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Info about B20a/B21a VTEC Head Conversion

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MustardCat
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Info about B20a/B21a VTEC Head Conversion

#1

Post by MustardCat » 18 Nov 2018, 04:07

ATTN: This is an information dump from the old LudeSPEED site, none of this stuff is sold anymore. Much of the information is waaay out of date.



7/21/00
Below are some pictures of when I first got the head and when I did the first step in making it fit.
The pics below are when I first got the head and intake. I just looked it over for a couple hours and put it on the Prelude block to see how close it was. IT WASN'T VERY CLOSE!! In fact, I originally gave up on the idea but then I found some information that made me realize that it will work.

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Up to now, if you wanted a gen3 VTEC Prelude, you had to do a complete motor/tranny swap. What a pain in the ASS! That costs SOO much money and takes SOO long to do that it is almost not worth it. And the problems that you run into along the way are enough to make you want to cry. I have heard some serious horror stories. Anyway, I am offering what I consider to be a better solution to the people that have to have VTEC.
This is something that I think is really going to be cool. What I am offering is a 'Bolt-On' conversion kit to turn Any 88-91 Prelude Si DOHC motor into a DOCH VTEC motor without swapping the whole motor/tranny. I am modify a VTEC head so that it bolts up to an unmodified B20A5 or B21A1 block. All that you would do is pull your stock head, intake manifold, exhaust manifold and install the VTEC head & intake manifold, along with a 4-2-1 header that will come in the kit. You will have to pull the oil pan as well and swap it out with the one that I send in the kit.
I am going to start buying the parts myself to make sure that you get ALL the B16 parts that you are going to need.
Or, you can buy a B16A head and intake manifold from a JDM B16A motor, 93+ Del Sol DOHC VTEC, 99-00 Civic Si or 97+ Integra Type-R from another source. All these will work. The GS-R head is different in regards to the intake manifold bolt pattern and cooling passage. The intake manifold is also VERY different and will not fit in the engine compartment.
If money is no object for you, a GS-R head with a Skunk 2 intake manifold is the way to go. The GS-R head is supposed to have the best shaped combustion chamber and larger ports. And the Skunk 2 intake manifold will fit like the B16 or Type-R manifold fits and flows like the Type-R unit.

What you will get back is:
  • Modified head
    Special copper head gasket
    All oil lines and fittings
    Modified Oil Pan
    JDM PR3 VTEC ECU and wiring instructions
    Non-OBD B16 Distributor
    LudeSPEED 4-2-1 header or turbo manifold (if you are purchasing a turbo kit)
    Fuel Pressure Riser
The cost for EVERYTHING is $2150. That includes the cost of the head and intake. If you supply the head and intake, the cost would be $1450.
An APEXi V-AFC can be used with the JDM ECU to tune the fuel maps and VTEC engagement point.
The whole point of this project is to make more power while spending half the money. Seriously, unless you have AWESOME hook-ups, you can't get an H22 or B18C motor and get it installed for anything less than $3000. It will cost the average person at least $4500 to do it. Just ask http://www.placeracing.com/ for a catalog and you [/COLOR]will see the prices yourself. They sell just the motor/tranny/ECU for $3500!! Then the custom mounts for another $600!!! Then even more for custom axles!!!!
I say that it will make more power because I am going to shave the head to raise the compresion to about 11.5:1 (unless you are planning a VTEC/turbo motor). The combination of stroke of the 2 liter motor, the air flow of the VTEC head, the high compression, the 4-2-1 header and the tunability of the fuel computer will make over 180 HP to the wheels!

If you are interested in purchasing the VTEC conversion package, email me and I will tell you exactly what you need to buy and what you need to send to me!
Tom@LudeSPEED.com




11/1/00

The picture below shows STEP 2 - creating the special head gasket. The picture is a comparison of all 3 gaskets.

[No Picture]

The design has been finished and a few copper gaskets have been ordered. I am also getting a plate cut out to use as a template for milling the holes. This ensures accuracy. Updates and a running B20A5 VTEC motor coming soon!




7/21/00
Below are some pictures of when I first got the head and when I did the first step in making it fit.
The pics below are when I first got the head and intake. I just looked it over for a couple hours and put it on the Prelude block to see how close it was. IT WASN'T VERY CLOSE!! In fact, I originally gave up on the idea but then I found some information that made me realize that it will work.

The head is bolted on by a couple of bolts:
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VTEC Conversion Update
3/21/01

Here is the update:

First, I have had the VTEC head running on my car. I did have some small problems but they have all been worked out and this is truly going to be a solid product that will make great power.
One of the problems that I had was I blew the head gasket on the first day. Why? Because my block had a low spot on it around cylinder #1. I did not know about it or know how to fix it without pulling the motor and having it decked. A friend told me of on old but effective method to check for low spots and a way to work it out without pulling the motor. Also, I have decided to have the head oringed for the best sealing ability. The combination of those steps will ensure good sealing of the head gasket. Another problem that I had was trying to tune the fuel curve using the stock Prelude ECU and an APEXi S-AFC and fuel pressure regulator. It wasn't easy and in the 2 hours that I drove the car, I could not get it tuned worth crap. So I did some research and it looks like it is going to be SUPER easy to run the JDM VTEC ECU in the Prelude. We just have to switch a few of the ECU plug pins around and it is good to go. Then if you wanted fine tuning, an APEXi V-AFC is what you will need. This will allow you to change the VTEC engagement point and tune the fuel maps.
I did get one dyno run on the motor before the head gasket problem exploded my radiator. The head gasket was leaking into the coolant passage and all the compression was going there and it caused excessive pressure in the radiator. Even with the blown head gasket and miserable tuning and lower than desired compression even in the good cylinders it was putting down 111ft/lbs at 2500 rpm to the wheels!!!!!! Consider that the Civic Si puts a PEAK of 111ft/lbs at the FLYWHEEL and you can see that this setup has HUGE potential. I say it had lower than desired compression because when I did the compression test, the results were - 130,160,160,160. At 160, that is about 9:1 and It needs 11:1 to make BIG power. Also, some of the best tuned LS/VTEC (1.8) motors out there put down 200 to the wheels on pump gas, so the 2.0 will make more torque because of the longer stroke.
Here is the dyno sheet. PLEASE keep in mind the condition of the motor and lack of tuning. The graph starts out great but falls off because of a RIDICULOUSLY over-rich condition. I went there to make about 6 runs to tune it but I had to stop after the first run because of the radiator problem. I even had to be towed home :(


Another thing to keep in ind is that the stock 89-91 B16 cams are the smallest out of ALL the B series VTEC motors. All the LS/VTEC motors that make 200 to the wheels have pretty steep cams. I will be getting some Type-R or Crower cams down the road to see what they will do.
I have decided that I am going to start supplying the head and intake as well. I am going to have whole JDM B16A motors shipped to me. This ensures that ALL the parts that are needed will be there. When you buy a head and intake from someone over the net, you are pretty much garuanteed that some parts are going to be missing. That sucks. You can still buy a Type-R or JG prepped head if you like, but having me supply the parts is easiest and most cost effective for most people.
Having the motors is also a way to get some good high compression pistons for those of you that are interested in staying naturally aspirated. The B16 pistons are the same bore as the B20A5 motor. If you have the B21 you are going to have to keep your stock pistons. I plan on selling a rod/piston kit that will include the B16 pistons, new piston rings, polished rods with ARP rod bolts. This will allow the motor to rev to the 8100 rev limit if the JDM ECU. MUCHO POWER! You will have to run a hone in the cylinders so you might want to take the car to a mechanic to get this done. If not done properly, the motor will most likely smoke from the rings not sealing.
I will also be offering a turbo kit that will work with the VTEC head. That will make close to 300HP to the wheels at 7-8psi. For those of you that are thinking that you are going to have traction problems, I am also offering a Limited Slip Differential (LSD) for the 3rd gen Prelude for about $1000.
Some advantages to having the B16A VTEC head are the follwing:
More power (obviously)
Easier to find parts - no more searching the WORLD for parts for the Prelude motor. Almost ALL import parts compaines make parts for the B16. You can get parts like cams, valves, springs,sheet metal intake manifolds, fuel rails, etc,etc.....
Bragging rights (I have a 3rd gen with VTEC)
You get to look at the VTEC valve cover when you pop the hood. (when I had it in there, I just stared at it for like 5 minutes)
Since some things have changed in the setup of the kit, the price is going to change. I have not figured it all out yet but I am trying to keep it in the $2000 range. That is with me providing the parts as well, so you don't have to worry about that anymore.
I will mail some more news when I make more progress. Right now I am working on ALOT of turbo kit orders so I am not going to have the head on my car for another month. But if this is something that you want to do, start saving the cash because I will be taking orders for these kits within 2 months.
Here is are some sneak peak pics:


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VTEC Conversion
Updated 4/12/02


I have sold the last kit. I am leaving these pages up for anyone who might be interested in trying this conversion on their own. There is a lot of information here, I have spent a lot of time doing research and actual work on this project. I did have 2 seperate VTEC heads on my motor and they both worked fine with absolutely no machanical problems (except the first head gasket). The only problems that I had were wiring related, but can be worked out. I currently have a 2000 Civic Si B16 head on my car with an Integra Type-R intake manifold. I will be adding turbo VERY soon and it will be a powerful combination when I am done with it. Please use this information only as a guide and GOOD LUCK if you try this conversion.
This kit should only be installed by someone that has previous LS/VTEC swap experience and hybrid wiring experience. Someone that has done these 2 types of swaps will be able to install the VTEC conversion. To make 200HP at the wheels, you will need to install VTEC pistons (PR3 B16, ITR, CTR). This involves taking the rods to a mchine shop and having them install bushings to accpet the smaller piston pin of the VTEC pistons. You will also need ITR or better (JUN or TODA) cams and some adjustable cam gears to make the power. Of course, the setup will have to be dyno tuned to get the most out of it. Please be aware that it is unsafe to rev the stock rods past 7500rpm. If you install Eagle H22 or H23 rods, then 8000rpm will be safe.



Latest News
The VTEC conversion is no longer being offered. It seems to be too complicated for the average enthusiast to install and tune correctly. It also did not make as much power as expected with the stock cams. This conversion is totally possible but I don't feel that it is a good value. The time and labor to install the correct pistons and the head itself are very complicated. When you consider that you have to spend several hundred more dollars on cam gears and cams, it does not seem worth it to me. The turbo kit is something that is easy to install, you don't have to open up the motor and it works well from the beginning. So I feel that is a far better value.
Please do not email me about the VTEC conversion, I will not be answering those emails. Just remember that anything is possible. If you are determined to do this converions, it can be done. There are a couple people that have done it on thier own, but they have extensive knowledge of VTEC swaps and motor mechanics in general.
I will be leaving this page up for people that want to get ideas from it, but I will not be selling the conversion kits any longer.

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I forgot to show pictures of a working B16 conversion:

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MustardCat
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This info is from "vtecdelny" on Preludepower, originally posted 6-24-2010 to 4-16-2017

#2

Post by MustardCat » 18 Nov 2018, 19:53

This info is from "vtecdelny" on Preludepower, originally posted 6-24-2010 to 4-16-2017


just progress report on the impossible swap to show that it can be done.
to continue where tom @ludespeed left off.



1 the custom copper head gasket
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2 all parts laid out on work bench
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3 h23 rods with ctr pistons the pistons had to be machined to fit wirst pin
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4 rod and piston in block..
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5 block with arp head studs with custom fitted all four corner dowl pins
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6 front shot of test fit of head on block
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7 timing side shot of head on block
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8 test fit of hytech lsvtec 4 to 1 header to see where it would hit
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will put more pics as i continue with progress..

vtecdelny;2555373 wrote:i've been researching the "reving" issue for years now, and pretty much have modified the oiling channels to ensure that the bearings are fed enough oil to survive at high rpm's...
vtecdelny;2555382 wrote:trying to show that u dont need "custom" internal parts...thats y i went with h23 rods and ctr pistons....all oem stuff except cams so that it can "breath" better at higher rpm's....got oiling issue handled and beefier rods and arp rod bolts... did a base run on dyno for b20 and got 110whp and when im done, will compare with new vtec setup... like i stated b4, just wanna continue where tom left off and actually complete it and get it running well enough on dyno and street to see what numbers it puts up with out blowing the gasket on dyno like his did....
vtecdelny;2556468 wrote:thanx for the support first of all...and a quick breakdown, this "project," is meant to be a daily driven vehicle with daily use and some weekend track time....i have been working on this for many years now, ever since tom offered it and i was gonna do it with him and had been in contact with him till he fell off the face of the earth...ever since then i knew it was a project that i would want to conquer...i've done many swaps and builds for many years now but its finally time to complete the most important one...i have definately researched and researched over and over every angle i need to cover and address to make this happen...i would just like to make it possible and reliable and a "dream" off a wish list come true. so as u can guess and see by the pictures i will be going n/a on this build (im all for n/a over boost). im going with a stock b16 head, and 81mm b20a5 block. stock crank, stock h23 rods with 81mm ctr pistions, n i am going with aftermarket skunk2 cams for better breathing along with a "small tube" hytech replica header for now...and i will hopefully aquire a after market intake manifold and throttle body...basically it will be a "stroked" b series with high compression....and it will all be managed with a hondata s300...and yes i will be using a copper headgasket for now, and in order to not run into the same problem that tom ran into on the dyno (blowing headgasket) i will be having the block machined for o-rings...at this point i will not be paying cometic $1000-$2000 for a custom mls gasket as they quoted me, even with an aluminum template that i have made already....like i said i did a base run on the car and it was a sadly 110hp to the wheels...but thats fine with me...it just gives me a # that i will have to raise with this project...and if all works out, i will be willing to offer help or parts to those willing to do the swap...
vtecdelny;2731404 wrote:hey guys, sorry to have not been able to keep u up to date on the progress...but i will assure u that i have not given up! and i assure u also that this has not been "just another half ass thread." i have been busy building customer cars and engines, gotta do them first so i can "finance" the "me projects." and just a quick update, i got my head back from machine shop last week, got some welding done on it, resurfaced it, and got a valve job done on it. i have also ordered some sealing rings for the copper head gasket and they will be in this week. which leaves the me to send the block out to machine shop and get basic work done on it...hot tank, hone, deck. and from there its on to getting gaskets, bolts, pumps etc...so it is very close to being done, the hardest obsticals have been conquered and its all becoming all to real for me as well, that years of planing and researching and trial and error are finally gonna come to an end the engine will be assembled. so to the people that talk "crap"...."screw em"... and to the people that have hope, keep it...cuz i promise u all that this is a project that will be completed soon. thanks again.
vtecdelny;2733860 wrote:i will try to get some updates here in the next couple of days...i'll try to get some pics as well. (p.s. i'm not all the "savvy" with forums and posting pics, any hints on how i can post em up so that they show up in the thread without having to click a link, would be helpful). believe me, i want to share as much as i can, im not trying to "leave any1 in the dark," its just that even im not 100% sure of how its gonna turn out and react or run...im pretty confident in it, but just being cautious. i feel that when its up and running, then would be a good time to review all of the relevant work that i did, parts that were purchased, steps i took so on and so forth, and share them with the prelude comunity. i just dont feel right now that i should put every step of work i've done, cuz i dont want to lead any1 down the wrong path....cuz i myself have taken a step and had to back track what i've done or thought was going to be a "good idea" and start over again. just as a small example, i've had to make more than one head gasket design, the procedure with that is i get cardboard paper come up with a "to scale" design and then send it to get scanned. after that it gets cut up into an aluminum plate, i recieve it, mock it up and modify if i need to...then send it back if it needs to be modified or say go ahead and make a copper one. and if had to do this a couple of times and each time i get a plate cut it cost $80! but the copper finished product is only like $30 or so... like i said, i've been working on this for a number of years, each time finding stuff i missed, or adding beneficial improvements that i've found work well as i do other engines through the years. my intentions are to get this as close to being done right the first time...i know that once i start it up there will be some possible issues to address, but my goal is to minimize them as much as possible. that way i go through the "tough headaches" and not you guys if you all would like to do the project one day in the same way.
and just fyi, right now its just being built to run as "daily driver"
if it can survive that, then it would be worth looking into making some power to drag with it. thanks again.
vtecdelny;2854470 wrote:the "normal" b series engines are "wider" front to back, which means once the vtec head is on the A5 block it "hangs" over on the intake side and exhaust side. so i brought the head to the machine shop and had him weld up some oil return/drainbacks that were exposed.

The sealling rings are some specialized metal rings that are supposed to be able to be used without machinng grooves in the head or block. i had them oversized to 82mm.

as far as the gaskets, the only "custom" gasket is the head gasket, the rest are oem

and as far as bolts, no "custom" ones here either, gsr arp head studs, gsr arp rod bolts, and the rest i believe are regular

and yes, on pumps, just basic oem water pump and oil pump

and just some minor/major info: depends what u think of it....i was looking at all the parts for the project (other words, bored one day and my wheels were spinning) and i got curious on the whole "oiling issue" i decided to investigate the bearing delivery channels. our b20a5 brings oil to the bearings from the "bottom." it strats its flow from the pump pick up through the pump through the filter through the block to the cap bridge and the caps to the bearings. the bridge sits on the caps and centered via dowels. i took the bridge and caps and bolted them together on the bench and simulated them being installed in the engine, i then pressurized them to check the how well it sealed. and to my surprise it did not seal very well at "low" pressures. there were many areas of leaks that were found and only got worse as pressure went up, and i simulated the psi's that the oil pump would push out. this could be a "big" issue and probably leads to why our bearings always get starved of oil and tear down. this is also comon on the single cam engines, the d series engines i come across with, a lot of them "develop" rod knocks and tear up bearings. and guess how those bearings get oil fed to them...with the same style bridge cap combo. I've decided to seal these areas of "leaks" along with the previous oiling modifications i did before. hopefully all this will prevent any oil starvation to the bearings.

just trying to do this right the first time and hit every area i think needs improvement...part of the reason as to why this is taking as longs as it is. but i did get the block back from machine shop, had basic work done to it, so it is ready to be assembled. like i said before, i will complete this very soon and you all will be the first to know.


First and foremost, sorry for being "away" for so long, but had some minor "life issues" that kept me away for doing my "normal" day to day work. but i still have not stopped or gave up, i wont until its done and running. here are some pics of the finished modified header, decided to use an itr header instead, and one quick pick of the piston to deck clearance. also ordered a set of 81.5mm ctr pistons and should be here monday. reason why is after measuring the piston to wall clearance i found it to be way too far out of spec, i believe they were at .0025" and should be in the region of max .0015." also i measured all bearing journals, rods and mains and have come up with all different color sizes to give me the proper clearances im looking to reach or get close to at least, i attempted to use acl bearings , but again, once i measured clearances i was not pleased with the results for both sets. i have researched and checked specs and actual physical measurements....and i have decided to use b20a5 oem mains, and oem s2000 modified rod bearings. i chose those for rods since they are made to withstand the heavier loads placed on them for the 9k rpm that the f20c spins at . p.s. hopefully i got this loading pics thing correct and will now be able to provide better updates for you guys.


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vtecdelny;4099929 wrote:Finally have everything finalized , all custom work and parts completed. Its ready for assembly. Prior to that , instead of doing the long forum posts , I've decided to explain all I can via video/videos. Once the first video is completed I will for sure post on here. Sorry for such a delay but I've not given up and promise to keep you updated with the build and the process and results



And that is where it left off for vtecdelny...

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MustardCat
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Info about B20a/B21a VTEC Head Conversion

#3

Post by MustardCat » 18 Nov 2018, 20:06

This info is from "low12s" on Preludepower



B20-VTEC Conversion:

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it's a ctr head with a dpr port and polish. It needs a new valve seat and valve. The conversion is very similar to a b20b conversion, but you will need a custom headgasket, b16 pistons, and aftermarket rods if you want to rev it at all. The redline is currently 10,500, I can go higher but the tranny wont keep up. It grinds as is. I probably won't ever dyno it because I have a 3rd gen rx-7 and I don't really care what the prelude puts down. If I had to guess I would say 300whp, but I have a ton of mods and custom parts to get that hp number.

...See how far the head hangs over the block? The bearings are toda race bearings, and they are good to 12000 rpms. I'm running longer rods and you need the b16 pistons so the valve reliefs will line up with the valves. I'm selling just the head and nothing else. Ok sorry guys I don't really have the time to answer all of the questions on here but if somebody buys the head I will give you all of the info and support you need to do this swap.

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Gasket info: ....it was a custom thing...its a hybrid gasket between the b20a and the b16
...tom coleman used to get the gaskets and sell them with the vtec head conversion
as far as I know, he is one of few that actually know what to modify to make this head work properly...

...I tried the ludespeed gasket but it didn't work out for some reason. So I made my own. It has been going strong for about 10k miles. My compression ratio is roughly 13.6:1., that helps out a lot in the midrange with the big cams. Race gas is my friend . But like I said I dont really drive it that much anymore, the rx-7 gets all the love now. Yeah the engine bay is messy I had to take it all apart a few times and mess with the motor mount. The pics are taken as I was putting it back together, you can see the air intake and the nitrous aren't completely installed in those pics. If anybody is serious about the head pm me. I'll give you the info and the price. Thanks for the interest guys.

Setup: ...Sorry guys I just realized that I never posted all of my mods or weather or not I am spraying. So just to clarify things I am spraying a 50 shot.
So I'll list my mods and I'll probably forget a few things like I always do. The car used to be turbocharged with the stock b20a engine by the way, but it isn't anymore. Ok so my mods are: b20 block sleeved, custom forged destroked crank, custom made long rods, custom made ross pistons, all arp hardware, toda bearings, ctr head ported and polished by dpr, 1mm oversize titanium valves, titanium springs and retainers, jg full race cams, adjustable cam gears, venom intake manifold, fuel rail, 75mm throttle body, rc engineering 440cc injectors, afpr, walbro 255, zex kit custom made header, 2.5" exhaust. Redline is 10k right now, I think thats all of it. If there are any doubts about this I live in nw washington and anybody who wants to come take a look or go for a ride just pm me. As for timeslips I have slips for my mid 12 runs and I think they are posted in imagestation. I don't know if I still have the low 12 runs and yes it was using turbo and nitrous. But seriously pm me and you can come take a look. I could really care less if people doubt this engine, I am not really that interested in it anymore, I have bigger and better things in the works so it doesn't matter to me. I just want to sell this head it's taking up valuable space. As for tuning this setup it's not that different from any other b20/vtec. It can get a little tempermental at times but the guy that tuned it knows his stuff. But seriously why do you think it would be so hard to tune? and I dont run b16 pistons. I have run b16 pistons in the past but this is the 3rd buildup of this motor. I had to work out most of the problems in the first 2.

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