BP-4W Build? Thoughts?
 

Hey guys haven't been on here in a while. Sold my 95 na a few years back to much rust. A few months ago picked up a 99 nb and she's healthy and up to date on maintenance. Just couldn't stay away.
Anyway was browsing my local Craigslist and came across a bp4w engine, flywheels, clutches, and a 10AE dash with airbag all for 100 bucks.
The motor spun #4 rod bearing and I think it might be salvageable but I don't know yet. The head looks clean but the guy said it has the "exhintake" cam and I don't know if its right has the 197.5* hole drilled in the cam gear but I am not sure if its correct
Anyway I plan to build the motor and head up for boost and really want it to be able to rev out to 8k. Looking to pick your brains for ideas on the build. I've got an idea, again just want to hear your thoughts on it. Anything is appriciated
https://cimg6.ibsrv.net/gimg/www.mia...bd018876af.jpg
https://cimg1.ibsrv.net/gimg/www.mia...62247bdac9.jpg
https://cimg0.ibsrv.net/gimg/www.mia...96213e7a6e.jpg
https://cimg6.ibsrv.net/gimg/www.mia...516d6e6581.jpg
https://cimg1.ibsrv.net/gimg/www.mia...0df7357332.jpg
https://cimg4.ibsrv.net/gimg/www.mia...72b5da18a8.jpg
https://cimg6.ibsrv.net/gimg/www.mia...58b39d1195.jpg
https://cimg1.ibsrv.net/gimg/www.mia...f9f0bdc224.jpg
https://cimg3.ibsrv.net/gimg/www.mia...6d3ce98909.jpg
https://cimg2.ibsrv.net/gimg/www.mia...0f7bcb2c30.jpg
https://cimg0.ibsrv.net/gimg/www.mia...bcbcdaa6bc.jpg
https://cimg1.ibsrv.net/gimg/www.mia...f7ea6baeba.jpg
https://cimg6.ibsrv.net/gimg/www.mia...a90dbcf986.jpg

First you should figure out why it spun a bearing.

The bottom end stunk of burnt oil like really old burnt oil I'm thinking it ran low on oil was gonna replace the pick up and get a main bearing support plate from a newer motor and get a boundary pump

That crank looks rough. Take it to a machine shop and see if they think it's salvageable, or pick a better condition used one on Craigslist /scrap yard.

​​​​​​You're sitting on a lot of parts that are going to be replaced for a "build "

I know the pistons rods and bearing are going and the clutches, but you don't think its worth working the crank to run oversize rod bearings?

Get a second opinion from the machine shop. Me personally I'd be hunting down another crank. But if they can polish it and it hasn't breached the nitride depth, it might be feasible. Again, see what the builders say

I second the finding a second crank. You have to pay to get it ground down and polished, then you pay again when you get it balanced. By the time you've done that, you could have just gotten a good (used) crank in the first place.

I found out the hard way that, when sourcing oversized bearings (for the undersized crank), you run into problems if you need to have the option to have slightly odd bearing sizes (1mil under or over). Especially if you have your blocks mains bored/honed out and need slightly oversized (1mil) bearings. You can't get both oversized (1mil) and 20mil undersized at the same time.

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Taking 0.001 off the rod journals would need rebalance?
So you are saying all the journals need to be the same size?

Generally you buy bearings of the same dimension in a set. If it's all oversized or all standard depends on the wear and re-polish on the crank over time. Maybe you can buy a single oversized bearing? But that just seems half assed and you can find a decent miata crank or a lighter protégé cast crank relatively easily.

I never knew about the over/under limitations. I guess those who ever run billet mains and have it line bored, have otherwise pristine cranks.

Well what I was wondering is if I could just have that journal worked and then have the other rod journals match and not even mess with the main but I don't know if that's possible or I'm just dreaming
you said the protege crank is lighter? By how much?

That's completely possible. A good machine shop can work wonders. But those of us out here in internetland are pretty limited in the advice we can give you as compared to a competent machinist who is holding the crank in their hands.

Any time you touch the rod journals, you re-balance the crank.

And, no, the journals don't all have to be the same. You can always mix-n-match bearings from different sets. It's just that if you do, some future engine-builder will find you what you did the hard way, and hire a witch to place a curse on you. Now, admittedly, there are a lot of incompetent witches out there, but is that a chance you want to take?

I wouldn't personally switch to a Protege crankshaft. No personal experience, just a gut feeling that there's a reason you rarely hear about people breaking stock Miata crankshafts even in engines making 2-3x the original torque.

Yeah that was more or less a last-ditch effort suggestion. Miata cranks are forged Protege cranks or cast something something counterweights do a search

Ok so I'll just take it down to my local machine shop, my buddy has a build b16 ek hatch that had the crank worked from some shop down here so I'll just go in and see what the machinist has to say. Hopefully something good if not I'll start look in for other cranks.

Thanks for all the advice :bigtu:

My crank needed to be ground and I ended up getting a new one off her for 200 I think. Treasure coast maitas also has them pretty cheap. Then to balance my pistons rods and crank was $100-150 if i remember right.

I still have no idea if his exhintake cam swap is correct don't know if you guys have any clue what it should look like.

Well I might be in the market for a crank haha. Just need to see if this one is salvageable compared to the price of a good crank.

Dig up a thread that tells you how to appropriately clock the cam gear, then make sure the two front lobes of the intake and exhaust cams are pointing away from each other during install at TDC.

Ok thank you I will check when I get home and do some more digging.

Can anyone verify that my cams are actually intake cams? The guy said they were exhaust cams. https://cimg1.ibsrv.net/gimg/www.mia...14bbfa17ed.jpg
https://cimg5.ibsrv.net/gimg/www.mia...f22a77ccc4.jpg

Those look like intake cams to me. Is the back end slotted for a CAS?


Here's the back of a Bp4w exhaust cam also found on VVT motors
https://cimg6.ibsrv.net/gimg/www.mia...0f2575dd19.jpg

It's clear from the photo that there are not, since the last lobe (#1 aft) is basically sitting on the floor.

First-gen NBs had one sensor on the crankwheel, and another about halfway back the head on the intake side. I had this backwards.
The tabs were on the intake cam between #2 and #3 from '01-'05.
Nope, that's wrong too. They're at the rear. I just can't brain today.


From the bottom photo, it sure looks to me like there are sensor tabs between #2 and #3 on both of those cams:


https://cimg9.ibsrv.net/gimg/www.mia...59cec63d54.png


These are very clearly both '99-'00 intake cams.
These are very clearly both '01-'05 intake cams.
Maybe they are both '99 intake cams...

That's a bummer I guess. Anyone ever run 2 intake cams? 😂 any way to run them or just go ahead and find an exhaust cam from a donor? Anyways this is what me and my pal are up to tonight. Just got it dropped in.https://cimg8.ibsrv.net/gimg/www.mia...c2f4b783b6.jpg

Why is it sideways?

My best friends 96 ek civic hatch b16a turbo car. Helped get the drivetrain in tonight. Just a little off topic.

That doesn't really help me understand why the motor is facing towards the side of the car. Is he only driving the right-front wheel? If so, it seems that handling would be adversely affected.

Bruh this is a completely different build. Its a civic hatch with the b16a motor and a jdm b16 trans with lsd. He needed help tonight

Still confused. It's normal for Civics to have their engines put in sideways?

Not sure if trolling... :ugh:

Did some googling, found that this is considered "normal." Apparently, the engine drives the same wheels that do the steering, the differential is built into the transmission, and the wheels at the rear are pretty much just there to keep the back end of the car from dragging along the ground.

Hondas are weird.

Strange machines indeed... I hear Audi does the same thing. But get this, they connect the back wheels to the drive train as well. :idea:

?!

Wouldn't that basically just be this, but without the ability to do useful work?


https://cimg2.ibsrv.net/gimg/www.mia...4320d2a57c.png

What's that thing that's on the front of that? I think it's that thing that gets done to moms? And a thing that Audis and Hondas do?

Cool splitter bro

BRUH

Why would you put a FWD engine in a RWD car? That's just stupid.

Its a civic hatch how the hell is that a rwd car. Anyways back to the dual intake cams should I find an exhaust cam from another motor or is there anyway to run them

I'd find a different motor.

This.

Spun bearing, wrong cams, who knows what other surprises lay ahead.

Sometimes, life hands you a lemon. Unless life also hands you water, sugar, and ice, you gotta just toss that lemon over the fence and move on.

Well time and money isn't an issue for this build so if I have to take time to get the right stuff and find an exhaust cam and get it all refreshed that's what I'm doing the crank is first on the list but until I get it to the machine shop its gonna be cleaning and more cleaning

I'd get a different motor. What you have here is a pile of broken/destroyed/unusable garbage. Scrap it all. Maybe keep the bare block and head.

Well I did only pay 100 for all of it so if I need to get the crank ground, polished and balanced for 170 bucks what's that compared to just buying a better crank. Don't think I'm gonna scrap the whole build.
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The head itself has to be worth at least $100

I don't know. I buy motors with good cranks because it's better/easier/cheaper/less work/cures my IBS.

I'm not suggesting you scrap the build. I'm suggesting you start with something that isn't scrap.

Debatable. People aren't going to pay anything worthwhile for a dirty used up head with wrong cams in it.

Like I said if I have to take my time source the right stuff and spend a little more money then so be it. I don't have much in just the block and head.

Ok, so what's the discussion at this point?

The discussion was thoughts from the peanut gallery. So thank you for your contribution. Anyone else?

Hey guys I found this bucket of six week old shrimp on the sidewalk what should I cook?

A cheeseburger.

Tell you what fry them suckers up be just fine.

So why not source... a good engine?

https://cimg5.ibsrv.net/gimg/www.mia...b124b24961.png

Tell you what, find me a good, full 1.8 bp4w for 100 bucks and I'll buy it.

If you ever crawl inside an old hollow log and go to sleep, and while you’re in there some guys come and seal up both ends and then put it on a truck and take it to another city, boy, I don’t know what to tell you.

If you think you have a $100 engine, you are dumber than I assumed.


https://cimg1.ibsrv.net/gimg/www.mia...c7adf2e93d.jpg

I got mine as a trade for fender flares. Just have to search a bit and they are out there

I thought time and money were not an issue for this build?

Well with no budget 1-800-Andrew @ Trackspeed. I want a built motor and turbo kit please

A good BP4W costs more like $800-$1500. For a reason.

You bought $50 worth of scrap for $100. Congrats. We're all impressed. Not a single person here is going to align themselves with your stupid decision, so give up already. Either do what you're planning on doing and ignore our advice, or take the excellent advice that has been given to you multiple times in this dumpster fire of a thread. Either way, do SOMETHING and stop talking about it.

In the even that your budget is $100, i suggest you find another hobby.

They only made a couple million BPs so I'd hold onto the one you got. You're lucky enough to have one of those! There's only 21 million Bitcoin and those are what, $7-8000? You scored a motor that's even more rare than that for $100! These people are just trying to steal your motor & money.