7afte pistons and rods, time to rebuild Options

[Kwanza26]

hey quick quest...is it possible to get mr2 pistons n rods? or was that a dumb question lol
[right][snapback]248919[/snapback][/right]

Depends which MR2 you're talking about here. There are 3 different versions with 3 different engine families.

1st gens... that will be the 4AG... and yes... you can use the pistons from the gen 2 4AG (20mm wrist versions)... but not the rods (from either version). The 7A crank journals are too big.

2nd gen... no. The pistons/rods are much too large.

3rd gen... no... too small.

This post has been edited by Kwanza26: Feb 22, 2005 - 5:21 PM

[playr158]

so whats the plan here?

cause i need new pistons and rods

thinking of a CR around 9-10

[Exile04]

hey i need them to bu ti dont knwo what cr, i want to turbo later to what do i need

[playr158]

eh i think i'd just stay around 8ish for the turbo just forged stuff

[FallenHero]

2zzge rods length  5.429 (wiseco)
7afe  rods length  5.217 ( Pauter)

difference .212
[right][snapback]238675[/snapback][/right]

I've been looking everywhere for those specs... I don't have them in my database...
As for fitment... gotta do live measurements... compared to the block. The 7A has a larger stroke than the 2ZZ also... so this might not be so good...
[right][snapback]238855[/snapback][/right]

ok, bringing this one back from the dead in order to discuss rod options.

Ok, in regards to 2zz rods: They are Basically two millimeters too long. However, in my reading, the crank journal diameter is two millimeters too small. If you were to machine the rods to be one millimeter shorter when attaching them to the 7a crank, that would make the fitment fairly close with the 4age head. If you were to use new 18mm pin diameter 4agze 8:1 compression pistons (machined in a way to a decrease the length by one more millimeter) which would have to be cut to the 20mm pin size of the 2zz rods... you have quite the combo, and rods that can live with 270whp boosted no problems. All that machine work has a cost though, so here I will discuss another option I came accross.

A LONG time ago I discusses using a set of B-series honda forged pistons. Why? they are hella cheaper than forged pistons made for a toyota. The problem is, they have a pin diameter of 21mm compared the the 20mm of the 7a rod. What about B-series rods?

Amazingly, I have found that the B16 rods are near to identicle on the spec sheet in comparison to 7afe rods. So, let me lay the specs down

RODS \\\\Length\\\\piston pin\\\\\Crank journal diameter
B16\\\\\\\\5.290\\\\\21mm\\\\\\\\48mm
7afe\\\\\\\\5.2165\\\\20mm\\\\\\\\48mm

Honestly guys, that's bleeding close. With the 4age head and forged 4age low comp pistons, we are looking at virtually no size difference between the 7a and B16 rods. With that in mind, I leave you this link

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...7973848842&rd=1

Those are eagle H-beam rods that can handle more boost than you would want to throw at them.

Opinions?

Jon

This post has been edited by FallenHero: May 18, 2005 - 10:14 PM

[playr158]

lets stick with on a stock 7afe head

with b16 rods
you still have to find pistons that will

a) fit the motor with a 21mm wrist pin
b) get a known cr

[nik]

in the end for me i looked into other rods for similor size and just made the chose to go custom rods.


i just though keep the crank get custom rods and use the 4agze psitons i though would be the best route and probably the cheapest also instead of your guys alternative routes Because when you start getting down to it fitting different rods to the crank and custom pistons or 4agze psitons then the machine time to get everything to work plus all that math for volume and cc displacment i already went through this on my head and chambers so its not a easy as you guys think so just something to think about

[playr158]

"then the machine time to get everything to work plus all that math for volume and cc displacment"

i really dont' see the machine time with fallen's idea of the b16 rods

minus the fact you'd need a 21mm wrist pin
so you'd have to machine each 7afe piston 1mm? or whatever piston you chose?

the only machine work i see is the wrist pin at this point the rest should all bolt up

[nik]

"then the machine time to get everything to work plus all that math for volume and cc displacment"

i really dont' see the machine time with fallen's idea of the b16 rods

minus the fact you'd need a 21mm wrist pin
so you'd have to machine each 7afe piston 1mm? or whatever piston you chose?

the only machine work i see is the wrist pin at this point the rest should all bolt up
[right][snapback]289085[/snapback][/right]

i wouldn't machine the wrist pin size just get 21mm custom pistons or a piston that comes with a 21mm wrist pin size but then you run into size problems will it work your engine if youre going b16 rods but do you even know the width of the lower part of the piston and the throw of the rod

does the big end housing bore match
what about the beam width
big end ring diameter
will rib to rib width be an issue
one of the biggest ones your center (big end housing) to center (pin end housing) length


see you have alot to look at you cant just throw any rod in there the looks close
and if you do that path you need to do your math on your pistons so they dont push past TDC or push your comp into the 12 or 13:1 range then what do you think it will do with your head need to flow check that and find your cc volume and it goes on and on if you want your motor to last do your research on those numbers

[doGGy]

Amazing find Fallen I hate to say...... but ....... B16 pistons are the same bore as 7A pistons......

And there are lots of versions availible on them... low CR, High CR. And i DO think - using them with the B16 Rods - the Celica 7A rods/piston problem would be solved.

2zzge rods length  5.429 (wiseco)
7afe   rods length  5.217 ( Pauter)

difference .212
[right][snapback]238675[/snapback][/right]

I've been looking everywhere for those specs... I don't have them in my database...
As for fitment... gotta do live measurements... compared to the block. The 7A has a larger stroke than the 2ZZ also... so this might not be so good...
[right][snapback]238855[/snapback][/right]

ok, bringing this one back from the dead in order to discuss rod options.

Ok, in regards to 2zz rods: They are Basically two millimeters too long. However, in my reading, the crank journal diameter is two millimeters too small. If you were to machine the rods to be one millimeter shorter when attaching them to the 7a crank, that would make the fitment fairly close with the 4age head. If you were to use new 18mm pin diameter 4agze 8:1 compression pistons (machined in a way to a decrease the length by one more millimeter) which would have to be cut to the 20mm pin size of the 2zz rods... you have quite the combo, and rods that can live with 270whp boosted no problems. All that machine work has a cost though, so here I will discuss another option I came accross.

A LONG time ago I discusses using a set of B-series honda forged pistons. Why? they are hella cheaper than forged pistons made for a toyota. The problem is, they have a pin diameter of 21mm compared the the 20mm of the 7a rod. What about B-series rods?

Amazingly, I have found that the B16 rods are near to identicle on the spec sheet in comparison to 7afe rods. So, let me lay the specs down

RODS \\\\Length\\\\piston pin\\\\\Crank journal diameter
B16\\\\\\\\5.290\\\\\21mm\\\\\\\\48mm
7afe\\\\\\\\5.2165\\\\20mm\\\\\\\\48mm

Honestly guys, that's bleeding close. With the 4age head and forged 4age low comp pistons, we are looking at virtually no size difference between the 7a and B16 rods. With that in mind, I leave you this link

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...7973848842&rd=1

Those are eagle H-beam rods that can handle more boost than you would want to throw at them.

Opinions?

Jon
[right][snapback]288800[/snapback][/right]

[nik]

Amazing find Fallen I hate to say...... but ....... B16 pistons are the same bore as 7A pistons......

And there are lots of versions availible on them... low CR, High CR. And i DO think - using them with the B16 Rods - the Celica 7A rods/piston problem would be solved.

[right][snapback]289114[/snapback][/right]

answer one question guys whats the BIG END HOUSING SIZE on a b16 rod

if this is off and your using the 7a crank it will either push your piston into your head or not far enough the cumbustion

im not trying to rain on you guys i just dont want you to waste money on something that might not work but we wont know until we get more info or some trys it so if someone has money to throw at this go for it hopefully it works out if not just sell your rods or pistons

[playr158]

Amazing find Fallen I hate to say...... but ....... B16 pistons are the same bore as 7A pistons......

And there are lots of versions availible on them... low CR, High CR. And i DO think - using them with the B16 Rods - the Celica 7A rods/piston problem would be solved.

[right][snapback]289114[/snapback][/right]

answer one question guys whats the BIG END HOUSING SIZE on a b16 rod

if this is off and your using the 7a crank it will either push your piston into your head or not far enough the cumbustion

im not trying to rain on you guys i just dont want you to waste money on something that might not work but we wont know until we get more info or some trys it so if someone has money to throw at this go for it hopefully it works out if not just sell your rods or pistons
[right][snapback]289115[/snapback][/right]

so if we can find out the "big end housing size"
(please define what that is)
and it comes out the same
we should be good to go on forged b16 rods? and pistons

[playr158]

honda b16 big end width in inches = .935
bore = 48

[nik]

go here on page 161

http://crower.com/misc/m_cat.shtml

[playr158]

does anyone know the 7afe BE specs?

i already found the honda b16 specs as posted above ^^^
but if the 7afe is the same :/ we should be good to go with b16 rods and pistons?

This post has been edited by playr158: May 20, 2005 - 12:46 PM

[nik]

does anyone know the 7afe BE specs?

i already found the honda b16 specs as posted above ^^^
but if the 7afe is the same :/ we should be good to go with b16 rods and pistons?
[right][snapback]289527[/snapback][/right]

i have to find my 7afe rod spec sheet

[playr158]

hurry nik

[FallenHero]

I wish coomer would sticky my engine tech thread...

[playr158]

umm nik have your sheet

or does anyone know

7afte
Big end info?

[playr158]

bump
honda size is 48mm
NIK post the celica size when you get it today