2g Prelude Se-I BT1 swap

[OldTimer2gS]

Hey guys...

I have a '84 Accord S and I'm starting in on a full tear down and rebuild.
I have aquired a full '86 Prelude Se-I from Vector and plan to use the engine & tranny, as well as the rear brakes, feul system, etc.

My question is this.... I've see conflicting information about the BT & BT1 engines. So far, i've been able to fine NOTHING on the internet to tell me that the BT1 even exists.... I am fairly certain it does, as my engine is stamped with this code. :).

Vector has told me that this engine is a 1.8L EFI engine. The only specs i have found on the net are for that of the BT engine code, which is a 2.0L.

Has anyone heard of the BT1 or is this just a BT.....

Thanks in advance....

[2ndGenGuy]

Hey man, I think I found some info for you.

Looks like the BT1 is the Canadian version of the A20A with FI.

This link will give you the info. The actual page is down, so I posted a cached Google search. The page has some interesting info. Hope it helps.



http://66.102.7.104/search?q=cache:17qSx46H0wUJ:www.luk-korbmacher.de/Autos/engines.htm+honda+bt1+engine&hl=en&gl=us&ct=clnk&cd=1

[OldTimer2gS]

Thanks a lot... I've been searching for this info for about a week with no luck :)

[Ichiban]

Yeah I've got a BT1, it's just an '86 A20A3, mine is non-egr

[OldTimer2gS]

Yeah I've got a BT1, it's just an '86 A20A3, mine is non-egr

You have a BT1 in a 2nd gen? or in a 3rd gen?

Just cuious... i know that an A20A should be basically a bolt in, with a bit of fiddling, and wiring,... but i have yet to see anyone actually do it...

Also... what are the actual numbers on this engine... i'm seeing 110 - 120 bhp with the EFI, is that acurate?

Thanks again

[Ichiban]

I have an 82, which is the early 2nd gen. You have the later 2nd gen, and it's engine bay is nearly identical to the 3rd gen, so your swap will be a bolt in, mine will not, as the front crossmember is about 3 inches closer to the engine. I need to fab up a custom front mount (easy) and custom header to route the exhaust to the right and under the tranny (not so easy), reason being, my original engine had rear exhaust. Also, I'm using an 87 Prelude tranny, 85 Accord SE-i shafts, wheel bearings and drive flanges. Have a look at the axle-swap how to in the 2gen forum. As for the hp ratings, the 86-87 FI engines are around 110 hp, and the 88-89 engines I've seen ratings from 120 to 137 (who knows?) the difference being the exhaust manifold design. With a cam, port job, different intake, slight bore, head shave, new injectors and custom header I'm hoping for around 140 hp, realistically.

enjoy!

edit: Phydeaux, one of the 2gen board administrators has done the swap on the late 2gen, like yours.

[OldTimer2gS]

Hey guys, it's been a while, but I have actually gotten on this car now (I found an '88 Accord Ex-i coupe that i've been playing with so i got a bit side tracked :).
So far on this build, i've torn down the front end, extracted the EZ 1.8 l OEM motor and tranny and swapped in rear disks from the '86 2.0SI donor.
Plans for the rest of this car:
BT1 2.0SI engine swap & tranny
Fuel Cell
Roll Cage
Exi / Lxi Front brake swap (10" rotors)
86 'lude 2.0SI rack & pinion swap
And that's just the start :)
This is my race project so it's going to continually be built.
Because it's a "race car" it'll be gutted and lightened and probably ripped apart a couple of times, but it'll be fun....
I'll put some pics up later tonight of the work so far

[2ndGenGuy]

Sweet! It will be the first "full race" 2g that I've seen (aside from the one with the V8-RWD conversion).

Just curious, which EXi / LXi brake swap are you considering? The 3rd gen Accord? Were you going to make an adapter bracket for the brake caliper and move it out then toss on some 10 inch rotors? Or were you going to adapt some different knuckle onto the car? Just curious. I like hearing different ideas for these cars. :)

Can't wait to see the progress!

[MessyHonda]

wow that sounds cool...any pics of your cars?

[OldTimer2gS]

Just curious, which EXi / LXi brake swap are you considering? The 3rd gen Accord? Were you going to make an adapter bracket for the brake caliper and move it out then toss on some 10 inch rotors? Or were you going to adapt some different knuckle onto the car? Just curious. I like hearing different ideas for these cars. :)


Yeah, i haven't figured that part out yet, i am thinking about adapting the entire strut mount system from the '86 lude SI donor that i have. That would give me the same mounts up front as the lude and the 3g accords. Then i could use the knuckles from a Exi or Lxi and mount them up. It also would give me more options for springs and shocks.

I have pictures, and can take more, it's not much to look at right now, but the ones i've taken are on my phone, and seemed to fail when sending them to myself, so i'll try that again today.

I'll also take my digital out and take some snaps, but that'll have to wait until later today at earliest.

Once this phase is done, i also have a B18A1 that i'm thinking about building up for this application. Currently i only have the long block so i have to source the rest of the swap before i can go ahead with it, that's why i'm doing the BT1 first. Should be a good first step to see what the balance of the car is like before the monster goes in :)

[OldTimer2gS]

Hey guys, it's been a while, so i thought i'd update while i'm on here, and let you know that the project is still running.

So far, i've got the following completed:
- Car is completely stripped
- Prelude 2.0SI rear disc swap complete
- BT1 test fit in the car.
- Fuel system ordered: 5 gallon fuel cell, steel braided lines, MSD 85psi fuel pump: should be here this week.
- interior metal work done

I have a question for those of you that have completed a A20 or derivative in a 2.5 gee. I'm seeing some issues with the Oil Pan and the Driver's Side Mount.

The Oil Pan seems too tall for the support that runs between the front and rear crossmemebers. Will i need to use the Prelude support to gain the clearance that i need, or should i use the Oil Pan from the EZ motor?

Also, the Driver's Side Mount's mounting bolt holes are a touch different. I haven't seen any reference to this on any of the other threads to do with Engine Swaps. Are people using the 2.5 gee mount and drilling out the A20 block's mount holes to fit? or are people simply using a different mount all-together. The BT1 mount bolts onto the car horizontally, but the EZ mount bolts onto the car vertically. if i leave the mount in the car that came with the 2.5 gee, then i'll need to use the 2.5 gee mount, however it's crooked with bolted to the block.

Anyone that could give me some insight into this, or suggestions on how to solve it, i would be greatly appreciative.....


Anyway, everything's coming along nicely, but slowly. I'm trying to make a push to get it finished due to the fact my 3gee has seemedly going through it's 3rd engine in 2 years! lol.

Keep up on the progress by clicking on the link in my sig for the 'Race Car'.

Thanks in advance, for any help available.

[Ichiban]

I do believe that the side mount from the EZ needs to be bolted in place of the A20 side mount. If you remove the timing covers, you can access the bolts easily.

[OldTimer2gS]

Yeah, i feel like a bit of an idiot... I made that post, and then i went outside and did just that :).... sure enough, the mount unbolts from the engine and should bolt right onto the BT1 aka A20A3.

Thanks for the response!

I should be able to get the engine in the car by the end of the week. Pics to follow....

[OldTimer2gS]

Ok, well, i got the engine in the bay now... i think i need to swap out the rear mount for the 2gee one, but other than that, the mockup is done. Picks @ http://www.kelownaimports.com/?page_id=96 or by clicking on the link in my sig. for '84 Accord.

[Ichiban]

Looks good, Darren. You're in Kelowna? I'm over in Castlegar, next week I'm moving to Red Deer for a job. We just got done shooting a "custom red" on my 82 hatch. Have to take it to the nazi inspection on friday.

[2ndGenGuy]

Sweet! I'm jealous of all the A20 swaps. Seems to be getting popular...

[OldTimer2gS]

Finally got the motor in the car now, with the intake on all the correct mounts.... took a little touchy feely, but here are some pics for ya'll....
http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1155_thumb.thumbnail.jpg (http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1155.JPG) http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1154_thumb.thumbnail.jpg (http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1154.JPG)

[2ndGenGuy]

Sweet! Man that engine looks good in that engine bay. Like it belongs there. It does belong there!!! :D

[MessyHonda]

nice. i know mustard cat did a similar swap...look up his thread

[OldTimer2gS]

Sweet! Man that engine looks good in that engine bay. Like it belongs there. It does belong there!!! :D

I keep seeing references to you possibly doing an A20 swap of your own... when's that going to happen?

BTW, this "A20" came out of a '86 2.0SI prelude which would have a similar transmission to the one you put in your car... So i'm pretty excited to see what the extra power will do with the shorter gears...

[2ndGenGuy]

Uh yeah... my swap... Well, I keep researching and I keep finding more details about performance upgrades. I don't like to be a big BSer but I'm looking to do a complete performance rebuild from the ground up. I have been talking to some people, and they're suggesting maybe not even an A20, but maybe my ES2 block, bored out with an ET head on it and 272 cam to run nicely at 7500RPM to build a little more horsepower...

BUUT, I'm looking to finish my '81 Hatch first because my 2g is my daily driver right now. The hatch should be done quickly, within the month. I'm selling stuff to get money to knock it out... I'm just sucky with my finances is all... Getting paid once a month doesn't help either. The 2g is starting to get valve clatter at 296,000 miles, so it's telling me it wants a new motor fast!

[Ichiban]

The 2g is starting to get valve clatter at 296,000 miles, so it's telling me it wants a new motor fast!

Shit, we forgot to do a valve set, we were so busy. All you need is some feeler gauges and some time, and she'll be quiet for another 296K.

[OldTimer2gS]

yeah, i hear ya. I've got some experience now with the a20, so i like the platform, it's harder to get really high numbers from it, but for the most part you can make some good reliable power from it.

The plan for the BT1 is to put the EX-i style intake manifold, and exhaust manifold (4-2-1), with the 2 downpipes cut and re-welded into a dual exhaust. I have one of those 272 degree cams from colt cams that i was using in my 3geez coupe until i turned a bearing, so i'm going to use that in the BT1. I also am going to run flow benched f22 or h22 injectors and a 85psi MSD fuel pump. That should be good for about 140 hp or so to start, so i'm looking to build from there. The main problem, as everyone knows is that there still aren't any companies out there really backing this engine.

For that reason, the BT1 is simply the mock up engine for my A20A3 build. I'm going to be taking the block that i spun a bearing in, it only had about 170,000 k on it, and rebuild it for boost. that's the only way to build real power without breaking the bank. By boost i mean about 10-15 lbs max, so i'm not going to spend a fortune on internal parts, only what i have to do make it bulletproof for 10-15 lbs.

The ES might be a good choice, though, the EZ that came out of my 84 has mild head work done, and i was easily able to push the revs up to the 8000 range. Until the carb finally packed it in, anyway. the long block is still in good condition. I was always really impressed with the power that came out of that small package.

[2ndGenGuy]

Shit, we forgot to do a valve set, we were so busy. All you need is some feeler gauges and some time, and she'll be quiet for another 296K.


I got the valve adjust done last night. The exhaust valves are good, but the intake and aux valves were a little loose. It's quieter now, but there is still some clattering. I found my timing belt tension was a bit more slack than I care to admit, so I'm going to re-tension that too.


yeah, i hear ya. I've got some experience now with the a20, so i like the platform, it's harder to get really high numbers from it, but for the most part you can make some good reliable power from it.

The plan for the BT1 is to put the EX-i style intake manifold, and exhaust manifold (4-2-1), with the 2 downpipes cut and re-welded into a dual exhaust. I have one of those 272 degree cams from colt cams that i was using in my 3geez coupe until i turned a bearing, so i'm going to use that in the BT1. I also am going to run flow benched f22 or h22 injectors and a 85psi MSD fuel pump. That should be good for about 140 hp or so to start, so i'm looking to build from there. The main problem, as everyone knows is that there still aren't any companies out there really backing this engine.

For that reason, the BT1 is simply the mock up engine for my A20A3 build. I'm going to be taking the block that i spun a bearing in, it only had about 170,000 k on it, and rebuild it for boost. that's the only way to build real power without breaking the bank. By boost i mean about 10-15 lbs max, so i'm not going to spend a fortune on internal parts, only what i have to do make it bulletproof for 10-15 lbs.

The ES might be a good choice, though, the EZ that came out of my 84 has mild head work done, and i was easily able to push the revs up to the 8000 range. Until the carb finally packed it in, anyway. the long block is still in good condition. I was always really impressed with the power that came out of that small package.

Yep, there's not a ton of aftermarket for these engines. I think it just comes down to researching sizes, seeing what fits, and good old-fashioned machine work to get the job done.

That's interesting about the EZ though. I always wanted to really check one out ever since I saw it in the wrecking yard. It would be awesome to compare the heads and parts to see what could be done to increase performance.

Good luck with the boost project! That motor should have no problems holding boost and get you 250hp easily (from what I've read here). It might be time to look into adapting Prelude equal length halfshafts as well, and an LSD while you're at it!

[OldTimer2gS]

Hmm, i didn't think that the ludes or any of the a20 trannys came with or were adaptable to LSD... do you mean custom, or do you know of something...

[OldTimer2gS]

Update:
Well, i got some more work done on my project, today, i got the brake booster and master cylnder from the prelude donor car cleaned up and installed into the accord. It's tight, but it should be ok.
I also ran all the steel brake lines back through the car, i had removed them so they wouldn't be damaged during welding and other repairs, and mounted the prelude proportioning valve.
I don't know when i'll be able to work on it this consistently again, i've put in a lot of work this week :). Feels good to see some stuff get done.
Started the exhaust, planned is using the 4-2-1 manifold from a 2nd gen prelude and splitting off to dual exhaust.
Here's the current state...
http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1159_thumb.thumbnail.JPG (http://www.kelownaimports.com/wp-content/uploads/2007/08/dscf1159.JPG)

[2ndGenGuy]

Phantom Grip supposedly has an LSD setup, people say you need Integra internals, but from my understanding, the 3rd members are the same in the Integra or are at least close enough to make it work...

Also, I'm pretty sure these guys make an LSD that will work:
http://www.opmautosports.com/products/index.html

Sounds like you're making progress... Are you planning on making some bastard halfshafts? Or did you test fit the EZ halfshafts to the Prelude tranny... Because it was my understanding that the 2.0 Preludes have bigger splines in the tranny for the halfshafts.

[OldTimer2gS]

I've got the driver's side shaft in right now and it seems like it fits just fine. I guess time will tell if there's an excess of play that will prove me wrong, but they the one that's installed as snug as i've seen any a20 shafts fit.
I haven't tried the passenger side, but it all looks the same and seems like it should fit... the only visible difference between the EZ shafts and the BT1 shafts are the lengths that i can see.....
Thanks for the info on the LSD, that may come in handy very quickly :)

[OldTimer2gS]

Well, i got the last of my fuel system parts in today. Should be fun putting them into the car. On the list of goodies today was:

5 gallon fuel cell w/ foam
filler necks for the fuel cell
20' steel braided fuel line w/ fittings & host clips
85 psi MSD fuel pump
RCI 5 point harness

Once this stuff is in the car, it won't be long before we fire her up..... I'll post some pics as soon as i get the work done :)

[2ndGenGuy]

Badass! I'm excited as hell! Keep up the good work!