Hiroshima_Hairdryer_92

So as an early Christmas present my dad bought me a 94 block for me to rebuild. So I have the motor all the way stripped down to the bare block, and I am going to get it machined later this month. Once I get it back I plan on putting forged internals in the motor as I will be in there anyway so I might as well do it right the first time. I was informed that a local salvage yard has a 99 Miata with a BP4W head, I called them up and asked how much they charge for a head and they quoted $100. I am picking it up this afternoon, I was just wondering since I'm sending the head into the machine shop what would be some things to do with the head while I have it disassembled. On a BP do aftermarket cams do well wither forced induction, or should I just leave the stock ones? I am really trying to build this motor right as I don't believe in doing things twice, especially once you stick this kind of money into a motor. Anyways any tips are appreciated, this is the first motor I have ever built.

matrussell122

iTrader: (1)

Having built a no limits #allofit motor. Just do a adjust the valves, do some springs and seals and call it a day. Have them make sure none of the valves are bad and if you need to replace them just do oem sized stuff. Leave the cams alone if you are doing boost. Then obviously have them clean and deck the thing.

SpartanSV

Power goals and planned use for the car are critical pieces of information.

Ramonn

Welcome Brody! Now that is a christmas gift

Stock cams on miatas work quite well with forced induction. No personal experience, but I know some people got bigger lift exhaust camshafts on their turbo build to see less than expected gains. If you're really going to push that 2560 close to or beyond 300 whp most will advise you to for sure do it right the first time. However this does not mean upgraded cams. Horsepower goal is really something to consider though. How much are you able and willing to spend on the "total" build?

shuiend

iTrader: (24)

Get the Volvo valve springs, throw in new valve seals, and adjust shims and call the new head good. Not worth putting more money into it then that.

Turbomack

I’m curious to see the builds and talk to these people with less than expected results. What were they expecting? From someone that HAS done it AND LOVES the 264/264 cams, I would highly recommend them. Was expecting a low 3 build result and ended up with an easy north of 4 build which would/could have been 5 (i.e 500 HP) if we had gone to 9k rpms like motor is built for. 405 in a safe zone was enough for now.

As was already asked, what are build and budget goals? I’m not asking why as that can be too personal but “what” is necessary to get better targeted advice.

Cheers and and good luck!

Hiroshima_Hairdryer_92

I would like to see 300whp on E85, and honestly, I still live with my parents and the budget is ballpark $12000 more or less. It is a progressive build, at this time I am still a student and its just a side project so I may decide to change up my setup and my budget depending on what opportunities arise.

Ramonn

I always believed the stock miata exhaust cams and valves are very big to begin with and respond very well to especially small turbos. Nice to hear that 264 is working very well for you @Turbomack, gonna try and remember that. Whats the lift on those? And do you have some kind of comparison on stock vs those? Soorry I'm curious Would you still recommend them on a build like his though?

@Hiroshima_Hairdryer_92 As you've already been told, 300whp is the somewhere in the middle and will most likely require you to get rid of that 5-speed. However, I think it's perfectly fine to build it right and get your power goals on the safe side. 12k usd is a lot and I believe (not american) is realistic to get to your goals and will for sure leave some room for a few chassis upgrades besides the drivetrain when going with the FM DIY kit you said you were. Personally I would not go with cams as for me they over-complicate things stock ones never hurt no1.

Turbomack

You need to keep reading and studying. As I and many others have posted, 300 is somewhat of an awkward number. Most stock part projections are up to about 250. You put the parts in for 300 and they are basically the same, including E85, for 350-400 or even more like my build. That’s really how I ended up at a north of 400 build. Now I’m actually pretty close to having a good build for nearly 500. All I really need now is a better tranny and diff and I can be at 480. To conclude, my 2 pennies worth of advice for you is that you plan for either 350 on E85 or 250 on pump gas. But, my 2 cents may only be worth 1 cent.

The additional complications of, for example, E85 and other stuff for a 350 build probably shouldn’t be on your first big turbo build. Now you can probably discount my 1 penny advice to half a penny.

Turbomack

Sorry Ramonn, we posted on top of each other at that same time.

Turbomack

My cams are 264/264 Kelfords with 8.95/8.95 lift. Supertech HD dual valve springs. Picture of box and springs are in my album.

I really don’t have an apples-to-apples comparison with previous build that was a 250’ish setup. 264’s give you more HP at sacrifice of some TQ. I think it is perfect. Sounds amazing, throws off about 280 WTQ which isn’t as apt to break the 6MT or 3.9, and fit with the Stage 3 clutch we already had that is good for 320 WTQ. This last build also added a nice precision turbo, EBC, E85, MAXX ECU, etc, etc.

WigglingWaffles

As far as cams. If you're up for the extra work involved in setup, you could always go for an exhintake setup later on down the line.
There's not massive gains to be had, but it's likely worth it.

Ramonn

Oh sweet. Wow 405 whp 280 ft lbs wtq sounds great tbh haha. You said to get a better tranny and diff. You run 405 whp on the 6 speed? I suppose torque is the trans killer here so those cams might be a good bet with the 6 speed after all. But like Elliot said it's no problem to upgrade cams later on.

matrussell122

iTrader: (1)

Just K swap and live happy with 250 then as budget allows swap in some cams and be happy at 300.

borka

iTrader: (1)

Honestly a rods only engine build is perfectly fine for 300hp.

I'm running a $100 94 block, 94 pistons, new acl bearings, rings and ebay rods.

Had a this motor for 2 years now, first with a 2560r at 17psi 270hp. And now a efr6258 at 17psi at 309hp 273tq.
pump gas. Zero issues, done autox and track days, and a couple drag days.

I say you better spend the extra money on a kraken setup with a 6258 turbo, rather than cams.

With a built block and a refreshed head, you can push 400hp on e85 with a 6258.

SpartanSV

Rods are all you need for 300 whp on E85.

Hiroshima_Hairdryer_92

I've had a late night tearing into the head getting it ready for the machine shop in the coming weeks. I was having trouble with a 2 or 3 of the caps as they wouldn't wiggle off and were being very stubborn. I used a shop towel and a screwdriver to gently pry them off not using large amounts of pressure. Once I got them all off I noticed I scraped up the surface under the caps, I'm just wondering if that will come out in machining or not? Should I be worried? Sorry for the noob questions lol

Ramonn

Lol what part did you scrape? If the surface is rough cast it most likely can take a lil scratch. If it's a machined bit like the camshaft bearings it may be more of a problem

I just use a rubber hammer to gently tap side to side for the caps tbh.

ryansmoneypit

iTrader: (6)

I'm building for 300 hp, I used a screwdriver to pry the cam caps off.. you better step your process quality up about 7 notches for this build.

Hiroshima_Hairdryer_92

I used a rubber mallet and they just wouldn't budge, it was getting very frustrating, I looked up how people got caps off that were stuck and they said a screw driver with a shop towel so I tried it and it worked fine on the 2 stuck ones. The only spots that are scraped are under the caps, I assume I should be fine because nothing went from end to end of the surface it's just a few spots. I know it was kind of a redneck way to do it but they were being a little too stubborn lol. I will post pics when I get home.