jason12 Posted April 28, 2010 Report Share Posted April 28, 2010 (edited) Hey, pulled apart my 4k to change the head gasket and found these pistons, done a bit of a search and think they may be 4k-u ones? can anyone tell me for sure / tell me if theres any benefit or downside to them. Cheers, Jason Edited April 28, 2010 by jason12 Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted April 28, 2010 Report Share Posted April 28, 2010 Yeah they're 4ku pistons. Aparently 4ku's (if it is the whole motor) had a bit more grunt than our ADM 4kc's. Quote Link to comment Share on other sites More sharing options...
Felix Posted April 28, 2010 Report Share Posted April 28, 2010 They are the 4k-e or twin squish type. Jap import motor you have there. Shares same head as dished 5k. Downsides none, unless you try to get replacement pistons. Upside, they make more power than the normal flatop motors. Quote Link to comment Share on other sites More sharing options...
jason12 Posted April 28, 2010 Author Report Share Posted April 28, 2010 Sweet, cheers guys! Quote Link to comment Share on other sites More sharing options...
tioklou Posted April 29, 2010 Report Share Posted April 29, 2010 there are two types of 4k dished pistons.. the first one is just like those in my engine.. my engine is a 4k-II twin squish with electronic ignition. the second type is with valve holes just like 5k ones... Quote Link to comment Share on other sites More sharing options...
philbey Posted April 30, 2010 Report Share Posted April 30, 2010 Hmmm, I've not seen 5K's with valve reliefs in the pistons though!? They'd have to be aftermarket. Quote Link to comment Share on other sites More sharing options...
Felix Posted April 30, 2010 Report Share Posted April 30, 2010 (edited) Same here. My 5k has the D shaped dished pistons. I've had a few 4k's with dished pistons. The ones with the D shaped dish were supposedly 4k-u when I researched going by the numbers on the inside of the piston. The twin squish (or ones that look like they have valve reliefs) were 4k-e by the numbers on them. I've had one 4k with the D pistons and two with the twin squish pistons. EDIT: Found a pic I took of the two 4k dished type pistons: part no. on left piston is 13101-13020 4k-u type part no. on right piston is 13101-13022 4k-e type Edited April 30, 2010 by Felix Quote Link to comment Share on other sites More sharing options...
jason12 Posted April 30, 2010 Author Report Share Posted April 30, 2010 Is there any way to tell if the whole motor is a 4k-e? Quote Link to comment Share on other sites More sharing options...
madKE35coupe Posted April 30, 2010 Report Share Posted April 30, 2010 it should say on the side of the block mate. from memory if you are looking at the motor it is on the left hand side at the back? if I'm wrong please correct me. Quote Link to comment Share on other sites More sharing options...
Felix Posted April 30, 2010 Report Share Posted April 30, 2010 It won't tell you what model the motor is on the engine number. Usually there is a sticker on the timing cover, but it could have fallen off over the years. The motor with the pistons on the right in the pic I posted had a 4k-e sticker on the timing cover when I got it. Quote Link to comment Share on other sites More sharing options...
tioklou Posted April 30, 2010 Report Share Posted April 30, 2010 my engine had a sticker on the valve cover which tells you to use only long spark plugs and not the typical ones just like those in the picture...the other one had fallen off... Quote Link to comment Share on other sites More sharing options...
jason12 Posted June 3, 2010 Author Report Share Posted June 3, 2010 Now being that is engine is different to the std 4k's... could i still put a std 3k / 4k head on? If so how much could i have shaved off? Also is the usual 20 - 60thou off still applicable for the 4k-e head? Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted June 3, 2010 Report Share Posted June 3, 2010 Now being that is engine is different to the std 4k's... could i still put a std 3k / 4k head on? If so how much could i have shaved off? Also is the usual 20 - 60thou off still applicable for the 4k-e head? Because its a dished piston motor it has a head with a shallow combustion chamber just like a 5k head. Using a normal 3/4k flat top piston head will give you a low CR. Quote Link to comment Share on other sites More sharing options...
jason12 Posted June 3, 2010 Author Report Share Posted June 3, 2010 Ah yes that makes sense, cheers. How much would you reccomend i have taken off the head on it now then. Only mods will be an exhaust and gemi carby... I'm guessing 20thou would be ok? Quote Link to comment Share on other sites More sharing options...
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