i am rebuilding a 1988 T2
i wanted to get it streetported at the same time

question is should i go with 2mm seals or 3mm seals?

 

This one should stir up lots of inflamed opinion, if anyone will touch it Let me get the ball rolling.

I'm running on stock internals, so I'm no expert, most of what I know in area is from the forum (search!), and talking to Maxthe7man and other local builders in person, whose expertise I would place great stock in. 3mm seals are pretty much a North American phenomena, I gather - which should probably be a bit of a heads up right off the bat, since the 7 scene is pretty active in Japan and Australia - why wouldn't they be doing it if it works well. Machining rotors accurately for 3mm seals is one issue, and whether or not they really accomplish improved sealing is another. Yet another is are any manufacturered to standards that meet or exceed the quality of Mazda seals? Max showed me samples of some popular ones (unused), that once the differences were pointed out, side-by-side with new Mazda seals, my untrained eye could see how they deviated from Mazda specs, in ways that would likely lead to poor sealing.

I'd recommend sticking with Mazda 2mm seals.
Let the flamefest begin!

 

mine has 3mm.... , its not a TII but its a turboed NA... honestly you can barely tell a difference, but im guessing in the long run, and reliability,... go 3

 

Id say thats a really good point with the whole japan not using them!

 

hmmmmm

 

If your rotors are worn too much for 2MM seals and you have a good machine shop to enlarge the groove, go with 3MM.

If the rotors are fine, stick with 2MM.

2MM seal better, generate less friction, are just as strong as 3MM, and don't require the rotors to be machined.

 

2mm, but like Aaron said about going 3mm

 

One of the main advantages to 3mm is the fact that worn out rotor slots can be machiend to accept the 3mm's - and therefore save the cost of new rotors.

The greater mass means **in theory** greater sealing ability at high(er then stock) RPM.

The greater mass also means **in theory** better detonation resistance.

All of that being said,

a) I'd be using spec'd rotors in my builds (and have) as opposed to machining material (and thusly strength **in theory**)
b) Unless you plan on revving sky high (which will take many many other mods and even then 3mm is an option) then you don't need it. But even as I said, an engine setup for 12K rpms can use 2mm just fine.
c) Your tune and setup shouldn't allow detonation to occur ayways and in that sense the 3mm are "insurance" and a solution I compare to wiping the blood off your arm instead of bandaging the wound.

/Debate onward

 

factory 2mm seals FTW!