Dry Sump oil pump gear ratio calculation help need it..

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Ibrahim Kuzu
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Dry Sump oil pump gear ratio calculation help need it..

#1 Post by Ibrahim Kuzu » Mon Aug 12, 2019 12:24 pm

Working on our new sand cast timing cover dry sump oil pump design.
Need to add material on the surface of existing oil pump casting for suction side .
What would be the 616 push rod 1600 cc, 1800 cc and 2.0 liter engine configurations ratio....

As an example ;

Factory 1958 small pump 616 aircraft 678/4 engine uses 1:5 ratio on the suction length of the gear (pusher 24 mm x suction 36 mm.. 9 teeth count small gear pump 32.5 mm OD )

4 Cam Carrera 2.0 liter uses 1:8 ratio on the suction gear length (pusher 36 mm x suction 65 mm 10 teeth count 36 mm OD )

old 911 with magnesium case oil pump uses 1:345 ratio on suction gear length ( Pusher 43 mm x Suction 58 mm 10 teeth count 36 mm OD )

Thank you for your input ,appreciate it....

IK
Attachments
20190626_174538.jpg
Spin on full flow oil filter ,twin dist. sand cast timing cover
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678/4 1958 aircraft dry sump factory pump
20190812_110814.jpg (84.26 KiB) Viewed 186 times
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4 cam carrera 2 liter oil pump gears
imagejpeg_0 (5).jpg (163.89 KiB) Viewed 186 times
20190812_110506.jpg
older 911 oil pump
20190812_110506.jpg (88.08 KiB) Viewed 186 times

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Jacques Lefriant
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Re: Dry Sump oil pump gear ratio calculation help need it..

#2 Post by Jacques Lefriant » Mon Aug 12, 2019 9:51 pm

Hi
I would think that the pressure side will be external. you should incorporate an internal bypass to that like Porsche did on the later 911 and on the 4-Cam as a Le Mans kit. so why don't you do like the 678 and use the existing large pump 36mm gears in the 3rd piece and the 24mm with the 36mm OD for the pressure side. and put a thin plate between them.
j
 

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Ron LaDow
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Re: Dry Sump oil pump gear ratio calculation help need it..

#3 Post by Ron LaDow » Mon Aug 12, 2019 11:53 pm

Exhaust pump volumes for dry sumps are strongly influenced by the sump geometry.
Once the theoretical benefits of dry-sumps were recognized by the drag-race guys, it took those like Grumpy Jenkins to understand that the benefits were minimal until the sump geometries were designed to take advantage of them. Ditto NASCAR and that obnoxious twit Yunick.
Pretty sure you need to define what you hope to gain and how much you're willing to modify the sump before you spend any time on deciding how big a pump should be.
Ron LaDow
www.precisionmatters.biz

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Vic Skirmants
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Re: Dry Sump oil pump gear ratio calculation help need it..

#4 Post by Vic Skirmants » Tue Aug 13, 2019 8:28 am

"that obnoxious twit Yunick."
So you read his book too?

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Jacques Lefriant
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Re: Dry Sump oil pump gear ratio calculation help need it..

#5 Post by Jacques Lefriant » Tue Aug 13, 2019 10:09 am

Hi Ron
In this case the sump geometry is the existing one that is used by the stock pump so it should work. Even your filter implementation does not address one of the Achille's Heel that the pump and gears can have FOD damage in a dry sump like the 911/4-Cam even large ratios will not ensure that the sump will not end up with too much oil and the oil press will drop due to low levels in the tank and excessive foaming and windage losses in the sump. sending the pressure relief output to the suction side does help like what was incorporated in the early 70s on the production 911s.
j
 

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Ibrahim Kuzu
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Re: Dry Sump oil pump gear ratio calculation help need it..

#6 Post by Ibrahim Kuzu » Tue Aug 13, 2019 10:54 am

Thank you Jacques.
So
If we use existing 36 mm OD and 36 mm length C/912 bigger pump gear on the existing oil pump galleria ( Which will be Suction area in dry sump configuration,
and between thin plate pressure gears 36 mm OD 24 mm in length in the upper dry sump casting
Would this ratio ( which will be 1.5 on suction side ) would be OK for larger say up to 2.0 liter 616 engine builds ?
IK
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Jacques Lefriant
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Re: Dry Sump oil pump gear ratio calculation help need it..

#7 Post by Jacques Lefriant » Tue Aug 13, 2019 12:14 pm

Hi
I don't think there is an optimum ratio we can derive from our limited data set to many factors. It would seem that the important outcome is to achieve at least 10psi/1000 measured at the end of the oil galley. in your instance I would think that the bearing clearances would be to factory new specs. one helpful hint would be to reduce the oil feed to the no 4 bearing since VW did that in the type IV and you will have to extra clearances to permit the fitting of the add on cover. in the cover eliminate the pressure relief and the viscosity diverter to the oil cooler and full flow the output to the filter/thermostat/coolers. on the pressure side you could add a filter but it is overkill. I see you have a non dry sump version of your twin plug timing cover but maybe you could create a different version for the dry sump(yes and keep the overkill filter.

j
 

Erik Thomas
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Re: Dry Sump oil pump gear ratio calculation help need it..

#8 Post by Erik Thomas » Tue Aug 13, 2019 4:07 pm

I used a VW dune buggy two stage pump . These are used in sand rails with VW 1600 based engines. These slide right into early 3 Pcs 356 cases. The only issue is that the 4 studs need to be moved slightly, and increased in size from 6mm to 8mm. These dune buggy pumps are cheap and easy to come by, perhaps you could use the gears?

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Ibrahim Kuzu
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Re: Dry Sump oil pump gear ratio calculation help need it..

#9 Post by Ibrahim Kuzu » Thu Aug 15, 2019 11:26 am

Thank you every one...
Looks like we are good to go .
Will see how the testing will go down the road...
IK

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