internals, and a rev-happy nature. Importantly for me it has the potential to be mated with a B-series tranny with the H2B kit. From the limited amount of information available on it, it does appear that simple I/H/E upgrades can yeild fairly decent power and come within my goal.

I know there are a number of posts on here about the F20B, but i haven't found much information on possible upgrades.

On a side note, I do not feel that i have the money or resources for a k-transplant, so please do not bring that up. Also, I do not have enough money for serious head porting or block re-sleeving. Due to a friend having reliability issues, h-series is also not on the cards. A B20vtec (84-84.5mm bore) with decent internals and head bolt ins, or this F20B are my two viable options. There is plenty of info out there about the b20vtec, so no need to discuss that here.

My questions relate solely to the F20B. If i decided to go this route, does anybody have any information on possible options to upgrade? I would want to look at whole valvetrain upgrade, intake, a decent header and exhaust. So, due to the limited products available for it, i am really looking to see what h-series and other engine parts can be used on it.

So, in simple terms:

My goal = around 135-140 atw kw
Application = daily driver with occasional circuit use
Requirements = high end n/a power (it is alrady a considerably lightened car so low end torque not hugely important)

At the moment, a b16b will be going into the car in a few weeks if i cannot find any information on the F20B.

So,

- Can h-series cams be used in the head? (i am of the opinion that they can)
- Can h-series valves and springs be used (i do not think that they can becuase of increased port diameter in the h-series)
- I have also heard that the intake plenum on the F20B is different to H-series plenums - anybody have any information here?
- How different are the h22a and F20B head castings and what are the advantages (if any) over the h22a head?
- Can the h22a head be mated to the F20B block (i am under the impreesion that it can)

I have searched all over the web for a solid source of information on this engine. I am relatively inexperienced with engine internals so if i have got any of the facts wrong, then feel free to correct me. If it appears as thought i'm a little niave about engine tech in general.. it's becuase i am. So any constructive help would be much appreciated....

regards,

Joe

[Samo]

Jase_ek has one in his ek1 .. might pm him for info ..

stock F20b in a lighten ek with I/H/E and ecu would kick as already

f20b is revier than h22 .. why would u want h22 cams??

[d15z1SUX]

i think he meant aftermarket cams that fit a h22. hes wondering if they will also fit the f20b.

[joewalsh86]

Yeah, in case i wasn't clear before, I'm wondering if aftermarket h-series cams will fit into the F20B head and if so, what supporting valve train would be necessary to run them.

Also, does anybody have any information on any difference in weight, if any, between the H22a and the F20B?

[Jase EK]

Jase_ek has one in his ek1 .. might pm him for info ..

stock F20b in a lighten ek with I/H/E and ecu would kick as already

f20b is revier than h22 .. why would u want h22 cams??

Samo is correct
i have f20b with I/H/E and hondata all in ek and car kicks ass:thumbsup:

[flipstar]

yeh 4 sure the f20b can rip up the road but you need to look more at the after market aspect of it if u went with the b20b route there is alot more after market support in parts and knowledge where as the f20b is rarely done and hard to find parts as well as people who can help you if problems do come up if u want qwik power jus drop a h22a in there or jus go wit d b20b i got a b20b and that has so much torque as well and it can keep up to h22a civics as well

[d15z1SUX]

wonder what the stroke and bore of the f20b vs b20vtec is. and their power delivery?

[joewalsh86]

From what i have found:

F20B
Stroke = 88mm
Bore = 85mm

B20vtec
Stroke = 89mm
Bore = 84mm

I'm not sure what the redline is on the F20B - maybe Jase EK can let us know, but given the ability of the b-series to carry power past the 8500rpm mark, i see no reason by the F20B could not do the same if not better.

I believe that the engine was originally desined for Mugen to use in the JGTC series and also used in BTCC because of 2.0 ltr restrictions. As a result, the engine is overall very well engineered and was the platform for the later F20C (S2000). The crank has 55mm mains like the 98+h22 but with smaller rod journals that are closer to b-series size. The rods are also aparently quite beefy.

All in all, this should be a more than capable all motor platform. But aftermarket support is my only concern - any input here - pistons, cams, intake manifolds?

Maybe custom is the way to go?

[Jase EK]

glad to see someone else got their eyes on f20b
just quick run down from wat i know, first off when i got the puppy in, yes it was fun to drive around, good power but ended at 7500 i recall, so 2000rpm vtec wasnt enough for me lol but the torque was nice. so later on track when i saved up money, i purchase DC headers, skunk2 pro intake and hondata s300. and got it all in and tuned and made 130kw at wheels, very happy i was and suprised now the bad boi redlines at 8ish, was told by tuner and can see on graph it still was making power till 8000. If you do your research you find out that the f20b is a great engine for the price. PM me if your looking, i know where theres some or might even sell mine :)

[barefootbonzai]

Due to a friend having reliability issues, h-series is also not on the cards.


That statement would make no sense, if you're wanting a F20B and not a H22. The F20B is pretty much the same as a H22, just the 2L version. Built to rev a little more, is less seen around and comes with a blue valve cover, lol.

Either way, both of these are great engines.

As for aftermarket support, generally most things you can fit on a H you can use on the F20B.

[joewalsh86]

agreed barefoot, the two engines are very similar and i do not doubt the h22 is also a great platform,

but the engine dynamics suggest more than simply a destroked h22a - there are a few more trick little features which make the f20b more appealing to me. For instance, i've heard that the h22a doesn't like forged pistons due to the FRM sleeves (correct me if im wrong) - but the f20b uses iron sleeves so forged pistons shouldn't be a problem.

And as i've said before, i belive the port sizes to be different in the heads - meaning that the valves are not interchangeable between h and f20b. Also, with different bore dimensions, h22a pistons will not fit - i do not know where i could find some that will though

[grumpy rooster]

You can always get custom pistons made up. Not cheap but there is always that option.

[burma]

how much are these engines? seems like a very good engine,
130kw at wheels from I/H/E and ecu is really good Jase EK. have you taken your car down the 1/4mile Jase?

[joewalsh86]

have a look on ebay.com - the one i have my eyes on is from the manual accord SIR T and is costing me around $2000. I am only buying the engine becuase i want to use an H2B kit, so i'm using mainly b-series parts for the swap.

I'm still a little unsure about whether i shuold do it. Jun and Skunk 2 do cams, springs and retainers. i've also found out that the Euro-R manifold is worth a go once some further headwork is done, and a header shouldn't be a problem.

My concern is raising compression and finding a set of 85mm pistons that will fit. I don't know if there are any head gaskets available for this engine or valves, and if i ever need replacement parts then i'm going to struggle.

Still looking for some info on valves and head upgrades if anyone has any input!

[siksivic]

Dont quote me but i THINK Jase did something like a 13.4 or 13.5 on the quarter from memory... however this was sometime ago so im not sure if this time has improoved.

[Jase EK]

it is very hard to find info on the f20b, however from my knowledge the h22a valve train will fit into the f20b, but if you plan to fit wild cams make sure to check valve clearance i read up, i think the valves are different too, the pistons you can find but con rods will be custom and pretty much everythin else u can use from h22a, oh and h22 head gasket will not work for f20b, if you need help finding parts for the f20b let me know