Donations towards server fund so far this month.

 
£0.00 / £100.00 per month
Page:
Home > Help Needed / General Tech Chat > crankshaft, crossdrill or not?

R.Rodrigues

User Avatar

67 Posts
Member #: 8956
Advanced Member

Algarve/Portugal

As per title, crossdrill or not, just finish wedging and polish my crank, and start thinking in drill the mains, does it wort? whats the best way to drill them, across the main or 90º whit existing hole?

I´m using old bearings whit a full-circle groove around them, should be safe lining up the holes of the crank whit the groove in the bearing, but what about big ends, there is no oil groove in there.

Engine will be a 1330cc, 16V k1200 head whit the RS cams.


Joe C

User Avatar

12307 Posts
Member #: 565
Carlos Fandango

Burnham-on-Crouch, Essex

with the RS cams your going to be spinning pretty high, peak will be in the order of 8-8.5k, so i would cross drill,

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7535

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



R.Rodrigues

User Avatar

67 Posts
Member #: 8956
Advanced Member

Algarve/Portugal

Just drilling straight across the mains and big ends or any specific angle?


slater

User Avatar

1030 Posts
Member #: 1291
Post Whore

Suffolk / Birmingham

I'm not so sure it's worth it personally.

Edited by slater on 22nd Aug, 2017.


Earwax

109 Posts
Member #: 10368
Advanced Member

Australia

I think cross drilled mains are a good thing, along with checking oil slot alignment, removing hard edge off feeder holes etc, to make oil flow to bearings as unobstructed as possible,,,, as to whether it makes a difference, i haven't been wanting to back to back test one with cross drilled crank against one without until destruction... so it sounds good in theory but maybe just done to make me feel better.... ?


Sprocket

User Avatar

11046 Posts
Member #: 965
Post Whore

Preston On The Brook




On 22nd Aug, 2017 slater said:
I'm not so sure it's worth it personally.


I concur

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........


Turbo This..

User Avatar

1767 Posts
Member #: 9165
Previously josh4444

Australia, brisbane

isnt the whole point of x drilling the journal to help reduce the centrifugal force as the rpms rise?
so there for its only needed on the big ends.. and its only going to work if the factory holes are blocked to force the oil to be re directed to the shorter less rpm affected distance

if anything id only bother with the center two big ends and get some grub screws taped into the old holes with the new drillings at 90 degrees to the crank throw

and if your doing that you probably want to look at bearing clearances vs oil pump flow volume


TurboDave16V
Forum Mod

10979 Posts
Member #: 17
***16***

SouthPark, Colorado

I'm pretty sure that when using the solid/solid bearing shells, the benefits of cross drilling (the mains) are there. With the later grooved/solid mains though, I'm struggling to see the need as oil is able to be fed for approx half of the crank rotation instead of a small amount of time with the older mains.
I'm sure the migs and everyone else with seemingly bottomless pockets still do cross drill, but I'm not convinced it's neccesary...

On 17th Nov, 2014 Tom Fenton said:
Sorry to say My Herpes are no better


Ready to feel Ancient ??? This is 26 years old as of 2022 https://youtu.be/YQQokcoOzeY



Sprocket

User Avatar

11046 Posts
Member #: 965
Post Whore

Preston On The Brook

The attached is worth a read. It does only touch on the subject but supports the idea that the plain bottom bearing is better. It also talks about the intermittent oil supply to the big end does not really affect big end reliability.

What you have to understand with hydrodynamic lubricated bearings is the oil feed hole should always be just ahead of the highest loaded point in the journal's travel.

By all means drill your crank full of holes, but surely this also introduces stress points in a highly stressed part?........

All 'cross drilled' forged/ billet crankshafts are 'cross drilled' and have the big end oil feed holes in the right places. You only need to compare those to the modified standard cranks with a keen eye to see where the differences lie.


Attachments:

On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........

Home > Help Needed / General Tech Chat > crankshaft, crossdrill or not?
Users viewing this thread: none. (+ 1 Guests)  
To post messages you must be logged in!
Username: Password:
Page: