I'm in the process of purchasing a rebuilt engine for my Turbo II. My question is should I go with these 2mm cryogenic treated apex seals this site is pitching to me or the beefier 3mm seals? Need you advice, the guy I spoke to told me 2mm is the only way to go and if I want the added protection from detonation, to get them cryogenically treated and they will be stronger than 3mm's could ever be. What do you think?

 

the stock 2mm seals are better than the stock 3mm seals

mike

 

Cryo treatment generally tends to greatly lengthen the life of normal internal parts, i don't know about seals though

 

It's my understanding that cryotreating makes a material stronger, but a *bit* more brittle. It would wear better, and hold up to age, but a good bit of detonation, and kiss em' bye bye.

Anyone with more experience w/ cryotreating than myself, please respond and re-enforce, or disprove my previous statment.

 

What do you mean? As in, what do you consider "better"? I seriously doubt the 2mm seals are stronger. Some argue that the 2mm have slightly less rotating weight, but what about the material removerd form the rotor grooves in order to accomodate the bigger seals?
Juts wondering why you consider them to be better.

 

I think the biggest problem people experience with 3mm apex seals involves the engine builder. Most builders do a straight cut so the seal and rotor housings wear down faster, experienced rotary builders use a very slight angle in milling the rotor to allow for less wear and tear.

I'm not sure what kind of temps the apex seals are subjected to, so I can't comment about cryo treating.

As for the old 3mm vs 2mm, I say 3mm > 2mm, only if the engine builder is competent

 

WEll 3mm is thicker so it would withstand detonation better...FOr this reason people use them more in boosted cars. For n/a the lighter the better for higher revving although like someone stated it should be the same because you have to remove material for the 3mm to fit. Hmm

Then think of it this way. With 3mm thiers more surface area of the apex seal thats sliding on the housing wich means more friction wich means more wear.

Or look at it this way....The weight of the entire rotating assembly ex.( rotor+seal) But the seals inertia itself is still heavier then 2mm meaning bigger chance of apex clatter or chatter at high rpms !!!

Please correct me if im wrong ?

 

Oops i mean

The weight of the entire rotating assembly ex.( rotor+seal may be the same but ...........