Swap - ET2 / A18 / B20A (JDM) / B20A5 / B21A : Head - A20A : Block

[Ichiban]

why not adapt vtec components to an a20 head?
the vtec system is dirt simple, it just switches between 2 camshaft profiles depending on rpm. im sure even a 3 valve head would benefit from that.

oil feed is simple, tap into a gallery and use a solenoid control valve. the hard part is making a cam with 3 lobes fit. I m not sure but the lost motion rocker could be made to fit the intake rocker shaft somehow? the vtec oil feed is through the rocker shaft is it not? might be worth looking into perhaps

[P|eszczoH]

I know that all of You can call me stupid,
but did anyone try to match our A20A block to the F20A head ?

it was SOHC also l but 16 valves, a little benefit from that i suppose.
and I'm not sure but there where some F engines sohc vtec i think.

I did not try this, and I have no idea that would it fit....
but F series engine looks more like A20 than any B series motor.

[Doward]

So what happened with the Prelude SI B20a head on the A20 block? The bolt pattern is the same.

Correct, 3G Prelude head. If you're selling the head, let me know - I'd be interested in it. I matched up the head gaskets - looks like it'll bolt down fine - it's a matter of where the water/oil goes.

[halxi]

What year doward?

if its a 86-93 (i think thats the end of the 3rd gen, 93) its not vtec. Thus canceling out the "a20 dohc vtec"

[NotSeen2000]

i know this may seem stupid but r there ne frankinstien swaps i can do wit my A20? its fuel injected and its n an LXi. is there like a head swap i can do with like a B20 or another DOHC motor?

so head swap is out. i dont hav the money 4 a b16, b16, or b20 swap. i would like 2 put a turbo on my A20 but 4 right now what could i do just 2 raise the HP enough 2 b satisfied wit. by satisfied i mean, b on the street and b able 2 at least HANG wit a modded civic(I/H/E and other little things) or CRX, or CB7(90-93 accord)?

nice advise man. somethhin i needed. i got a good enough job its the time im worried about. i can stand watin and probaly my problem. lol. but i might b sellin it ne way.but ne other suggestions on HP and TQ gains would b appreciated

lol. good point. id rather hav I/H/E on my car than get the crap beat out of me by a a20 wit N2O on it. I/H/E it is then. custom exhuast though b/c i dont like pacesetters exhuast looks 2 stock. ill get the headers though

the muffler on the pacesetters exhuast system looks like a stock muffler. i kno its rice but id rather hav the muffler from APEXi or HKS or somethin like that. looks better 2 me

[Swap_File]

I do not think any other heads fit on the A20, people have tried.

B series intake manifolds can be used with the A20, 2 of the bolt holes line up, but the other two need to be drilled (not a big deal).

[bobafett]

yeah b series intake will work, and a18 head, if u felt so inclined, but i think that head is really the same as the a20 head...
your best bet would be custom b-series swap, or just work over your a20

yaeh its definetly nothing that is worth pursuing! ;-)

if you dont have money man, dont put yourself in a financial burden trying to mod your car.... seriously.. nothing wrong with having a slow car or a stock car... plus if u dont have money for these things, i know you dont have money for the tickets you get from racing cars on the street.

just take it easy until u have some cash saved up , get a better job, or whatever needs to happen so that u have some disposable income.

yeah ihe will help a lot, but its stlil not anywhere near swap power.. but its a start, and its what most people do... good mods for the money!

[masterkillalw]

a18 head would have to be bored out to 2.0L...and a18 head would hurt more then help...

[phrenology]

and a18 head would hurt more then help...

Not According to Rjudgey...ask him and do yourslef a favor...and search!!!

[lostforawhile]

if you are going to go through that much trouble,why not swap a better fuel system onto the existing head? i mean bigger injectors and a different control system,you would have to swap more sensors and stuff but it could be done. if you get more fuel and air flow into the head you would be better off. i think the efi did has the top dead sensor and cyl position sensor in it these could be adapted to a different control system.

[3G Jester]

which one? h0ndavtec? the kid from mass with that turquose franken-hatch?

the more i look at those pics i relize it was photochopped.

Electronic Fuel Injection not carburated.
but he has an Ex so hes not in america and it should be the equivalent to a USDM SE-i. which means hes fuel injected. and if your not in america...for example the b20 here doesnt fit in the engine bay as does the JDM b20...so would the heads differ greatly? or could he still do a b series head swap?
where you at davke? your english is actualy very good. we have a member in russia (paul) and the translating program he uses is not so good...and his english is even worse. but hes a good kid. we like him any way hahaha.
accords. you might want to talk to some of the boys in australia, malyasia or even the guy we have in japan. they migt be able to score you some parts that would work. us US boys wouldnt be much help at getting you the parts you would need.
here are threads started by people who might be able to help you:
england with a20a4: https://www.3geez.com/showthread.php?t=46382
chris in japan: https://www.3geez.com/showthread.php?t=46906
NZ https://www.3geez.com/showthread.php?t=47631
australia https://www.3geez.com/member.php?u=131
rehv from estonia but he hasnt be on in ages...you could try and use MSN messanger to get a hold of him https://www.3geez.com/showthread.php?t=36500

[gfrg88]

is the b21 head vtec?? dohc?? has anyone actually seen this "swap" in person??

umm, which car came with a b21a1??
holy shit!! and this is the DOHC head right?? i might have to look into this pretty soon....
i think the h22/f22 exhaust manifold porta i think are the same for the jdm b20, atleast thats the turbo mani (h22) that adam has in his b20

[FyreDaug]

I/h/e?

Nitrous is good power, you get about 10-15 from a full IHE when done properly, typical shots start at about 50. So putting 400 bucks into a full intake/header/exhaust isnt as beneficial as spraying. A system could cost you about the same 400 bucks, and nitrous isnt that expensive anyways. On a 50 shot you shouldnt go through it that fast. Get a 10lb bottle and youll be fine. With a stock a20 you got about 115hp, b20 obviously have more, rev easier and are a better motor to work with, but spend 2grand on a swap to be beaten by a juiced a20 isnt justifyable. Since your EFI, its much easier.
EDIT: And you can spray stock

Looks too stock? What?


On a side note: Someone should replace the rings on those pistons, that doesnt look too healthy.
(Now me and the mad scientist godda rip apart the block and replace the PISTON rings ya fried)

[86hatch]

After I/h/e do some research on nitrous. I have a zex dry system on my 86 hatch and I love it. I can beat ls, b16 hatches all day long and bad too. I have a friend with a b16 in a eg coupe with toda spec A cams I/h/e and high comp head gasket. I can beat him by about 3 cars. Although I am building a 400hp b16 for nitrous to swap in my accord.

[davke]

i have soch 2.0i ex 12V engine. it is possible to put the cilinder head with 16V from B series engines?

A20A4...my head sux.. but why the each piston of this engine has four cuts for valves?

Yes you can.
I put my B21A1 head on an A20A1 block. (didn't actually use it, just aligned bolt holes, head gasket, etc)
It'll work. You'll just have to deal with getting things like the sensors to all connect right.
It'd be a LOT easier if your car was already EFI

whats EFI? , anyway 2.0 i ex A20A4 engine, my head isn't good enough - the oil is coming out always from the head. i am going to change the head and also wondering or will 16V doch fit on my block?
so, racerx , does the only B21A1 from prelude 90-91 fit on my block?
ps : i am terrible at english, i hope you will understand
yes, its fuel injection - 90kW. I NEED MORE!!
i live in Lithuania . The most bad thing in the east europe is RUSTING. 99% accords (86-89) are allready rusted and it is hard to find a good accord or performance parts.
anyway, i need more power ! so i need b21a1 head (Si)?? but i haven't seen anything about prelude 2.1Si (

90-91 prelude Si (not the 2.0Si)

maybe 90-91 prelude is SiR, not Si, Si is 2 litre, not 2.1
the head from B20A5?? would it fitt on a20 block???
mm, i dont know really, but i saw this http://hp3.lt/content.php?content.5.
anyway i need 16V, dohc. what head would fit on A20 block except B21A1? i can't get B21A1 head here.
in the accord! fuck damn, i got flustered totaly, i don't know what me to do.
v-tec? is it possible?
3rd gen of accords and prelude or only accords? anyway thanks

[snoopyloopy]

is that the a20 engine you're talking about or the f22? well, doesn't really matter because it won't work for either one. you can frankenstein an f22 with an h22/h23 head, though.

so you i can go out and pick up a b20a5 head and bolt that on my a20a3?

go look. not really that much reading. there's speculation as to cooling issues, which heads work because of the different bores. one of the fellows says he used a b20a gear on the a20 crank, but it has to be shimmed. and pictures show that you have to either mod your hood or run with no hood at all.

[snow_man_20]

good question, i would say for balance or equal compresion. mabie plug clearance?

[rjudgey]

Ultimate piston would b custom with two left handed and two right handed sut outs to maximise the CR ratio without having to have such a high rasied section on top of the piston, but as you said maybe a balance issue but would have shout unlikely as the inlet valve cut outs are smaller than exhuast but the difference is very small maybe not enough to efect motion of piston. Cost of manufacturing on this one i think!!

[accord_rcr]

i need, to know. can i swap out just my a20 head with a b20b head? is it a direct bolt on?

[Legend_master]

i need, to know. can i swap out just my a20 head with a b20b head? is it a direct bolt on?

no

so you i can go out and pick up a b20a5 head and bolt that on my a20a3?

if this were true I think alot of people would have doen thsi already. Also what timeing belt would you use?

go look. not really that much reading. there's speculation as to cooling issues, which heads work because of the different bores. one of the fellows says he used a b20a gear on the a20 crank, but it has to be shimmed. and pictures show that you have to either mod your hood or run with no hood at all.

I think the dowls need to be relocated for the oil. From what I can understand he had to have the head machined just as I did to make my Vtec head fit on the LS block. The thread is kinda hard to fallow with all the opinions and the fact that the guy can't speak english very well.

Not to sidetrack the thread too much, but I thought for putting a VTEC head on LS engine you could just drill a hole and tap it for an oil feed line?
Edit: Like this http://www.sportcompactcarweb.com/tech/0411scc_hybrid/

yes but you have to tap a spot in the block for the GSR dowls to fit into the LS block then get the golden eagle head gasket. I am running the factory LS head-gasket(well actually comsetic 2 layer .20 bore headgasket but you get the idea), and all I have to do is tap a spot in the head and run it to the oil sandwitch on the block.
it seems to have an extra dowl in the middle that the a20 dosent have.
I wouldent be so worried abotu DOHC, I would try and find a SOHC vtec head that might fit on these blocks. I mean if you look at the bottem of the d16 vtec head they are very similer to ours. There are also F-series SOHC Vtec heads. With the added valve per cylinder and vtec we could pull some good HP # from our cars.
http://cgi.ebay.com/ebaymotors/ws/eB...ayphotohosting
according to Thisthe f23 is vtec and comes from the 98-00 odyssey.

ok i possibly missed this and will go look again but if somebody got this to really work what do you do with the spark plug holes? our plugs go in the side of the block but the B20 head has the plugs in the head its self sooo what do we do with the holes in the side of the block?

I was thinking that myself, but when I pulled my head and put the new one on yesterday I noticed the plugs were in the head. This means that they would still work if you had them comeing down from the top.
I just tried a b18a head gasket and the bore was the exact same as the accord, but the head bolts and oil channels don't match up with the accords. So look away from any B18, B16, B17, B20. I think we will have to look at the F, H, D series motors.

We were talking about using the Prelude B20A/B21A head, It is different than the B20B and B20Z, B18, B16, B17.
From wikipedia : "Partially unrelated to the Honda B-series engines are the B20A and B21A. By some, these are not considered to be part of the B-series group of engines because they are not compatible with any of the other B-series parts or chassis. " http://en.wikipedia.org/wiki/Honda_B20A_engine
The Prelude B20A/B21A (and Accord B20A) shares alot more with the A20 series than with the "normal" B series.

I know all that, I was just letting you guy know.

F23a is OBDII which could cause a problem. It came in the 98-2000 accords and is VTEC.
A better option would probably be the F22a/b head from the earlier accords simply because they're OBD1 and will cause a LOT less headaches then trying to put a VTEC head on our motors.

You can change the Distributor and the Ecu and make it OBD-1

I just got back from the Northern U-Pull-R-Parts, they had one 1990 Prelude with a B20 or B21, but the head was gone. I will hopefully check out the Southern one next week.
After I looked at this Prelude, I got to thinking... Anyone know the easiest way to identify what Preludes have a B21A1? Junkyard cars can be pretty stripped...

The block code is your best method, but I think that motor was available in the SI model .

[HondaBoy]

i think the problem was completely because of the positioning of the cylinders, and the positions of the oil and water passages. no, not happening. or else yeah, me and everyone else with access to junk yard's would have a prelude head.

hey, if thats all true, i want in on it! i was just remembering stuff said before a few years back when someone asked this kind of question. i'd go for a custom lenth belt. i'm sure you could more or less use the stock prelude T belt, but use a different tensioner or modify one to work. i dunno, maybe we ought to look into it all?

[adams86lxi]

if this was true then i would be buying a20 head gaskets. I am almost 100$ postive they way different and the problem isnt just the timming belt, otherwise tons of people would have this. But try it and find out.

Anyway. yes the h22 exhaust manifold works but its pretty far off and needs some modifying to fit. But the b20a5 is basically the same...

[Swap_File]

I did see this post:

https://www.3geez.com/showpost.php?p=556444&postcount=120

Hood clearance wouldn't be that hard to fix

Here's to hoping it works

I found more, still reading:
https://www.3geez.com/showthread.php?t=20759

Pictures:
https://www.3geez.com/showthread.php?s=&postid=320117

Edit: I guess the person who did it never had video of it running, and people assumed it could have been faked by just setting a different head on. Other people also said there was too much work involved for too little gain. I still wouldn't mind looking into it since the DOHC VTEC head idea did not work out. ( see here: https://www.3geez.com/showthread.php?t=13223 )

Edit AGAIN: This is why the DOHC VTEC project was scrapped: https://www.3geez.com/showpost.php?p=228741&postcount=58

I think the dowls need to be relocated for the oil. From what I can understand he had to have the head machined just as I did to make my Vtec head fit on the LS block. The thread is kinda hard to fallow with all the opinions and the fact that the guy can't speak english very well.

know lets talk about the thing that i had to do that i didn't think about but i found out as i whent along
there's an oil jet in the a20 and b21 the oil jet in the b21 is level with the block.
the oil jet in the a20 sticks out of block about 1/8" of an inch. the a20 head has a place for it . the b21 head dosen't . the oil jet in the a20 is made of aluminum so i ground it off level with the block."

Not to sidetrack the thread too much, but I thought for putting a VTEC head on LS engine you could just drill a hole and tap it for an oil feed line?
Edit: Like this http://www.sportcompactcarweb.com/tech/0411scc_hybrid/

This is a quick summary of the other threads for people who do not want to read it all:

1. Put the A20 headgasket on the B20 head see where something doesn't line up, and weld some stuff shut (unsure of what or how much) and get the head shaved (because of the welding).

2. Grind off the oil jet on the A20.

3. Have a shim made for the B20 crank timing gear to work on the A20.

if you look at the A20 or B21 bottom timing gear you will see that they both have keyway made into them. A20 has smaller crank diameter then the B21. to make the shim they had to remove the keyway notch and then they made the shim out of brass. after the shim was in place they cut a notch through the shim and into the gear. they also gave me some key stock to use.

4. Get a different intake, or bigger hood to make it fit.

5. These parts were used:

heres a list of parts i used in my motor
block A20A3
head B21A3
intake B21A3
exhaust B21A3
cam s B21A3
camgears B21A3
timing gear on the crank B21A3
distributer B16
cranksensor B16

So there is an ECU upgrade involved too it seems. I did check on preludepower and it seems the B16 distributor will work with the B20/B21 as long as you have a Integra/Civic ECU setup.

And we still do not know for sure if it all worked in the end.

I believe the A20 and Prelude B20/B21 intake manifold are interchangeable, so that should mean that the Prelude B20/B21 could take any B series intake with only slight modification (B16, B18, B20, aftermarket, etc). Maybe one would be low enough to not require major hood modification.

Edit: After reading up on preludepower and looking at some pictures, I see that the Prelude B20A has very different exhaust manifold spacing than the A20. The Prelude B20/B21 also has a slightly different bolt pattern than the Accord B20A. According to people on preludepower, a DSM or H22 manifold can be modified for use with the prelude B20/B21.

I will definately keep an eye out for these parts in the junkyard, but I do not see this as being a quick or easy project.

Edit: Adjustable cam gears are also easily available for the Prelude B20/B21 head, if you need/want them.

[B16KILLA]

If you live in lithuania why dont you just swap a DOHC VTEC in it. No smog tests right??

Wuts the redline on that motor? Can you tell us atleast sum ballpark numbers on horsepower.Have you raced it yet?

[baby D]

i think the hardest part of getting this motor to run is getting the valve timing set right along with the stock crank gear (which determines the TDC for every single piston) and in relation sets the valve timing of when to open and close.
i dont know if the B20A5 used a water pump that ran off the timing belt or not and if it did not, we might be able to use the B20A5 timing belt and the crank gear. I wish i had time to go to the junkyard and compare these things or better, work at a Honda dealership.

check this out my dad tought me this and if im right you guys are on to something sweeeeeeeeet!!!!

check this out my dad tought me this and if im right you guys are on to something sweeeeeeeeet!!!!

look at these pics, and read the tabs if im right the most you will have to do is modify the gasket so that the oil and water flow the same, if there is no prob. then it will run, also see if you can use the timing sensors off of the b21, if you can and the cam timing matches the crank, you guys will have found the most usefull trick in the performence section, b ecouse the fact that it will breath the way the engin wants, but it would also make a turbo produce more ponies(horse power). so if you can please tell me and ill see if it runs, also can you find me more pics and email them and ill see if i cant ad to the knoledge you guys have found. but if you say that im right on the pic, then ill try it.

correct. Water is the little holes around the cylinder's on both engines.
Coincidentally enough, the oil holes are also in the same place, outer rim, so there'd be no modification necesarry.
Also, the B20 and B21 engines DID have a water pump run off the timing belt, unlike the A20.
However, all of this is completely useless information since the bending and routing of the belts would set off the length anyway.
What's going to be important is that the crank gear has exactly 1/4 as many teeth as the cam gears, which it should. however, if it does not, you'll need 2 A20 cam gears on the cam shafts. not a problem either way. and again, that could affect the timing belt length.

im on it ill talk to some friends of mine around here that do custom engines, maybe with the right set up we can tell people what they need for a 'kit' but hopefully it will work, im always into trying, if i could do this i know of an 86 crx in need of horsepower, pulling thirteens stock. any way thanks.