Menu toggle

Knife edging

M

mushtykev

New member
Following on from my earlier post ....http://www.porscheclubgbforum.com/tm.asp?m=755259&mpage=1&key=&#755259

My engine is now out to have bores honed, new rings/big end bearings etc etc

My crank and flywheel have now gone to be lightened and balanced but wondered if these cranks can be "knife edged"to help combat the windage issue when running at high rpm's.

Planning to track the car so wondered if people had had this done and if it helps, or if they fitted a crank scraper from the US?

Cant seem to find anyone in this country who does the scrapers so thought if it is effective to have the crank edged i could get it done this week also.

Cheers.
 
Yer tell me about it! ha

Is there anyone here who tracks their car without a scraper?

Be interested to know if they have ever had any oil pressure problems?
 
Had the crank on my 1964 mini cooper knife edged, and it revs so freely I was worried about over doing it, so fitted a rev limiter....

I think I probably wasted my money. Unless you're looking for the ultimate and prepared to rebuild the engine every year, in which case go for it!

 
Id be looking at trying to lighten it and then balance it back up. Porsche cranks are very well balanced but weight is always a compromise in a road car, so therell be some meat to come off. What sort of redline are you proposing? I believe that 7,000 is achievable.
 
Yeah, this is the issue. I think knife edging will be too extreme for me as i really am aiming for a road car that i can take to the odd track day.

As mentioned, both the crank and flywheel will be lightened and balanced just to help the engine rev more freely and allow the revs to drop quicker, but now i see these engines suffer with this windage issue i just wanted to avoid regular strip downs and rebuilds.
 
I would have thought you'd gain as much by having the engine blueprinted:

Rods balanced to all the same weight

Pistons balanced to all the same weight

Crank, flywheel and Clutch mechanism dynamically balanced

Yours

Chris
 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Back
Top