Im looking to upgrade my stock b20 rods and pistons for OEM ctr rods and pistons. My only question really is will I need to make any other modification to the block in order to put in the ctr rods & pistons.


Also I have a b16a head & I might just go ahead and buy some ctr cams, so would it be wise to use the b16a valvtrain or would that need to be changed as well?


Thanks for any help!


(if anyone's done this set up before, what kind of gains did you see?)

 

OEM CTR pistons are 81 - 81.25mm B20 Pistons are 84mm. They will not fit, OEM for OEM.

 

I thought the b20 pistons were bigger but I was hoping I was wrong.

Is there any OEM piston that would be better then the b20's?
Im trying not to go aftermarket, I really dont want to spend 1k
on just these parts but I do want some kind of gains.

 

i thought rs machine made the 84mm-up ctr pistons

 

never mind they only come in 82mm

 

rs makes itr style 84mm pistons for the b20 and i heard sparks racing does too

 

You can get wiseco pistons anywhere from 450-550 depending on where you shop. Aftermarket is pretty much the only way to go once you go that big in bore.

 

If you have a B20B you can put in the OEM B20Z higher comp. pistons, but that will only give you about 2hp.

 

Well 2hp sounds pretty sick and all lol but seeing as how thats about the only OEM piston I can swap in I think im going to go with the wiseco pistons.

 

I also have read that stock b20 rods a very weak, as well as the cylinder walls this is all true correct?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Corey_sl &raquo;</TD></TR><TR><TD CLASS="quote">Well 2hp sounds pretty sick and all lol but seeing as how thats about the only OEM piston I can swap in I think im going to go with the wiseco pistons. </TD></TR></TABLE>

Hard to say how much they would REALLY add. Stock for stock, the B20Z puts out 20 more HP than the B20B. But this increase is also due to an improvement in intake manifold (irrelevant since you are probably already using an LS manifold, which is better than either) and an improvement in the cams (only relevant if you are running non-VTEC). On the other hand, even this modest increase in compression (from 8.8:1 to 9.6:1) should significantly improve low end torque and fuel economy.

As for the pistons, I would look into the RS pistons before going with Wiseco. Wiseco pistons are race alloy (low silicon) forged pistons, and will have to be run loose. This will make for a noisy engine when cold, and reduced life. So unless you are going to be running MAJOR boost that is going to require REALLY strong pistons, you are better off using a cast piston like the RS pistons. They can be run stock-tight, and will last as longs as stock. They are DEFINITELY the better choice for an allmotor street car.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Corey_sl &raquo;</TD></TR><TR><TD CLASS="quote">I also have read that stock b20 rods a very weak, as well as the cylinder walls this is all true correct?</TD></TR></TABLE>

B20 rods are actually exactly the same as LS rods. And as such, they are certainly not the strongest rods in the world. But MANY people use them successfully after upgrading to stronger ARP rod bolts. If you need something stronger, you will have to upgrade to aftermarket rods, as there are no stronger stock rods of the right length. As an alternative to aftermarket rods, you could use GSR/ITR rods. But that would necessitate the use of a GSR/ITR crank, which would reduce displacement slightly.

As for the sleeves, they should be fine for all but the most severe allmotor applications. Typically, it is boost that gets people in trouble with B20 sleeves.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Corey_sl &raquo;</TD></TR><TR><TD CLASS="quote">I also have read that stock b20 rods a very weak, as well as the cylinder walls this is all true correct?</TD></TR></TABLE>

Yes and no. B20 sleeves are weak, but not because they are thin. K series sleeves are actually thinner. Its because B20 sleeves are cast as one monosleeve design. When one sleeve flexes do to detonation or something similar they are flex. Then they crack. I cracked all 4 sleeves on an all motor B20. My advice would be to have a blockguard installed. Have installed the right way and welded in place. Do not bore over 84.5mm on stock sleeves. If your starting off with a stock B20 block, change over to some arp rod bolts and arp headstuds.

 

hello I'm new to this topic, I have a problem with my recent project of a b20 engine with a b16a2 head, after putting high compression ctr pistons, the car doesn't work, it's because the spark doesn't hit the middle or I'll have to add more fuel?