PSPEC

Hello everyone. I am doing a bit of research on align boring (align honing) a 1992+ H23a1 block or 1993-1996 H22a block (JDM or USDM doesn't matter) to accept a 1997+ H22a4 crankshaft. The 1997+ H22a's have 5mm larger main bores and I would like to use a crank with these larger mains in my 1992 H23a1 block. Here is a really crappy microsoft paint drawing of what needs to be done. Anyone who is familiar with align boring should be able to understand these pic.

Any info appreciated. Thanks

Knives

I see you post the same topic on differnt forums like I do......good luck.

Andy

Are you asking if it's possible? Your going to not only have a large amount of material removed from the block, you'll also need custom made caps to secure the crank. I'm assuming you want to keep the '92-'96 closed deck block and use the '97+ larger crank (I acutally wasn't aware they were different but I don't have much experience with H-series engines). You'll probably find yourself in much safer waters by resleeving a '97+ block and converting it to a closed deck design. At least I know that's been done successfully before and is very strong.

I'm aware of align honing, but I'm not sure if I've heard of anyone boring that space out, at least not 5mm worth of material away. You actually don't hear that much about align honing with Honda, or any import blocks. I think the best place to find your answers would be a local engine shop or a larger Honda/import specific shop you would trust to do the work, they would know a lot more than I would.

PSPEC

Knives: Yeah I try to ask as many people as I can. The more exposure the better.

Andy, I don't see why I would need custom main caps, because they get bored out at the same time as the block. Also, in the H series and F series engines, its a girdle, not caps. The 97+ H22a has the same main girdle and its bored out bigger.

Align honing and align boring are two different processes that try to accomplish the same goal. I have engine building books that verify that.

I actually have a 2000 H22a4 block that I am saving for another project. I would much rather do the crank conversion in my H23a for now.

I remember about a year back I think I read about someone doing this in a forum. I just don't remember who or where. Hopefully they will see one of my posts and come around and let me know whats up.

Some of the issues im concerned about are what bearings to use once the boring is done, will the bearing tangs have to be re-grooved into the new bores, how is a machine shop to locate the crank centerline so that they can accurately bore out the the block without moving the crank up or down in the block, and how do they go about machining the thrust bearing surfaces in if its even necessary.

I'll get some pics of both blocks side by side when I get back from school or tomorrow. I am going to start calling shops today too. I was posting around the net on the weekend.

Andy

I've never seen the underside of an H-series engine, I wasn't sure how much material made up the caps (or girdle in this case) that you could afford to take that much away without compromising strength. If the '97+ blocks are done that way, I'd imagine the earlier units can also be done the same way. I also wasn't sure if you could machine away and then replace the bearing surface on a set of main caps or not. I guess you could use custom bearings or '97+ one's.

From what I heard, boring is the process of taking larger pieces of material away and honing is a finishing cut (so to speak) that only removes a small amount of material but leaves a nice finished surface.

I'd assume that a machine shop would have some way of locating the block so that whatever machine they use to cut or mill the material away stays dead center. I work in a small tool and die shop and we have vices built into milling machines that you can zero out and work right dead center of whatever material you were using. You could never fit and engine block in one but the theory is probably the same with a larger custom built machine. Let us know what you find out, I'm interested to see if it would work.