Hi,
I'm trying to figure out the difference in the number of sprocket teeth between the standard OEM E46 M3 oil pump and VAC's Competition Pump. From pictures on the different boards I count 27 tooth on the VAC Competition Pump (From VAC's site actually).
I also count 27 teeth on different pictures of the OEM sprocket.
If you have one of those sprocket in your drawer or have a picture that shows all the teeth of your installation (With or without the chain mounted) I would like to confirm the sprocket tooth count is the same or not.
I understand VAC Competition Pump flows more oil but the Website mentions this is achieved by an increased diameter over the OEM sprocket. I think it's a marketing term since the radius of the sprocket will not influence the ratio. Only a different tooth count will.
If indeed the tooth count is the same it means that VAC is increasing the flow by modifying the pump internals.
It matters to me because I'm trying to figure out an hybrid setup using VAC's Competition Pump. It makes all the difference in the world if the increased flow is a result of modifying the sprocket (Which I can also modify) of from the pump's internal which I will not attempt.
Thank you.
I believe the internal volume is increased to accept the M/S5X internals. There is some machine operations that are preformed to increase the internal volume.
A sprocket (generally) cannot add or subtract teeth without changing diameter or pitch. There will be no speed change without changing diameter of one (most likely both) sprockets and a length change of the chain.
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Correct — it's the VAC Competition oil pump's internals that are modified to increase output, not the sprocket. A sprocket with a different diameter and number of teeth wouldn't work without also changing the drive chain length.
VAC does have two sprockets available for it, because one is for the S54 (same as S50B32 Euro) application and one for the S50/52US. Here they are:
DSC00880-Sm.jpg
The S54 sprocket has two more teeth because that engine revs higher than the S50/52US; adding to the tooth count (and therefore diameter) keeps the oil pump rpm down at max engine rpm. Even if you did compensate by using a different chain length these sprockets would still not be interchangeable, since one is dished and the other flat. Using the wrong one would misalign the drive chain. Note that the VAC sprockets also have a modified centerbore to match their custom shaft.
Neil
Edit: The pic shows a sprocket labeled as being for the S50B32 (E36 Euro 3.2 M3) engine. The S54 also uses this same sprocket P/N.
Last edited by NeilM; 01-28-2019 at 09:22 AM. Reason: Clarification
Well I guess that means that smaller S52 sprocket helps bring back some of the volume for S52's running a stock S54 pump.
Compared to what the S54 pump would deliver at the same engine rpm in an S54 engine, yes. But the issue is that it’s less oil volume/pressure in the S52 than the original pump we’re replacing, which slightly spoils the upgrade.
For a dedicated race car that spends most of its life at medium to high rpm the owner may may decide that doesn’t matter. Bump up the idle rpm to keep the oil warning light from coming on all the time in the paddock and call it good? Maybe.
My own car gets driven to the track, and so sees more varied operating conditions. Highway cruising in 6th with the 3.46 rear end is only around 3K rpm, giving oil pressure of only 40-45 psi on a hot day with the unmodified S54 pump.
Now that’s fixed, plus track oil pressure is improved too. At some cost...
Neil
Last edited by NeilM; 01-30-2019 at 04:41 PM. Reason: Clarification
Thanks for the picture.
Much appreciated. Indeed the alignment will be checked.
I decided on the BimmerWorld kit.
It is sold as plug and play reusing the S52 sprocket. I will make the measurements to confirm the alignment and report back.
Last edited by Franky goes; 01-30-2019 at 09:09 AM.
OK.
The new pump is in.
I checked the alignment with the S54 sprocket:
IMG_20190204_200543.jpg IMG_20190204_200527.jpg
It is clearly off.
Buy the way the sprocket is so large that it takes everything to install the assembly.
This is the absolute largest size sprocket that will fit.
With the S52 sprocket this time:
IMG_20190204_205317.jpg IMG_20190204_205302.jpg
The alignment is perfect.
It means the sprocket on the S54 crankshaft is positioned to the left (Relative to the picture) of the same sprocket on the S52.
The pump height is different on the 3 legs which nicely removes a lot of the slack in the chain that is usualy present with the OEM S52 setup.
This is the stock S54 with the S52 sprocket. We will see what the pressures are once the car is back together. I will report then.
Thank you.
Last edited by Franky goes; 02-25-2019 at 09:06 PM.
Some also install the oil pump chain tensioner in their S52s to try and deal with oil pump shaft failures during higher rev limits.
Would that be the tensioner from the E46 M3 ?
I'm intrigued...
There was a thread on this some years ago. IIRC (not a given...) it’s from the S50B32 Euro. You can check RealOEM. Timing chain cover has to come off, but not hard to install with the engine out. You have to hand tap a hole for the mounting bolt.
If someone gets a PN for the tensioner, post it. I will be installing an S54 pump machined for S52 pump rotor later this year. Might as well add the tensioner at the same time. Have an ATI crank damper to put on so it won’t be much more work to pull the cover.
This looks like it here. Does not seem to be a bolt attachment.
Be nice to know the location in the cover for the pivot. And, how does it interface with the front cover as there does not seem to be a seal for a thru shaft. Is there a boss on the inside of the cover and block? What does the tensioner spring react against?
Euro S50B32
http://www.realoem.com/bmw/enUS/show...diagId=11_6119
Here is the same in the S54
https://www.realoem.com/bmw/enUS/sho...diagId=11_1579
Looks like the block is (or needs to be) drilled and taped to accept the tensioner pivot ‘bolt’ (stud) and reaction spring stop, as Neil states.
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Last edited by bluptgm3; 03-06-2019 at 10:06 AM.
Maybe chikinhed can take a picture for us if he has not put the engine back together yet.
Another option, there were several posts about using a Iwis race oil pump chain that had less slack in it.
https://www.bimmerworld.com/BMW-Parts/BMW-Oil-Pump-Chain-E36-E46-E34-E39-Z3-Z4-11417576915-Iwis-Racing.html
Last edited by Adker; 03-14-2019 at 06:05 PM.
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