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Discussion Starter #1
Hey guys. So I haven't posted on here for a while due to school and the Lude being in storage, but now that I'm finished it's time to get back into Luding.

for those who don't know I own a 1990 Honda Prelude SR (I swapped in 4WS) with the B21a1. about 4/5 years ago in highschool I attempted to rebuild the engine (never gotten inside an engine prior), and long story short spent to much money didn't do enough research. It started ticking a while back, but today the rod bearing finally just went. Super loud clacking, no power, I tried to make it home but it stalled and wouldn't start back up.

Luckily I've had plans to swap the engine anyway, and I've JUST started collecting the pieces. I've started a couple build threads (I apologize) but now it's ACTUALLY happening, because I have no choice. Which is kind of a good thing. Anyways.

I'm doing a B20 build. Please don't talk to me about going H, because I wish more than anything I could go that route, but I simply can't afford it. Nor can I afford to turbo :( One day. Any help or parts you guys have that you could sell and ship to me for cheap, I'd be more than appreciative. So here we go, this is my plan.

B20A5 block - I'll be getting a fresh hone and the top machined, and of course the entire thing pressure tested.

B21A1 head - As much machining will be done as long as I can afford it. I hope to have shaved flat, pressure tested, and hopefully mild port and polish job.

(Acquired) Camshafts - B18a1 Intake, B21a1 exhaust. I'd love to get my hands on some adjustable gears but I can't find any anywhere. Any help would be great. Also, in terms of getting cams re-ground, is this worth it to do?

(Acquired)There was an H22 at Pick and Pull the other day so I grabbed the valve springs. The engine was in rough shape.

I originally planned on using B16 pistons and think I still might go this route. I read that the compression is around 12:1 and some people are concerned about not having access to 94 octane. That's not an issue for me, and I plan on carrying around some octane booster incase I'm ever in a situation where there's not a Chevron. Some of you guys have used GSR pistons correct? which sit around 11:1? Thoughts?

(Acquired) Connecting rods - H23 which I'd like to get balanced and of course machined to fit the pistons I go with.

Crankshaft will be the stock B20a5 crankshaft which I'd like to get balanced and polished. I'd basically like to have the entire engine balanced. Again, $$.

I'd also like to lighten up the flywheel, I've been reading this helps a lot with acceleration and power in general.

In terms of tuning I NEED to have it tuned correct? Especially if I'm running 12:1. And from what I've read I've come to the conclusion that you can't tune our stock ECU? is Hondata my only option? 500$ is a lot to spend in my situation. But if it has to be done and it's my only option I'll figure it out.

In terms of head gasket, any suggestions? I wanted to go with a metal HG but I think I got laughed at last time I asked this because those are only for high output engines? But I mean I'm running high compression here, I want this engine to be very reliable.

Does ARP make head bolts for our engines? or does anyone have any experience using an ARP stud that's meant for another engine? Is this overkill? I read LudeBob89 Got ARP's made up, so I'll give ARP a call and see what's up. But again, if this is overkill let me know.

In regards to clutch. From your guys' experience will I be fine with a stock clutch or is this is dumb question where I should obviously be going with a stage something. I WILL be driving this car fast.

I also grabbed a Vigor Throttle Body.

So I'm going to grab a B20a5 complete engine from pick and pull most likely, or from the guy that I'm grabbing my rods from in Lumby BC, who has a bunch of preludes. I'll be using the B21a1 head from my car as long as it's not toast.

I realize my questions may sound nooby, as I'm using words lie "I'd like to", and "Hopefully". But this IS happening, so I'd appreciate your best advice. I've been reading Ninjas build thread and others and they've helped a lot, but I'm trying to do this as cheap as possible without cutting important corners.

I know the guys at the machine shop in town so hopefully I can do some cash deals. So again, if you guys have any parts that would benefit me and you wanna get rid of them, let me know. Thanks guys.

- Cory
 

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ARP does not make a kit specific for the B20a5 anymore, but with a little searching you can find the part numbers and call them directly and they will make you a kit.

If you are going to tune your gonna need a OBD1 ECU like a p28 or 72, and have it chipped the old fashioned way, you can always to a budget build like megasquirt but for pain free installation and easy tuning a Hondata is the way to go. 500$ is nothing if your going to do a lot of tuning, and may save you money

Doing a 12:1 compression would work best if you set up your engine for E85 as its alot cheaper then race gas, I would be little nervous using anything less than 92 octane on 12:1 set up unless your going to baby it.

Get a stage 1 clutch just to be safe, but an OEM would be fine, that dude named acidcracker sells them right here on preludpower and I think he sells FLywheels also
 

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B20A5 block - I'll be getting a fresh hone and the top machined, and of course the entire thing pressure tested.
Thought about boring to 2.1?

B21A1 head - As much machining will be done as long as I can afford it. I hope to have shaved flat, pressure tested, and hopefully mild port and polish job.
Port and polish is a bit of a waste of time/money. Just a cleanup will reap best results per dollar.


I originally planned on using B16 pistons and think I still might go this route.
I've never read anything on this one where I've thought... "Mmmm.... that's a good idea".
Seems like an awful lot of work/time/money for .... well not sure what for tbh.
Thoughts?
Why not source some high CR pistons for the B21 and use those?


I'd also like to lighten up the flywheel, I've been reading this helps a lot with acceleration and power in general.
A lighter flywheel is a good thing to have.

In terms of tuning I NEED to have it tuned correct?
Yes. Btu depending on what you do the stock ECU might cope OK.
I know an A7 ECU runs at 165hp and 11.5:1 CR just fine.

And from what I've read I've come to the conclusion that you can't tune our stock ECU? is Hondata my only option?
No, a replacement ECU such as those Rev mentioned. You could get a PowerFC to run it as well (but no, I'm not sharing that out here in publicland or anywhere else for that matter). Or you could have my MegaSquirt if you're feeling adventurous.
I also have a socketed OBD0 ECU but haven't bothered running it yet.
So there are a few options with that.

In terms of head gasket, any suggestions? But I mean I'm running high compression here, I want this engine to be very reliable.
A good stock type will easily cope.
You're only talking 12.1, mine ran with 11.5:1 for 8yrs of abuse.


In regards to clutch. From your guys' experience will I be fine with a stock clutch or is this is dumb question where I should obviously be going with a stage something. I WILL be driving this car fast.
I ran a stock Exedy clutch in mine for 4+ years, you won't be giving yours any harder time than that got. Unless you're into doing drag starts or burnouts (or can't drive)!
A stock or Stage 1 will be OK as long as you don't get some cheap crap.

I also grabbed a Vigor Throttle Body.
That will help a little.
 

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Discussion Starter #4
Thanks guys I appreciate it.

YES, sorry, I will be boring the block. If I can find 84mm pistons I'll bore it out to that, if not, I'll stick with 83mm.

Thanks for the advice on the port an polish, I'll save some money there then.

Thanks Rev_Rage for the input on the ARP's, I'll be ordering a set hopefully soon. Using a stock Honda Head Gasket, am I able to torque the head down tighter? Anyone know what ft.lbs I can safely torque it down to?

My lude is OBD1 so I'm lucky there. And I think I'm going to take the risk and try and save money on the Hondata, even though it's more work, I'm okay with that. By A7 ECU I'm assuming you mean the ECU from a B20A7? I'm thinking of grabbing a P28 ecu from the wrecker and having it chipped.

I've heard a lot of good things about Exedy clutches, thank you for confirming my decision :)

As for sourcing out HC b21 pistons, I didn't even know those existed O.O I'll have to look into this.
 

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Multi layered steel headgasket. Sean has a hookup with cometic.

Go high comp b21 pistons on the over bored b20 block

Hondata is a must

New oil pump, gates timing belt, light weight fly wheel and came should suit you well
 

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Discussion Starter #6
Thanks Ludeman, appreciate it.

In regards to the oil pump, what do you mean by "new". Like literally go to Honda and buy a new stock one? Or are there aftermarket ones I should be looking at?

Also, I've read about shimming the oil pump to increase oil pressure, but haven't been able to find out clearly what that in-tales. Help on this?
 

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Discussion Starter #8
Any ideas where I can find HC B21 pistons? I'm using google but sometimes other's know keywords that I do not.

Awesome, thanks Rev I won't worry about that then.
 

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I wonder if a guy could take H22 rods and B21 pistons and then get a thick MLS gasket with some tootsie rolls to check for clarence
 

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Discussion Starter #10 (Edited)
Lol

I missed something. My plan has been to use a B21A1 head. But isn't the B20A5 block/ B21 head combo for Turbo? Won't it lower my compression?

Should I stick with the B20 block and head? Also, I grabbed a B18a1 intake cam, is there a difference from it to the B18B? (I'm noticing that's what everyone is using).

As for Cam gears, I can't find any that I trust for the B20/B21. Do B18 adjustable cam gears work?

And also, is there such thing as 12:1 B21 pistons? Wiseco don't get even close to that, and the highest I'm seeing is 10.5:1
 

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Discussion Starter #12
They're just wider? That's all? Wow. Go Honda.

Thanks for the offer! As it is though, I enjoy cutting stuff up ;D
 

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The only way your gonna get a higher compression with b21 pistons in a b20a5 block buy buying custom made piston from wisco, or you can shave the head and block. The reason I mentioned H22 rods is because they are longer and will cause the head of the piston to push pass the plain of the block. then you can layer up a MLS gasket to get the correct piston the head clearance. But I'm not 100% sure that would work
 

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Discussion Starter #14
Interesting. Yea see I did't know enough to know wether you were joking or not lol. The B16 pistons still seem like a good option for me to reach the compression I want without doing anything experimental.
 

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I missed something. My plan has been to use a B21A1 head. But isn't the B20A5 block/ B21 head combo for Turbo? Won't it lower my compression?
But you can use the B21 baseline as a starting point for what you're doing.


As for Cam gears, I can't find any that I trust for the B20/B21. Do B18 adjustable cam gears work?
Yes the other B series cam gears work. I run them on mine but as said, they can rub on the cover.

And also, is there such thing as 12:1 B21 pistons? Wiseco don't get even close to that, and the highest I'm seeing is 10.5:1
But with a little head work that is enough to get 11.5:1 CR without any issues.
Mine stock was 10.5:1, to get 11.5:1 I merely had the head skimmed, and not to anywhere near it's limit.
 

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I wouldn't bother with a MLS head gasket or ARP head studs on this build, they are nice things to have but money better spent elsewhere.
 

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Discussion Starter #17
Thanks 88SE. I'm going with 84mm B16 pistons so I'll be boring the B20A5 block out and keeping the B21 head so that the size of the quench area is closer to same size of the piston.

In terms of ARP head studs, I think that's now not even an option. I emailed ARP and they said the parts that I requested (I got the part #'s from the ARP FAQ) are no longer available and a custom set would cost me between 800-1200 bucks. No fucking way.

So I guess I don't have much choice. You guys think I'll be fine with my proposed compression?Will stock bolts stretch under these circumstances or am I overestimating 12:1 compression?
 

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I'm going with 84mm B16 pistons
Nto going to pretend I know why you'd do that but it's your choice to make.


You guys think I'll be fine with my proposed compression?Will stock bolts stretch under these circumstances or am I overestimating 12:1 compression?
You'll be fine, and yes, I think you're over-emphasisng what 12:1 is.
 

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Discussion Starter #19
I guess I'm just use to seeing compression being around 9:1. To me 12:1 is high compression, but I guess it's nothing to get excited about :/

I don't understand why I would not. Wiseco pistons aren't an option for me. They're overkill, way to expensive, and I don't even think B21 pistons are even available anymore so it'd have to be custom. No one is currently selling any used pistons so again, I have basically 0 options here because I'm limited by cash yet I want more power. Aftermarket YCP 84mm B16 pistons give me a bigger bore, a higher than stock compression and a price that I can afford. Added to which I haven't yet read anything bad about YCP, guys have used them in builds a lot more intense than mine. So again, why wouldn't I?
 

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Discussion Starter #20
So my whole plan is falling apart unfortunately. I foolishly wasn't aware of the money involved in doing a performance build.

I went to the tuning place in town and they told me I'd be looking at 1000$ for a tune. They also said (like most of you) that I need to get Hondata, and I'd need and want a wideband gauge. Same input Rev_Rage gave me. So I'm past 1500$ and I haven't even bought a single part yet. I don't know how to tune Cars myself and I currently don't have a vehicle so I don't have the time to learn. So tuning is now out of the question. So in my current situation, I'll be building an engine that can run off my stock PK3 ECU. So basically stock. Yay.....

Oh well. I've never had the pleasure of driving a non oil burning prelude before so I guess anything's an upgrade for me. Any advice on adding the most power I can without needing a different ECU would be appreciated! The build is now looking as follows:

B20A5 block
B20A5 Crankshaft
H23 Rods
B21A1 pistons
B21A1 Head
B18A1 Intake Cam
B21A1 Exhaust Cam
Vigor Throttle Body (Although I matched it up with my original and....it's the same size. I don't get it)
And hopefully a decent exhaust when I find a used decent Header.

Disappointed, But I guess that's what happens when you have to many expensive Hobbies.
 
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