Don't exintake for FI - do BP-DE intake cam instead
 

Hello gents.

I figured I'd offer this up while I am busy making enemies over in the suspension area.

Here's a freebie.

If you are perusing your local junkyard and come across a 97-98 protege with a BP motor and an automatic trans you'd be smart to grab the intake cam. Well, and the crankshaft while you're at it (we'll do another post about that).

So, the intake cam. As you can see, some good lift but short duration. In stock location it'll give 13deg overlap (short overlap). This should be good for FI, and it's nearly free.
Also, it's solid lifter so it'll drop right into a BP4W.

BP-DE (US/Can) (MY1997-1998)

Intake cam duration
233° @ 0.003"

Intake cam opening
3° BTDC

Intake cam closing
50° ABDC

Intake cam lobe height
45.0mm (1.772")

Intake cam base circle
36.0mm (1.418")

Intake valve lift
8.9916mm (0.354")

Valve overlap [assuming stock rotation]
13°

(97-98) direct shim over tappet actuation, timing belt

Interesting find. Especially in a Protege and Auto only version

Overlap is used with both cams' Are you getting the 13 Deg with the Protege or BP4W exhaust(or are they the same)?

Edit I found this info:

"For the BP-ZE engines (I will list only the 99-00 Miata cams, since the 97-98
Protegé ones don't give real performance increases):
BP2Y-12-183 lifter bucket (need 16, and also 16 shims)
BP4W-12-420 intake cam
or BP5A-12-420 JDM intake cam (237° vs 241° duration @.003", either
cam maintains the same 17° overlap)".

The BP4W Exh cam has 0.004 less lift but a few degrees less overlap (can be fixed with cam gears). the MSM cam has a little more duration with the same lift. Protege cam might save you the trouble of repinning it but finding a cam in good shape 20 years later is tough.

for the Hydraulic lifter guys I also found this:

MazdaSpeed also have cams and cam gears
for the BP-ZE and BP-ZET engine. The part numbers are:
QEP6-12-420 intake cam (255° duration @ .003, 9mm lift)
QEP6-12-420 exhaust cam (255° duration @ .003, 9mm lift)

Yes exhaust in the BP-DE is the same as the BP4W so if you drop the DE cam into the BP4W head (in stock location) you'll get the 13 deg of overlap. The shorter duration of the DE cam enables the sorter overlap. Also it's an easy swap - no re-pin etc and what are you going to pay for it? $30 at boneyard?

How much do you need the shorter overlap? Don't know but should be a bit more efficient with boost.

I've got a lot of miatas. I've got one running na with this motor and it's fun in lower revs. But I'm anxious to pressurize it and find out if the less overlap helps in FI.

Yes I suppose where you pin a BP4W exintake will determine the overlap of that set-up. Then the question becomes one of shorter duration.

I run that crankshaft... Some have told me I'm a fool for doing it... The more you learn sometimes the more the masses think youre an idiot if you don't follow conventional "wisdom"

Is that another source for the lighter cast crank that was in the old B8 SOHCs? Asking for a friend.

Yes. 26lbs.

Makes a 1.8 rev like a 1.6

So.... slower? Seems backwards.


Is it the SAME crank as the old B8 SOHC? Or is it a different cast crank?

You've been wise. That crank makes good things happen.
I've got a 90 with the BP- DE motor (with the lighter cast crank) and it's a happy engine. Revs quick and eager. I just bought a BP4W head for it. I'll shave .080 off it and just go NA with the intake cam from the DE head. It's a really fun motor. I've got a FI'd '97 Miata with 220whp and the DE motor'd car is more fun (with nearly 100 less whp).

I didn't say less power like a 1.6, but the 1.6 is clearly more happy to rev than a regular 1.8. The lighter crank from the DE used in the 1.8 makes it rev quicker (obviously load dependent). I've got a picture of it somewhere with the casting number. IIRC it is same crank as B8 SOHC.

I'm making a joke at the expense of "Shit M.net Says." The 1.6 does not rev faster than a BP. It's not "happier to rev" than a BP. It just sucks that much worse below 5000rpm that when it finally decides to break triple digits crank HP, it feels like an event.

I like lighter rotating assemblies though, so i thank you. :) Would be interested in pic. Just has two counterweights, correct?

It has single counterweight at each journal (vs 2 per journal).

Also interesting on that crank. Half the counter weights eh?

Somethings tells me a BP4W w/ 10.5 pistons, B8 crank, MSM/BPDE intake cam and a Squaretop manifold would make a fun all-Mazda n/a motor

So like this?

http://i16.photobucket.com/albums/b2...6.jpg~original

It's a thing of beauty and a joy to behold
good for up to 300hp.

https://cimg4.ibsrv.net/gimg/www.mia...31836373a5.jpg

It's got oil squirters too (my motor).


https://cimg9.ibsrv.net/gimg/www.mia...4590033ed.jpeg

I'd need it to hold about.... 200hp.

ive always advocated the auto cams for a 1.6L for FI.

are we suggesting to put a hla cam and lifters into a bp4w?

"Also, it's solid lifter so it'll drop right into a BP4W."

"(97-98) direct shim over tappet actuation, timing belt"

97+ Protege BP's switched to solid lifters. Too bad the 97 Miata's didn't as well

missed that part. sorry it got messy with the mention of HLA guys