5k flat top pistons yay or nay ?

 

dished....

CR is 9.3:1 as standard.

http://www.rollaclub.com/board/index.php?showtopic=32280&st=0

 

Whats this one?

I thought there was a piston discussion in the FAQ but I couldn't see one there.

There are 2 types of 5k dished piston. O dish and D dish. I also have O dish in my 5k.

Edited September 12, 201016 yr by GJM85

O dish is what most refer to as 5k flat top, which is what youve got, 5k don't come in a proper "flat top" piston

you should also have solid lifters in there... :D

Hydraulic lifters.

I also have a switch on the side of the sump. I'm guessing its an oil level low switch.

 

my 5k has this removed, i think i plumb my turbo return through this :yes:

I've got the same thing on mine. Was thinking it was oil temp but oil level might be the better shot.

I'm using a 4k sump on mine so I don't need to worry about it.

The "5k flat top" pistons are refered to as O dish in the parts manual. Though apparantly you can use 4a pistons, I never looked into it as compression ratio could become an issue for a supercharged motor.

I converted the lifters to holdwen solids, but have had to shorten the pushrods. Unless your going crazy Des just leave is hydraulic. Though you will have to get them refaced when you get the cam done or buy new ones.

CC the piston, my O dish piston (Mahle aftermarket 40 thou over) are about 8cc. From the look of it AE70, those you have look like even less dish again.

 

Factory D dish pistons are abou 22cc.

 

GJM yours look like new pistons, are they Toyota items or aftermarket?

O dishes range from 6-8cc. Those top ones have another couple of CC's worth of carbon on them! :lolcry:

 

Yes plug on the side of the sump is oil level switch.

 

GJM85 - Datsun A12 pushrods are the correct length for Holden lifters in a 5k, that what I have in mine except they're Tomei Chrome Moly versions.

Staying hydraulic lifters as I'm not going nuts on the cam or revs. Will have a look this arvo as to what after market pistons are available.

I'm using a 4k sump on mine so I don't need to worry about it.

I was under the impression this was not possible? The 5K sump is slightly wider, it doesn't fit... I haven't actually tried this myself so I could be wrong.