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Discussion Starter #1
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.
 

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

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well honda put the blance shaft for a reason..

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

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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.
 

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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?
 

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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.
 

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Discussion Starter #10
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.
 

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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.
 

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Discussion Starter #12
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.
 

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

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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.
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.
 

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Discussion Starter #15
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.
They used the A2 pump because no one has looked at the actual pump on the Z3 before. Plus the Z3 pump can not use the pan baffle that they have.

I only changed the balance shafts out to use it on a K24 build, you match your balance shafts to the crank/piston/rods used.

So how do you feel about a track whore?
Idle time only makes up 1 -2% of the time the engine is running?
For a trackwhore I would use the A2 pump with the pan baffle, or the F20c pump.
 

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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.
I'll buy it off you if you don't feel like keeping it. :)


talonxracer, what about a daily driver that sees the track once or twice a month? Stick with the K20Z3 oil pump?
 

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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:
 

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Discussion Starter #18
I'll buy it off you if you don't feel like keeping it. :)


talonxracer, what about a daily driver that sees the track once or twice a month? Stick with the K20Z3 oil pump?
I would stick with the Z3 pump for a DD that occaisionally sees the track.
 

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

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They used the A2 pump because no one has looked at the actual pump on the Z3 before. Plus the Z3 pump can not use the pan baffle that they have.

I only changed the balance shafts out to use it on a K24 build, you match your balance shafts to the crank/piston/rods used.



For a trackwhore I would use the A2 pump with the pan baffle, or the F20c pump.
Yes we have them in stock the cost is 350.00 for the baffle and 240.00 for a new modded rsx oil pump + shipping.

this is what the hytech guy said. is the baffle anything that is needed for the power? would the pan make a difference? how?
 
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