Here's the deal, 4 years ago I bought a blown C5 block withou knowing a thing about motors. I got ripped off, but I kept the block in hopes of some day using it.

Well, I finally got my hands on a B20z short block. The thought of turning my current B16 motor into a B20/vtec has crossed my mind lots of times. After a lot of research on this forum, I have decided to build my C5 block using the B20 crank.

I have tried to research about the crank and the rods I will need to make this motor work. I only found one topic about a B18c5 with ls rods in it....but I know I can't use those rods, or can I??? The B20 crank is 89mm right??? Which would make an Ls crank, but will I need to make any modifications to the block ???

What I am trying to prevent is spending a lot of money on parts that will not work. I do not want to find out that the rods are too long or too short, or that the pistons stick out to far. I am not sure if the C5 block and Ls block are the same height. If they are, then I don't see any problem with using ls rods with the crank. By preferance, I would much rather use something that was intended for Vtec but if I can't use vtec rods...then Oh-well. Any suggestions would be greatly appreciated


Modified by civicR99 at 1:47 PM 9/14/2004

 

this is the way to go use the LS crank and rods in the c1/5 block, you'll get to benefit from the longer stroke and you already have the block girdle (sp?) and oil squirters. the b18,b20, and b16b all have the same deck height, so you wont have a problem there. good luck on this build, how wild do you plan to make this..street or strip or combo?

 

Just to claify, the ls and b20 crank are the same stroke 89mm, so you will need to use ls or b20 rods. When you choose pistons, remember the advertised cr will vary depending on what stroke crank they were using on the spec sheet.. I have seen to many people put ls cranks in and cant figure out why there 11.5 cr gsr spec pistons are knocking so bad..

 

My build will be po-folk. I plan on using all honda parts for the bottom end with the exception of the main and rod bearings. I just want something reliable yet quick when the need arises or when I am having VTEC withdrawals. Here's a list of what I plan to do in stages.

Have machine shop line bore main caps
Hone cylinder walls and/or if needed bore it out to 81.5mm
Clevitte or ACL bearings
Use B20rods
balanced crank, rods, pistons, flywheel and clutch.
P30 pistons, PR3 or possibly use original ITR pistons
Brand new oil pump and ARP rod, main caps, and head stud bolts

If there's sufficient funds during build:
Toda Flywheel or with a little more research maybe something else
Toda valve springs will be a must have

That's it for stage 1. I do plan on chipping my P28 ecu with hondata S200. I have some DSM injectors laying around that I will be using and as far as the head goes. I plan on doing a simple polish on it and possibly a valve job. I am trying not to lose focus on the block which is the most important part. Getting the valvesprings will allow me to drop new cams in but for now my CTR cams will do the job.

Stage 2:
ITR header
68mm throttle body
CTR Intake
Toda Spec B cams
Test pipe
2.5" exhaust (will need more research)
Toda Cam Gears

Stage 3:
Possibly JDM ITR tranny
or
Si tranny with ATS final driver and 1-2-3 gears
LSD (need more research)

Trying to make the build up as simple as possible. I have read about people hitting 200whp with simple setups. I just hope mine will get there in the end. I would love to see a higher number but for now close to 200whp will do.

One more question, will I need to use B20 rods or can I use ITR rods??? I have read a lot about honda's product, make it as good as it has to be. I don't think I will be spending a lot of time in the 89000 rpm zone, but for piece of mind I would much rather spend the extra money for better rods. Things might be a little different once I feel the extra power.

 

You cant use the itr rods because the bearing journals are differnt sizes and the rods would be too long.
Looks like a nice build up.. I personally dont like arp rod bolts, but thats a personal gripe because of a spun bearing with them..I cant let it go..lol

 

I am new at those so please bare with me.....I am having problems deciding on what pistons I should use. I used the B-Series compression calculator get some ideas and this is what I found:
PCT (type R pistons) 12.0:1
P30 (JDM B16) 11.31:1
PR3 (USDM B16) 11.14:1
P73 00 (JDM ITR) 11.13:1

Calculations were done using a 3-layer gasket, B18C block, B16 head, and bore set to 81.25mm. All compression numbers look really except the R pistons. That's too high for my taste. I have found JDM ITR pistons for $259 but I haven't been able to find any P30 pistons. I will still need to get rings for the new pistons and JDM ones go for $180. Is there a differance in terms of materials used to make USDM and JDM piston rings? I am trying to pinch some pennies where I can without sacrificing too much durability.

I am liking the P30 compression, but I also don't know if using a B20 crank and rods in a B18C5 will increase compression or loose some. Like some one else said above, I don't want too much compression. Any ideas as to what pistons may possibly yeild in compression with this combo?? I understand that it is impossible to know exactly what compression it will be....I just need some input with this.

My target compression is 11.4. It seems to me that the higher the compression, the harder it is to make streetable power without sacrificing reliability. I don't want to use racing fuel everytime I have to fill up. I just want some extra umph from the B16 I am used to.