Piston options, Just a thought Options

[FallenHero]

Ok, the 7a has a 81mm bore, and so do the B-16/18 honda engines. I wonder what the difference in pin diameter and such is...

take a look:
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...7933659089&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...7934016265&rd=1

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...7932518309&rd=1


Any ot these would make a great set of pistons. I just don't know if they would work with the 7a rods. But hey, NICE forged pistons for like... $200, you gotta love that. Especially if we could get a general idea about the compression they would produce.

Jon

[FallenHero]

mostly looking towords edo and doggy on this one...

[Kwanza26]

They can potentially fit... but those specific ones (on the auction) are overbored pistons at 84mm (too big). The wrist pin diameter is a bit bigger than on the 7A rods (21mm) so you'd have to match that. There may also be cleareance problems depending on the height of the piston... which I think is a bit taller. The B16 factory pistons are usually domed which can cause all sorts of hazards in a Toyota head. Only way to tell is to try. I'd reccomend just using 4AG pistons to save from any custom machining...

[thedevilmaycrie]

STOP the best option is the sr20det pistons they are 82mm and WILL fit nice and snug ae86 guys do this alot with there 4age high comps

-DMC

[playr158]

yea, that and those are not even a good thought to buy "used for 8,000 miles, used and potentially bad heads" and " i lose the rings and pin"
those don't sound like smart people....stay toyota leave stupid honda's were they are

[Kwanza26]

STOP the best option is the sr20det pistons they are 82mm and WILL fit nice and snug ae86 guys do this alot with there 4age high comps

-DMC
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Umm... SR20 pistons are 86mm...

[thedevilmaycrie]

not possible ive seen them get put into a 4age.....

[FallenHero]

STOP the best option is the sr20det pistons they are 82mm and WILL fit nice and snug ae86 guys do this alot with there 4age high comps

-DMC
[right][snapback]206954[/snapback][/right]

Umm... SR20 pistons are 86mm...
[right][snapback]207011[/snapback][/right]

He's right. Stock honda bore is 81mm. I was just putting those up as an example. I would use 81+ overbore pistons anyway, were I to build a bottom end. There are just so many options here... I wonder how the honda/acura rods would fit a 7a crank...

light weight pistons would be a huge plus, especially if they were forged. And these, like all honda parts, are hella cheap. I could get foged pistons for a B16 for $300, or for a toyo for 600. And don't say use GZE pistons because there are compression problems assiciated with them. I wonder how the compression would be on a 7ag though...

See, I just don't know. I figured this would be a good topic for discussion...

Such as, we know the 2zz pistons work well if you bore out the 7a, but I wonder if the rods work on a 7a crank. I have heard the 2zz crank is Remarkably similar... we just need the information to check it.

[Kwanza26]

not possible ive seen them get put into a 4age.....
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Heh... if you're not very sure... don't bother going any further.

He's right. Stock honda bore is 81mm. I was just putting those up as an example. I would use 81+ overbore pistons anyway, were I to build a bottom end. There are just so many options here... I wonder how the honda/acura rods would fit a 7a crank...
light weight pistons would be a huge plus, especially if they were forged. And these, like all honda parts, are hella cheap. I could get foged pistons for a B16 for $300, or for a toyo for 600. And don't say use GZE pistons because there are compression problems assiciated with them. I wonder how the compression would be on a 7ag though...
See, I just don't know. I figured this would be a good topic for discussion...
Such as, we know the 2zz pistons work well if you bore out the 7a, but I wonder if the rods work on a 7a crank. I have heard the 2zz crank is Remarkably similar... we just need the information to check it.

Yeah... I understand that... but if you compare the typical Honda B series piston to a Toyota Piston... the tops are designed very differently. If proper machining is done to insure a fit... then I'm sure they will work fine (costs $$$)... but if we're talking using a relatively stock piston... chances are, the domed design of the Honda B series pistons may be a bit too tall to clear a Toyota head. The pictures don't really show how the piston top really looks. Toyota A series pistons are very flat on the top, almost concave.
As for 4AGZ pistons... the only reason they increased compression in edo's 7AFE is because of the combustion chamber design of the FE head. The FE head is narrow, hence the combustion chanber is very different from the 4AG... so that's the reason for the compression increase. If placed in a 7AG... then compression should correct itself. I wouldn't try to make a guess... cause the rod/stroke ratio would be different hence yeild a different compression ratio compared to a regular 4AG.
As for the 2ZZ rods and pistons... apparently pistons do fit with some minor machining, but I can't say for the rods. It would be a very nice stock upgrade if they do fit... The 2ZZ rods can handle upwards of 9000 rpms. I'd like to look into this myself.

[FallenHero]

there was a guy on club 4ag supposedly running not only the rods, but the crank also. Did he ever get it to work?

I wish one of those guys woud smoke his engine so I could lift some pistons and rods for a comparison...