Crank swapping - Honda Forum / Acura Forum

Dennisman · 06-28-2002, 03:13 AM

Im planning on building a B20 w` B16A2 head for a 92 VX. What I need to know is if a GSR crank will drop right into the B20 block. I almost bought an ITR crank but was told it wouldnt/it would/it wouldnt fit. I couldnt find any dimensional specs on Honda cranks anywhere. Anyone know for sure?

pissedoffsol · 06-28-2002, 04:11 PM

the rod length will be differnt, as its a differnt storke.

Why do you want to use this crank? use the b17a crank if you can find one- thats the crank of choice for crvtec/lsvtecs

Dennisman · 06-28-2002, 05:15 PM

Reasoning is its a high rpm crank by honda design, stronger than the B20 piece and the slightly shorter stroke will drop displacement by only 40cc, hardly noticeable. What I would like to accomplish is improve the rod/stroke ratio as much as possible by resizing the rods and finding pistons with a higher pin center. Im really trying to become informed on piston science - what the practical limits are - so I can build a long lived NA streeter that I wont have to worry will break when I run to redline. Ive had the car for 4 years and just got the B16A2.

pissedoffsol · 07-02-2002, 10:31 AM

your best bet is the b17 crank

B20BbenN · 07-03-2002, 07:04 PM

HELLO! crvtec or lsvtec have a 89mm stroke! Dont call an engine(crvtec or lsvtec)if you have a 81.4mmstroke!!!!

All honda B-serie crankshaft are bulletproof so dont worry about which crank are stronger than the other!

If you want maximun reliability and maximun power, take the b20b crank(b18a-B) and put some sleeve like golden eagle sleeve!

Dennisman · 07-04-2002, 03:51 AM

My thought was to drop to a GSR/ITR crank with their 87.2 stroke. Thats 1933 cc`s vs 1972 with the B20 crank. Not a big loss of displacement. I almost bought an ITR crank but the seller told me it wont fit. Im just trying to find out what can be swapped straight accross without machining. Goal is building a bottom end that will live at 9K+ RPM in perfect health and to that end, optomizing the R/S ratio and having a rigid, balanced reciprocating assembly seems essential.

B20BbenN · 07-04-2002, 03:16 PM

All B-serie cranks will fit in any B-serie block

The S2000 engine can rev to 9000rpm all day long but the rod ratio of this engine is 1.82:1
gs-r(typeR) rod ratio=1.58...doh!!!you can still rev to 9k but the cylinder wall and the piston will wear a little bit more than if you have a good rod ratio!It's the price to pay!But you will not be at 9k all day long so the gs-r(typeR) crank is a good choice.
If you find some piston with higher pin center you will need custom rod!!!------custom piston+custom rod=$$$$

B17 crank is a good choice too but you will have less torque...!
But if you choose to stay n/a, you can put sleeve and bore to 86-87mm and make some good power!

Dennisman · 07-04-2002, 04:02 PM

To my way of thinking, destroking a B20 with the much shorter stroke B17 crank and loosing around 200 cc`s is kind of pointless. Why not just use a GSR motor to begin with! Its not perfect but Honda did design high RPM durability into it. Yeah it costs to optomize the geometry, I think I found $50 per rod to change centers and I dont know about custom pistons but optomizing R/S ratio does yield extra horsepower in reduced friction and I`ll bet its significant. Im now thinking balanced B20 bottom end and limit the redline to 8K, thats probably past the B16A cams peak anyway.
Think $1100 for a B20Z is reasonable?

sweet · 07-09-2002, 07:31 AM

as was mentioned, take the B18C1 block and resleeve/overbore it to 86 mm with custom higher comp. pistons. that will give you more displacement than the B20, a better rod to stroke ratio for higher revs and more power throughout the rpm band from the C/R.

then you can match it with a nice int. man./cam/header setup and make some serious and reliable N/A power.

later

Dennisman · 07-09-2002, 05:36 PM

What Ive really been trying to find out is which cranks will/will not drop into a B20B/Z. Ive been told sleeving so far oversize wont be everyday streetable and long lived. Also changing bore size alone wont change R/S ratio. I have a B16A-2 motor which I consider too small for the low end torque Im looking for, not a B18C. Im not intending the use of its block cause of the shorter deck height. What I wanted to do was: install ITR crank into B20 block modified for main bearing girdle. Install block guard. Resize GSR/ITR rods to greatest possible center/center size plus full floating. Custom pistons to match with 10.5 -11/1 CR and fully balance. Im looking for a super tall 5th gear and as there is a machine shop available at work am considering getting a 2.0 second gear and turning it around for a .5 top gear. At this point Im not sure what can & cant be done, price is a concern and where do I find the parts I need reasonably. I want to get moving with this project. Tnx all