lil_foy

Hey guys,

Didnt really know where to put this..
Ok so im piecing together my motor for boost currently and ive run into a few problems with specs that i need to figure out urgently as I want to order my parts this week!


Now my proposed setup is (aiming for around 10.8:1~11:1);

b16b head (oem valves, same as b18cR)
b16b block (same as b18cR)
oem headgasket
b18cr crank
b18 eagle rods
81.5mm 11:1 b18c1 cp pistons (1.5cc, CH 1.181")
0.010" mill head/block total

Now i ran this through the Zeals Calculator and it came back with an unusually low number of 10.47:1. Now I knew the pistons were to suit the C1 head so I switched and it came up with 10.7:1.

Strange! So i emailed Darius Tarman @ CP saying that the stats are not working out and got the following reply;



Switching to his 212mm deck height with 0.010" b/h mill it works out perfectly.
Now im just wondering what to believe, ive done a lot of searching and I actually cant get a solid answer on the deck height of the block, some say 212mm, some say 212.39mm.

So can anyone shed some light on this situation, does CP have the wrong specs and inturn been selling incorrect pistons (I see this as unlikely) or is there just mis-information going around.

Thanks,
Andrew

Muckman

iTrader: (2)

10.47 is close enough to 10.8. The CP catalog is missing a lot of the information you need to accurately calculate compression, such as Dome CC. Are you sure its +1.5cc?
Pistons should come with a compression range not a set number. There are too many factors for a manufacturer to say with certainty what compression a piston will make on a customer’s engine.

boosted_D

iTrader: (1)

b16b and b18c have the same deck height. therefor your b16b block with b18c internals is exactly the same as a b18c bottom end. The pistons were made for 11:1 c/r in a b18c, the only difference with your motor is that you have a b16b head. The b16b head has slightly larger combustion chambers than a b18c head, this will very slightly lower c/r vs. a b18c head, so yes, you will end up somewhere around 10.5 to 1 c/r or very slightly higher, either way, it will all work the same.

lil_foy

CC is listed in the white and green section (dome/dish) "1.5", i've contacted cp about this as well and it's correct.


Not to be rude to either of you but you've missed what im getting at with this thread, I need to know the correct deck height for an oem block, cp lists theirs as 0.01535 inches shorter then 90% of people say, this makes almost .4 static compression lost. Motors shouldnt just be slapped together and say "close enough".

Just to be 150% im going to reinstall my b16b crank, rods and pistons this week and ill measure the P2D clearance and compare to the b16b piston, rod, crank specs.

lil_foy

Measured it up today, 212mm deck height for those that are interested.

boosted_D

iTrader: (1)

Correct, as stated, it is identicle to all B18/B20 deck height.

That bare b16b block is exactly the same as a gsr/itr block, that's exactly what I said in my reply.....

98lude-t

Uuuuhhh get some^

lil_foy

I know b16b and b18c are same block hence me using a b18 crank, pistons and rods and I also stated clearly they are the same in the first post, the deck height for both I was uncertain of though, cp lists as 212mm virgin block, zeal calculator I linked in the original post states 212.39mm. Going off my measurements of my virgin block it is 212mm, meaning the zeal calculator is wrong, which is what I needed to know.

So all you did was repeat what I had already said....