semipimpedauto

I picked up a 97 m-edition with 141k on it for $700 about a month and a half ago running on 3 cylinders. Compression test verified low compression on cylinder 3 and I'm planning on building this car into an exocet next year. I decided that I'd like to get the mechanics right before going into exocet mode and would like some advice on how to proceed. The reason for the low comp was a cracked exhaust valve that did not damage the cylinder walls at all. I had a lock on a PnP'd '99 head but the shop that pulled it determined it was too warped and would need line bored. So my real question is, what should I be doing while the engine is out and the head is off to set myself up for 50-60k worth of spirited driving and hopefully be in the 150ish N/A power pocket? Budget is about $2k.

hornetball

iTrader: (4)

A head needs to be line bored? Don't understand that.

Check out Emilio's recommendation for parts combination that will get you ~140RWHP. Search on "949 + 95R" or something like that. There might be a link in my red car build thread.

Sparetire

Basic stuff:

Engine Mounts - get the MazdaSpeed ones.
Cooling, get it properly routed, though I really have no clue have an Exocet might change this, probably less necessary, but a good proper reroute is still a good idea.
Clutch and Flywheel - I'll be getting the Supermiata setup when the time comes.
Clean the engine, probably does not matter much if you clean the chassis in this case.
If you think there's any chance of going turbo in the future, maybe drill and tap the oil pan for an oil drain now, and just run a plug in it if NA.
????

curly

iTrader: (25)

Hornetball, If a head is warped, the cam bores have to be line bored.

You'll need a '99 head, mspnp, racing beat or better header, maybe an exintake swap, and some dyno time for 150ish hp.

Leafy

iTrader: (1)

Or it could be unwarped. Bogus SVO claimed that he could do it, but the head had better be worth it.

hornetball

iTrader: (4)

Ahhhhh! Forgot cams. Have BB MOPAR on my mind (working on the Sport Fury).

semipimpedauto

Excellent advice guys, keep it coming. Also, the head was coming off a motor that went to compression readings in the 60's and it overheaded and warped the cam journals. I am still pissed about not getting that head.

my97miata

Is that 150whp with the stock bottom end?

Savington

iTrader: (31)

I've been told that straightened heads tend to re-warp extremely easily.

Leafy

iTrader: (1)

I guess it depends. In theory if you completely took the heat treating out of it while straightening it, then re-heat treated it before it cooled after straightening it wouldnt want to re-warp because any previous stresses would be gone. But thats probably a multi thousand dollar process I just described.

semipimpedauto

Well, I got a nice deal on some ACL race bearings but am not sure I want to start throwing money at the bottom end for 150hp. Help me understand what kind of money I'd be looking at to have the +.25 bearings installed correctly. And with that kind of work being done I might as well have the cylinders bored out a little and then I should upgrade the rods and then.. and then.... I am struggling with the slippery slope mentality and want to do what makes sense and not throw $1k in for 3hp.

curly

iTrader: (25)

Well, I'm going off other's dyno results, not my own.

But as far as I know, 150hp is done with a stock bottom end. I can't think of much that actually makes power down there. As long as you have the 10:1 pistons of course. If you can get the 10.5:1 JDM pistons, that's obviously the best course of action.

Ah, just realized you're probably referring to boring out with larger pistons and/or stroker crank. Yes, I believe close to 150hp has been made with a stock bottom end, the above mentioned mods, and some dyno time.

Leafy

iTrader: (1)

There's plenty of power down there. The top STL miata engine is making just over 190hp with a VICS manifold on a 99 head with a 11:1 compression limit, a 0.485 cam lift limit, and only allowed to port 1" into the runner on the head. That 50hp he's making over a normal VICS 99 build with a custom intake and RB header cant all be from the cam, pimpy header, minor porting, and the unlimited valve job. Its got to be coming from the fact that there's no limit to the piston, rings, and bearings besides the fact that it cant be higher than 11:1 compression. I dont know what, but I know its there.