A1/2/3/4 vrs K20Z3 oil pump

talonxracer · Apr 11, 2008

Here is a pic comparing the A1/3 oil pump and the A2 pump. Notice that they use the same exact inner and outer rotors with the same exact oil pressure relief piston and spring.
There is more of a reservoir for the oil after it has left the rotor of the A1/3 pump as it has to travel back across the pump housing before entering the block.

The only major difference is that the A1/3 pump is driven at exactly 2x crank rpm(due to balance shaft requirements), while the A2 spins at approx 1.62X crank rpm. The crank sprocket has 34 teeth and the A1/3 pump has a 17 tooth sprocket while the A2 has 21 teeth.
So when the A2 engine is at 9500 rpms the pump is spinning at 15,390rpms which is slightly above max for the A2 pump without some mods. The A1/3 pump on the other hand has a oil pump speed of 15,600rpms when the engine is only at 7800rpm's. This is the point that everyone says gives the A2 pump the edge, but I do believe that the balance shaft equipped oil pumps can spin at higher RPM's before excessive cavitation occurs because of the passageway design and pump exit being at less of an angle.

The A2 pump is on the bottom

So the balance shaft equipped pump provides MORE pressure at idle and low rpm's.

I see two benefits of running the balance shaft equipped oil pumps now, more pressure at idle, and a much smoother idle(K24)

There are significant differences in the pump rotor both inner and outer between the A2 and Z3 oil pumps. The Z3 has a larger dia, with 8 paddles vrs the A2's 6.

There is also alot of difference in the pressure relief, Z3 on the bottom. The A2 spring is longer and requires alot of effort to push in while installing the cap, but the Z3 spring is shorter and is almost effortless to install the cap.

The rotor housing has different porting and passage design.
Z3 on top, notice it is already "notched" for the 8mm deeper girdle of the Z3/K24A2/A4

The Z3 oil pickup is also significantly deeper than the A1/2/3/4
The RBC has a different pump inlet design.

K24A1 on the left and A2 on the right

Here is the Z3 housing cover showing the areas that need to have material removed as it is hit by the K24 balance shaft weights.

Here is a pic showing the two different oilpump covers. The Z3 pump is enclosed so that drainback oil doesnt get whipped up. And it is already "notched" to fit the K24A2/A4 8mm high step on the girdle.

sirtifiedacc · Apr 11, 2008

very nice info.. so are we concluding that the Z3 oil pumps are just as adequate..if not more, than the A2s?

soft_step · Apr 11, 2008

Awesome...thank you very much for the visual comparison and sharing what information you gleamed from it. :up: :up: for informative posts!

TransformedBG · Apr 11, 2008

Humm very interesting lol

signalpuke · Apr 11, 2008

Great post, stuck.

bossman032 · Apr 11, 2008

well honda put the blance shaft for a reason..

little differencfes tsx has no oil cooler and the type s do..

kommon_sense · May 8, 2008

bossman032 said:
well honda put the blance shaft for a reason..

True, but it still leaves a lot to be questioned. For example, why does the k20a3 from the rsx use the k20a2 oil pump, but the k20a3 from the ep3 uses a pump with balance shafts?

Scourge · May 8, 2008

Subscribed... So, would it be possible to turn a K24 oil pump into a K20Z3 oil pump? Or would it be better to just get a complete K20Z3 oil pump? I'm going to guess that used K20Z3 pumps will be hard to come by for a bit unless you buy from the stealership.

I'm getting a CRV block shortly which has the oil pump included. So, other than the balance shafts, what do I want to keep from the K24A1 pump? Also, how big of a difference do you think the oil pump covers make? I just figure it'd be easier to reuse the one from the K24 than modifying the K20Z3 one.

kommon_sense · May 8, 2008

Scourge said:
Subscribed... So, would it be possible to turn a K24 oil pump into a K20Z3 oil pump? Or would it be better to just get a complete K20Z3 oil pump? I'm going to guess that used K20Z3 pumps will be hard to come by for a bit unless you buy from the stealership.

Given the crucial nature of the oil pump, I would probably go for buying a new pump instead of trying to convert an old one.

talonxracer · May 8, 2008

Yeah, I dont like reusing someones old oil pump either. It would pay to have a new one, especially if you do anything internally to the engine like forged components.

Rene M · May 15, 2008

So, were the balance shafts installed to provide a smother idle or are the internal vibrations that bad? Has any one run with out the shafts?

Great write up. my complements.

Sorry if this sounds stupid but i am playing catch up.
I am still running a B18c5 in my track R.

talonxracer · May 20, 2008

I had swapped a A2 pump onto a K24A2 that was in a RSX several months ago for a guy. The difference in smoothness was very evident. The owner had me swap back in the stock K24A2 pump the next weekend. For a daily driver that seldom sees the track, I will opt for the balance shafts every time. The Z3 pump spins reliably well past the point I would feel comfortable spinning a K24, even a built one. The extra mass being spun can be compensated for with a lighter flywheel for the most part.

ainokea_si · May 23, 2008

so are you saying that the z3 is ok if you rebuild the inside? i have the k20z3 and was looking at the hytech build, and they used the K20A2 or Z1 because the z3 was not good enough.

Rene M · May 20, 2008

So how do you feel about a track whore?
Idle time only makes up 1 -2% of the time the engine is running?

ainokea_si · May 23, 2008

http://www.hondatuningmagazine.com/tech/htup_0710_2006_honda_civic_si/prices.html

for this build then i should be ok with just the components? titanium internal head (valve, springs, retainers) and 12:1 pistons eagle h rods and spec 1 hytech cams, and i dont need that baffle pan thing?

do you guys know of a place that sells the engine components? i was searching and saw sctuned but they have my engine spec up on the website. i want to start buying all of these parts like yesterday.....eager can you tell?:silly:

drumnatural · May 23, 2008

I'm assuming the A2 and Z1 pump are the same?

talonxracer · May 23, 2008

They are the same.

Scourge · May 23, 2008

drumnatural, I believe even the K20A3 pump is the same (edit: in base RSX, not EP3). I think the Z1 pump is the same. Just gotta compare part numbers.

ainokea_si, I think the baffles is just to prevent oil starvation in hard turns since the oil can't completely shift to one side. Can someone confirm?

ainokea_si · May 23, 2008

Scourge said:
drumnatural, I believe even the K20A3 pump is the same. I think the Z1 pump is the same. Just gotta compare part numbers.

ainokea_si, I think the baffles is just to prevent oil starvation in hard turns since the oil can't completely shift to one side. Can someone confirm?

i have no clue, i would like to save the 600 bucks but dont want to run into a nightmare. i can not seemed to get a good response from the hytech guy either. i want to do this setup and trying to find all of the parts is starting to get annoying

JasonMann · May 23, 2008

ainokea_si said:
I think the baffles is just to prevent oil starvation in hard turns since the oil can't completely shift to one side. Can someone confirm?

Yes. That's what the baffle is for.

ainokea_si · May 23, 2008

yea he said that even on the highway with high rpms turning could hurt the engine. the baffle and new pump keeps the oil thrown. YES
SIR

katman · May 25, 2008

subscribed...excellent info Talon!

Just a quick question...
My curiosity is wondering if you can do an oil pump swap without having to pull the motor? or does a pump swap require the timing chain to be removed n' all that?

thanks..

talonxracer · May 25, 2008

That depends alot on the chassis. With the DC5 and EP3 chassis you will need to slightly drop the subframe to remove the pan. I am not sure about other chassis. But yes it is rather involved as the timing chain has to be removed first.

JasonMann · May 25, 2008

Talon, what mods need to be done to the a2 pump for it to rev to 9500 rpm?

Would it be possible to use any of the parts from the z3 pump in an a2 pump in order to have more pressure at idle and low rpm? Could you swap the pump rotors to accomplish this?

talonxracer · May 26, 2008

I havnt modded any A2 oil pumps, but Hytech does this on a routine basis. They blend where the pump cavity makes the turn to exit the pump, it is a very acute angle and presents an obstruction to the flow. John said he carries them in stock.

The Z3 components will not fit in the A2 housing.

Scourge · May 26, 2008

How do you think the K20Z3 oil pump would work in a K24 while retaining the K20Z3 balance shafts? What if the K24 had lightened rods, pistons and possibly crankshaft?

Ihockey1 · Jun 2, 2008

I wanna know this as well

ainokea_si · May 26, 2008

there is a guy on 8thcivic that did the k24/k20 in his 06 civic and he used the rsx-s oil pump and pan with baffle

Scourge · May 26, 2008

^ Yeah, you showed me that already.

I have a K20A2 oil pump too but I just found out it's been sitting in oil and coolant for almost a year now. I wonder if it's still good. Coolant becomes acidic when mixed with oil.

I want to explore Talon's stuff just because balance shafts make the car nicer to daily drive.

sleepycivichb · May 27, 2008

I assure you that with my K24A2/K20A2 with cams that is untuned the motor is smooth as hell. There is no way you can feel vibrations from the motor over your motor mounts it's rediculous how people jump on a band wagon because one person tries to be different. My car is daily driven with a lightened flywheel and drives amazing. Do what you wish but I think you're wasting time. -J

Scourge · May 27, 2008

Well, I know a K20A2 is pretty smooth. Had one in my RSX until it blew. But ever since I drove the TSX (yeah, I know it's got softer mounts) I've loved how smooth it felt.

Smooth is still pretty relative. Just like "fast" is relative. My RSX with ESMM shook like mad. Everything rattled. I can't say how it'd be with balance shafts but if I can reduce any of that, I will. I'm willing to sacrifice some HP for comfort.

sleepycivichb · May 27, 2008

Well. I will bet dime to dollar that the motor mounts didn't make your car shake because of a non balanced oil pump. But hey we all try to do over the top things at some times... -J

Scourge · Jun 2, 2008

The Energy Suspension motor mounts just carry any engine vibration into the cabin. Before I put them in, my RSX was super quiet on the inside. The stock rubber mounts absorb the vibes much easier. I'm just hoping this helps. If not, I still have a K20A2 pump laying around.

A1/2/3/4 vrs K20Z3 oil pump

Top Contributors this Month

Recommended Communities