Sideways Posted August 4, 2007 Share Posted August 4, 2007 Did a search and couldnt find my answer, but maybe im not searching for the right thing? Anyways im hoping theres a way to easily tell if the f54 block i have came with flat top pistons or dished pistons, short of pulling the head. Does anyone know if theres something visual i can look for, or a specific number on the block that can be used as any indication? Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted August 5, 2007 Share Posted August 5, 2007 If I'm not mistaken, the NA- F54s had flat tops. Mine did. I think the turbo F54s had dished pistons. I could be wrong though. Quote Link to comment Share on other sites More sharing options...
z_cars_rule Posted August 5, 2007 Share Posted August 5, 2007 Look for "F54" cast into the block. crazy idea i know. it will be on the intake/exhaust side just near the engine mount. Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted August 5, 2007 Share Posted August 5, 2007 He already knows he has an f54. He wants to know if it has flat tops or dished pistons. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted August 5, 2007 Share Posted August 5, 2007 If space allows, you can remove one spark plug and probe something into the chamber and "feel" the piston top. You should be able to determine whether the piston is dished or flat. The dish on my stock L28ET is around 3mm deep that's pretty significant. That requires the engine be in your possesion, sorry I don't know how to check IF it is not available for checking. If you know the year/model of the car, then perhaps you can figure it out by visiting some of the informative Z websites dedicated to L engines. Quote Link to comment Share on other sites More sharing options...
Sideways Posted August 5, 2007 Author Share Posted August 5, 2007 Look for "F54" cast into the block. crazy idea i know. it will be on the intake/exhaust side just near the engine mount. Thanks for taking the time to actually read my question TheNeedForZ, thats a great idea and am actually feeling stupid for nothing thinking of it sooner. I purchased a 71 240z with a turbo l28 (p90 head and f54, both supposed to be rebuilt), im just trying to find out if its an NA block or turbo block, and am not feeling zelous enough to pull the head to physicaly check the pistons if i dont actually have to. Thanks for the great suggestion. Quote Link to comment Share on other sites More sharing options...
nbesheer Posted August 6, 2007 Share Posted August 6, 2007 Maybe could you check the compression ratio ? The NA's had higher CR because of the flat pistons and Turbos had lower CR because of the dished. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted August 6, 2007 Share Posted August 6, 2007 im just trying to find out if its an NA block or turbo block The block is going to be the same, the difference is only in the parts i.e. dished pistons or flat top pistons. I agree that the best way to check is to put something through the spark plug hole to feel the top of the piston. The compression idea sounds good but your static compression is controlled just as much by cam design as by piston shape and if the cam has been changed or reground you could find yourself falsely believing the wrong thing. Without documented history or a build sheet (spec sheet) on the motor you have to accept it as is or check and measure yourself. Dragonfly Quote Link to comment Share on other sites More sharing options...
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