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914World.com _ 914World Garage _ Feeling Cranky....
Posted by: wndsrfr Jan 12 2012, 08:04 PM
Sooo....with the P&C's off to do a simple bump up in CR with thinner shims, I
contemplated going ahead to crack the case and replace the main & rod
bearings since I was this far along. Well, lo and behold, as I got the
crank out it looked like one of my gray hairs had fallen down on the
journal.....wait a minute, there's another one---OMG, there's cracks on
this thing!! Take a look at the pics--surprising that the thing didn't
let go completely! I didn't even need a magnaflux...could see them with
the naked eye--I put a bit of white paint on & rubbed it off to
highlight the cracks for the pics.....ain't this a hoot?
Attached image(s)
Posted by: Valy Jan 12 2012, 08:18 PM
The nice thing about those welded cranks is that you can always predict this will happen.
Make sure you get a NEW one and not a rebuilt one.
Posted by: windforfun Jan 12 2012, 08:33 PM
Posted by: saigon71 Jan 12 2012, 08:47 PM
Man that's a rough beat...but it could have been a lot worse down the road.
I knew a guy years ago (not a bullshit guy either) who said he was still running a type 1 case that had never been split with 225K miles, top end rebuilt twice with no problems. So I thought I could get possibly get away with a top end rebuild when needed.
This thread makes me think twice...unless you know exactly what's in there after 35 years. 
Posted by: ThePaintedMan Jan 12 2012, 09:33 PM
Man that's a rough beat...but it could have been a lot worse down the road.
I knew a guy years ago (not a bullshit guy either) who said he was still running a type 1 case that had never been split with 225K miles, top end rebuilt twice with no problems. So I thought I could get possibly get away with a top end rebuild when needed.
This thread makes me think twice...unless you know exactly what's in there after 35 years.
Yikes! Goooood save!
Posted by: SUNAB914 Jan 13 2012, 08:27 AM
Good info! makes me think twice about my next rebuild.
Posted by: Dr Evil Jan 13 2012, 05:32 PM
Attached image(s)
Posted by: 76-914 Jan 13 2012, 05:52 PM
Doc, your beginning to worry me.
Posted by: majkos Jan 13 2012, 05:55 PM
Doc, your beginning to worry me.
Posted by: yeahmag Jan 13 2012, 10:21 PM
Yikes! What crank is that?
Posted by: wndsrfr Jan 14 2012, 08:45 PM
Yikes! What crank is that?
It's an 80mm stroked VW crank with counterweights welded on....something like 5 years old but with relatively little mileage on it. 6 DE events this past summer & fall put a bit of stress on it--lets see...three 30 minute sessions per day, 13 days in all, maybe averaging 60-70mph at VIR, CMP, SUmmit Point.....maybe something like 1300 miles of HARD driving might have something to do with it, eh? Oh, yeah, something like 7000 miles on the street in the same time period....who knows?
Posted by: Jake Raby Jan 15 2012, 02:20 AM
Detonation can lead to this.. It is perfectly in line with the other modes of failure that your engine has exhibited. Not saying that's the only thing that leads to this, but it is a serious contributor. The tuning issues tht plagued the car when you bought it could have been impacting the crank even before you bought the car.
We have used and sold north of 1200 of these crankshafts. Of those 2 have failed and two more have had cracks form that were caught before they failed completely.
I'd like to see this one and try to force it to break to see where the weakest spot actually is.
Posted by: PeeGreen 914 Jan 15 2012, 03:23 AM
I bet he'd sell it to you 
Posted by: stewteral Jan 15 2012, 12:22 PM
Sooo....with the P&C's off to do a simple bump up in CR with thinner shims, I
contemplated going ahead to crack the case and replace the main & rod
bearings since I was this far along. Well, lo and behold, as I got the
crank out it looked like one of my gray hairs had fallen down on the
journal.....wait a minute, there's another one---OMG, there's cracks on
this thing!! Take a look at the pics--surprising that the thing didn't
let go completely! I didn't even need a magnaflux...could see them with
the naked eye--I put a bit of white paint on & rubbed it off to
highlight the cracks for the pics.....ain't this a hoot?
Hey Windsurfer,
To my mind, you should a VERY happy guy: you found the bad crank BEFORE it blew your engine apart!!
As far as still running while broken: It's always AMAZING! I tore down a Ford 260 V8, years ago, that had 4 pistons with fractures right across the top of the crowns.
When removed, they fell apart, and yet the engine ran fine before the tear-down.
Sometimes the gods of engine bits smile on us.
Best,
Terry
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