Maybe you should just be quiet now - you know, given you're supposed to be a mod and diffuse situations, not cause them.

to be fair mate, Begbie gave you a real life experience on how a none hardened (giggady) crank will dent with out a lot of force... and a hardened one will not.. giving you a good example of the safer bet.

be it a 16vt/20vt ect

the last thing you want to happen is build a N/A monster and shortly after have the bottom end rattling out.

in my experience, go for the best you can get, and in this situation, get a none ground crank.

the otehr main question is.. would you want to risk it?

I think maybe you should take a bit of the advice you're so freely issuing here Nedge! I've read this whole thread and while I agree Begbie was a little short with his reply, it's you that now needs to show some restraint.

Back on subject now please guys.

hence the whole reason for the thread

NONE RELATED TO 20V CRANKS:

My 2.0 TS Suffered from a HUGE crank failure but didnt crack... re-ground 20 though' and used appropriate bearings to suit, 10k miles to this day and all driven hard, no isses.

good to know, cheers

Odd test tbh, besides which unless you used tool steelm, hardened or similar i find it hard to see how a proper whack with a centre punch wouldnt leave an impression at all. If that were the case rockwell measurements would ne very difficult to carry out without an impression to measure!

A conventional way to identify surface hardening is with a blunt file on a non bearing journal surface. Simply put unhardened 'grips', hardened slips.

Could you elaborate on your "another reason"?



How did you come to that conclusion?
Could you elaborate on the test results what HV did you obtain? Did you do a Rockwell test? Did you test all five journals? Was the crank tested brand new or used?

Just read this. lol
That's NOT a Vickers test, that just sounds like you you scraped a file across the journal and saw no marks so it will be ok. Hardly an "Investigation". If somebody wants me to test a 20V crank i can put in in our metallurgy department, don't expect it back in working order.

Neither ACL nor Mahle/Vandervell do race bearings for the 20v engines. Glyco are fine for the mains but not for the ends - not sure about the OE ones but unless they're cast tri-metal, not trying them.

The plan was to use C20XE +0.75mm bearings and have my rods made to suit - crank would have needed a polish but thats about it. As it turns out, they only go to +0.50mm which leaves me short so I'm considering grinding about 0.3mm off the end journals and using Audi 5-pot bearings.

Anyway, with the XE bearings, imagine I would have been fine. With the Audi's, will need re-hardening.

actually it is, granted not vickers or rockwell but the file scrape will tell you if it is hardened

With respect talk like that warrants digging deep into your pocket for a custom crank.

Aftermarket parts were never made for this engine because there was never a racing series with a Fiat 5 pot.

Why do you want "race bearings"?

You would risk grinding your crank to buy shells to protect your crank sounds like a paradox

I think you are treading on thin ice "frakenstiening" an engine together.

Nevertheless good luck

Equotip / Niton tester will let you know....

Equotip is invasive, Niton tester is not.

Cheers, will look into that.

All in good time.

Right, found another bearing that only requires polishing 0.0013-0.0017" off so even if the nitiride layer is, as suggested by GC for the twin cams, 0.005" thick, that's more than acceptable

I'd suggest OE bearing will be absolutely fine for what you are building, needing only a good lubrication system regular oil changes, clear galleries and oilways, radiused oilways, correct oil, correct oil/engine running temps and constant oil feed will be the items which ensure that metal metal contact won't occur.

TurboJ i'm with you on that one, sounds like the chevvy bearing fiasco in 4pots.

it's 1-2 thou, it's fine. if it goes bang, shit happens. i'd rather try something new than stick my head in the sand.

Had 2 engines fail within a thousand miles of having them built by a local engine builder.

Regrinding of the cranks is a grey area but is widely used as a good solution to an expensive problem.
Average grinding cost is around £100,average crank is around 10 times that.

The failures i had were down to the fact the company used top limit shells on a bottom limit crank.
So the oil gap wasnt big enough.
In static rotation on a bench you can use very tight shells and the engine will turn over nicely.But running in the car its a different story.

Grinding the cranks on these has always got people in to trouble but in my opinion grinding the cranks doesnt cause failure.
The shells are hard to come by these days so most people will risk whichever Fiat or OE parts supplier send them.

A ground crank may significantly reduce the life of the crank in terms of the wear rate but it would still do circa 100k easy enough even without the Nitri-coating.

+1......

I just spoke to Farndon Engineering who manufacture steel cranks and do nitriding, regrinding etc

They nitride to 0.6 mm depth and say their cranks can have three re-grinds before needing re-nitriding. They said that nitriding done by an OEM would be a typically be at least 0.5mm. Nitriding can be upto 2mm thick if desired.

Good news is, Farndon will regrind AND re-nitride your crank for typically £175-£200. Much cheaper than a new one.

There is only one F in Farndon

???This procedure was supposed by the metallurgist in my laboratory, a professor for metallurgy...
A quick method to detect a surface treatment anyway.
This test was done with a precise hardness test machine.
The Nitide surface has a size of max. 100um, according to my prof.
Therefore we grinded away some of the surface in an inconsiderable area and repeated the test, result no changes in Vickers...
In my eyes a very good test!

That must have been a re-ground crank already? That's 0.001mm / 0.00003937"!!

Anyway, cheers for all the input guys, will all be worth it in the end

(sneaky peaky...)

haha, so it is, dunno where i got that from!

I had a brand new crank on top limit,and Joe 78 had a ground crank on bottom limit.We got them both hardness tested and they were identical.So i agree with Stichl.
I cant quote figures as it was two years ago.

cheers jbt

like what i've done with your manifold btw?

Nedge didnt realise your a L,boro chap.
Have i seen you before?