I have just stripped down my motor as it has lost compression on the front and rear rotor,everything is fine except the tip seals have warped like a banana in the middle part of the seal,what could of caused this as i have never seen this happen before,thanks Roy UK.

Is your engine ported??

Is it Hurley seals? I had the same experience a year ago when I used Hurley Racing Tip Seals in my rebuild.. After 500 miles it suddenly started to sound like a v8,and the engine lost alot of power. I managed to limp back home, to find out I had very low comp. on the rear rotor. 2 apex seals was broken, the rotor and housing where trash.. It looked like the the area of the apex that`s exposed to the ex. port, just had broken off in 1-2 mm high pieces. Both of the seals had the same damage, and the ex.port hardly showed any sign of it..One of the seals was missing a 5mm long piece from the middle, I found it stuck on the rotor face. It had dented the rotor and trash the housing. the rest of the seal was stuck in the seal groove in many pieces. Both the chambers had strange wear pattern between the spark plugs.

The engine was run in with no boost,never over 4000 rpm and 1% premix in the fuel,it was given special care and then it just "popped" for now reason..

The seals are mazda 12a,3mm two piece,and yes it has been ported.

Sounds overreved, overheated, insufficient oil injection, or bad oil to me... :(





-Ted

or to large an exhaust port

Ted, what about the oil could do that?



To thick, to thin, not enough, no pressure?

Not with the new 2-piece Mazda OEM apex seals. https://www.nopistons.com/forums/pub...IR







-Ted

Oil injection into the combustion chamber is supposed to lubricate the apex seals...primarily. If the oil is "bad" (i.e. bad quality, too thin, etc.), you get inadequate apex seal lubrication, and this basically overheats the apex seal and causes warpage...







-Ted

Ahhh, thanks.