Largest bore possible?

[POS carb]

What the largest bore anyone has done on the A20? I want to replace the pistons with bigger ones (no sense in rebuilding a 98 hp setup is there? lol)
Just wondering what kind of bore sizes can we get out of old ironsides A20A1 without worrying about stress fractures and stuff, maybe .060? More??


Maybe de low compression ones for de turrrbo

[shepherd79]

.03 is thge max you can do.
the walls between the cylinders are too thin to go any bigger.

[Vinny]

Like Alex said, the most I have seen is .030. Thats the biggest bore Honda sells, so I would think it safe to assume thats the most you can go. Sean and I have talked alot about bores and there may be a lil more that you could go, however if Honda says the max is .030 I don't know if I would risk anything bigger.

So whats the story here Eric doing a lil NA buildup or what? PM Me if ya get a chance and fill me in

[POS carb]

damn lets see.
3.25 inches x 3.58 inches is standard bore. Lets say I did a .030 over, then it turns into 3.28x3.58
(3.25/2)squared X (3.14)=8.2915625sq. in.=piston area
(8.2915625sq. in.)x(3.58in stroke)=29.6838ci. x 4 cyl =118.735ci

(3.28/2)x(3.14)=8.445344 sq in
8.445344 sq. in. X 3.58in stroke = 30.23433 x 4cyl = 120.937ci

So we jump from the rated 119ci to a 121ci which works out to a gain from:

119 cubic inch = 1.9500606 liter
121 cubic inch = 1.9828348 liter

So our cars go from being a 1.95L to a 1.98L....... hardly seems worth it

[NXRacer]

unless you were to find by some miracle a longer crank.......but yeah, its pretty much not worth it.

[Vinny]

true true, like i said me and Sean were working some numbers to see what would and wouldn't work. I wanted to go all out motor with the spare LX-i engine in the Garage but you start running into engine management issues unless you go carb. when it comes to power....... Its out there just alot of work to find it

[BootMachine]

Get a V8 if you want NA power...or if you happen to have a million bucks to spend on your a20!

I would go FI if I had the money!

[Justin86]

Yea the bore doesen't help much. If there was a way to get longer rods it would help but with the longer rods the Redline would be lower.

[shepherd79]

stoke it. it would be custom crank and rods and pistons but it will be worth it.
talk to Sean about stroking it.

[guaynabo89]

.030 is the largest you could go and keep reliable.

YOu could go 40 or even 60 over but I wouldn't expex it to last very long.

Last time I checked 30 over turne out to be like 2.5 liters? Maybe my math was off.

[dj_004]

cant you just bore it out .040 or .060 and just sleeve it? i would sleeve it anyway cuss the sleeves are steel and that would strenghten it.

[Justin86]

Originally posted by dj_004
cant you just bore it out .040 or .060 and just sleeve it? i would sleeve it anyway cuss the sleeves are steel and that would strenghten it.

Negative

[dj_004]

Originally posted by Justin86
Negative

well then tell me how i am wrong because i was told that since Honda's have Aluminum blocks that if you bore them out you have to sleeve them

[Justin86]

The A20 is a cast iron hog. Basically bullet proof.
Don't worry about it

[dj_004]

damn i thought they had an Aluminum block. so if i bore my block and .030 over, get nem pistons about how much would that cost?

[Justin86]

Well my pistons cost me $90 so I would say somewhere between 90-130. For the bore need to check a local machine shop, unless you have the stuff at school to do it.

[dj_004]

Where can i get the pistons? and what are yours? forged, flat head, or what cause i heard forged is the best

[Justin86]

I just have the stock 8.8:1 pistons. I you want to turbo or run a lot of nitrious then getting forged pistons is the safe way to go. https://www.3geez.com/showthread.php?s=&threadid=25166