[k20gt40r]

heres something i found on hondanews.com

Engine Block/Crankshaft

The RSX engine features a compact aluminum block with cast-in iron liners- a design known for its light weight, high rigidity, and excellent durability. The block has a one-piece aluminum crankshaft carrier, which has ferrous-carbon inserts in the bearing caps for additional strength. The Type-S version also incorporates a stiff, cast-aluminum oil pan. The crankshaft is a highly rigid, forged-steel design that uses a special micro-polished surface finish for reduced friction and increased durability.

In addition, the Type-S engine uses high-strength connecting rods and crankshaft as well as high-compression cast-aluminum pistons for increased resistance to wear

The transversely mounted engine block with front- mounted intake manifold, positions the exhaust manifold closer to the catalyst for improved light-off and reduced emissions at start-up.

Dual-Stage Intake Manifold (RSX Model)

Now it doesnt say that the jounals are different sizes but it does say it uses a higher strength crankshaft. Now all we need is specs!!!

 

[NRN GT4]

So from the sound of things the a2 and the a3 are the same except the cranks.....

So does any one know about the k24a4 vs. k20a2?? Are the cranks in the k24a4 engine larger than the k20a2 or are they the same. I heard somewere that the rod journals on the k24a4 are wider than the k20a2 but cant seem to find any materials to back this up any clues anyone? Thanks for your time in advance.

 

[pb16b]

so, today, i put an a2 crank beside an a3 crank and checked the differences.

stroke - same
journals - same - that's why the a2 rods and a3 rods can be interchanged.

difference: counterweights. the a2 crank has more than a3. i'm guessing because the a3 uses balance shafts.

this is from a glance... if anyone finds anymore info or can correct me, please do so.

 

[pb16b]

top: k20a2 crank

bottom: k20a3 crank

 

[cheetah]

they're not the same, the size of the journal of the a3 is smaller 1.777 measure it. I bought a2 eagle rods and couldn;t use them on my a3 crank. the a3 rod journal is the same size as the gsr.

 

[pb16b]

that's interesting as crower advertises and swears that they're the same rods for both applications. i'll measure them and post my findings.

 

[sf-si-02]

Not much involved in the conversion. Jut need a competent machine shop to drill and tap a few holes. As for parts ... www.acuraparts247.com .

Like I said, the block is already tapped for the oil cooler coolant return, just need to remove the plug, and then yes, drill one hole, but honda already did it most of the way... its like a 2 minute drill job (use a carbide bit and cutting oil)

 

[Hyaboosta]

so by swapping in the a2 crank in an a3 block there is no need to balance? seeing as how the conterweights are different. anyone actually have this done? This would be much cheaper.

 

[pb16b]

i wouldn't say there's no need to balance but you're on point. i'm about to balance an a2 crank in a few weeks... i'll let you know how off it is from the factory if any.

 

[Hyaboosta]

would it be cheaper to build the a3 or just buy a a2 bottom. I might have the complete head if it's in tact but the block is what i need.

 

[pb16b]

i highly doubt building will be cheaper. the pistons and rods alone will run you over $1k. find a crank, at least $100. bearings, seals, pump, pickup, pan, hardware, etc? machining? assembly? i'd say definitely cheaper, easier, and quicker to just buy an a2 block and slap a head on there.

 

[civdx94]

thats interesting on the journal sizing..i ve researched this question a million times with no real answers so this helps. did anybody happen to notice thats the same rod journal size as a d15 i believe.. i guess honda did one thing right on an a3. personally i think i d buy rediculously cheap a3 swap and find an h22 crank with 55mm mains and have the crank snout modded. then you ve got a 90mm stroke,nice rod journals,CHEAP off the shelf rod selection, blah blah. i really dont understand why more people don t go this route.

 

[kommon_sense]

that's interesting as crower advertises and swears that they're the same rods for both applications. i'll measure them and post my findings.

Yup. However if you look in the helms manual to look at the service specs for the rods. It shows that the a2 rods have a 3mm larger bore than the a3 rods.

k20a2: 51mm bore (2.01in.)
k20a3: 48mm bore (1.89in.)

 

[pb16b]

good info. i haven't checked the helm yet so i wouldn't know.

 

[cerebrous]

Just the info I was looking for

 

[Turbok20civic]

I can also verify that, did the same thing A2 crank A3 block.... A few notes, you do have to drill one of the oil cooler lines in the block and remove the stock small plug. You will then run into a problem finding the new larger plug, (30,32mm don't remember) Honda does not list it with either block for some reason, but fear not, it's the same plug used in most of honda's manual transsmissions. You will also need a Type-S water pump. As for the oil squiters, don't waste the money on the parts or labor, just get your pistons coated, (www.swaintech.com) it's a million times better and will run you about the same $. See pics.... -Chris

 

[pb16b]

so, if you were to not run the factory oil cooler and leave it plugged, would you have to run an a3 water pump then?

 

[cheetah]

so, if you were to not run the factory oil cooler and leave it plugged, would you have to run an a3 water pump then?

i'm runnign the a3 water pump and no a2 cooler ... just simple build with A2 crank and eagle rods, wiaseco 12.5:1 comp pistons in the A3 block ... no oil squirters either (hurts performance especialyl on new ring sealing) --- puts too much oil weight on the pistons too at high rpms .. i did the same on my b-series race motors where i jsut plug of all the vtec oil squirters.

greg

 

[pb16b]

nice. our builds are very similar - except obviously, mine's not complete. i've just got the shortblock assembled. a3 water pump it is!

 

[cheetah]

mines not complete yet either, everyone's got me buildign their k24's doesnt seem like they all like the k20's ... I just finished 3 K24s and have two K20s to finish building.

I'm trying to finsih my own k-buildup but customers come first so have to wait