RB24 piston help

[sci2000tech]

Ok, so I'm gathering parts to build an RB24 and all I have left is pistons and a head gasket, but can't seem to find the info I need for the pistons.

I will be using the RB26 crank/rods. I know 4agze pistons can work, but need to be notched to clear the oil squirters. The pin size is also 1mm smaller on the 4agze pistons.

Taking that into consideration, I opted to go with custom CP pistons. I decided to take advantage of the 10% off sale Rawbrokerage had and ordered them up. The problem is, I can't seem to find the info I need for my setup. Right now, it's looking like I might have to get 82mm CP pistons made for the 4agze, but to suit the 21mm wrist pin for the rb26 rods. Then I would still have to get them machined to clear the oil squirters, but at least I know they'd work.

I did find some specs on the Tomei RB24 pistons, but it doesn't seem to be everything I need.

http://www.tomei-p.co.jp/_2003web-catal ... specs.html

Then I also found some specs for a set of 83mm Ross pistons a guy was using for his build:


3.465 A dimension (for Ross engineering dept only)

56690 Ross Job Card (number on piston)

7/8/2008 Date Pro/Engineer program was run

TEST CP Program run by
0.326 Deck thickness major front
0.312 Deck thickness major rear
0.173 Minimum thickness under intake valve pocket
0.180 Minimum thickness under exhaust valve pocket
0.200 Minimum thickness at top of flat top / dome / dish
0.367 Minimum thickness of dish to top ring groove
0.251 Intake valve pocket to top ring groove
0.270 Exhaust valve pocket to top ring groove
Lox to oil ring groove
0.153 Skirt
N/A Side relief
Spark Plug notch
Spark Plug slot
0.114 Pin hole to side of pin boss
0.680 Pin engagement in pin bosses (each side)


So I guess what I'm wondering is if the above information should be all I need(aside from the bore size), or If I should just go with the 82mm 4agze cp pistons and have them machined? Since I'm having custom pistons made anyways, it would be nice if I could get some made that will drop right in without any extra machine work.

My head hurts from scouring the internet for an answer, so hopefully someone can enlighten me.

Also, I understand that it would be cheaper/easier to do an rb25. Not going that route because everything in my car is already setup for a 20 that I feel the need to keep wasting money on

[Yellow4g63]

member JDMSER build a RB24 or RB23.5 as he likes to call it. He went with 82mm pistons. follow the link.
http://forums.freshalloy.com/showthread.php?t=196409

[l0nestar]

Not trying to be an a**, but have you contacted CP's tech / pre-order department?
They should also be able to machine the reliefs for the oil squirters also.

Also, what are your plans for a head gasket?

[sci2000tech]

Yellow:

Thanks for the link, I'll try getting ahold of him to see how he ordered his pistons.


Lonestar:

Yep, I emailed Ricky the info and he's contacting CP to see what they say. Never thought of having them machine the reliefs tho, that's a good idea. I hate when I overthink things so much that the simple answer doesn't even cross my mind.

For the head gasket, I know both Tomei and Cometic make ones that will work with this setup. Gotta talk to my engine builder first to see what size/thickness we wanna go with.

Thanks again guys

[Coolwhip]

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