I thought I knew what this ment, but from looking at mine it doesnt look like what I thought.

 

Can someone explain what they are and what they should look like, lol.

This is a knife edged crank. If you look at the leading edges of the crank, you'll see they've been ground down. Basically it just means the crank turns through the oil with less resistance than if would do if it was a standard crank with chunky leading edges.

 

Thats what I thought it was, but when I had my sump off yesturday mine didnt look anything like that, unless I was looking at the back edges and not the front edges. DOH!

They should be knife edged both sides as you'll create turbulance behind the crank as it slices through the oil without.

Hmmmmmmmmm, seems like its not a knife edge crank then, eventhough its spose to be.

Hmmmmmmmmm, seems like its not a knife edge crank then, eventhough its spose to be.

 

why's that bud, is that what you paid for some time ago or previous owner said had been done.

smithy

Its one of the things done to the engine while it was rebuilt.

 

Had 3.1 bore, pistons, rods and the crank knife edged. Im really sure I would have noticed the knife edges. I did have a good look cause I've never seen one before, just read what its spose to be like.

 

All done by a previous owner.

this is a knife-edged crank of a Zed, so that's what it should look like:

 

Mines nothing like that :headvswal :headvswal :headvswal :headvswal

Well it depends allso on what amount has been taken off,theres a case for too much causing more larger counter weights neede to be added,material can allso be taken off in other areas of the crank but again theres a relibility issue.When i bought it (some time back now)i had no reason to doubt him,as why bother saying it was done if it was not,would be no gain from him,but then it depends how much was removed when edging it,best thing to do is to get a pic or an old crank off some one to compare,as to the bigger picture of things,knife edging the crank may make it cut through oil better causing slight less drag/windage/oil splash,but,does not mean its as reliable compared to stock crank.To be honest unless i was running huge power and looking for very quick 0-60 its not worth doing,and as by the time you try getting every ounce of power out of it it would prob break sooner or later,defo sooner than stock.

 

Tony

I might be wrong in this, but arent crank counter weights used to drag and splash oil into the piston bores to lubricate them. So if you knife edge them, you might gain 1-2 H.P., but won't the lack of oil in the piston bores cause premature failure of the piston rings and damage to the bore.

I might be wrong in this, but arent crank counter weights used to drag and splash oil into the piston bores to lubricate them. So if you knife edge them, you might gain 1-2 H.P., but won't the lack of oil in the piston bores cause premature failure of the piston rings and damage to the bore.

 

the block is fitted with squirters that direct oil to the underside of the pistons and bores ;)

 

the counter weights are also used to keep the crank/rods/bearings lubricated, aswell as the bores etc

 

i dont think knife edgeing a crank will gain any HP all it means is it will cut through the oil better and cause less drag

Deffo didnt see any signs of grinding, big or small.

Deffo didnt see any signs of grinding, big or small.

Mate i have a standard TT crank here off my old block if you want to come over one day and compare them ;)

Also did you manage to strip down the oil pump to find out what was causing the noise??

I have stripped two down this week too only to notice just like Greg said that the alloy back plate seems to wear alot even on low mileage pumps!

It looks like they are able to pick up any dirt from the sump as they only have a strainer to block large deposits but not fine material from damaging the pump!

The Pump then sends oil through the Oil filter!:(

It maybe a good idea to do an engine oil flush every now and then to make sure all the crap is removed from the Engine and Sump.

There was a little wear here and there, but not as much as I was hoping for!!!

 

Lets jsut hope that was the problem.

 

Im not too worried about the crank, only thing that went through my mind was, if that wasnt done, what else wasnt done that he said was done.