2mm or 3mm
2mm or 3mm
Im getting my engine rebuilt with a nice size port. The guy that is goin to do it for me said i should go with 3mm apex seals. the question is which is honestly better 2mm or 3mm apex seals?
Rotary Freak
Joined: Dec 2001
Posts: 1,668
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From: Hattiesburg, MS
This is an on-going debate. Try searching. Most people say the 2mm apex seals are fine, and to use 3mm only if the rotors are damaged (or worn) to the point where you have to machine the tips.
Senior Member
Joined: Nov 2002
Posts: 586
Likes: 3
From: Half Moon Bay, CA
I don't know what's been said on other threads on this matter, but when I had my engine rebuilt at 78K miles (I have 116K on it now), Rick Soderberg of Rotary Performance recommended the 3 mm seals as I am running higher boost (13-14 psi). The 3 mm seals give you an added measure of security if/when you experience detonation.
There is a school of thought that an engine that spends a lot of time at high rpm (racing, e.g.) would be better off with the 2 mm seals as the 3 mm seals may float and "bang" the housing more due to their greater mass.
There is a school of thought that an engine that spends a lot of time at high rpm (racing, e.g.) would be better off with the 2 mm seals as the 3 mm seals may float and "bang" the housing more due to their greater mass.
Rotary Enthusiast
Joined: Feb 2001
Posts: 1,213
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I went to the technical session at Seven Stock last year. Basically, 2mm will give you a better seal between the rotor and the housing since it's slightly less cross section scraping/sealing the housing. However, if you car is highly modded (running on high boost with aftermarket ECU), 3mm may provide better protection against apex seal fracturing.
You should consult your rebuilter. But basically, get a 2mm if you are running stock or lightly modded.
You should consult your rebuilter. But basically, get a 2mm if you are running stock or lightly modded.
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HARRRRRRRRR
Joined: Jan 2002
Posts: 1,858
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From: Marietta GA
What do you want? Honestly it almost comes down to which you would prefer (not much difference). If you detonate bad enough to blow a 2mm seal you think one extra mm is going to help out? Most stay with the stock 2mm until the rotors need milling and you are basically forced to go with 3mm. Also, the OEM seals are supposedly better at higher boost. I have heard of guys going from hurley race seals to OEM ones when trying to boost more.
Really the only answer to this question is what do you want it to be?
Really the only answer to this question is what do you want it to be?
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