Tooth count on the S54 and S52 crank shaft sprocket that drives the oil pump

**Franky goes** · 01-23-2020, 10:05 AM

Looked everywhere and can't find the information nor a picture angled correctly on the Internet so I could count them.
Eyeballing it with incomplete information it looks like they are both in the 18 to 21 tooth range.

If someone has the exact number, or have one in their parts bin, I would really appreciate the information.
I'm trying to figure out the rpms of the oil pump relative to the engine RPM with those 3 set-up:

S52 OEM
S54 OEM
S52 with S52 sprocket installed on an S54 OEM pump

The S54 and S52 pump sprockets have respectively 27 and 25 tooth.
I'm looking for the tooth count of the respective crankshaft sprockets to figure out their ratio.

Thank you.

**NeilM** · 01-28-2020, 12:13 PM

I don't know either, but I can think of a methodology for finding out.

Looking at photos of the S52 double-row crank sprocket, we can see that both the oil pump drive and the cam drive sprockets have the same number of teeth, even if we can't see them all to count. We also know that the cams are driven at half crank speed, so the cam sprocket must have twice as many teeth as the crank sprocket.

Can we find a photo of the S52 exhaust cam drive sprocket, P/N 11311722841? Yes we can, here: https://www.eeuroparts.com/Parts/116...er-11311722841. Its tooth count is 36, so the S52 crank sprocket must have 18 teeth.

Because its cam drive uses a double row chain, the S54 engine has a triple row crank sprocket, P/N 11211401036. Googling the P/N to find online photos, we can see that all three crank sprockets have the same number of teeth, so the same methodology as above applies. One of the S54 cam drive sprockets is P/N 11367832031, and here's a photo: http://www.autobahnparts.com/part/bm...utlet-sprocket. Tooth count for this one is 38, so the crank pulley for the S54 must have 19 teeth.

Now you've got all your oil pump drive ratios.

Neil

**Franky goes** · 01-29-2020, 10:42 AM

Well Neil,
I'm without words. Very clever. Very clever indeed.
I will get back with the ratios for both engine configurations
Thanks !!!

**pbonsalb** · 01-29-2020, 11:14 AM

What is the project? Seems like it could be interesting. I have an S54 pan and pump that I may put in my S52. I had the pump housing machined to take the S52 pump rotor.

**Franky goes** · 01-30-2020, 01:09 PM

Pbonsalb,

I failed to explain why I was looking for this information.
I am in the process of installing the dual pickup upgrade from the S54 into my S52 race engine / 150,000 street miles + 50,000 racing miles on the engine.
After dismantling the head following 7 years of racing I was disappointed to discover major scoring on both camshafts and the caps.
I had high aluminum levels in the oil that were pointing to piston issues but I believe this aluminum is from the caps.
I have been using the turner baffle with an OEM 'new' pump.

I have a choice of installing the S54 oil pump 'as is' with the S52 sprocket or send the pump to VAC to increase flow by 22% according to their website.
When asked if the 22% increase came from using the S52 sprocket or from machining the internals of the pump the sales person was quite clear it came from the internal machining. I believed him... but I wanted to believe him even more so I asked the question here about tooth counts. As mentioned in the original post the tooth count on the 'driven' sprockets are 27 for the S54 and 25 for the S52 pump. Assuming the 'driving' sprocket is the same on both setup (Lets say 18) the reduction of 2 teeth works out to an increase RPM (Flow) of approximately 10% (From .66 rpm for each rpm of the driving sprocket to 0.72).

Now I'm offered a 22% increase and the two teeth difference is already delivering a 10% increase for a total of 32% increased flow. I do want more oil going to the head but a 32% increase would activate the bypass valve pretty much permanently while on track. This was based on my assumption that the 'driving' sprockets were the same on both applications. To be sure I asked here and Neil came up with a very clever way to get the answer.

Redoing the calculation with a 19 teeth driving sprocket in the S54 and 18 in the S52 yields quite a different result. What's in a tooth you ask ?
For the S54 my calculation (that may be wrong so feel free to confirm) comes out to a ratio of (19/27) 0.704 Revolutions of the driveN sprocket by one Revolution of the drivinG sprocket. Let's call that unit RNRG ratio.

S54 stock ratio = 0.704 RNRG For every revolution of the crankshaft, the oil pump shaft has a corresponding .704 revolution
S52 stock ratio = 0.72 RNRG (18/25)

Assuming the sweep area from both internal pumps are similar (Which they may not) this confirms the S54 uses less flow because the lifters are solid. Versus the hydraulic lifters of the S52. One also has to remember the S54 has an oil cooler that will increase pressure in the system by keeping the oil viscosity lower. Flow is great but it is useless without the necessary pressure to push the oil to the head, which is my ultimate goal.

S54 pump in the S52 engine using the S52 sprocket = the same revolution ratio as the stock S52 setup which is (18/25) 0.72
But this time it is the S54 pump that is being driven at that ratio. So in a plug and play mode the flow increases from 0.704 to 0.72 RNRG. That is a 2.2% increase.
Edit February 9th: I should have added that this 2.2% increase is in the oil pump RPM. Since I don't know the specifications of both pumps internals I can only assume the flow will be 'similar'.

So armed with this information, the swap of the 2 pumps yields approximately the same flow in a system that runs hotter, so less 'pressure' in the system. I'm potentially reducing oil flow to the head even if starvation is eliminated in high G corners. My aim is to increase flow so I will purchase the upgraded S54 pump for my setup.

According to VAC, they do not achieve this increase by installing the S52 rotors into the S54 pump.
You should have the same oil flow as the S52 OEM setup using 18 and 25 teeth sprocket with the S52 pump internal. So you have the benefit of the dual pick up with the OEM oil flow for the S52.

I wanted an increase flow to the head myself, thus the installation of the upgraded S54 pump from VAC

If anyone spots a flaw in the calculations please feel free to chime in. Hopefully this information can serve others but only of it is accurate...

Thanks

**pbonsalb** · 01-30-2020, 03:50 PM

That is a thorough explanation. I my first thought was you did great putting 50k racing miles over 7 years on a 150k mile S52. Good thought about potentially triggering the bypass valve. I had been planning to run my S52 sprocket with my upgraded VAC shaft and S52 rotor in the S54 pump. Using the S54 sprocket might require adding a link to the chain?

**Franky goes** · 01-31-2020, 09:35 AM

Honestly racing is good for a lot of parts in your engine.
I can guarantee you it eliminates sludge and varnish very efficiently.
I run stock so the engine should last forever if maintained properly and supplied with enough oil to the head.
I know the ticking coming of track is dismissed but if the lifters were not fed enough oil so did the cams.

If you do what I think you are proposing, the ration will be 27/18= .66 ratio which is 30% reduction of oil flow.
It's a mute point as the S54 sprocket is not in the same plane as the S52.

Pictures of the S54 pump with S54 pump in the S52.

IMG_20190204_200543.jpg IMG_20190204_200527.jpg

**aeronaut** · 01-31-2020, 08:53 PM

My personal experience with lifter tick when coming off track, is also that it's not something to ignore, as commonly believed. I just discovered lifter damage in my engine, but I think my cams are ok. SO.....sub'd to this thread, although I'm pretty sure I'm going the accusump route. It feels like the S54 dual pickup solution is actually a $2500 solution if all new parts. Ouch.

**Franky goes** · 01-31-2020, 10:35 PM

BimmerWorld sells the kit I got for $2,000. Indeed $2,500 if you have the pump modified. It is not cheap.

**aeronaut** · 02-02-2020, 08:07 AM

Yea with the modified pump, it's bumping up against the cost of a dry sump?
I did price out the cost of the parts for the standard S54 dual pickup conversion, and separate it's more than $2000.
If I could find a used oil pan and pump, that'd reduce the cost of the kit considerable. Hard to find.

**pbonsalb** · 02-02-2020, 08:39 AM

Used kits go for about $600. That is what I paid and I have seen others at that price. If you want a VAC modified rebuilt pump, it is more. Seems silly to buy a new oil pan for $1000.

**aeronaut** · 02-02-2020, 08:43 AM

I passed on a used one last year for $800. My mistake. Now of course my engine is out of the car and I'm starting to get under a time crunch.

**aeronaut** · 02-02-2020, 08:48 AM

On this topic of buying used, is the Euro S50 oil pan essentially the same in this application?

**pbonsalb** · 02-02-2020, 09:02 AM

Message member bigjae. He may have at least a pan, and maybe the pickup if not a pump.

**aeronaut** · 02-02-2020, 09:10 AM

Sweet, thanks for the lead.

And, ebay. Duh.

**aeronaut** · 02-02-2020, 11:27 AM

Originally Posted by Franky goes

.....

Redoing the calculation with a 19 teeth driving sprocket in the S54 and 18 in the S52 yields quite a different result. What's in a tooth you ask ?
For the S54 my calculation (that may be wrong so feel free to confirm) comes out to a ratio of (19/27) 0.704 Revolutions of the driveN sprocket by one Revolution of the drivinG sprocket. Let's call that unit RNRG ratio.

S54 stock ratio = 0.704 RNRG For every revolution of the crankshaft, the oil pump shaft has a corresponding .704 revolution
S52 stock ratio = 0.72 RNRG (18/25)

I'm with you up to here.

Assuming the sweep area from both internal pumps are similar (Which they may not) this confirms the S54 uses less flow because the lifters are solid. Versus the hydraulic lifters of the S52. One also has to remember the S54 has an oil cooler that will increase pressure in the system by keeping the oil viscosity lower. Flow is great but it is useless without the necessary pressure to push the oil to the head, which is my ultimate goal.

I would think pressure in the head would be most affected by a) the passage ways in the head, and b) the bypass valve setting. If I were a BMW engineer (I'm so far from that), I'd engineer the system such that under all conditions I'd get enough oil pressure in the head. The bypass valve would allow me to design the system to have enough pressure at worst case (for example) at very hot oil at idle. My guess is that bypass valve is in bypass mode A LOT on track even in a stock S52 or stock S54 engine. Interesting, I just checked the part # for that spring in the bypass valve, and it is the same over a ton of models and engines, including S50, S52, M50, M52, and a bunch of others. But...the regulating valve 'system' seems to be very different for the S54. So it's hard to tell what it's doing different, if anything.

S54 pump in the S52 engine using the S52 sprocket = the same revolution ratio as the stock S52 setup which is (18/25) 0.72
But this time it is the S54 pump that is being driven at that ratio. So in a plug and play mode the flow increases from 0.704 to 0.72 RNRG. That is a 2.2% increase.

So you're saying the S54 pump with an S52 sprocket has an increased flow of 2.2% compared to an S52 pump with an S52 sprocket? Right?

So armed with this information, the swap of the 2 pumps yields approximately the same flow in a system that runs hotter, so less 'pressure' in the system. I'm potentially reducing oil flow to the head even if starvation is eliminated in high G corners. My aim is to increase flow so I will purchase the upgraded S54 pump for my setup.

I don't think it's quite this simple. Investigating...

According to VAC, they do not achieve this increase by installing the S52 rotors into the S54 pump.
You should have the same oil flow as the S52 OEM setup using 18 and 25 teeth sprocket with the S52 pump internal. So you have the benefit of the dual pick up with the OEM oil flow for the S52.

I'm not sure what you're saying above.

I wanted an increase flow to the head myself, thus the installation of the upgraded S54 pump from VAC

If anyone spots a flaw in the calculations please feel free to chime in. Hopefully this information can serve others but only of it is accurate...

Thanks

It almost sounds like you've figured out a solution except for your fear that hotter oil will cause lower head pressure. And you're buying a $700 pump to fix that. Isn't an easier/better fix simply to install an oil cooler, and 'replicate' the S54 system as much as possible?

And, with all your excellent analysis, I'm now confused as to what problem the VAC modified pump is trying to fix?

**aeronaut** · 02-02-2020, 12:39 PM

So, here's what I keep coming across. For any particular multi weight modern oil, as temp increases, kinematic viscosity decrease is non-linear. Meaning, I think, that oil pressure won't change much between say 200 F and 250 F, for the oil you're using.

external-content.duckduckgo.com.jpeg

Graph_Oil_Sotrax_15W40_1024.png

**BlackHawkRacing** · 02-03-2020, 09:25 AM

Sub'd.

**NeilM** · 02-03-2020, 10:26 AM

A couple of things. One is that oil temperature really isn't the issue, at least within a normal working range. The other is that it's difficult for us to reverse engineer a complex system when we really don't have much insight into what BMW did or how they did it — example, the E36 head and valve gear.

On the other hand we can at least make reasonably accurate observations about what happens under various usage conditions.

After fitting the Euro S50B32 dual pickup pump/pan over 10 years ago I noticed that, while the oil starvation problem under hard cornering was largely solved, once the oil's temp was up to normal the oil pressure was somewhat low except at very high rpm. Driving to the track at highways speeds, with rpm in the mid-three-thousands, oil pressure was barely above 40 psi. Note that I already had a very effective oil cooler, and that I always used the same oil, Mobil 1 15W-50, so oil temp and viscosity don't really enter into my comparison.

Since my oil pump was a used part purchase, I figured it might be worn or defective, so I substituted a new S54 pump. No difference! After taking apart both my Euro pump and a stock S52 pump, I realized that the stock pump has a gerotor pair of larger displacement. So we have a situation where the Euro oil pump system is a better design, but it also has a lower output pump. It's generally supposed that the US engine's hydraulic lifters require more oil flow that the Euro pump is designed for, such that under some conditions the pump is unable to deliver and oil pressure drops. This seems reasonable to me.

While researching all this I became aware that VAC offers an S54 oil pump modified for higher output. It's kind of pricey ($700 if you send in a stock S54 pump, and upward from there), although that does include their shaft upgrade and matching drive sprocket. After a period of maidenly reluctance I gave in and bought one.

The bottom line is simple: the VAC pump puts out oil pressure and flow like a champ, and under all street or track conditions.

As for how they do it...well, they may say they don't just bore out the housing and fit the S52 pump guts. Maybe. But they do something an awful lot like that, perhaps with custom parts? Based on max oil pressures I've seen, I think they may also shim the relief valve spring a bit, although it's important to understand that this alone won't help if the pump itself is undersized for the application, as the S54 pump seems to be when installed in an S52.

Note too that while the S54 pump is driven slower in its native application, the S54 engine revs quite a bit higher, so the pump's max output isn't ever reached when installed in the lower revving S52, despite the smaller sprocket's more favorable gearing. To get more pump rpm it would need a yet smaller driven sprocket and a shorter chain.

Neil

PS: The E36 Euro and S54 pump/pan systems have some physical differences, but are functionally the same. They do use different main pickup pipes.

**aeronaut** · 02-03-2020, 10:38 AM

Great info Neil, thanks much.

I'm gathering the bottom line for a true turn-key S50/S52 oil starvation solution using S54 dual pickup, all new parts it's $2700.
Used if can find, well, at least $1500.

I'm trending back toward accusump. I gotta make my mind up soon!

**Franky goes** · 02-09-2020, 01:52 PM

aeronaut
I edited my post to be more precise about the 2.2% revolution increase. 'Flow' was not the correct word to use. Thanks for flagging it.
The viscosity tables are great. I would be curious to sea a table that goes to higher temperatures. I have seen 250 F (120 C) on track before I added the oil cooler.
Thanks

**aeronaut** · 02-09-2020, 04:33 PM

I'm not sure I buy into the belief that the hydraulic lifters on the S50/52 require higher oil volume (or pressure) under normal conditions. The way I understand how they work, there's very very little flow into/out of those lifters once they are pumped up. And even if they are 'empty', they pump up very slowly.

**aeronaut** · 02-09-2020, 05:25 PM

Neil,

Prior to the VAC modified pump, and with the S50 Euro pump/pickup setup, you say you were seeing 40 psi oil pressure at around 3,500 rpm.
What were you seeing at idle?

FYI, I have read that both the S52 and S54 oil pressures are limited to 58psi. Wondering if anyone can confirm?

Thanks.

**Franky goes** · 02-10-2020, 08:33 PM

VAC would know but intuitively I figure the S52 hits the oil filter bypass at around 68 PSI with a redline of 6,800 RPM
80 PSI for 8,000 RPM red line in the S54.
Key word is intuitively...

**Franky goes** · 02-10-2020, 08:43 PM

aeronaut,
you may be right about the hydraulic lifters not needing more oil than solid lifters. I don't know that they do.

My whole premise was to increase pressure/flow to the S52 head on the basis that lifter tick is a symptom of a lack of oil in the head when puling lateral Gs on track. That would explain the scoring on the camshaft journals. Scoring that is pretty common when I looked at used S52 cams. I'm looking for increased flow regardless of the way to achieve it, based on my assumption that the head is starved. I could be wrong.

I will update at the end of next racing season. Hopefully with good news.