b18b1 piston to wall clearance question.
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Honda-Tech Member
Joined: Apr 2011
Posts: 1,197
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From: Near Pacific Coast Highway
b18b1 piston to wall clearance question.
Hey h-t im building a b18b1 right now.
Eagle rods
Wiseco 9:0.1 pistons. (81.5)mm
Precision t3t4 60 ar 63
Titanium springs and retainers
Rc 750 cc injectors
3 inch downpipe
Clevite main and rod bearings
I located a new set of pistons online but the guy doesnt have the spec sheet for them. I have the block here with a fresh bore 81.5 mm how can i get correct piston to wall clearance without specs?
Can/should i just drop them in?
What are my risks?
Also my goal is 350 MAX hp. Do i even need forged pistons? If so whats the best compression ratio for me on 91 pump gas
Thanks in advance
Eagle rods
Wiseco 9:0.1 pistons. (81.5)mm
Precision t3t4 60 ar 63
Titanium springs and retainers
Rc 750 cc injectors
3 inch downpipe
Clevite main and rod bearings
I located a new set of pistons online but the guy doesnt have the spec sheet for them. I have the block here with a fresh bore 81.5 mm how can i get correct piston to wall clearance without specs?
Can/should i just drop them in?
What are my risks?
Also my goal is 350 MAX hp. Do i even need forged pistons? If so whats the best compression ratio for me on 91 pump gas
Thanks in advance
Honda-Tech Member
Joined: Jul 2003
Posts: 1,344
Likes: 1
From: Ontario & Alberta, Canada
Re: b18b1 piston to wall clearance question.
You "typically" cannot just drop in a set of pistons without spec's, they need to be measured and/or given to a machine shop where they can measure each piston and bore/hone each cylinder to the specific P2W clearance you want.
Horsepower wise, .0035"-.0038" for your setup and if you ever plan on pushing abit more power just go for .004".
Although P2W clearance will also depend on material make-up of the pistons themselves (ie. high/low silicon = differing expansion rate) etc.
Also just because you have a fresh hone, it doesn't mean anything. Hone process, cross-hatch angle and procedure all depend on the type of rings you will be using (ie. CP shelf pistons typically use a gas-nitride coated top ring and require a different hone procedure than say factory honda steel piston rings do for proper ring seal) Normally in the box of pistons/rings/pins is a guide for hone procedure, calculating ring end gap etc.
Just throwing unmeasured pistons into an engine can cause more than a few issues, P2W clearances can be different, too tight can cause skirt/cylinder wall damage after warmed up, too loose can cause piston slap, which also causes skirt/cylinder wall damage.
Both fitment problems can/will impair ring seal and oil control.
Uneven cylinder sealing can cause excessive blow-by, unbalanced cylinder pressure and poor performance from 1 or more or all cylinders.
Ofcourse this is usually in extreme cases. Regardless, attention to detail when building an engine is key.
350hp is pushing the factory "cast" pistons to their breaking point. You will be on the verge of piston ring-land failure. Seen some survive higher horsepower, seen some break with less. Depends on tuning aswell.
Now with all that said.
Do you "REEEAAALLLY" want to just throw a set of unmeasured pistons into a block that is supposed to have very fine tolerances for proper operation?
Common sense comes into play here.
Take it all to a machine shop, tell them you want such-and-such P2W clearance in this block, with these pistons.
Good luck.
Horsepower wise, .0035"-.0038" for your setup and if you ever plan on pushing abit more power just go for .004".
Although P2W clearance will also depend on material make-up of the pistons themselves (ie. high/low silicon = differing expansion rate) etc.
Also just because you have a fresh hone, it doesn't mean anything. Hone process, cross-hatch angle and procedure all depend on the type of rings you will be using (ie. CP shelf pistons typically use a gas-nitride coated top ring and require a different hone procedure than say factory honda steel piston rings do for proper ring seal) Normally in the box of pistons/rings/pins is a guide for hone procedure, calculating ring end gap etc.
Just throwing unmeasured pistons into an engine can cause more than a few issues, P2W clearances can be different, too tight can cause skirt/cylinder wall damage after warmed up, too loose can cause piston slap, which also causes skirt/cylinder wall damage.
Both fitment problems can/will impair ring seal and oil control.
Uneven cylinder sealing can cause excessive blow-by, unbalanced cylinder pressure and poor performance from 1 or more or all cylinders.
Ofcourse this is usually in extreme cases. Regardless, attention to detail when building an engine is key.
350hp is pushing the factory "cast" pistons to their breaking point. You will be on the verge of piston ring-land failure. Seen some survive higher horsepower, seen some break with less. Depends on tuning aswell.
Now with all that said.
Do you "REEEAAALLLY" want to just throw a set of unmeasured pistons into a block that is supposed to have very fine tolerances for proper operation?
Common sense comes into play here.
Take it all to a machine shop, tell them you want such-and-such P2W clearance in this block, with these pistons.
Good luck.
Honda-Tech Member
Joined: Sep 2010
Posts: 525
Likes: 2
Re: b18b1 piston to wall clearance question.
You "typically" cannot just drop in a set of pistons without spec's, they need to be measured and/or given to a machine shop where they can measure each piston and bore/hone each cylinder to the specific P2W clearance you want.
Horsepower wise, .0035"-.0038" for your setup and if you ever plan on pushing abit more power just go for .004".
Although P2W clearance will also depend on material make-up of the pistons themselves (ie. high/low silicon = differing expansion rate) etc.
Also just because you have a fresh hone, it doesn't mean anything. Hone process, cross-hatch angle and procedure all depend on the type of rings you will be using (ie. CP shelf pistons typically use a gas-nitride coated top ring and require a different hone procedure than say factory honda steel piston rings do for proper ring seal) Normally in the box of pistons/rings/pins is a guide for hone procedure, calculating ring end gap etc.
Just throwing unmeasured pistons into an engine can cause more than a few issues, P2W clearances can be different, too tight can cause skirt/cylinder wall damage after warmed up, too loose can cause piston slap, which also causes skirt/cylinder wall damage.
Both fitment problems can/will impair ring seal and oil control.
Uneven cylinder sealing can cause excessive blow-by, unbalanced cylinder pressure and poor performance from 1 or more or all cylinders.
Ofcourse this is usually in extreme cases. Regardless, attention to detail when building an engine is key.
350hp is pushing the factory "cast" pistons to their breaking point. You will be on the verge of piston ring-land failure. Seen some survive higher horsepower, seen some break with less. Depends on tuning aswell.
Now with all that said.
Do you "REEEAAALLLY" want to just throw a set of unmeasured pistons into a block that is supposed to have very fine tolerances for proper operation?
Common sense comes into play here.
Take it all to a machine shop, tell them you want such-and-such P2W clearance in this block, with these pistons.
Good luck.
Horsepower wise, .0035"-.0038" for your setup and if you ever plan on pushing abit more power just go for .004".
Although P2W clearance will also depend on material make-up of the pistons themselves (ie. high/low silicon = differing expansion rate) etc.
Also just because you have a fresh hone, it doesn't mean anything. Hone process, cross-hatch angle and procedure all depend on the type of rings you will be using (ie. CP shelf pistons typically use a gas-nitride coated top ring and require a different hone procedure than say factory honda steel piston rings do for proper ring seal) Normally in the box of pistons/rings/pins is a guide for hone procedure, calculating ring end gap etc.
Just throwing unmeasured pistons into an engine can cause more than a few issues, P2W clearances can be different, too tight can cause skirt/cylinder wall damage after warmed up, too loose can cause piston slap, which also causes skirt/cylinder wall damage.
Both fitment problems can/will impair ring seal and oil control.
Uneven cylinder sealing can cause excessive blow-by, unbalanced cylinder pressure and poor performance from 1 or more or all cylinders.
Ofcourse this is usually in extreme cases. Regardless, attention to detail when building an engine is key.
350hp is pushing the factory "cast" pistons to their breaking point. You will be on the verge of piston ring-land failure. Seen some survive higher horsepower, seen some break with less. Depends on tuning aswell.
Now with all that said.
Do you "REEEAAALLLY" want to just throw a set of unmeasured pistons into a block that is supposed to have very fine tolerances for proper operation?
Common sense comes into play here.
Take it all to a machine shop, tell them you want such-and-such P2W clearance in this block, with these pistons.
Good luck.
Honda-Tech Member
Joined: Feb 2003
Posts: 9,820
Likes: 12
From: schooling kids in ny, usa
Re: b18b1 piston to wall clearance question.
as stated, .0035 to about .004 is where you want to be for piston to wall.
since you dont know where you are at you can either measure pistons with dial calipers an the bore with a dial gauge, or just have the machine shop measure it out. dont forget to measure down on the skirt
since you dont know where you are at you can either measure pistons with dial calipers an the bore with a dial gauge, or just have the machine shop measure it out. dont forget to measure down on the skirt
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Thread Starter
Honda-Tech Member
Joined: Apr 2011
Posts: 1,197
Likes: 0
From: Near Pacific Coast Highway
Re: b18b1 piston to wall clearance question.
Thanks guys my block is beibg bored at the shop tomorrow. I requested .004 p2w clearance in case i wana grow later on.
Another question.
What ring end gaps should i run?
And i got some piston rings with the wiseco pustons i purchased but no install instructions.
4 rjngs say n50
8 rings are blank real thin
4 rings are up and down pattern
And 4 ribgs are black on one side and metal on the other.
Please if anyone can help its greatly appreciated
Manny
Another question.
What ring end gaps should i run?
And i got some piston rings with the wiseco pustons i purchased but no install instructions.
4 rjngs say n50
8 rings are blank real thin
4 rings are up and down pattern
And 4 ribgs are black on one side and metal on the other.
Please if anyone can help its greatly appreciated
Manny
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