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View Full Version : a2 internals in a3 block



lonestar
07-12-2008, 12:42 PM
did a search but did not find anything on this just wanted to know what i would need besides the ovious (a2 internals) and what needs to be machined on the a3 block thanks in advance.

Ep3T0n3y
07-12-2008, 12:45 PM
Its gonna cost more time and money to put a2 internals in an a3, than it would be to just buy the damn a2, and you still wouldnt have the power of an a2

illusionsoflife
07-13-2008, 09:38 AM
Its gonna cost more time and money to put a2 internals in an a3, than it would be to just buy the damn a2, and you still wouldnt have the power of an a2

whys you think that? ive seen the internals for pretty cheap. you could get the head crank and internals for half the cost of an a2.

Ep3T0n3y
07-13-2008, 11:03 AM
whys you think that? ive seen the internals for pretty cheap. you could get the head crank and internals for half the cost of an a2.

I for sure wouldn't do the work. Id let someone who knows more about it than i do, do it. Nor would i put in used internals. I think thats dumb. If you want something reliable you should just buy it new and not have to worry about the integrity. How ever a used a2 out of something that was totaled from rear end damage i would buy.
And that i would put in myself.

So FOR ME it would be cheaper to buy an a2 and put it in then buy the internals and put them in an a3.
:amen:

classiccelica
07-13-2008, 01:14 PM
But if you wouldn't use, used parts then why would you trust a used engine itself. You can easily find eagle pistons forged for $529, eagle H beam rods for $300, then the only expensive work which when I get my a2 I will do anyway would be to make sure the center bore of all the journals are still straigh, and I am going to have the crank balanced. So for roughly $8-900 you can have all the internals ready to be put together and get a head off crsx for at the most 900 I have seen, then bodda bing bodda boom there is your forged and built a2.

dobbs02si
07-13-2008, 03:21 PM
But if you wouldn't use, used parts then why would you trust a used engine itself. You can easily find eagle pistons forged for $529, eagle H beam rods for $300, then the only expensive work which when I get my a2 I will do anyway would be to make sure the center bore of all the journals are still straigh, and I am going to have the crank balanced. So for roughly $8-900 you can have all the internals ready to be put together and get a head off crsx for at the most 900 I have seen, then bodda bing bodda boom there is your forged and built a2.

Hell if your not looking for 600whp just use the stock a2 rods with some 9:0 wiseco's. There are a few all stock bottom end a2's making 480-515 with 11:1 compression.. And as far as used goes I LOVE my $50 dolla p29's haha.

classiccelica
07-13-2008, 03:59 PM
What are p29's I know that was probably a noobie question but I am still fairly new the these cars and power train. How high can you rev with the stock rods though. Just curious.

Lucid Moments
07-13-2008, 05:24 PM
did a search but did not find anything on this just wanted to know what i would need besides the ovious (a2 internals) and what needs to be machined on the a3 block thanks in advance.

To actually answer your question instead of just giving my opinion as to whetehr you should or not, yes you can use A2 rods and pistons in the A3 block and they will fit just fine but you have to have an A2 crank as well. The rod journals on the A3 crank are smaller than on the A2.

I'm not sure if you can run A2 pistons on A3 rods. I don't think so but I can't remember why.

classiccelica
07-13-2008, 05:29 PM
oh ok well should still be cheaper even finding the a2 crank.

dobbs02si
07-13-2008, 06:50 PM
Haha, the p29's are twin cam d-series pistons used to up the comp on single cam d's for more power. Not even K related, just expressing my opinion on used parts.

classiccelica
07-13-2008, 07:28 PM
Oh, ok well look I learned something new today. I would rather stick to my wicked fast ep3 a3 motor that can desimate all.

dobbs02si
07-13-2008, 08:47 PM
Oh, ok well look I learned something new today. I would rather stick to my wicked fast ep3 a3 motor that can desimate all.

You cant imagine 'wicked fast' until you see my 1.5 build..im shooting for 170whp lol

Ba82Ep3
07-13-2008, 09:03 PM
I'm not sure if you can run A2 pistons on A3 rods. I don't think so but I can't remember why.

I remember Chunky posting on k20a.org saying you could drop the a2 pistons onto the a3 rods. I would like clarification on this myself... i was planning on adding them just to up the compression a little bit. Anyone know for sure if this can/cant be done?

stepintoliquid
07-13-2008, 09:10 PM
a2 crank is the most significant a2 upgrade for an a3 bottom end.

02EP3SI
07-13-2008, 10:44 PM
To actually answer your question instead of just giving my opinion as to whetehr you should or not, yes you can use A2 rods and pistons in the A3 block and they will fit just fine but you have to have an A2 crank as well. The rod journals on the A3 crank are smaller than on the A2.

I'm not sure if you can run A2 pistons on A3 rods. I don't think so but I can't remember why.

also to clarify a little more... the internals will work fine... You will have to have an a2 head for the a2 pistons to work or else you will have some major damage

or a machined a3 head for the a2 pistons to clear the casting.

if you compare the combustion chamber of the two heads, the a2 head is circular and the a3 head is not.

classiccelica
07-14-2008, 08:27 AM
No real point in keeping the a3 head. A2 head is a hell of a lot more fun in my opinion.

Lucid Moments
07-14-2008, 08:48 AM
also to clarify a little more... the internals will work fine... You will have to have an a2 head for the a2 pistons to work or else you will have some major damage

or a machined a3 head for the a2 pistons to clear the casting.

if you compare the combustion chamber of the two heads, the a2 head is circular and the a3 head is not.

Good point that I forgot about.

Ba82Ep3
07-14-2008, 06:38 PM
also to clarify a little more... the internals will work fine... You will have to have an a2 head for the a2 pistons to work or else you will have some major damage

or a machined a3 head for the a2 pistons to clear the casting.

if you compare the combustion chamber of the two heads, the a2 head is circular and the a3 head is not.

Good info. I wonder if the same issue exists with the k24a1 head. I imagine the larger combustion chamber would help? Ill have to pull some pix up of the a3 and k24a1 combustion chambers to compare.

Still no fo' sho on the a3 rods and the a2 pistons working? Can someone measure an a2 wristpin and tell me what the size is??

illusionsoflife
07-17-2008, 02:51 AM
I for sure wouldn't do the work. Id let someone who knows more about it than i do, do it. Nor would i put in used internals. I think thats dumb. If you want something reliable you should just buy it new and not have to worry about the integrity. How ever a used a2 out of something that was totaled from rear end damage i would buy.
And that i would put in myself.

So FOR ME it would be cheaper to buy an a2 and put it in then buy the internals and put them in an a3.
:amen:

not being a dick but do some research. ive seen used internals in other motors. why would it be a problem? we all put used bolt ons and turbos on our cars. we all probably have some sort or used product. so now its not reliable?

03ep3 stapel
07-26-2008, 03:36 AM
just buy a k20a2 and work with that much easier

K20Nemesis
08-01-2008, 08:19 AM
also to clarify a little more... the internals will work fine... You will have to have an a2 head for the a2 pistons to work or else you will have some major damage

or a machined a3 head for the a2 pistons to clear the casting.

if you compare the combustion chamber of the two heads, the a2 head is circular and the a3 head is not.


that is false u can put a3 head with a2 pistons. my setup includes a2 rods, pistons, cause u cant put a2 pistons with a3 rods also have a2 cams with rocker on a full a3 motor. the only problem i am having is my tuning i haven't tune yet but my A/F is at 32:1 at idle because of the cams need to find a map for this setup

MugenReplica
08-01-2008, 08:42 AM
http://www.youtube.com/watch?v=ugYXwelHJUc