Golding.racing

Hi. Due to a bad tune my all motor f20b has destroyed its bottom end.
The head is fine but the block would need a bore and the crank is shot on the mains.
What are my options. I've read a few posts about using k20 pistons. F23 crank and rods.
I really need to be at least 12:1 cr for my cams.
Any advice would be much appreciated.

Adam

Golding.racing

If I ran k20 pistons they have a compression height of 30mm where as f20b have 31mm. Could I deck the block to compensate?

d112crzy

Build an f22 bottom end. 95mm crank, h22 rods and custom pistons.

Hinta Project

Post up your full build info,

you have cams?
how much hp/tq did you put down on the last tune?
what are using to tune?

If you have a half built engine.. i just can't see the idea of jimmy rigging it up and expecting results other than a repeat....

but if you're rocking just a cam, and some bolt-ons... just leave it oem and a clean tune you
should be all set.

Golding.racing

hi.
thanks for the input,
my broken engine specs are...
244 bhp at the flywheel, 174 ftlb tq, 8700 rpm limit

HEAD. (this is still ok)
stock f20b, light clean up of port castings, crane vtec delete roller cams .520 lift 272 duration. ferrrea roller rockers, ferrea springs and retainers, supertech guides, stock valves. crower gears, twm 52mm itb's. plm 4-2-1 header.

BLOCK.
stock f20b, stock crank, eagle off the shelf H beam b series stroker rods 5.862", custom 12.5cr cp pistons (short compression height to compensate long rods) KS Tuned balance shaft delete kit.

bores are worn big time, pistons have been slapping bores, one rod started to spin a shell and has been hot. crank has picked up on the mains but the rod journals will polish up ok.

was on stand alone ecu. over fuelled (mapped by a different company) as engine builder could smell fuel in the oil.
my problem is i'm in the UK and need an engine for 5 weeks time.
will be going elsewhere for a tune this time


at the moment i'm thinking about boring block to 86mm, using k20 pistons and stock f20b rods, decking the block to compensate for the 1mm difference in piston compression height, and dropping the rpm limit.

a better option would be if i can find someone to copy one of my 85mm pistons but make it 86mm, then i could just buy some more eagle rods the same as i have.

hope this helps with the input,

many thanks Adam

d112crzy

You have custom pistons and you're using eagle rods? Those things a little heavy for an na application IMO.

Do you have access to another of those cranks? I'd assume there is some damage due to spun bearing.

The f20 head can be adapted to the f22 block quite easily. Use the f22 crank, lighter h22 rods and custom pistons.

97_hcivic

came across this post and my son just blew the bottom end out of his honda prelude H23 and i cant find a motor anywere... is there any other motors i can use without changing the ecu and wiring? PLEASE HELP...

Golding.racing

Thanks for the input.
Just to keep you informed. I'm going with bisimoto f20b rods and +1mm 11.1:1 cr pistons.

Is it ok to grind the mains on these cranks. Rod journals will polish.

Adam

Julio@Bisimoto

Thank you for the support Adam. Give us a call and I will gladly help you out with a few options.

charlaycooljay

Hey Adam I came across your post about the F20B and running B strokers rods with no issues?

Golding.racing

Hi. I bought the rods and pistons from a member on here that had the pistons custom made to suit rods.
However my engine didn't last long. Apparently due to a bad tune and washing the bores.
I've now got a set of bisimoto rods and pistons to rebuild with. But engine isn't completed yet.

DDTECH

Washing the bore..? Running too rich, i assume? Pics of damange?..