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

[Hoshizakido]

What heads will swap on to tha A20 block?

I know someone that put a B20A3 head on a A18.... it worked but had coolant problems
I posted 1 year ago that someone installed a B20A3 head on an A18A... the problem was the cooling passages and the timing gear location. He said in the other thread the he shimmed the bottom gear... fine, I can beleive that.
However, the distributor and crank sensor are NOT from a B16A... they are from a D16 (Integra 86-87 engine)
The major problem I see with this setup is that you need a custom intake manifold to make it work... or a monster hood
Like sean said, for all the trouble involved, you could use a VTEC head instead... no need for a custom intake with that head since the engine leans in the proper way.
Nice work tough... I wonder if it actually runs.
That's because of the exhaust valve location isn't at the same place on cylinder #1-2 and #3-4. This way honda can make only 1 model of piston instead of making 2 different pistons for the same engine...
The F23A head isn't bad but I would prefer to have the DOHC F22B head on it. Interesting project tough.
It sure seems to line up properly.
Once the head is bolted to the engine, the rest would be fairly easy.
However, the JDM B20A head would be a better option to mod in my opinion. The intake manifold wouldn't need to be modified to fit in the car since the B20A uses the same mani as the A20A.
The problem is findind a B20A head in North America, which leaves us back to square 1.
With the B20A5/B21 head, you would need to mod the intake mani so it fits inside the enginebay. Just a cut N weld thing.
I would run the PK2 ecu with that setup but the PJ0 could also run it.
For the Manifold, I was refering to the Accord B20A. The Accord B20A will not bolt to the B21A or 88+ Prelude B20A
The A20A has a 82,5mm bore if I remember.

I finally logged into 3geez after being gone for a few months, and saw a few PMs asking about this project. Here is a quick summary:

Here is what you would need (Mostly from memory):

B21A1 (from 1990 - 91) or B20A5 (from 1988 - 91) head from a Prelude. B21 head lowers compression just a bit, B20 head bumps it up just a bit. B20A5 heads are much more common in the junkyards around here.

Custom lower timing gear (Modify a B20/B21 gear to fit A20 shaft)

Some other timing belt - Unsure of what is needed

Tap and plug the extra oil drain holes in the new head

Redo the one head bolt that does not line up. Probably make the hole in the head a little bigger and oval shaped, and then make a special washer for it.

Redo the oil feed, since the head bolt that doesn't line up is used with the head's oil system.

Upper timing belt pulleys do not quite align with the tensioner and bottom pulley. Probably has to have some shimming done.

You need the B21A1/B20A5 intake.

I remember that the A20 distributor had a different number of teeth than the B20A5/B21A1. You will probably need to switch to one of the OBD1 ECUs to make tuning simpler. Look for the instructions on what distributors fit on the B20A5/B21A1 head on preludepower.com. The ECU swap is a project in itself...

My suggestion: Do the head swap if you are looking for a challenge, if you want cheap power go turbo. I am sure that the head swap could be done, but it will not be easy.

I am currently (slowly) working towards going turbo. College has been keeping me very busy, but I am slowly making progress.

[meanaccord]

My friend has a 2.0 with DOHC F.I. . I have an 2.0 SOHC with carburation. He is getting rid of his car so would his DOHC fit on my car, i mean anywayz possible?Thanks

I found an a20a1 DOHC head running to a carb. . I have an a20a1 with SOHC carbed.....will that head fit on my block and bolt to my intake? If so then what else would i need for the conversion.

[AZmike]

Sounds like he has the B20A. You can't just switch the heads. You have to swap the whole engine and transmission. Then you'd need a few other parts to get it all to fit and work properly.
You may consider buying his car and selling yours unless you've already done a lot of work or yours is in much better shape.

I think Sean was going to use some shift light feature of the GM ECM to control the VTEC, switching it on at around 4k.

[88boy]

is it possible to put k20a from an rsx heads on the a20a3. or even the f20 heads off the s2000?

[dXsquared]

HAHAHAHA are u on glue??? they are DOHC... and the block is soooo different! not even close to a swap there... try a 2 gen lude head...

Travis

[flamed89]

try a 2 gen lude head
sorry to let you know this but that is the same head as what is on the 86-87 accord!

my suggestion is to go to a machine shop and have yours ported and polished!

[1989 DX R]

There were never any DOHC A20a1's. You might have a B20a1 or something else.

KMS, would you be able to make a manifold for some Weber 40DCOE carbs and how much would one of those headers cost?
Also, how much should a good rebuild of my whole motor cost? I want everthing regasketed and reground to make it smooth.

I'm just looking for an estimate on a price for a rebuild...I'm in Texas so the work is going to be done locally.
For the DCOE manifold, I'm sure you can get your paws on the flanges and stuff, if not, then I can probably get that stuff done here as well.

Originally posted by KMS
Sure we can make the manifolds you need. I just need the set of carbs you want to run and they would be in the price range of $200.00 to $300.00

Ok, so I can get my hands on some Weber 40DCOE carbs and the flanges, and then ship em to you, and then you can get it all hooked up correctly, including the tilt angle? I will do the carb tuning myself, but need the manifold to connect it to my block.

Well $200-300 is a good deal for a manifold anyways. No group buy, but KMS could have like a mold or something so he can make more if he wants.
Would it be possible to have it tapped for the PCV valve?

[socal3rdgen]

I think this should go in the performance section since that what he does. This thread is a Q/A Thread. 3geez. members and KMS were off to a bad start. So these are pics of his work. Hopefully this can be a good thread for him and for us.
***Warning- dail-up users***
this will take a while for you.
IS THIS AN ACCORD ENGINE BAY?
More pics below
IS THIS A ACCORD HEAD. IT HAS 4 VAVLES. THE ACCORD ENGINE AS I UNDERSTAND IT HAS 2 INTAKE 1 EXHAUSTING MAKEING IT ONLY 3 VALVES PER CYLINDER.
That all the pics. Please post Questions and comments.
so i still have to ask even if you dont have a dyno sheet. (i would like to see one but oh well). the engine in the civic is N/A right? what quarter times have you gotten with this and what torque/ horsepower have you gotten.

Originally posted by quagmire
And are the time slips for a single cam, or is it with the DOHC head?

good question. to add to that. is it a
the A20 engine with a20 head. and modifications? otherwise those slips are for a hybrid engine.
i think most of us want to know how far are a20's will go.
yeah ide like to see the twin cam. what kind of dohc head are you using. from what engine.
oh ok.

Originally posted by Sean
problems with your head swap plans.
both the intake and exhaust vavles are gonna hit the cylinder walls. the shrouding form the valves being so close to the cylnider walls is gonna screw up airflow. secondly why not work on getting the a20a head to flow.
btw from your ET i derive 198hp in an accord but i feel that these times slips are in the civic which works out to 155hp.
have a good day.

thats what i was getting at when i was talking about the engine bay. how much of a weght didference is there between the 2 cars.

Originally posted by KMS
I have been answering questions for 2 days and all the ones that step up to talk have not said one thing that makes them an expert nor have I seen their success.

kms this thread was started to test your knowledge and no one elses without fighting. i think its going good so far. we want to see your skill since as far as i know no one has your products. late
Joel

yeah im thinking i want to do that also site.

swim

read your pm's

[KMS]

This cyl head is a conversion that i am working on to convert to a dule overhead cam Note the accord head gaskit it is starting to come together the pistion is for the orignal accord that i run in the singel cam
No this is a civic engine bay i run the accord engine
Yes the header bolts right up. with no mods its an ok design we have better but it dosent pay for us to build them for the old cars
the block in the cnc is to an old school 1200 civic this is adam mallys car http://www.scca.org/amateur/club_rac...togal/hp-7.jpg
Price ? the cam in my car is a weld cam it gives a better base circle and more overlap
List price on the cams for a grind and than re hardend is$185.00 and a hard weld That being in my opinion the Best because you can change the overlap for real power$550.00
I dont have a dyno sheet on this engine anymore and i have just started tuning agian this year . this car is old and i havent used it to much if i can get it to hook up it will run 12s best so far 13.5 but i have both time sheets if you need them and thay will show that it will hit 12s
Knifeedge and balance crank shaft $350.00 and micro polish
Who can i send these time sheets to?to post
Let me know if you got them
An 88 prelude. regrinds are cheap. the only reason thay are welded is that nowon maks a billet cam cores.When thay are welded you can change duration and overlap And it also gives you better rocker geometry.
Thanks
a 4-2-1 builds low end torque 4 into one would be for top end power but i have found that having 1 exoust valve all ready controles torque.And WOW have you seen the exoust ports on the s2000? all i can say is wow thay are huge.
Yes that is the price unless it is a volum deal.
forgot the E
Yes for a hardened grind.$185.00
It will pass EMI but it could add a littel more emissions but as long as you werent on the edge to begin with . but as for specs i have several i can use. I try to use customer info to decide but i have cam lifts and durations that would Never pass
The time slip is a single over head cam. No it would be crazy fast twin cam
I have not run a twin cam head yet. But i should be Fun
Got to go. leave questions i will Check in periodically through the night. Or i will be here all day tomorrow
Thanks
88 pralude
Prelude
Sure stop buy . Did you see the 89 lxi head gaskit siting on the head? the combustion chamber is small but thay line up fine.
Get of on exit 82 turn right go 6 miles to browns brige turn left go 3 miles after brige turn right first black fence on right
No its not finished but its not a rush for me I build new engines every day. The block needs nothing but a larger timing gear and buy larger i mean wider gear and an oil pump adaptor all the work is in the head lots of welding.
I believe that this head flows more than it should but please look at the picture before talking .The head is on the table the head gasket is on the head the gasket is from an 88 accord lxi do you see that the combustion chamber is smaller than the accord bore size? and what do you think the normal head on an accord flows ? and what do you think a prelude head flows ?and how much can you port an accord till you see day light and not loose velocity?
FPR? I can give you lingth in the morning just Email me I like the super coil and a 6AL
Ok WOW what a pain but the carbs i run are gravity fed and thay love to leak that why on my street car i used CBR 1100 carbs . yes the FPRs are a pain the ASSSS Thay are built buy Holly
That was the point I was looking for power and that helped .you don’t want the water pump to spin as fast as you rev it starts to cavatat and you loose cooling
The compression ratio is about 13.7 to 1 I havent CC the head sense I cut it for a new head gaskit the cam lift is .465 duration.284 springs have a seat pressure of 100 pounds oversized valves with narrow shafts and titanium retainers. and you have seen the pistons thats what i was holding.
Cool
I Owen a flow bench what is the water drop in with your test were done ? Be careful I will call Bull Shit my bench will pull 1000 cfm At 28 inches of water.
And do remember there is a point in witch a head will stall so if you are talking over your head stop now .This is for a No BULL SHIT talk .
PIC. http://www.honda-performance.com/pic...owbench300.jpg i can provide beter pics in the morning . when I open my shop.
And sean have you been DRINKING?you no talk so good
Point taken on the typing skill. And my spelling sucks also . But it just upsets me when someone jumps in and won't stay around to talk about the subject .I have been answering questions for 2 days and all the ones that step up to talk have not said one thing that makes them an expert nor have I seen their success. BUT back to the subject. See it is right to ask about the lift but has anyone asked about rocker ratio but there is just to much to talk about and we haven't talked about lobe centers yet .
On timing belt line up I just spaced the timing gear on the block and we are using adj cam pullys to dial in the cam card . and using one extra adjuster .
On the front side like the mugen to take the belt slap out. the car weight is about 1800 pounds .
Thank you for your support and I have enjoyed it. Sorry I get a little bent out of shape some times but there's nothing like being in rapid fire discussions.
Thank you for your support and I have enjoyed it. Sorry I get a little bent out of shape some times but there's nothing like being in rapid fire discussions.
Thanks and I didnt mean to piss everybody off at the begining .
What?
I get it now sorry kinda slow. Had A Bad day $
Now how are you going to fit that much lift under the rocker assy?And there is a little thing called coil bind But I am just asking. With the lift in the head now I had to notch the back side of the rockers.
1989 DX R Call me770-784-1801 we need to find out Just what you want.
Sean so What do you have for a car ? Just Wondering you sound like you have a clue . No when I Get serous I will build A Billet Head Thats why I have a CNC . But this old school stuff dosen't make me any money so I won't be spending alot of my time on it .So When you reduce your base circle do you find you'r losing overlap?But Sean if we talk to much we will lose the people Watching the thread. So drop me an email and I will give you a call to talk.

Ok but we will have to start explaining LOT'S See What hapens now is we go into theory and no one wins except on the track . And it gets real Boring But whatever.

Sean what times do you run?What do you have for a set up?

Sure we can make the manifolds you need. I just need the set of carbs you want to run and they would be in the price range of $200.00 to $300.00

Sean what center line were u using On the cams I have few that have worked well ?

If thats what you want Thats what you get.

[Site]

I'll post them. Send them to [email protected]. Let me know if you want me to post them in this thread or create a new thread for them.
Here ya go:

Originally posted by KMS
I have been answering questions for 2 days

I for one am glad you're here and are taking the time to answer so many questions. Like you don't have others things to do, if you so wished. I know you're hoping to get some business from this forum sent your way. I'd say you're establishing yourself well enough to accomplish that. Results speak, you know?
Personally, after Christmas I'm planning to send a crankshaft to you for balancing. I like the results you've posted so far.

[quagmire]

Ok, its $550 for a hard weld regrind? And what motor is that DOHC head from?
I'm aware of what goes into a hard weld, but wanted to be sure of the price. So is it $185 or $550? You didnt say. Its hard to read these posts that are one or two long run-on sentences.
So what is involved in the DOHC head swap? Redrilling the head bolt holes? What about modifications to the timing chain? Does the Prelude combustion chamber match up to the A20 cylinder bore? And have you done hard weld cams for the Prelude head? Are the valves the same size? And are the time slips for a single cam, or is it with the DOHC head?
So its $185?
Cool, what are the specs on the regrind? And since I get inspected in Houston, does it increase emissions significantly?
Cool, 'cause right now I'm looking to mainly improve my power with stock head and intake manifold. I don't know exactly when I'll be able to do it, probably over spring break (early March) or during the summer. Over Christmas break, I'm going to try and get all of my cars little problems( brakes and other little shit) worked out, along with a header, cat( probably Catco) and muffler( Dynomax). So thats probably what I'd be camming the motor for.
He said an 88 Prelude, so whatever DOHC motor came in a Prelude in 1988.
KMS-
Have you finalized the conversion process yet? You didn't say what you had to do to get it work on the A20 block.

Sorry, I was afraid the thread was dead. Mea culpa, mea culpa. Thanks for the specs.

Pretty salty going up against Sean. Anyway, I'm sure most of us on the board would be most interested on your work on the A20 head. Sean is right, .465 is pretty low lift. But anyway, is that 284 degrees duration, is that at .5?
P.S. Not to be a bitch or anything, but you dont type very well either. Lack of periods and such.

I didn't mean anything by the typing comment. And I think Sean was just making sure you weren't some random douche who didn't know what he was talking about. But you've satisfied me that you're qualified, for what that's worth. I also plan to send some business you way next year, but most likely a cam. Thanks for the info. Later.

I find your conversation quite stimulating. I'm learning a lot.

[Sean]

question how in the hell do you plan on swapping on a prelude head. the bore centers are further apart. ?
problems with your head swap plans.
both the intake and exhaust vavles are gonna hit the cylinder walls. the shrouding form the valves being so close to the cylnider walls is gonna screw up airflow. secondly why not work on getting the a20a head to flow.
btw from your ET i derive 198hp in an accord but i feel that these times slips are in the civic which works out to 155hp.
have a good day.
i did look at the overlay ofr the lxi headgasket onto the preulude b20a5 head. the intake vales are gonna hit the cylinder wall. please done tell me your gonna notch cylinder youll hit water for sure.
and ive gotten the a20a head to 220cfm intake and 190cfm exhaust. without welding or dropping alot of port velocity. it can be done but do you want to invest the time on the flowbench to make it sing like that is the question
also thats a .450 lift. im sure it could do more at 500 0r even more lift. and yes the prelude head is a bad idea. it not gonna work right. you should do a bit of reasearch on head flwo dynamics when being modled in a cylinder. the srouding your gonna introduce there is gonna reall bunch flwo up alot. use the a20a head and make it flow.
hmm the prelude engine is aluminum and has a wider bore spacing. not every intake valve will hit but every other valve will hit.i found this out trying to fit a b20a5 crank into a a20a block.its the same reason wever never tried to swap the accord b20a head. look at the headgaket ovehanging the intake valves. that the give away. then again even if you do get the head on the engine and fix the valve contact issues you still have to do alot with piston shape. you cant just up the compression and expect good results you need to work at qunech and using the flame front to propogate good combustion. ive seen plenty of high compression engines get beatne by a lowe compresion engine using the same specs. combustion efficency is whee its at.
and KMS if you would like to talk to me about head porting fine. but stop putting that head on that motor. how much flwo do you need. come at me with a cfm number and i should be able to help you.
as for port stall the factory ports stall a 550 lift. the last head i did stalled a .675 roughly. ive spent alot of time modeling cylinder head flow with this motor. but then ive been porting heads in general for the better part of the last 10yrs. i dont do it proffesioanlly cuase the aint no jobs paying what i need to make. i turn a wrench day in and day out.
ps 28inch of water the normal
well i used a reduced base circle to prevent this very issue. with the the follower being hit by the cam lobe. then i used ford small block valve springs and had the spring pockets cut out. ive run .500 lift cams. its nto hard. but what exactly do you need for airflow. ?send me a head.
actually i found that reducing base circle has zero effect on overlap. you can just grind off center to split the difference. and the a20a head is easy to port. just have to know where. ive spnet lots of time on the where and alot of heads. ive cut 4 into sections i know where the water is.

those motors are gone. i ran a 15.1 in a 4dr full stock bodied accord once. which i figured was good for about 185hp. i didnt know then what i do now about the head either. i was turning around 8200rpm. im confidendt i could make more power now a 6500rpm then i used to at 8200rpm. ive learned much about this engien and its like and dislikes.
anyways id rather talk about head porting and flow dynamics.


----
im going to get started on this soon is there any interest??
ok gotsome issue to work out but it looks feasable. not saying im 100% sure i can make it work but i cant see why it wont. alot of things fell into place. my biggest issues right now are oil returns, and oil feeds. aside from that it looks like itll work.
yes it uses the same bore centers spacing as an a20a. it has an 81mm not a 82.5 im not sure why they keep publishing it in all the headgasket catalos that way. anyways yes im getting my hand on a head soon so i can start making it al work. i plan to make this an integral part of the GM ecm project for sevral reasons.
first the stock computer cant switch the vtec on period. second i found the shift light parameters in the GM ecms can. third its easier to tune EFI for this then try and hack a stock system in the GM ecm is more flexiable and easier to program.
all in all i got lots of homeworks to do but i think forging so new ground and brining in technologys like Vtec to the older a20a could really change the way the import scene treats us and looks at our cars.
think about how powerful a b16a would be if it was poked and stroked ?? pretty TQ'e with a good bit of high end power.
im not waining whats killing me is developing parts for me as well as everyone else. i always try to make things kit able in term that means that if you want it i can sell it inexsepsnsively
would you like to send me a b16 head ?? i could really use one. the one i got is all fubared and ai need a good one to get moving. plus i need the timing gears etc. if you can do that email me thanx a bundle.
im gonna use the whole b16 head.
the R/R is 1.51:1 its pretty good that explain why the a20a has such a long ring life. that better then alot of the damn motors including the b16. which is 1.5. im not to worried plus with our bigger enignes the head will run out of air at about 7100rpm plenty enough rpm for me.
1,3,2,4 but that dont matter much the b16 is 1,3,2,4 and thats becuase there both 180 throw crankx.
Well as dandy as all this is. heres a startling factiod. intake to exhuast flow ratio in most high end racing applications shoots for 100/75-80 ratio. and as dndy as 16 valves is you can get enough flow out of te single exhuast valve with little to no trouble to no make the troube of fitting that big cubersome head on this engine.
Just a FYI. if i was gonna go 16 V id defiantely go vtec because the dual profile cams would make it a worthwhile venture.

[pric]

Sean: I'm not an expert but the A20A has a larger bore than the B20A so I was wandering if you could explain to me why the intake valves of the B20A would hit the cylinder walls of the A20A? Thanks.
KMS: My question for you is how do you plan on insinking the timing of the B20A cams with the A20A crank detailed explantion would be appreciated? Thanks.

On timing belt line up I just spaced the timing gear on the block and we are using adj cam pullys to dial in the cam card . and using one extra adjuster .

That makes sense but were are you mounting the extra adjuster at? Oh BTW your input is appreciated and I want to thank you for you time.

[2old_honda]

I know a few people want a manifold for dual DCOE 40's. Would you be willing to do a group buy of say 5 manifolds? I know that I would buy one if it was in the $200-$300 range. thanks

Originally posted by 2old_honda
I know a few people want a manifold for dual DCOE 40's. Would you be willing to do a group buy of say 5 manifolds? I know that I would buy one if it was in the $200-$300 range. thanks

Originally posted by KMS
Sure we can make the manifolds you need. I just need the set of carbs you want to run and they would be in the price range of $200.00 to $300.00

so you would do a group buy of 5 manifolds? these would be for dual weber 40 DCOEs. and I am sure you know about how the manifold needs to tilt back 10-12 degrees. If we could get 5 people to buy them, how much could you make them for? Also, I would be able to organize the group buy, I would get the 5 people for you and all you would have to do is collect the money, make the manifolds, and ship them out. you can email me at [email protected] if you would like to get something started.
thank you!

Originally posted by da6integra
wouldnt a d16 sohc vtec swap seem more of an acheivable feat... just a thought

no, I highly doubt the bores would even be close
the header will fit but the down pipe will either have to be modified, or a custom one wil have to be made.

[carotman]

Ok let me explain a little story that happened to a friend and that might apply to our cars
A guy I know owns a 1.8L Prelude 2nd gen.
He went to the junkyard to buy a head for his 1.8L with the Idea of rebuilding it with performance parts. He bought the head and took it to the performance shop.
When he brought the head back home, the head wouldn't fit, some things were different. All the bolts lined up except one on the back of the engine. He took the head back to the junkyard for some explanation, it turned out that he got a 2.0L head instead of a 1.8L, up till 30 mins ago, I had never seen the head myself and thought it was an A20A head. But when I saw the head, I instantly realised that this was in fact a B20A dual carb head (from the SOHC 3rd gen lude)
The guy didn't know that and since he put money into modding the head, he wanted to make it fit anyway, (thinking he had a A20A head on a A18A) he machined the bolt hole that didn't fit and modded some coolant passages,
The head bolted to the engine like a charm after that, the only problem was that the cam sprocket didn't alogn with the crank sprocket. He took care of that and installed everything else.
Beleive it or not I saw the engine running like a charm. SOHC B20A head on a A18A!!!!!! He had little coolant problems but he blew the bottom end of the engine before he could take care of that. (9000 RPM isn't that great for the A18A)
--------------------------------------------------------
Ok, the story ends..... now I hopw you see where I'm going..!!!
The SOHC B20A (B20A3 I think) and the B20A5 (DOHC) share the same head gasket, this means that the same modifications would be needed to put the B20A5 head on the A18A, That's something huh!!!!
Now I'm sure that the A20A could use the B20A5 head. If not, then we could just swap an A18A in our car with a B20A5 head....
I'll try and get pictures of this soon.

I doubt it will work with the A20A sinec the bore size of the A20A is 82.5mm while the B20a5 is 81mm, the combustion chamber will need to be resized (if this can be done) the bore of the A18 is 80 mm, so this can be Ok
I definetly need to check more on that, I was so astonished to see that the SOHC B20 head was used on a A18 that I forgot to take pics

I think there is a little problem with the coolant passages (from what the guy told me and rfom what I saw on the head)
I'm sure that coolant lines could be plumbed to patch for that.

[PhydeauX]

The bore size won't make a diference. Infact it would be better to have the head on the a20 block then the a18. No part of the piston comes past the deck of the block so there will be no interference. the outside of the piston will also come very close to the head giving it some quench, something that the stock a20a head lacks. What you need to worry about is that the chambers and bores have the same spacing and that the coolant and oil passages can be made to line up.
andy

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Did the bores actually line up?
andy

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Kinda like a crvtec but with a block that can hold up to the power.
andy

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I remember lude speed trying to put a b16a head on a b20a block, I think they managed to get that one to work. I also seem to remeber them trying to put a b16a head on a a20a block and having a bitch of a time with it. I don't remember if it ever ran. I've never heard of some one actualy trying it with a b21a head on the a20 block. Though there was talk of trying to put a jdm b20a head but I don't think anyone ever tryed it. Does anyone happen to know if the b20a3/5 heads are the same as the b21a. Those heads are alot easier to come by.
andy

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Well, now that I'm home from work I can look it up.
a20aX 3.25"
b20a3/5 3.19"
b21a1 3.27"
If this is possible I'd choose the b20a3/5 head. You might pick up a little quench around your ring lands from the smaller cc and it should add some squeeze too to help the mix. Plus it leaves room for oversized valves. That is if the head has the proper bore spacing and the bolts are close enough to allow the mod.
andy

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He probably had some of the coolant and oil passages welded and re-shaped so they would line up with the passages on the a20 block, then he had some of the head bolt holes redrilled.
andy

[KaMiKaZeE]

you might need to do a custom oiling setup as in b20b/b18c hybrids. It could be made to work with a little ingenuity provided the bore spacing is correct as phydeaux said.

[SQ is the SQUAD]

arew you going to do the oil feed lines and return like on a ls/vtec with tapped oil lines. i got a b16 block in my basement so yuo need any parts off it, i tihnk it might have oil squirters

i just happen to hav ea d16z6 head and a b18c1 head

[markmdz89hatch]

Sean, if it helps at all, I think that OpenLoop did a ITB setup on an A20A3. 'Least that's what I think I remember about it. And, if I'm not mistaken, they used a B16 kit and made a few modifications to it.

Originally posted by AccordEpicenter
if you wanna spin the a20 engine well past 7 or 8 k you need valvesprings, lighter valves, rods, entire engine balanced, and pistons. BTW the a20 block doesnt have sleeves, the bores are cast in. Youll have an easier time making the engine take the 20psi then you will making it reliably rev to 9k. From what i hear, all you need to do to the bottom end of the a20 is get the forged pistons (for turbo), because the stock honda rods are strong as long as you dont overrev the engine. How you prevent it from blowing head gaskets is another problem.

...and Johnny-O can certainly vouch for that one. He's melted head gaskets like there's no tomorrow in his 11.8sec Turbo A20A3-powered 3G Hatch down at Englishtown.

[da6integra]

wouldnt a d16 sohc vtec swap seem more of an acheivable feat... just a thought

[Grant2k]

Originally posted by PhydeauX
Kinda like a crvtec but with a block that can hold up to the power.
andy

in that swap isn't it the rods that become the weak link?

Originally posted by 2old_honda
as someone stated before, will the a20 rods hold up to the power?

what i was thinking was that the LS or whatever block people use for this swap usually is strong enough to withstand it, the problem is they change the R/S and the rods get all stressed out and become the weak link. i imagine that anybody willing to do all this work is going to pay for forged rods and do it right. Andy just commented that now it'll have a block that can stand it, and it will, but i just never thought the block was the issue. it must also become hard on the rings too if they are getting pushed into the cylinder wall all the time. i would guess that none of these swaps have been around long enough for people to study ring wear though. but i would factor it in in the long run.

actually i think his best was an 11.9 and he ran it in New York somewhere. 11.8, now that's just silly.

[Scorpion88LX]

if there is a chance in hell that sean can make a vtec then couldn't you we use a latter sohc vtec cam and acces.
One ques could we even use the whole head.

two ques. if you get this done (hoping) how will you get the timing belt right and what type will you use. the second is will b16 exhost headers and down pipe fit under the a20 block.

[AccordEpicenter]

ynot, unless you overrev the engine. For example, A20 rods couldnt withstand b16 rev limiter of 8000 or 8100 rpm or whatever it is, youd have to stay at the stock rev limit
why would you do that? If yore looking for power, go with the gold, the b16. In any event, controlling the vtec is easy, its just a solenoid. Most guys when they do a mini-me conversion use one of those msd rpm switches to mess with vtec.
i believe the b20A head is better than the B20A5/B21A1 etc... not sure though
hey, which intake is better for power, the 88-89 intake, bypassed maybe, or an 86-87 intake (both efi) im looking to make the car pull harder past 3 or 4k. I have my bypass open all the time in my 88 lxi and that gave me a boost of power past 4k but I also have a spare 87 lxi manifold and an 88lxi manifold around here somwhere but i was wondering which is better for speed? Also how much power can be had with intake and head porting, and which is worth the most power?
if you wanna spin the a20 engine well past 7 or 8 k you need valvesprings, lighter valves, rods, entire engine balanced, and pistons. BTW the a20 block doesnt have sleeves, the bores are cast in. Youll have an easier time making the engine take the 20psi then you will making it reliably rev to 9k. From what i hear, all you need to do to the bottom end of the a20 is get the forged pistons (for turbo), because the stock honda rods are strong as long as you dont overrev the engine. How you prevent it from blowing head gaskets is another problem.

did you say 11.8?

lol.... those are scary times for an accord. I think he could improve on those actually from what ive heard (wheels spinning all the way down the track)

[wprocomp]

will the ignition firing order be the same?I think its diff on the b16.the intake size on the a20 is1.52,1.51,1.52,so the b16 head should work well with the better valve diameter.and you can always concrete the head or block to seal off unused oil passages.good luck Id like to see this work.

[iiviasterp]

it seems as though you would have to have a vtec controller too to switch over to vtec at a lower rpm, because im pretty sure b16's switch over pretty high, and if your sayin that the motor would only be able to rev to about 7100, thats not alot of vtec to play with......just something i was thinkin about......