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How do you know which pistons/rings to use on a bored engine?

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Old 09-22-2010, 02:02 PM
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Default How do you know which pistons/rings to use on a bored engine?

Let's say you had the engine bored .020". How exactly do you know what pistons & rings to use?
 
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Old 09-22-2010, 02:28 PM
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Here was my guess, so that you guys know I at least put some thought and reading into this:

I don't know the original bore, but let's just assume it's 85mm for this scenario's sake.

If I have the engine bored 0.020", which is equal to just over 0.508mm, would I buy pistons that have a diameter or 85.5mm? And then piston rings to match the pistons? (Which, from what I've seen, the piston rings come with the pistons when you're buying new pistons.)

Also, let's just say I'm not boosting, and I have to options for pistons as far as compression goes. Should I go with the 11:1 pistons? There are 8.5:1 (I think?) pistons, but I assumed the lower compression was for boost so that you don't achieve detonation with such a high compression after boost.
 

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Old 09-22-2010, 05:48 PM
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when buying the pistons ask the dealer or whoever your buying them from for the size bore you want. That's not a bad c/r you just don’t want to go to high or you will have to run race fuel. Some one else should chime in on the c/r part I’m a little unsure myself
 
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Old 09-22-2010, 06:12 PM
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Normally domestic engines are measured in thousands over, where imports are usually just measured in millimeters.

I know when I got my engine machined, I had them do it 1 or 2 millimeters over, and got pistols that match. Say stock bore was 85mm so I got 87mm pistons.

You usually can't find pistons that are less than 1mm over.

Shop around different piston companies and see what they offer, most also offer custom pistons for a reasonable price. 11:1 isnt bad for a N/A build, but its not going to be a huge power maker. 13:1 is where you start running into issue. Just for comparison, 11:1 is what a JDM H22 has for compression, 8.8:1 is what a F22B1/2 has(insanely low for a non boost engine).

Also keep in mind that non stock head(say H22) and head gasket factor into compression ratio, and all want to be calculated before you buy pistons.
 
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Old 09-22-2010, 08:27 PM
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I'm using a stock f22a6 head. I'm probably going to replace some of the head parts, but just with OEM parts.

Also, I was just using the numbers above as an example. I hadn't looked at pistons right before making this thread, so I wasn't sure what the original bore was nor did I know what the bore is for the other after market pistons.

So if I plan on buying, let's say 87mm pistons, I need to just take the block to a machinist and tell him what pistons I'm using?
 
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Old 09-22-2010, 08:36 PM
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well you have a 85mm bore...you can bore out to 87mm but very bad...way to thin there will be like no meat left on your cyl walls. I have seen ppl bore out to 86mm on f22 blocks but again not the best to do. Yet better than boring out to 87mm. I know bisi sells 86mm pistons for f22 blocks...maybe you need to get with him and see what he has to say,. Now all my b series friends take OEM 3 layer head gaskets ad drill out the rivets and make it a single layer head gasket to bump up the c/r

search for my "destroked" thread...there is a calculator you can use for c/r's and all kindas of stuff
 
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Old 09-22-2010, 09:05 PM
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I can't seem to ever come across f22b pistons. I always find f22a pistons, though. They wouldn't, by any chance, be interchangeable would they?
 
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Old 09-22-2010, 09:06 PM
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Just tell the machine shop the bore you want.
 
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Old 09-22-2010, 10:06 PM
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yes they are...all f22 blocks are the same!!! Iv said this like 10 times yo. the crank rods pistons the works are all the same...just diff heads. Sorry if that’s sounds mean...not tryin to be...just have said it bunch of times in your threads.

https://www.hondaaccordforum.com/for...ad.php?t=33975
 
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Old 09-22-2010, 10:37 PM
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Yeah, sorry, wasn't thinking. Thanks, though.
 


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