F23 Internals Info

[turboputz]

Is piston compression height the amount the piston comes out of the hole?

If yes does that mean that the high comp. aftermarket pistons designed for the K20 are going to be safe for piston to valve clearance with the F23 head?

Specifically the Wiseco 11.5:1

What is the maximum bore that would be safe to run on the F23 block for an NA set-up with high compression, 11.5:1 or higher? Can we go to 88 mm on the stock sleeves? Wiseco also makes 87.5mm.

Basically my problem is this, I'm building my top end this winter and hopefully the bottom end next winter. I want to mill the head .035 so I get the best results for this year, but I don't want to rule out the possibility of using those 11.5:1 K20 Wiseco's in the future.

Then I'm worried if I bore out a short block, I gotta take the head off and send it back again to get deshrouded for the bore size, which is just getting ridiculous. Makes me wonder if I should do the full build form the start. However I really don't know if I have the juice to go through with that and deal with spend and wait... spend more wait more.

Aggh well I'm really curious what in house experts have to say about the piston clearance issue and the max bore without sleeving.

We got so many threads seemed like a good enough one to add to.

 

[AFAccord]

Very nice question. The issue is that our F23's are interference motors, meaning without proper timing (ie timing belt snaps) the valves can come in contact with the pistons. Basically, you're asking if the high compression pistons have enough "valve relief" to operate without interfering with the valves.

I don't have a definitive answer for you. But since we're on the topic of n/a building, you've probabaly considered a more aggressive cam. You might keep all of your lift/duration specs in mind, while considering these clearances.

Otherwise, Bump for an answer to a good question!

 

[Sonnick]

Very nice question. The issue is that our F23's are interference motors, meaning without proper timing (ie timing belt snaps) the valves can come in contact with the pistons. Basically, you're asking if the high compression pistons have enough "valve relief" to operate without interfering with the valves.

I don't have a definitive answer for you. But since we're on the topic of n/a building, you've probabaly considered a more aggressive cam. You might keep all of your lift/duration specs in mind, while considering these clearances.

Otherwise, Bump for an answer to a good question!

Yea, he bought my Stage 2 Bisi cam, so he's definitely looking at some nice power N/A

 

[BlkCurrantKord]

Is piston compression height the amount the piston comes out of the hole?

If yes does that mean that the high comp. aftermarket pistons designed for the K20 are going to be safe for piston to valve clearance with the F23 head?

Specifically the Wiseco 11.5:1

What is the maximum bore that would be safe to run on the F23 block for an NA set-up with high compression, 11.5:1 or higher? Can we go to 88 mm on the stock sleeves? Wiseco also makes 87.5mm.

Basically my problem is this, I'm building my top end this winter and hopefully the bottom end next winter. I want to mill the head .035 so I get the best results for this year, but I don't want to rule out the possibility of using those 11.5:1 K20 Wiseco's in the future.

Then I'm worried if I bore out a short block, I gotta take the head off and send it back again to get deshrouded for the bore size, which is just getting ridiculous. Makes me wonder if I should do the full build form the start. However I really don't know if I have the juice to go through with that and deal with spend and wait... spend more wait more.

Aggh well I'm really curious what in house experts have to say about the piston clearance issue and the max bore without sleeving.

We got so many threads seemed like a good enough one to add to.

Compression Height - http://rosspistons.com/custom_compression_height.php

With something of that high compression and the cam your using, it'd be wise to clay the motor to check for valve/piston contact or whatever shop builds your motor for you. If you dont know what claying the motor is, google it, it'll be a better explanation than what I can give you. 87mm is the max you should take the stock sleeves, even that is pushing it. Remember its an open deck motor. Thats not just me saying it, PirateMcFred has said it too.

I'd just do the whole motor in one shot, why spend the money twice? It's much easier even though you think it may cost more. It'll cost you more do tear it apart twice.

 

[turboputz]

This is good to get the information out there about what it really involves to correctly build a radical NA F23. Yes I have heard of claying and it sounds expensive, that's the genesis of my question. And if they do make contact, what then? I guess the way to fix that would be through cam timing and if necessary a thicker head gasket.

I just thought I'd throw it out there since we have all these threads talking about using these high comp K20 pistons, but no concrete evidence that it is safe without fragging the head. What about this Stinker fellow I've heard about? Is he still around and which exact pistons is he using? Its all about learning from other people's experince to minimize the labor costs, redos, etc. I can't see spending the money on sleeving to use 88mm slugs if the block is not going to see boost, but boy would that torque benefit this car.

I suppose there's no harm in picking up this shortblock I found in Jersey if I can get a good deal on it. What an expensive addiction to have.

Useful limitations that i have learned from other accord tuners thusfar:

.035 mill on the head is safe
87mm is the maximum safe bore on a stock sleeved F23

 

[iHazSnail]

what abt a turbo build? I am thinking abt doing my bottom end for a turbo but not too sure abt wht could actually be good for some serious power

 

[BlkCurrantKord]

What about it?

Low compression pistons and beefier rods.

 

[Sonnick]

^^ And a good cam. Boosted with the right cam, the F23 could really be a monster. Stinker over at E-H and Notorious both got over 350whp I believe with a built motor with t3/t4 turbos. With a GT30R or 35R..

Bisi over at Bisimoto.com knows basically everything there is to know about Honda's and is a great help too.

 

[nighthawk]

I'm just doing some research and found this compression calculator:

http://www.bsperformance.com/compcalc/compcalc.htm

So it seams the F23A1/4 has -13,6 cc piston dome displacement and the F23A5 has the -18cc's as listed above.

Maybe important for some

damn, my site has gotten around the net

these piston cc's were come up with using all the other specs and then finding the value. should be pretty accurate since all the other specs are known to be correct.

the F23A5 is the non-vtec engine in the DX. F23A4 is the ULEV and has the same pistons as the F23A1

 

[AFAccord]

http://www.zealautowerks.com/hfseries.html

Here's my bread and butter for compression calc.