piston to wall clearance
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Junior User
Joined: Dec 2002
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From: Denver
piston to wall clearance
My block was bored and honed at .20 over and I have the ohio flat tops. The machine shop used torque plates (had my pistons and arp head bolts) but only left between .001 and .0015 clearance between the piston and the wall.
Just want to get some feedback on this. Seems pretty tight to me(don't want this thing to seize on me), but I'm new to this engine building stuff.
I did not get a spec sheet with my pistons but the machine shop said they looked it up and said it was .001. You guys runnin these please let me know what kind of clearance you ran.
I'm thinkin that the piston will be hard to put in and will need a quality ring compressor..any suggestions? Oh yeah.. and I have sealed power moly rings. Thanks
Just want to get some feedback on this. Seems pretty tight to me(don't want this thing to seize on me), but I'm new to this engine building stuff.
I did not get a spec sheet with my pistons but the machine shop said they looked it up and said it was .001. You guys runnin these please let me know what kind of clearance you ran.
I'm thinkin that the piston will be hard to put in and will need a quality ring compressor..any suggestions? Oh yeah.. and I have sealed power moly rings. Thanks
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
piston to wall clearance
Your piston supplier is the one that specs the clearance according to the design of the piston.
Factory OEM specs are: 0.0014" - 0.0022". They use a selective fit at the factory. High performance engines open up the tolerance because the high power levels expand the piston more. They may run .004+ which is OK because the Hot rodders don't care if there is some piston slap noise when the engine is cold.
-Edited by Torque1st
Factory OEM specs are: 0.0014" - 0.0022". They use a selective fit at the factory. High performance engines open up the tolerance because the high power levels expand the piston more. They may run .004+ which is OK because the Hot rodders don't care if there is some piston slap noise when the engine is cold.
-Edited by Torque1st
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Junior User
Joined: Dec 2002
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From: Denver
piston to wall clearance
torque1st..
Do you think that this is too tight? The machine shop I have it at is a performance shop. They used torque plates with my new arp head bolts. Being that the torque plates were used it would give a more accurate bore and maybe allow for less clearance? They measured all the pistons and then went for between a .001 to .0015 clearance. I've been searching high and low for the recommended clearance for this piston. I found this off a guy selling the flat tops on ebay..see if this works will try to post picture.
pic didnt work--
It shows piston skirt clearance? at .0025-.005 almost seems like too much.
Let me know what you think...thanks
link to old ebay listing
Do you think that this is too tight? The machine shop I have it at is a performance shop. They used torque plates with my new arp head bolts. Being that the torque plates were used it would give a more accurate bore and maybe allow for less clearance? They measured all the pistons and then went for between a .001 to .0015 clearance. I've been searching high and low for the recommended clearance for this piston. I found this off a guy selling the flat tops on ebay..see if this works will try to post picture.
pic didnt work--
It shows piston skirt clearance? at .0025-.005 almost seems like too much.
Let me know what you think...thanks
link to old ebay listing
Last edited by sampsin; Jul 21, 2003 at 10:55 PM.
Senior User
Joined: Jan 2002
Posts: 109
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From: Green River USA
piston to wall clearance
I am running KB flat tops and since they are mad of Hypereutectic Aluminum, they say they can be run tighter than normal pistons. Interestingly enough, they recommend a .0010-.0015 clearance compared to .0020-.0025 clearnce for cast aluminum pistons (which the Ohio's are). Just something to consider.
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
piston to wall clearance
Nothing in my Ohio/Ertel piston catalog lists a street clearance for these pistons. The catalog refers to the "sheet included with the pistons". The clearance required will depend on the application, street, circle track, drag, etc. They list 0.0025-.0035" for most racing applications. I would not be afraid of the 0.0015 but the 0.0010 seems a little tight.
Hyper-eutectic pistons are also cast, it is just a specific type of aluminum alloy. The Ohio pistons are listed as a silicon aluminum alloy.
Hyper-eutectic pistons are also cast, it is just a specific type of aluminum alloy. The Ohio pistons are listed as a silicon aluminum alloy.
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