pistons
 

i got a 92 protege dx im wanting to change out my pistons should i go to 9.5 to 1 or 10-1 compressions. i dont know which i should get

Get whichever you can afford, what are your goals for this car??

goals for car
 

going to build up for natural asp. with a dohc head on a shoc. with a metal head gasket

well fi you want a DOHC you might as well just swap engines. believe me it is a hell of a lot easier.

if you are going for a N/A buildup spend the money and get 11:1 compression pistons and a proper ignition control.

ok .......I have a 92 DX SOHC if i get new pistons like him what will they do or help with???

tuned correctly increasing compression makes more power

Metal head gasket
 

The Protege, Escort GT's have from factory a four layer metal head gasket, better than any FELPRO sold in auto shops. Poeple say to install a new one everytime the head is pulled, but thats just because most vehicles use the "cardboard type".

I have used and reused my metal head gasket and never have had any problems as long as you keep it flat.

ANd guess what the intake and exhaust are made of metal too, from factory. I even installed a brand new header with the 10 year old exhaust gasket and works perfect.

Go with the highest you can. Whats goin to happen is when installin the 9.5, you will like the new HP increase and then like after three weeks the 10 to 1 will be in the list. Curiosity killed the cat.

i've heard from a reliable source that installed them that the miata pistons don't work with our head... that you will wind up with vavles tapping on the top of the piston because the miata has a different combustion chamber in the head and also the miata pistons are domed more...
could be just a rumor but it worth looking into before you go blowing up your motor.

my 2 cents.

i have seen a miata piston in a protege long block hit valves. though it is possible to make it work, you just run a serious chance of creating an interferance engine if you have had your block/head decked. cam timing is everything.

LOM, thats all!
 

The only reason the pistons will hit the cylinder head is because of LOM, lack of mechanix...


Well, It is better to spread the erroneous rumors so others dont have the combo!

well running 11:1 miata piston in a protege does not keep it a non interference engine. the simple fact that the miata head and protege head are different comes into play.

i am not saying that if you change to higer compression miata piston you WILL, i am warning people that you run a signifigant chance of hitting a valve.

Decking the head or block wil slightly alter valve timing as well.
Incase that hasn't been mentioned.
The Miata head is only different from 99+ IIRC.

which is where most people get their pistons from anyway.

Why pay 200 bucks for 10:1 miata pistons when you can get a hot set of 11:1 wisecos for around 400 bucks...If your building an all motor setup and you want to be fast 11:1 is the MINIMUM I'd run...Especially in the all motor game, cheaping out on parts will kill your chances of reaching the cars full potential.