LowBoostn

The 1st step or step 1 would be as far as i would go. The port matching and valve job. 15 HP sounds to be a bit inflated, but possiable. If you got time and money then Flowbench your cleaned up head first, then get headwork done or do the headwork, then flowbench again for the results. This is the only correct way to gage performance headwork improvment. CFM! Not sure about miata's but bang for the bucks in most cases for me has always been, Cams. Turbo cams would more likely be a better choice. little more duration with less overlap, you could throw in more lift also since new springs would be a good idea at the same time.

hustler

iTrader: (6)

you need to talk to john day (972-235-7405, Trey Rozelle sent you). He believes in 3-angle jobs on FI cars from personal experience. He's done a ton of machine work for FI maitas, and is ultimately respected. Gary at TDR uses him exclusively and I've never heard of anything but happy customers, and Gary has a lot of them and they all go to the track. I don't know very much about machine work, or cars in general, but I grew up around drag racing in DFW, and I've heard good things about this guy's work for a really, really long time. There's also Max at "Long Racing Engines." He's done work on my father's cars for even longer, and my dad has always been happy (20+ cars). If you talk to him, let him know that you're friend's with Lonnie and Trey Rozelle.


Please tell me you didn't go to Stoid.

hustler

iTrader: (6)

Local Machine Shop.... - Dallasimports

this also happened to another local with a miata...and its going to court.

patsmx5

iTrader: (16)

Well, get to reading. You'll find what works and what doesn't on our cylinder heads. I might have a picture of the camgear marking. Have to look.

patsmx5

iTrader: (16)

Once upon a time there was a group of people racing in some class. There were of course rules that governed the class to keep it competitive. Of the many, one was the cylinder head had to be stock. No porting, no bigger valves, no seat work (IE-bowl blending (does ANYBODY even know what bowl blending is?)), etc. Well, to be competitive, the team was looking for an edge. A way to twist the rules to get there power up. Well, they figured out that by cutting various angles in the seat when rebuilding the head, they could get some of the benefits of blending the bowls, without actually blending them.

Fast forward to today where X angle valve jobs (seat cuts) are common in racing. But whether it's 3 or 5 angles you cut, it still won't flow as well as a blended seat. Angled valve jobs are just cheaper and easier to do. Not better. Blending is far superior.

Braineack

iTrader: (62)

yes, my bowl was blended.

Braineack

iTrader: (62)

Here's a 5-angle job with some DIY headwork:

patsmx5

iTrader: (16)

Your definition of bowl blending and mine are different. You're saying you blended the throat into the seat. That's not my definition of bowl blending.

As I described, you literally round out the seat. I just dug through a book on head modifications and they don't even mention bowl blending. It's not well known.

hustler

iTrader: (6)

I believe the 3-angle job helps longevity issues.

Braineack

iTrader: (62)

pretty much yeah.

Toddcod

iTrader: (8)

Well, I know one thing. and everyone can do what they want. If not many people use it. It usually has a down side.

If I'm only going to gain 10hp, I'll spend my money in other ways. I was wanting 250-300hp out of the 1.6L.

I might throw in the 1.8L.

What all is envolved in swapping in the 1.8L?

thesnowboarder

iTrader: (15)

I just did this myself for the first time.

You will need:
-To deal with egr, either blocking it off or not. FM of course has a small plate, but it can be made yourself.
-Either a 1.6TB adaptor or you can drill and tap threads into the 1.8 intake mani like mine is
-The motor of course, make sure you get the 1.8 motor mounts.
-The wiring is the same, so all you have to do is extend the CAS wiring, (you use the 1.6 CAS)
-Injector wiring is the same as well.
Obviously the heads are different, im sure your aware of it, but you will need 1.8 exhaust mani/turbo mani

I think thats just about it

Edit:
Changing a few settings in the MS and it was done.

Joe Perez

iTrader: (8)

Would not rounding the seat have the effect of reducing the contact area between the seat and the valve to a nearly single point contact around its circumference, thus seriously degrading the valve's ability to reject heat into the surrounding head? This is essentially the grievance that I often hear being asserted upon complex multi-angle valve seat facing operations on forced induction engines.

hustler

iTrader: (6)

keep the 1.8tps since you have ms so the intercooler pipes will fit.
if you get a 99 motor you will also need:
electrical system plug connectors for the tps and IAC
lengthen the water temp gauge wire to the new location
notch the 1.6 alternator bracket to clear a "tab" on the head

You should look at my car next time I'm in town. There are still a few things to clean up, but the swap will be much easier the 2nd time around.

I recommend you keep the 1.6 alternator, pulleys, and oil pressure sender.

patsmx5

iTrader: (16)

You still cut an flat in the seat for the valve to seal against. But the rest of the seat is round.

As for multi angle valve jobs, I've done them before, so I know what you're talking about. You have 5 cutters to cut all 5 flats or 5 angles. You skip the middle one and cut the two surfaces that go around it. This makes a sharp edge where the seat's flat should go where the valve will actually seal. You have to measure the diameter of the point and then cut one angle or the other to get the diameter correct. Of course you want it as large as possible as this gives a larger opening as well as more area for heat transfer. Anyways, you do all the intake valves and get them all the same.

Then you break out the middle carbide cutter and start cutting your flat, using cutting oil as this needs to be pretty good surface finish. It takes guidance and practice to learn to cut them right. It ain't easy at all. You make a couple turns and then you put prussian bluing on the seat and valve and then spin the valve on the seat. Then remove and check the valve to make sure you're getting a good seal in the correct spot. If not, you have to get out another cutter and move the seat. Once you know it's in the right spot, you put the cutter that will cut the seat for the valve to seal against in and keep cutting, measuring the seat width and keep checking with the bluing.

It's time consuming to get it right. Once you have those 3 angles right and the middle one is in the right spot relative to the valve's face and the seat width is correct, you cut the last two outer angles to make it a 5 angle. Then lap the valves. Then grind the valve stems to set the valve height correct as this has changed from cutting on the seat.

But all this work and time and it's still a compromise. Blending the bowls is far superior. But it's not easy. The right way to do them is to press in new oversized seats. Then,you establish where the seat must go for correct valve geometry. Then you shape the seat accordingly so that when you cut the flat, it will seamlessly transition into the rest of the seat. To do this you have to rough in the seat, then finish rounding, then when it's almost perfect, you finish cutting the seat.

So yeah it's expensive, time consuming, requires skill and experience, and isn't well known. But it works very well when done right. An old machinist/racer showed me how to cut angled valve jobs and how to bowl blend. Lets just say I don't do angled valve jobs anymore.

Toddcod

iTrader: (8)

I have a 96 1.8L with a 109,000 on it. The car was wrecked out.

Since I have MS can't I use the 1.8L throttlebody?

So basically, drill the mani, block off egr, and motor mounts, and a new manifold. That isn't bad.
Is the power differance even worth it? I don't really have to have 300.

I guess I'll drive the 1.6 till she goes to smoking, and swap the 1.8L in, and add a 6 puck sprung disk into the equation.

Toddcod

iTrader: (8)

Yea, that would be good.

It would answer alot of questions. " Like is it worth it" LOL. It doesn't sound bad though. I would probably bore it to a 1.9 as well. I bet .3L will make some differance.

Did you have to get different length rods to get 1.9 or just larger pistons.

hustler

iTrader: (6)

I'm not sure if its worth it, but even with the wastegate unhooked and no boost showing on the gauge, the car is a lot faster than with the 1.6 especially considering there is a snail on the exhaust.

Same side rods, low-comp pistons. My motor is way over the top though. If it were only a street car it wouldn't have the built motor.

mikef85

iTrader: (7)

You're so smart Pat. Bryce has a lot to learn from you.

patsmx5

iTrader: (16)

He, not hardly. I've only rebuilt a few cylinder heads. Five or six tops.

Bryce ever put his turbo back on? Ain't talked to him in a while. I might be turbo'd before he gets turbo'd again.