1990miata1.6

iTrader: (2)

That suck about what happen andi did the same thing and this is what happen to my connecting rods

Rafa

iTrader: (22)

I figure when I open my engine I'm going to find the same thing

I assume you're going to get forged Rods. If so, shoot me a pm

Gibscreen

What's the advantage of the MSM piston over the piston used on the 99-00 Miatas. They're both 9.5:1 CR. What other changes did they make for the MSM?

I'm running a normally aspirated 1.8L for racing and I'm currently debating what pistons to get. The rules allow a .020" overbore and upping CR by 0.5:1. So I'm looking at 9.5:1 pistons. Not sure if I should go with Supertechs or stock 99-00 or MSM. Any opinions?

18psi

iTrader: (76)

1) this thread is a yeard old
2) msm pistons are nothing special
3) get one of the sets of high comp pistons (n/a) or low comp pistons (f/i) from our sponsors

Ben

iTrader: (33)

The MSM motor is mostly the same as the 99-00 motor with the addition of a plate that is supposed to tie the main bearings together to prevent flex. The intake cam is the one they used on the JDM motors, and it has a little more lift than the USDM 99-00 intake cam. If you can go .20 over, why not look into the aftermarket?

Wake up on the wrong side of the bed?

18psi

iTrader: (76)

Maybe.

Gibscreen

I'm considering aftermarket but there aren't many I've found that have a 9.5:1 CR. There's Supertech/Belfab, the 99-00 and MSM pistons. If there are others pleasr let me know.

Also since I race this car in long enduros (25 hours) as well as sprints I'm interested in longevity. Piston slap doesn't seem like it would be good for longevity (even though a good machinist can limit or eliminate it).

18psi

iTrader: (76)

If you're n/a why not go higher? You could use the 10:1 from the newer nb's or even the 11+ from companies like supertec and a few others. I don't understand why you want specifically the 9.5:1 and not lower/higher depending on what your needs are.

If you're worried about slap get stock ones from a 01-05 with the 10:1 ratio.
If you're buying stock though I'd either get used ones for a good deal, or just get forged ones. Buying new stock pistons is almost as expensive as buying forged.

Ben

iTrader: (33)

There are quite a few piston manufacturers. Most will make you anything you want for a little extra over what they stock. CP, Wiseco, JW, etc etc. Really though tenths of a point are meaningless.

Piston slap occurs cold, not hot. If you're running the car that hard, that long, then I'd probably want the bores a bit oversized, so there's going to be some slap when cold. It will tighten up once hot. Forged pistons aren't idiot-proof, but they're more durable than stock, and going oversized is a no-brainer.

Gibscreen

I can't go higher than 9.5 or .020 becauser the rules don't allow it. Thanks for the input though guys.

18psi

iTrader: (76)

Oh THAT'S why. Ok, at least it makes sense now.
In that case I'd look around for used 99-00 pistons. You can get them super cheap.

Gibscreen

So we don't know the difference between the 99-00 and MSM pistons? They're definitely different part numbers.

Faeflora

iTrader: (2)

FYI the MBSP can be had for cheap.

Ben

iTrader: (33)

maybe they have different rings?

Midtenn

iTrader: (15)

Rings aren't part of Mazda's part number, but I guess maybe the ring lands could be different on the piston as well.