Future power plans, is it enough or should i build more?
 

I came across a super deal on a motor which consisted of

protege block
bored to aprox 1.9L
JE pistons
GTX rods w/ arp hardware
arp head studs
worked over 95 head, port polish, 99 springs and retainers
MBSP- which is the stronger baffle that miata roadster sells

This setup will be used with a gt2560r and begi's mani and SGDP

So my question is, since this protege has a smaller crank will the stock oil pump gears hold up?

And if not, should i swap the miata crank/oil pump and stronger billet gears sitting in my room into the motor? Thats if they are interchangeable.

OR start over with an early 1.8 block and build that with a 99 head?

How much would it cost in the end if you went with your Plan B rather then buying that protege motor? Consider that.

If the deal really is super, id take the built protege motor, I think its oil pump gears are the least of your worries.

I already have the built motor in my possession. I would say starting over from scratch would cost anywhere from 3-4k.

The only thing that really worries me about this protege motor is the gtx rods and protege gears.

How high would i be able to push this motor with a gt2560 safely? If 275whp would be completely safe i would be fine with that.

Ok, you know the rules man. You can't say "I got a hell of a deal" without telling us what you paid.

IMO, rods are the limiting factor in a sense. You could probably make 400whp with that motor at 7K running an asston of boost. But if the motor is still making power, it will be hard not to rev it higher and take advantage of it. Problem is, RPM is bad on the engine, specifically the rods. Granted, I know nothing about the rods you mention, so post whatever you know about them I guess.

With proper tuning, a stock 1.8 should be able to reach your power goals reliably, but there are a few constraints:

7Kish Fuel cut
Conservative enough tuning that you NEVER knock
Run a harmonic balancer

If you do that, a stock motor should last. If you rev it to 8K, it's hell on the rods and causes crank flex, which is linked to oil pump failures. If your worried, buy a set of rods and put them in. Then you're good to go. Sell the gtx rods to help recover some of the expense.

I paid 2k from a reputable local shop that had built the motor 2 years prior. The owner of the motor was an employee and said he built it, dyno tuned it and made 310 whp on it @ 10 psi on a t28. My plans are a bit more boost on a t25 and a bit less power. Im looking for reliability, hence the oil pump gears. But im just about done tinkering with this motor and want boost back again.

As for the rods, their isnt much info on the gtx rods other than them being forged and im guessing could be safe at or around 300whp. I dont plan on ever revving past 7300 tops. This car will always be in daily driven forum but i want it to be able to take a track beating as well.

Throw it in and drive it. The stock motor supposed to hold 250 good and iffy 300 ish. So with this one being built, It should be good for more hp than stock. I wouldn't worry.

You already bought it, And your only wanting 275hp. It sounds perfect.
Enjoy it.
The motor is used, it has already proven its self.

If the oil pump is that big of a worry, put one of those oil things Hustler wanted. If the oil pump goes out, mabe you can shut it down before damage.

I think you will be fine, especially for a dd with sometrack use.

I wouldn't think of going another route, MY OPINION, PUT IT IN, DRIVE IT LIKE YOU STOLE IT!
It is a built motor, and those rods are stronger than stock miatas. Paul is pushing 300hp on stock rods. So I think gtx's should be fine.

It isn't like you are pushing 400 hp out of it.:)
Run that beast.

Paul also broke his oil pump gears too at 300hp..

I think im just going to throw it in and drive it

Paul wasn't running a balancer on that motor when it lost an oil pump while bouncing off the rev limiter. He does now.

Almost all oil pump failures are from people not running balancers. I can't recall one case where they broke and the guy ran a balancer. I challenge anyone to find an example of someone that broke their OP gears that was running the stock harmonic balancer. And when you find one, since you're on a roll, then find some test results that shows a stock fuel rail is insufficient, or better yet, comparison test of a stock fuel rail vs aftermarket fuel rail that shows the aftermarket is better. (testing "performance" parts... *gasp*)

Pat, do u think the stock pulley would be good enough? I feel like the ati pulley would almost be overkill.

I'll answer this with another question. How many engines do you know of that run a stock harmonic balancer and broke the oil pump gears?

I dont know of any, so i guess that answers my question about that.

As far as cranks go, does anyone know if the miata 1.8 longnose crank fits or is a direct swap into my protege block? I would assume so since the pistons mate up to the head properly but just want to make sure.

I have a friend locally who is willing to let me grab his crank out of the bottom end of his 99 motor as well as the oil pump. Are there any differences between the 99 cranks and early 1.8 cranks?

All 1.8 miata cranks are the same. So it should work.

ok pat ill take your word for it, tomorrow im going to be pulling that 99 apart so ill report back with my findings. Wish me luck!

Are you sure the crank on the motor you have is differant from the miata crank?????
I thought they where the same???? You can interchange rods on them. And ford owns both companies, and patents. Just a thought.

And FWIW, unless you really know what you are doing, I would trust a machine's shops work over my own. But I still don't know what the differance of the crank will make on the oil pump anyway. If the stock miata's go out at 300, your still in the same boat. From the list of options above. It sounds like he intended for this motor to last and take a beating.

FWIW: I think you may be over thinking this. But it is not my car.:)
Before I did all that. I would talk to Corkey Bell, and Flying miata. They will shoot you straight. They build these motors everyday. Not just one car. But special order, and special function motors.
Then you know what you wanna do for sure.

you know what guys, fuck it!

Im just going to put it back together and wait for my parts from begi to arrive. I mean, the previous owner did make 310whp on it with a larger turbo so i should be just fine around 250-275. Thanks for all the info guys!

There is ZERO that is special about GTX rods. They are identical to the stock BP rods. The only stock rods that you should be interested in are the B6T rods or the GTR rods.

I may be mistaken then, the previous owner had stated that they were forged gtx rods. Even if they are stock rods they should still be good at my power goals.

Totally agree - GTX rods are piss weak. B6T are strong, GTR are stronger, H Beams are a good option

Click Here for the effects of GTX rods at 16 psi :mad: