F20B Pistons & Rods
05-02-2016, 05:36 PM
#1
Honda-Tech Member
Thread Starter
Join Date: Mar 2016
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
F20B Pistons & Rods
Hi been searching on here and other sites for info about piston and rod combo's
I want a high revving 9000rpm motor and want to keep it as close to 2 litre as possible with an Evo 5 turbo
Don't want to sleeve the engine as it has iron sleeves stock
F20B
Bore x Stroke: 85 x 88mm
Compression Height: 31mm/1.221
Pin Diameter: 22mm/.866
The complete F20B rod specs are with common engine matches:
Length: 145mm (5.709") - no engines
BE Bore: 48mm (1.809") - D16, B16A, B17A, B18A, B18B, B18C, B20
BE width: 23.75mm (0.935") - B16A, B17A, B18A, B18B, B20, F22, H22, H23
Pin Bore: 22mm (0.866") - F22, H22A, H23A
Pin Width: 23.875mm (0.940") - F22, H22A, H23A
Considering 4G63/4G64 pistons 28.7mm comp height, K20 pistons 30mm comp height & custom made 31mm com height
Problems will be valve-relief piston pockets clearances and rotation of motor, will need to rotate them 180 degrees to align valves / (and k20 offset pin)
What is the boring limits of the stock iron sleeves ?
What pistons 9.0:1 will work ?
What H beam rods can I use ?
Thanks in advance
I want a high revving 9000rpm motor and want to keep it as close to 2 litre as possible with an Evo 5 turbo
Don't want to sleeve the engine as it has iron sleeves stock
F20B
Bore x Stroke: 85 x 88mm
Compression Height: 31mm/1.221
Pin Diameter: 22mm/.866
The complete F20B rod specs are with common engine matches:
Length: 145mm (5.709") - no engines
BE Bore: 48mm (1.809") - D16, B16A, B17A, B18A, B18B, B18C, B20
BE width: 23.75mm (0.935") - B16A, B17A, B18A, B18B, B20, F22, H22, H23
Pin Bore: 22mm (0.866") - F22, H22A, H23A
Pin Width: 23.875mm (0.940") - F22, H22A, H23A
Considering 4G63/4G64 pistons 28.7mm comp height, K20 pistons 30mm comp height & custom made 31mm com height
Problems will be valve-relief piston pockets clearances and rotation of motor, will need to rotate them 180 degrees to align valves / (and k20 offset pin)
What is the boring limits of the stock iron sleeves ?
What pistons 9.0:1 will work ?
What H beam rods can I use ?
Thanks in advance
Last edited by B20MTR; 05-03-2016 at 01:31 PM. Reason: better information
05-02-2016, 07:51 PM
#2
Honda-Tech Member
Re: F20B Pistons & Rods
1. Normally 1mm over
2. Use the h/f compression calculator and use the piston specs from different pistons with the same bore and wrist pin size.
3. Do this along with step 2. So you get the correct compression and all that fancy **** your looking for. Use this guide.
F/H series bore, crank, piston and so much more! [Archive] - Honda Prelude Forum : Honda Prelude Forums
2. Use the h/f compression calculator and use the piston specs from different pistons with the same bore and wrist pin size.
3. Do this along with step 2. So you get the correct compression and all that fancy **** your looking for. Use this guide.
F/H series bore, crank, piston and so much more! [Archive] - Honda Prelude Forum : Honda Prelude Forums
05-03-2016, 01:59 PM
#3
Honda-Tech Member
Thread Starter
Join Date: Mar 2016
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
Re: F20B Pistons & Rods
thanks h22god
So have decided on wiseco pistons K631M86 K20 86mm 9.55:1 30mm compression height, 50.5 cc head on k20 from amazon $419.72usd is that ok ?
Do I just deck the block 1mm to get them setting at the correct 0 deck height because stock pistons are 31mm compression height ?
Using the H/F compression calc decking block 0.026 (1mm) will it be ok/need to to shorten head bolts 1mm, also will it affect valve / ignition timing etc ?
k20 head has a 50.5cc head combustion volume vs f20b 53.8cc = lower cr I worked out 9.38:1 ?
Do the k20 pistons need the exhaust valve pockets machined bigger to match the h22a intake valves or work with no mods ?
What head/manifold is best for 86mm bore x 85 stroke h22a with bigger valves or f20b ? what head gasket works with 86mm bore ?
Interesting that the stock turbo civic 2015/16 K20C1 uses 9.8:1 CR, 86 bore x 85.9 stroke @306 hp
Cheers
So have decided on wiseco pistons K631M86 K20 86mm 9.55:1 30mm compression height, 50.5 cc head on k20 from amazon $419.72usd is that ok ?
Do I just deck the block 1mm to get them setting at the correct 0 deck height because stock pistons are 31mm compression height ?
Using the H/F compression calc decking block 0.026 (1mm) will it be ok/need to to shorten head bolts 1mm, also will it affect valve / ignition timing etc ?
k20 head has a 50.5cc head combustion volume vs f20b 53.8cc = lower cr I worked out 9.38:1 ?
Do the k20 pistons need the exhaust valve pockets machined bigger to match the h22a intake valves or work with no mods ?
What head/manifold is best for 86mm bore x 85 stroke h22a with bigger valves or f20b ? what head gasket works with 86mm bore ?
Interesting that the stock turbo civic 2015/16 K20C1 uses 9.8:1 CR, 86 bore x 85.9 stroke @306 hp
Cheers
05-07-2016, 11:20 AM
#5
Re: F20B Pistons & Rods
thanks h22god
So have decided on wiseco pistons K631M86 K20 86mm 9.55:1 30mm compression height, 50.5 cc head on k20 from amazon $419.72usd is that ok ?
Only way to know is to get them. This is what "customization" is all about. If it were that easy to answer, more people would have the F20B already, so don't sweat it. If you're installing it, it'll all be on you whether or not we agree with the choice
Do I just deck the block 1mm to get them setting at the correct 0 deck height because stock pistons are 31mm compression height ?
No. I wouldn't. Just deck enough to make the block straight. Don't try to get specific number of millimeters.
Using the H/F compression calc decking block 0.026 (1mm) will it be ok/need to to shorten head bolts 1mm, also will it affect valve / ignition timing etc ?
k20 head has a 50.5cc head combustion volume vs f20b 53.8cc = lower cr I worked out 9.38:1 ?
Do the k20 pistons need the exhaust valve pockets machined bigger to match the h22a intake valves or work with no mods ?
This all is going to have to be determined when you get the pistons. I understand you're looking for guidance at this particular build, so that you can get every part right the 1st time, but be honest with yourself; no one is going to be an advocate for this build more than you. If that means that you have to clay the engine in order to answer these questions, (Which is exactly what will help answer them) then that's what you'll need to do, bottom line. These calculators online only give best guess. Don't be surprised, as a lot of what makes math and science what it is, is best guess
What head/manifold is best for 86mm bore x 85 stroke h22a with bigger valves or f20b ? what head gasket works with 86mm bore ?
No one can answer that really, but I'm sure it's narrowed down to the K20 /H22 family. There's probably no best manifoldeither. There's what exists in the market, and what you're willing to fabricate or alter.
As for the Gasket, I'd see about using an OEM one first. Take your original head gasket and try to compare it with the H and F series to see about commonalities in the OEM world for a match, or find another original one via the part number (if possible), and perhaps Golden Eagle has something similar that they can modify in the OEM world to fit that bore. If you did find another OEM one, you can send it to them and see if they can bore it to what you need.
Worst case scenario is that you can make a template of the original gasket out of cardboard or construction paper and mail it to Cometic for analysis and creation.(I did this with an Escort Cosworth engine a couple of years ago. It took about 2 weeks, but it was worth the wait. I ordered 2 just to be safe once they confirmed the matchup.) It may cost a bit more than you wanted, but this isn't a cookie cutter build anyway.
Interesting that the stock turbo civic 2015/16 K20C1 uses 9.8:1 CR, 86 bore x 85.9 stroke @306 hp
What makes that particular fact interesting?
Cheers
So have decided on wiseco pistons K631M86 K20 86mm 9.55:1 30mm compression height, 50.5 cc head on k20 from amazon $419.72usd is that ok ?
Only way to know is to get them. This is what "customization" is all about. If it were that easy to answer, more people would have the F20B already, so don't sweat it. If you're installing it, it'll all be on you whether or not we agree with the choice
Do I just deck the block 1mm to get them setting at the correct 0 deck height because stock pistons are 31mm compression height ?
No. I wouldn't. Just deck enough to make the block straight. Don't try to get specific number of millimeters.
Using the H/F compression calc decking block 0.026 (1mm) will it be ok/need to to shorten head bolts 1mm, also will it affect valve / ignition timing etc ?
k20 head has a 50.5cc head combustion volume vs f20b 53.8cc = lower cr I worked out 9.38:1 ?
Do the k20 pistons need the exhaust valve pockets machined bigger to match the h22a intake valves or work with no mods ?
This all is going to have to be determined when you get the pistons. I understand you're looking for guidance at this particular build, so that you can get every part right the 1st time, but be honest with yourself; no one is going to be an advocate for this build more than you. If that means that you have to clay the engine in order to answer these questions, (Which is exactly what will help answer them) then that's what you'll need to do, bottom line. These calculators online only give best guess. Don't be surprised, as a lot of what makes math and science what it is, is best guess
What head/manifold is best for 86mm bore x 85 stroke h22a with bigger valves or f20b ? what head gasket works with 86mm bore ?
No one can answer that really, but I'm sure it's narrowed down to the K20 /H22 family. There's probably no best manifoldeither. There's what exists in the market, and what you're willing to fabricate or alter.
As for the Gasket, I'd see about using an OEM one first. Take your original head gasket and try to compare it with the H and F series to see about commonalities in the OEM world for a match, or find another original one via the part number (if possible), and perhaps Golden Eagle has something similar that they can modify in the OEM world to fit that bore. If you did find another OEM one, you can send it to them and see if they can bore it to what you need.
Worst case scenario is that you can make a template of the original gasket out of cardboard or construction paper and mail it to Cometic for analysis and creation.(I did this with an Escort Cosworth engine a couple of years ago. It took about 2 weeks, but it was worth the wait. I ordered 2 just to be safe once they confirmed the matchup.) It may cost a bit more than you wanted, but this isn't a cookie cutter build anyway.
Interesting that the stock turbo civic 2015/16 K20C1 uses 9.8:1 CR, 86 bore x 85.9 stroke @306 hp
What makes that particular fact interesting?
Cheers
07-24-2016, 01:18 PM
#6
Honda-Tech Member
Join Date: Jul 2016
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
Re: F20B Pistons & Rods
Hi been searching on here and other sites for info about piston and rod combo's
I want a high revving 9000rpm motor and want to keep it as close to 2 litre as possible with an Evo 5 turbo
Don't want to sleeve the engine as it has iron sleeves stock
F20B
Bore x Stroke: 85 x 88mm
Compression Height: 31mm/1.221
Pin Diameter: 22mm/.866
The complete F20B rod specs are with common engine matches:
Length: 145mm (5.709") - no engines
BE Bore: 48mm (1.809") - D16, B16A, B17A, B18A, B18B, B18C, B20
BE width: 23.75mm (0.935") - B16A, B17A, B18A, B18B, B20, F22, H22, H23
Pin Bore: 22mm (0.866") - F22, H22A, H23A
Pin Width: 23.875mm (0.940") - F22, H22A, H23A
Considering 4G63/4G64 pistons 28.7mm comp height, K20 pistons 30mm comp height & custom made 31mm com height
Problems will be valve-relief piston pockets clearances and rotation of motor, will need to rotate them 180 degrees to align valves / (and k20 offset pin)
What is the boring limits of the stock iron sleeves ?
What pistons 9.0:1 will work ?
What H beam rods can I use ?
Thanks in advance
I want a high revving 9000rpm motor and want to keep it as close to 2 litre as possible with an Evo 5 turbo
Don't want to sleeve the engine as it has iron sleeves stock
F20B
Bore x Stroke: 85 x 88mm
Compression Height: 31mm/1.221
Pin Diameter: 22mm/.866
The complete F20B rod specs are with common engine matches:
Length: 145mm (5.709") - no engines
BE Bore: 48mm (1.809") - D16, B16A, B17A, B18A, B18B, B18C, B20
BE width: 23.75mm (0.935") - B16A, B17A, B18A, B18B, B20, F22, H22, H23
Pin Bore: 22mm (0.866") - F22, H22A, H23A
Pin Width: 23.875mm (0.940") - F22, H22A, H23A
Considering 4G63/4G64 pistons 28.7mm comp height, K20 pistons 30mm comp height & custom made 31mm com height
Problems will be valve-relief piston pockets clearances and rotation of motor, will need to rotate them 180 degrees to align valves / (and k20 offset pin)
What is the boring limits of the stock iron sleeves ?
What pistons 9.0:1 will work ?
What H beam rods can I use ?
Thanks in advance
Thread
Thread Starter
Forum
Replies
Last Post
chriscool888
Acura Integra
14
05-09-2012 07:24 AM
GB
Tech / Misc
1
10-21-2002 05:50 PM