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Crankscraper and windage setup

 
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Juho  



Joined: 03 Oct 2018
Posts: 255
Location: Finland

PostPosted: Wed Mar 31, 2021 2:12 am    Post subject: Crankscraper and windage setup Reply with quote

I am going to track my 924 frequently when its finished so is it worth the $$$.
What is difference with normal and teflon version, which one i should get? https://www.crank-scrapers.com/Porsche_924.html

Accusump im getting 100%
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Cédric  



Joined: 27 Aug 2004
Posts: 2114
Location: Sweden

PostPosted: Wed Mar 31, 2021 5:06 am    Post subject: Re: Crankscraper and windage setup Reply with quote

Juho wrote:
I am going to track my 924 frequently when its finished so is it worth the $$$.
What is difference with normal and teflon version, which one i should get? https://www.crank-scrapers.com/Porsche_924.html

Accusump im getting 100%


Me and friends have been tracking and racing 924s since 2003 when i started with 924s, never had an issue with the oiling system. For a track day car on the type of tracks we have up here in Scandinavia i wouldnt bother with any advanced solution if you arent building a very serious race car that will run on slicks or a screamer engine. But if you have money to spend of course its always nice with some safety.

Not sure if they are still in business, i bought scrapers there years ago, never used them yet though, but might do some day in the future. My tyre setup from this season and on will be 245/45 R16, so im prepared to have to maybe do something maybe, hence the discussion we had around the mittlemotor oil pan baffle. They have been racing pretty serious for years, so it should be enough.
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Juho  



Joined: 03 Oct 2018
Posts: 255
Location: Finland

PostPosted: Wed Mar 31, 2021 5:36 am    Post subject: Reply with quote

Would you recommend going mittelmotor baffle rather than windage setup.
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924RACR  



Joined: 29 Jul 2001
Posts: 8419
Location: Royal Oak, MI, USA

PostPosted: Wed Mar 31, 2021 9:40 pm    Post subject: Reply with quote

We've been using the CrankScrapers plain steel scraper for many years. Maybe 15?

For sure the Accusump is the more critical component... but the scraper is definitely worth having, if you have the motor open and time to fit it.

I had to grind down the head of one of the main bearing bolts (last one at the back) to get the oil pan to clear, due to the added thickness of the scraper.

You may likewise need the ability to grind the scraper to fit, as needed, around your rods.

We put a teflon version on my buddy's 944S2 track car motor; can't really speak to an advantage, though theoretically you can run zero clearance... for more efficient scraping...

On the one hand, the teflon design being multiple pieces would have more points of failure. OTOH, my plain steel has broken into two pieces at one weak point. Not that it matters, anyway; there's still enough attachment points on the mains caps to secure both pieces, still works fine.
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
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Juho  



Joined: 03 Oct 2018
Posts: 255
Location: Finland

PostPosted: Wed Mar 31, 2021 10:22 pm    Post subject: Reply with quote

are you using full windage setup or only scrapers?
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924RACR  



Joined: 29 Jul 2001
Posts: 8419
Location: Royal Oak, MI, USA

PostPosted: Wed Mar 31, 2021 10:24 pm    Post subject: Reply with quote

Ah, sorry - scraper only.
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Vaughan Scott
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Fifty50Plus  



Joined: 28 Feb 2008
Posts: 1158
Location: Washington DC area

PostPosted: Thu Apr 01, 2021 3:11 am    Post subject: Reply with quote

I'm using the steel crank scraper and an AccuSump system on my car. No oil pressure drops anywhere on track based on full data acquisition. The prior car that I had was outfitted the same way and the new owner lost an engine after forgetting to open the AccuSump during a session. As others have said, I'm not really sure that a crank scraper is necessary. But it sounded like a good idea when I started building 924 engines to race.
I did a lot of work with pan baffles on some BMWs that I raced and still had bearing problems until I started using AccuSumps in the mid '90s. I'v not lost an engine since.
AccuSump WORKS!
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
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Mike9311  



Joined: 14 Dec 2004
Posts: 1101
Location: Chicago-ish

PostPosted: Fri Apr 02, 2021 12:28 am    Post subject: Reply with quote

I am thinking strongly about accusump myself but it may all change dramatically when I get my oil squirter set up figured out

Windage tray set up on CS. Seems like there is much work to be done regarding fitment especially to the pan as mentioned






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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
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1980 924 NA (R&D lightweight)
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924RACR  



Joined: 29 Jul 2001
Posts: 8419
Location: Royal Oak, MI, USA

PostPosted: Fri Apr 02, 2021 2:08 am    Post subject: Reply with quote

Oil squirter won't change anything about the oil pump sucking air, unless I misunderstand?

Hell, I have a dry sump on my P2, and at one of our local MI tracks (Grattan) it'll catch air twice a lap... one of which can be taken at full throttle at about 10000-11000 RPM! Most cars have to lift before that point to brake enough to make the next corner... but not the prototype. But if I go WOT over it, the oil pump still sucks air because negative g's, and the oil pressure drops out!

So the mitigation is to simply lift over the jump... but the proper fix would be an Accusump.

Mostly - I just have to avoid that track if I have a motor I care about...

So I'm glad we have an Accusump in the 924...
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Vaughan Scott
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Mike9311  



Joined: 14 Dec 2004
Posts: 1101
Location: Chicago-ish

PostPosted: Fri Apr 02, 2021 6:40 am    Post subject: Reply with quote

924RACR wrote:
Oil squirter won't change anything about the oil pump sucking air, unless I misunderstand?

Hell, I have a dry sump on my P2, and at one of our local MI tracks (Grattan) it'll catch air twice a lap... one of which can be taken at full throttle at about 10000-11000 RPM! Most cars have to lift before that point to brake enough to make the next corner... but not the prototype. But if I go WOT over it, the oil pump still sucks air because negative g's, and the oil pressure drops out!

So the mitigation is to simply lift over the jump... but the proper fix would be an Accusump.

Mostly - I just have to avoid that track if I have a motor I care about...

So I'm glad we have an Accusump in the 924...


Yeah sorry that was extremely vague / misleading but you segue'd nicely with the dry sump reference. I am working on a piston cooling idea but have been wondering if I will need either an independent pump or dry sump or simply a different feed since I want to avoid pulling from the 'mains'. The accusump examples from you continue to prove its worth.
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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gegge  



Joined: 27 Jul 2007
Posts: 1093
Location: Sweden

PostPosted: Fri Apr 09, 2021 5:03 am    Post subject: Reply with quote

I bought the teflon scraper for my NA and changed the teflon part for a thicker one. Wouldn´t do it again, the gain is above 6000 rpm and the 924 engine does n´t perform well at those rpms. And the cost... Money is better spent elsewhere.
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