[YourOldPalElmer]

Ok so. Got a k24a2 for the E. Gonna rebuild it so I got a solid plant if I wanna throw something else at it. I’ve found lots of information about the various options and such for upgrading the oil pump, but never something explicitly stating what needs to be done to the s2000 pump to fit it to the engine. I’m only asking because I got an amazing deal on a stock pump and would like to run it for piece of mind. Thank you for any help/ suggestions on where to look.

 

[Them Witches]

so you got a stock oil pump for the K24a2 or the S2000 ?

 

[KBuilt]

so you got a stock oil pump for the K24a2 or the S2000 ?

S2k I believe. I’m in for some info on this as well, what needs to be done to the s2k pump and what part # needed to make it work on k24

 

[YourOldPalElmer]

Yes. That’s would be putting the s2k pump into a k24a2. I’m doing a rebuild and have a pump already I got for a steal. Not planning on going crazy, but 8000 rip’ems would be nice. That’s the only reason I’m not just doing the type s pump. I already have the part, and have the ability to do the work. Just need to know what to do. And I’m all about the learning process too. I’m going to be doing measurements eventually but was wondering if anyone had any foresight into this.

 

[KBuilt]

This has the part #s needed to install their “modified” s2k pumps , and a few pics of it but nothing actually describing what they do to it. It appears in one of them that a passage is blocked off with an Allen plug ?

Drag Cartel MODIFIED S2000 OIL PUMP

The Drag Cartel Modified S2000 Oil Pump is designed for the Honda K-series engines. This oil pump gives the Honda K-series engines the ability to run above 8500 RPM without cavitation. This product is the combination of a Honda F-series oil pump with an Performance adaptor kit. This conversion...

www.hptautosport.com

 

[YourOldPalElmer]

OK! So I did some eyeballing with the pump and lower girdle. It looks like it is actually pretty straight forward, utilizing 2 existing bolt holes and the existing oil passage

each of the respective colors seen matches it’s corresponding hole from the stock un-modifies pump to the lower girdle.

Red=oil passage
Blue=threaded bolt hole
Yellow=bolt hole with dowel pin

The biggest problem I can see are as follow:

1:Clearences

As you can see, some material from the lower girdle and it’s mounting bolts protrude up into the space of the oil pump along, with the s2k one mounting flat stock and the k24a2 pump having pylons (?) that prop it up over this. It would appear that drag cartel has 2 pieces of metal that they bolt on that take up this space so that the pump fits.

2: Tensioner. The stock oil pump tensioner bolts to the housing on the k24a2 pump, and the s2k pump has no such holes. To remedy this, drag cartel has a machined a piece that covers the existing index pin hole and mounts through the body of the pump. This is the only piece that I can see having a mill would be helpful for. The front of the pump and some of the integral chain guide are milled flat so the other piece can be indexed between the mounting in the body of the pump and the pre-existing hole for mounting the pump to the engine itself.

3:Missing mounting hole

The existing hole on the pump

and the mounting hole in the lower girdle

do NOT line up with one another as they are. To counteract this drag cartel has a plate that mounts through pump with a bolt through the misaligned bolt hole that does not protrude from the other side of the plate, and indexes on the oil passage dowel pin and proper aligned bolt hole.

~~~~~~~~~~~~~~~~~~~~~~~~~~​

So yeah. Looks like the major problems actually have pretty straight forward. The actual mounting utilizes 3 points of reference from the stock part which makes properly aligning it to the engine immeasurably easier. Wasn’t expecting this to turn into a write up, but I guess it has! I’m gonna take some measurements next time I can get to the parts and start mocking up some pieces. The plate for the oil passage should be simple enough to make without a mill, the one that holds the chain guide may be a different story. I’ll document everything, and try to do this in such a way that someone who wants to do this themselves can hopefully do so without a machine shop, but we shall see. The measurements will be helpful regardless.

 

[KBuilt]

OK! So I did some eyeballing with the pump and lower girdle. It looks like it is actually pretty straight forward, utilizing 2 existing bolt holes and the existing oil passage
View attachment 102718
View attachment 102719
each of the respective colors seen matches it’s corresponding hole from the stock un-modifies pump to the lower girdle.

Red=oil passage
Blue=threaded bolt hole
Yellow=bolt hole with dowel pin

The biggest problem I can see are as follow:

1:Clearences
View attachment 102720 As you can see, some material from the lower girdle and it’s mounting bolts protrude up into the space of the oil pump along, with the s2k one mounting flat stock and the k24a2 pump having pylons (?) that prop it up over this. It would appear that drag cartel has 2 pieces of metal that they bolt on that take up this space so that the pump fits.

2: Tensioner. The stock oil pump tensioner bolts to the housing on the k24a2 pump, and the s2k pump has no such holes. To remedy this, drag cartel has a machined a piece that covers the existing index pin hole and mounts through the body of the pump. This is the only piece that I can see having a mill would be helpful for. The front of the pump and some of the integral chain guide are milled flat so the other piece can be indexed between the mounting in the body of the pump and the pre-existing hole for mounting the pump to the engine itself. View attachment 102722
3:Missing mounting hole

The existing hole on the pump
View attachment 102723
and the mounting hole in the lower girdle
View attachment 102724
do NOT line up with one another as they are. To counteract this drag cartel has a plate that mounts through pump with a bolt through the misaligned bolt hole that does not protrude from the other side of the plate, and indexes on the oil passage dowel pin and proper aligned bolt hole.
View attachment 102725

~~~~~~~~~~~~~~~~~~~~~~~~~~​

So yeah. Looks like the major problems actually have pretty straight forward. The actual mounting utilizes 3 points of reference from the stock part which makes properly aligning it to the engine immeasurably easier. Wasn’t expecting this to turn into a write up, but I guess it has! I’m gonna take some measurements next time I can get to the parts and start mocking up some pieces. The plate for the oil passage should be simple enough to make without a mill, the one that holds the chain guide may be a different story. I’ll document everything, and try to do this in such a way that someone who wants to do this themselves can hopefully do so without a machine shop, but we shall see. The measurements will be helpful regardless.

Definitely far from the amount of work that a type s pump takes, but I would prefer the s2k unit myself. I can see why DC charges so much now that you broke it down.

 

[Bjorn]

Definitely far from the amount of work that a type s pump takes, but I would prefer the s2k unit myself. I can see why DC charges so much now that you broke it down.

Are there documented advantages with the s2000 pump over the k20a pump?

 

[KBuilt]

Are there documented advantages with the s2000 pump over the k20a pump?

I don’t know about documented, but 4piston says the oem k20 pump cavitates at 9k, and the ap1 comes from Honda spinning that high so I was just thinking the extra rpm that the f20c pump is capable of might be good for a race motor. Also curious about vibrational differences between the 2 pumps because that would affect things as well.

 

[YourOldPalElmer]

Exactly! While type s pump is designed for ~8000 rpms and is capable of going more, the s2k pump was designed for ~9000 and has been proven into the 1X,XXX rpm range. Its also what I have on my bench right now so its what I'm gonna use haha!

 

[Bjorn]

It's not a difficult thing to prove. I'd like to see oil pressure logs on a k20a that's being revved that high.

Im not saying the s2000 pump isn't better. But I'd want some evidence before i put in the effort of the conversion.

 

[Bjorn]

Exactly! While type s pump is designed for ~8000 rpms and is capable of going more, the s2k pump was designed for ~9000 and has been proven into the 1X,XXX rpm range. Its also what I have on my bench right now so its what I'm gonna use haha!

By the same token, the s2000 pump isn't designed supplying a vtc control like the k20a pump is designed to.

 

[YourOldPalElmer]

By the same token, the s2000 pump isn't designed supplying a vtc control like the k20a pump is designed to.

You are correct, but the s2000 did have variable cam profiles and supposedly the oil pump flows better according to the internet. That's the legend, at least.

 

[BlueES1]

Not sure about the S2K pump flowing better since I can't find definitive flow specs, but I wonder if that myth started because the S2K engine runs higher oil pressures than the K series. I have seen people say that the S2K pump must be better for this reason, but that is false logic since the S2K engine probably has significantly lower oiling demands since it has no VCT and possibly a bunch of other differences that could affect oil pressure.

Here's a side by side comparison between the Type S and S2K pumps. Both have 6 sided pump gears and they appear to be the same size from what I can tell, but it's very hard to tell from a video. The depth of the gears may not be the same either. It would be nice if someone would do a side by side comparison of the pump gears, that would put an end to the myth once and for all.

 

[KBuilt]

Not sure about the S2K pump flowing better since I can't find definitive flow specs, but I wonder if that myth started because the S2K engine runs higher oil pressures than the K series. I have seen people say that the S2K pump must be better for this reason, but that is false logic since the S2K engine probably has significantly lower oiling demands since it has no VCT and possibly a bunch of other differences that could affect oil pressure.

Here's a side by side comparison between the Type S and S2K pumps. Both have 6 sided pump gears and they appear to be the same size from what I can tell, but it's very hard to tell from a video. The depth of the gears may not be the same either. It would be nice if someone would do a side by side comparison of the pump gears, that would put an end to the myth once and for all.

I’m pretty sure the oem s2000 oil filter has something to do with the pressure as well, I’ve read some of the guys saying there’s a little trap door inside the filter that is designed specifically for the f series engine ? Not 100% on that just rumors tho. It’s a common swap to use the s2k filter on b or k series engines , I actually have one on my shelf for my k24a lol

 

[BlueES1]

I’m pretty sure the oem s2000 oil filter has something to do with the pressure as well, I’ve read some of the guys saying there’s a little trap door inside the filter that is designed specifically for the f series engine ? Not 100% on that just rumors tho. It’s a common swap to use the s2k filter on b or k series engines , I actually have one on my shelf for my k24a lol

Yeah I have heard of people using the S2K filter on other engines to try to gain oil pressure but I never saw any definitive evidence that there is any evidence. I looked up the Wix part number for the S2K filter and compared it to the regular D/K series filter and they both had the same max flow rate.

Also, while on the subject of oil filters, let's debunk a common myth: A smaller, more restrictive oil filter does NOT increase oil pressure available to the engine, it actually has the opposite effect. The pressure in the pump and the block's passage from the pump to the filter will increase since there will be more restriction, but pressure and flow through the engine will be lower. Ideally the filter's restriction will be as low as possible. The volume of the filter can has no effect on pressure, but a larger filter will take marginally longer to build pressure on a cold start if it is mounted sideways because it will take more time to fill with oil. That's about the only argument against using a larger filter.

 

[KBuilt]

Yeah I have heard of people using the S2K filter on other engines to try to gain oil pressure but I never saw any definitive evidence that there is any evidence. I looked up the Wix part number for the S2K filter and compared it to the regular D/K series filter and they both had the same max flow rate.

Also, while on the subject of oil filters, let's debunk a common myth: A smaller, more restrictive oil filter does NOT increase oil pressure available to the engine, it actually has the opposite effect. The pressure in the pump and the block's passage from the pump to the filter will increase since there will be more restriction, but pressure and flow through the engine will be lower. Ideally the filter's restriction will be as low as possible. The volume of the filter can has no effect on pressure, but a larger filter will take marginally longer to build pressure on a cold start if it is mounted sideways because it will take more time to fill with oil. That's about the only argument against using a larger filter.

That’s interesting to know, the s2k one is considerably wider than the regular d/b series one, but also shorter. So I wonder what’s the actual difference. 🤔

 

[BlueES1]

That’s interesting to know, the s2k one is considerably wider than the regular d/b series one, but also shorter. So I wonder what’s the actual difference. 🤔 View attachment 103887

Not sure, I'd love to know though LOL. I thought about using a bigger oil filter since there's plenty of room, the only reason I haven't is because my oil filter is mounted sideways and a larger filter would likely delay building oil pressure on startup since it would take longer to fill. Since it is said that somewhere between 75% and 90% of all engine wear happens on startup, I don't want to risk increasing startup wear. Sideways oil filters have always bugged me for that reason, but as long as Honda engines tend to last with sideways filters I don't know that it's much of a concern.

 

[KBuilt]

Maybe an oil pressure gauge test needs to happen between the two filters 🤔

 

[BlueES1]

Do you have a remote oil filter for the k swap ?

I do not. However, since I have an oil cooler setup, I considered installing a remote filter mount somewhere easily accessible so the filter sits upright and therefore stays full of oil at all times. Then I could use as large of a filter as I want with no worries about causing startup wear. Would be interesting to see if it builds oil pressure quicker on startup too.