h22a4 crank h23a1 block..... - Honda Prelude Forum

IALuder · 03-28-2006, 06:17 PM

i remember someone saying the mains had to be milled down for it to work, so could someone plz tell me how? what exaclty has to be done for this to work?
i know it has to go from 55MM to 50MM, but thats it.

alphajesse · 03-30-2006, 11:30 AM

I would say boring out the mains on the block would be a better way to do it.
However, I'm sure there are many on here who would happily trade you for a H22A crank to get the H22A4 one.

IALuder · 03-30-2006, 09:05 PM

i want to use the h22a4 crank for the fact its stronger.

this what i have been told in PMS with a member
I haven't seen a write-up about it. I remember seeing a debate on H-T that concluded with people deciding that most compentent shops can do it. Having an A4 girdle makes it easier since just the block's mains need to be machined to match the girdle. It it ends up being too difficult or pricy just exchange the A4 crank for an A1 crank.

so line bore the block to match the girdle and the a4 crank should work?

Bore it so the block & girdle match, then find the right bearing size that will work with the bore & crank. It's that easy. Definitely have a compentent shop do it.

so just making the girdle match makes the crank fit? does that seem right? not doubt any info just curious to make sure i do it right?

alphajesse · 03-30-2006, 11:26 PM

I think if you found someone willing to trade, they'd likely do an even exchange with you, and with the correct crank for the block you can continue to use OEM bearings.

71dsp · 04-01-2006, 05:28 AM

I don't see the advantage in doing something such as this unless you're going to be making very high HP numbers. In a nutshell, the machine shop would need to bore the main saddles and caps close to the finish diameter, then line hone the block. To do this right, you need to have the major parts bolted to the engine (head, main caps, girdle, etc) with the same fasteners that you plan to use. i.e. don't do a line hone with stock main bolts torqued to the stock spec, then install ARP main studs that are torqued to a much higher spec, you'll warp the main bore.

Also, in addition to the boring and honing, the machine shop will need to machine notches for the tangs in the bearings. Ideally, you'll need to get your hands on a 55mm main block and measure the main bore diameter. This might be in the Helms manual, but I'm not 100% sure. You won't be able to determine the diameter from the bearings.

Seems to me a more effective solution would be to either get the correct crank for the block, or get the correct block for the crank!

Also, in the meantime, make sure you store the crank correctly, or it WILL warp. Have the machine shop check it for runout prior to installation. I have one that I thought was good, but it turns out it has 15 tens of runout.