When I see people put ceramic apex seals in their motors on this forum, seems like most of the time they end up using a 1 piece design apex seal.

Are there any benefits to one piece design apex seal, if none, what benifits do 2 piece apex seals have over one piece?

 

Big benifit is in strength.

Two piece styles fail near the tapered part that fits to the wedge section, single piece are far stronger. Single piece dont impart the same side loadings to the end plates as multi piece do.

Even though they seal marginaly less at cranking speeds and below 4k rpm's anything above this speed the measurable differences in torque or power are less than 1% depending on who's data you look at.

One piece is favoured for a high output racing engine, if extra fuel efficiency below 4k and minor single digit HP gains are not being chased @ low revs. We had a racing customer sucessfuly complete/use 700lt of Methanol in their hi hp drag 3 rotor engine and survive all kinds of incidents that have left less products broken or worn out many times over,all on one piece racing seals.

 

so for a street car where power below 4K, cranking speed sealing, and fuel economy are a concern, but occasional track use, the 2 piece are perfered?

Im looking at all options for the next motor I will build, one thing is for sure though, I will pony up and use ceramics.

One other thing because ceramic seals are much much lighter, (about 2oz for both rotors) wouldnt this 2oz that is lost in the rotating assembly effect balance? Basically if one were to use ceramic seals, would you want to get the rotating assembly balance differently than if you were going to use steal seals?

 

Factor balance specifications are over and above the variaotion in apex seal weight (over 3 seals per rotor) so I would not worry about that aspect of it too much for a road car. My rotors were balanced by Darryl Drummond (speeeling?) to suit my seals and eccentric shaft and they have a variance of 6 grams per rotor 4441 V's 4447 grams. If you r real particular get it done

For all out cruiser where your **** about fuel economy etc then yeah stick with two piece, performance oriented 98% of my sales are for one piece items simply because of the unparralled strength and saftey margin. See what suits you most?

The negatives of one piece V's multi piece while being measurable are not noticable realy, you dont find a one piece harder to start for example (common mistruth unfortunatley) and in most cases with the massive variations in tuning of cars many one piece sealed cars make more low down power and use less fuel LOL !!! The differences are minor less than 5% at low revs and as I said around or less than 1% at well below racing revs, its very marginal...... hence most realy go for the extra strength V's the minor technical improvements in sealing at very low revs.

Hope that helps your decission a bit?

 

it does, thanks!