JarrettL

Alright, I have a very long-winded post for you about my plans to modify my damaged F20B. In one of the weirdest events I've ever seen it threw a rod at about 35,000 miles. The rod in the #1 cylinder just bent like a noodle at the bottom of the stroke and popped a tiny hole in the block. It's about the size of a dime. The cylinder has a very tiny scratch at the bottom of the bore that is lower than the piston travels and will easily come out with an overbore. Because of how difficult F20B blocks are to come by I will be having this one fixed. The casualties besides the block are the broken rod and that's it. The pistons and crankshaft are all perfect and the head is perfect as well. That's why it's so weird.

I also bought an F23A1 to use the crankshaft and stroke out the F20B. This will be going into a CB and I don't really like engines that you have to wind up in order to see any power out of them. I could just do the standard swap coupled with K20A2 pistons and be just fine but I'm a fan of long-rod engines and I want to try and do something different on this one.

So here's what I want to do. I want to use 145mm rods and a shorter piston. My choices for rods seem to be factory F20A/B rods that are .935' wide and having the rod journals on the crankshaft widened or the 5.700" SBC rods that use the "Honda journal" which is .940" wide. Either way, material needs to come off of the crankshaft.

So for my first question, can anyone give me a rough estimate of what I'll be paying for this? I've tried calling two machine shops and one referred me elsewhere and the other has not responded. But even still, I want to know what some of the experienced people on here think is fair before I just say okay to the first machine shop that gives me a price.

If I use the factory F20B rods then I'll already have a 22mm bushing in the small end but if I use the SBC rod then it will use a 23mm bushing. This would have to be rebushed for a 22mm pin at the very least in order to use most any piston that's going to be short enough for the application. Any ideas as to what this would cost per rod?

Lastly, the only shelf piston that I can find is a 4G63 piston designed for a 96mm stroke from CP Pistons that is 25.86mm tall. That's right about perfect for the compression height I need. It also uses a 22mm pin, comes in 85, 85.5 and 86mm bores, uses three rings that are the same thicknesses of nearly all of their other offerings but has a -5.5cc dish. This would put me at a ~9.9:1 static CR after a resurface. Hardly optimal. So, it looks like I'll need some pistons made instead. If I do, what company has the best prices for custom pistons? What will I roughly be spending here? Are there any other features I should look into designing into the piston with the long stroke and longer rod like a further pin offset? Will gas ports be something I'll have to specify or are they usually a given with custom forged pistons?

I apologize for asking very price-specific questions but I really have no idea about pricing unless it comes off the shelf. I plan on continuing to call machine shops but I wanted to get general ballparks as well to have something to go off of. Thanks a lot for your time and I'll be sure to make an actual build thread once I get started. The F20B is torn down already but I haven't gotten to the F23A yet. First thing is to get the block repaired professionally.

ESP.net

Someone on here just did this recently check the threads in all motor and hybrid. (rrrace) F20B is only $700 for auto version.

If there is a damage etc in the cylinder, scratch etc. You will need to have it checked out to make sure it hasnt cracked or looks bad enough to be a not so worthy motor to invest with. last thing you'd want is to sink money into it find out later has a crack or will crack...

F23 Crank and Rods is what you need with it seems the K24 piston is in the hole with 87mm bore and hone. Which going from 85mm to 87mm is a big jump and leaves the cynlinder walls pretty darn thin most of only been able to getaway wtih 86mm bore... F20B is not FRM like a regular H, uses normal iron cylinders so Bore and Hone would be straight forward. Pistons will be going in backwards being K.
Last thing you would have to factor is will the piston in deed be in the hole rather then out and your final compression number. Also does the F20B have oil squirters? those would need to be done away with 97mm stroke.

I am not even sure if anyone has figured a for sure deal on a F20B timing belt that is achievable to get?

Bserious

Unless you are willing to go ***** to the wall with a sleeved block and a huge crank beyond what OEM offers, I would highly recommend just investing in an H23Vtec and call it a day. To do what you are trying to do is not going to cost less than a $950 longblock. A N/A 87x95mm setup can easily acheive 250+whp.

ESP.net

H23V Blue Tops is all I deal with these days... Nice motors and for the price of under G you will have less money in it. They make about 10 hp and 10 more ft lbs of torqe out of the box then a jdm h22. However 97mm stroke would be neat and half to make a little more power... Next step I would go if I was keeping my H23V blue top NA would be 97mm or a bigger stroker however.... turbo and 95mm is all I want to go...

JarrettL

I take it you didn't read the whole thing. I already own an F23A1 that I will be taking the crankshaft from. I was looking at options other than the standard K20A2 pistons on top of an F23A rotating assembly, though. And I'm not really sure where you thought I wanted an 87mm bore K24 piston either. I completely understand that the F20B bores are even marginally safe at 86mm. And where does the F20B timing belt come into play in this? Even still: http://www.hmotorsonline.com/shop/wh...php?prodID=720

It seems you're more concerned with telling me the basic philosophy of building an engine. That's not really what I'm asking.

I already have another engine that will essentially be an H23A VTEC (H22A block, F22/H23 crankshaft, H22A rods rebushed for 23mm wrist pins, F20C pistons, PDE head) when completed. It was my original plan to install that into my CB before I acquired the F20B and F23A1. Now I want to build something for the sake of building it. That's really been my drive from the start. I enjoy parts acquisition, assembly and installation more than actually driving the thing so taking on a second engine is a plus in my opinion. I don't mean to come off as one of those douches that says "Cost is no object, retrieve me a parts list!" because that's not the case. I just want to know what machine costs I will likely be incurring and also get some advice from those who have ordered custom pistons before (the same questions I asked in the first post). I am a fan of the H23A VTEC, though. I always have been. I feel inclined to ask, though. Why do you omit the 97mm crankshaft from consideration? It's an OEM crankshaft. I understand that the rods are weak but what I want will effectively be removing that concern.

rrace002

You can use f23 rods with the f23 crank and k series pistons.

ivan93egreppin210

How are f23 rods weak? I make 194/164 with a sohc nonvtec and have been beating the **** out of it. Have you considered doing a g23 setup? Dont get too caught up on r/s ratio. Bore your f20b to 86mm. Put some aftermarket k20 8cc dome pistons in along with f23crank/rods and some pro2-3s. Or use f23 crank, k20 rods and your f20b pistons. That will fit as well.

rrace002

Strength of the f20b cylinder walls at 87mm would only come into play if you were using turbo or nitrous. I really don't think its going to be an issue, but then again my motor is still on the stand, so I am not speaking from experience.

rrace002

I used f23 forged rods from Race Engineering. They cost about $460.

rrace002

86.0 mm k20 pistons or 87.00 mm k24 pistons in combination with the f23 crank and rods will fit and the piston will be flush with the block deck at top dead center.

rrace002

A for the machine shop bill question- My total came to about $1350 for almost everything.

JarrettL

Are you post-whoring or are you actually trying to help? So you're telling me I can use the F23A1 crankshaft and rods with K20A2 pistons on top and call it a day? I understand that. Enough so that I even mentioned that it was the convention I was trying to get away from in considering other options. And saying what your total bill is at a machine shop without giving any sort of details whatsoever is not very helpful at all.

The F23A rods are weaker relative to the usual H22A or F20B rod from both a width and metallurgy perspective. I'm familiar with your build and I'm actually a huge fan of it. It's roughly what I suggest as an alternative to other people with Accords who want to swap to do instead. However, with this I'm not asking for people to suggest other methods in which I should spend my money and effort to build something I don't want to build. I really want to attempt a long rod 97mm stroke F20B. I know what the other options are as I'm not new to F/H-series engines.

And I don't really understand the benefits of ignoring r/s ratio. Are you disputing its validity as a concept to be considered? And why would you suggest a head swap onto a block that has to have oil drains blocked and in which there isn't a perfect headgasket match as opposed to following a well-documented principle for implementing longevity into an engine?

And suggesting other rod lengths even shorter than the 140mm F23A rod is not what I'm after here.

rrace002

I kind of skimmed through and answered one post at a time. I thought it would be easier to read that way. I was saying that you can use the k20a2 pistons and the f23 pistons /rods which is basically a "g23."

I don't think there is any other simple combination that will get you to zero deck height as easily, or as cheap using the f20b block or any f / h block. The k rods are cheaper but would require either custom pistons or a k24 crank.

I ended up getting a balance of the lower end - 250
bore/hone job- 250
3 angle valve job+ installation - 310
Bearings + valve seals + misc parts 150
I cant remember what the other 300 is but it adds up fast.

JarrettL

Thank you for clarifying the prices. I understand that machining is expensive. The head has already been rebuilt so that's done and one thing to check off of the expense list.

Pistons are a given. Either some random piston like the 4G63 stroker piston I found or custom units by one of the larger companies. I just didn't really have even a ballpark of what this would run me.

It seems I'm best off just approaching those companies and asking them.

Also, I understood that you were suggesting the F23/K20 combo as an option but in my first post I said that was something I did not want to do. I get that it works. I still want to run a 145mm rod.

rrace002

I guess I misunderstood exactly what you were looking for from the post. I was kind of getting the impression that you were trying to build something for cheap.

gstrudler

Custom pistons will probably run you ~$700 depending on manufacturer and any special options you want it designed with. Not sure if you had it done already on your other build, but re-bushing the rods will probably cost about $200 for the set including the bushings (when I rebushed my f23 rods they were $40/ea + bushings iirc). I honestly couldn't tell you cost on getting the crank worked on since I've never had that kind of work done, but I would guess anywhere between $250-$500 since they are not only removing material, but grinding and polishing the journals that are being widened, and then re-balanced. If it were me, I'd consider getting the rods shaved down to fit and either find bearings that work (stock F20B probably), or get the corresponding ones cut down as well. Although at that point you might be out just as much money, hard to say. Kudos to you on trying something different though.

JarrettL

Thanks gstrudler. I enjoyed reading your thread a while back about your build.

Those price for crank machining is about what I was expecting them to be, the pistons actually a little cheaper. However, the rebushing is much more than I thought it would be. Given the process it seems like robbery. If I were to stay with a factory F20B rod then a 22mm wrist pin could render this process a non-issue as I'd feel more comfortable going with a low compression height piston with a 22mm pin vs. the 23mm. Not much of a difference, but enough.

And no, I haven't rebushed my H22A rods yet. I was at such a standstill getting the PDE head, manifold and intake gasket (Finnish friend ordered from Honda) that it's been on hold for a while. Now even longer. My subconcious hope is that I stumble upon someone selling a sleeved H22A block for cheap that would allow a little better build than working with the confines of FRMs now.

ivan93egreppin210

You're next option is opening your f23 crank to fit the f20b rod and use a piston with a 26 mm ch. That is my future build. I have a sleeved f23 with 90mm 14.5 cr pistons using f20 b rods and a widened crank from Castillos crank. Sorry if I haven't been much help. Gluck.

JarrettL

That has literally been THE reason I've made this thread and what my plan is to do. It's the reason as to why I've primarily asked about crankshaft grinding to widen the journals.

ivan93egreppin210

As far as your rod bending and snapping by itself I would double check your injectors. Same thing happened to me last year. My injector somehow stayed open flooding the cylinder with gas causing my motor to hydro lock. Bent my rod pretty good. Did you smell gas in your oil?

JarrettL

My first bout of bad news came today. It doesn't affect me too much, though because it's bad news from a crankshaft shop that doesn't rebalance crankshafts(seems like not to valuable of an opinion). Anyway, they didn't want the job because the grinding stone could explode in his face from heat and he'd have to go lube it every 20 minutes to avoid that. He said if he had an offset lathe that it would be no problem. So now I need to find someone who has an offset lathe. I'm in Houston, TX so it seems like this shouldn't be too hard.

I didn't really investigate too much. The engine was pulled and left for a considerable amount of time before it was even opened up. At the time I don't recall much of a fuel smell. Either way, it will be using new injectors so that's not a concern going forward. That does seem pretty odd, though.

hella vtec yo

I've built a f23/h22 setup a year 1/2 ago for a close freind of mines and he also Daily drives it everyday.F23 block, 97mm crank, 86mm K20 type S pistons(Installed the same way as an h22 not backwards) stock h22 head, Skunk2 pro 2 cams, Suptech valve springs and retainers, Qsd K series manifold adapted to an RBC manifold. Dynoed around 260hp 190Tq

JarrettL

It seems that with all the grief these machine shops have been giving me about this job that my money could just go toward custom rods and pistons. I was already going to have to have custom-height pistons made anyway, but I might as well spend the money to be spent on the crank on the rods. If I did that I could have a few bonuses:

-forged rods where as my current plan does not include them(was planning on factory F20B rods)
-the ability to gain 2mm more of rod length if I elect an 18mm pin
-avoiding the ever-so-slight chance that grinding the crank actually weakened it

Rods are another thing I'll need to check prices on. However, given the number of people that have asked about F23A rods in the past couple of years maybe there's a small market for a long rod setup.

rrace002

Can I ask what your purpose is of going to custom rods and pistons on this build?

ESP.net

He is worried about R/S ratio. However with a beefier rod I don't think is insanely crucial some of the H strokers that have been out there for years dont have the ideal ratio.

I recently gone over with a few manufactures with the (95mm) H23AV Blue Top Motors... Trying to get them to come up with a custom rod for these motors so the H22 piston will stick in the hole rather then out 20k which isn't a big deal compensate with headgasket... this is how I run my H23V builds with a H23A1 rod 141.5mm. H23V had 20k shorter rod 141mm roughly

Anyways... Custom Piston with pin moved etc like $800-$900 and Rods were right around the same...

F23A crank and rods has piston sticking out of hole something like 80k with a H22 normal piston.

There is a guy on here that is very knowledgable with H and 97mm stroke he has I believe done head adjusting and H22 piston adjusting (milling etc) he is making around 250 hp 180 trq with H trans check around here in the Hybrid and All Motor forums, don't have his name but would be knowledgable on machine work...edit: F20bjones

The K20/4 pistons seem to be the best route keeping in the hole and a cheaper combo