Help deciding PTW tolerance.
#1
Honda-Tech Member
Thread Starter
iTrader: (1)
Join Date: Oct 2009
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Help deciding PTW tolerance.
Current build:
LS/VTEC
GSR head - mostly stock except for upgraded valve springs
b18b block bored to 81.5mm - stock sleeves
Redesigned low compression stock cast pistons as seen here. Opted for them to be machined to accept aftermarket rods.
Eagle rods
ACL bearings
What would you guys recommend I set the piston-to-wall tolerance to if I'm shooting for 400whp @ 17 psi? I have read all the recommendations for forged pistons but I need help deciding what it should be for a cast piston since they wont swell as much.
LS/VTEC
GSR head - mostly stock except for upgraded valve springs
b18b block bored to 81.5mm - stock sleeves
Redesigned low compression stock cast pistons as seen here. Opted for them to be machined to accept aftermarket rods.
Eagle rods
ACL bearings
What would you guys recommend I set the piston-to-wall tolerance to if I'm shooting for 400whp @ 17 psi? I have read all the recommendations for forged pistons but I need help deciding what it should be for a cast piston since they wont swell as much.
#3
Re: Help deciding PTW tolerance.
Cast will not expand like a low silicon forged piston. You should run tighter tollerances. I'm not sure exactly what though, I'll let someone else with cast experience chime in
#7
Honda-Tech Member
iTrader: (3)
Join Date: Jan 2000
Location: Bloomington, IN, USA
Posts: 10,180
Likes: 0
Received 3 Likes
on
3 Posts
Re: Help deciding PTW tolerance.
I've used up to .0020" without piston slap. I did a stock bore refurb with a ball hone once and the clearance was as high as .0028" and the pistons slapped a little on cold starts.
Trending Topics
#9
Honda-Tech Member
Re: Help deciding PTW tolerance.
I personally would stick to .0015 or stock specs. IMO if these are anything like OEM design, your going to melt or crack the ringlands on those pistons long before you run into PTW clearance issues.
#10
Honda-Tech Member
Thread Starter
iTrader: (1)
Join Date: Oct 2009
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
Re: Help deciding PTW tolerance.
These pistons are based of the stock LS design but also incorporate thicker ringlands to prevent such failures. Several members, such as boostedEF91, are making large amounts of power successfully without any issues. I will take your opinion into consideration.
#11
Honda-Tech Member
Re: Help deciding PTW tolerance.
ur not getting what i've said. i'm not saying these pistons are garbage or will break on you...
#13
Honda-Tech Member
Join Date: Aug 2009
Location: Kitsap
Posts: 303
Likes: 0
Received 0 Likes
on
0 Posts
Re: Help deciding PTW tolerance.
Well im telling you that I would not run that tight with a forged piston and 400 whp. Im running a LS @ 81.50mm and .003200 Ive got a little slap on start up for about 1 1/2 - 2 min. After that it goes dead quiet and all you hear is the injectors ticking away. .0015 is WAY TO TIGHT!! the people that are saying run stock tolerance are dumb! Sure if it was a stock piston sure, but the foged pistons will swell much more that stock due to the fact that its forged. I would at least run .002500, but no less.
#14
Honda-Tech Member
Re: Help deciding PTW tolerance.
Well im telling you that I would not run that tight with a forged piston and 400 whp. Im running a LS @ 81.50mm and .003200 Ive got a little slap on start up for about 1 1/2 - 2 min. After that it goes dead quiet and all you hear is the injectors ticking away. .0015 is WAY TO TIGHT!! the people that are saying run stock tolerance are dumb! Sure if it was a stock piston sure, but the foged pistons will swell much more that stock due to the fact that its forged. I would at least run .002500, but no less.
Thread
Thread Starter
Forum
Replies
Last Post
tspkenneth
Forced Induction
9
01-07-2005 03:46 PM