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Regrind a V8 Crankshaft

Engineering excellence.

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Steviegtr21/08/2021 17:28:01
2244 forum posts
311 photos

This guy is a pro. Regrinding a V8 crankshaft. The setup is enormous for the work to be carried out. If you have no interest in automotive , it's still worth a watch for the setup alone.


V8 Crankshaft grinding

Chris Evans 621/08/2021 19:37:10
1960 forum posts

SKILL ! kind of job where you could hold a bus ticket between a%%se cheeks. Thanks for the link.

noel shelley21/08/2021 22:24:25
770 forum posts
19 photos

As Steve has said ! A really skilled man who knows and understands what he is doing. Off set grinding to bring all throws to the same stroke length ! Very Good, thankyou ! Noel.

Emgee21/08/2021 23:27:45
2161 forum posts
265 photos

As others have said, excellent workmanship and dedicated to the work.


Howard Lewis22/08/2021 11:03:37
5346 forum posts
13 photos

Grinding crankshafts is a task that really involves knowing what you are doing, and having the equipment to do it properly..The grain of the wheel and the relative speeds of the work and grinding wheel have be held within fairly close limits.

If the primary surface finish is incorrect, the bearings will fail. Our spec was 16 u inch CLA MAXIMUM,

And secondary surface finish affects bearing life very greatly, if only by controlling the size of the leak path for the oil. The primary function of which is to cool, with lubrication as a secondary purpose. If the bearing temperature is too high the composition of the alloy of the bearing metal changes, and can lead to failure.

(On marine main propulsion engines main bearing temperatures are monitored more closely than oil pressure ).

At 18 CLA the bearings began to mark. At 22 CLA they failed and ruined the Con Rod, Block and Crank.

This provides a copious supply of fag paper thin blued steel, and decorates what is left of the block with sparking white metal!

Get the web radius wrong and a fatigue failure very soon follows..

Broaching of the bearing shells has to be very closely controlled, or that can be another cause for bearing failure.

Main and Con Rod bearings are very highly stressed by inertia loads, which exceed gas loads at high engine speeds, so things HAVE to be right!


Crankshaft grinding is like marriage, not an undertaking to entered into lightly!

Howard (This wireless keyboard can't keep up with even my slow typing speeds! )

Edited By Howard Lewis on 22/08/2021 11:04:38

Neil A22/08/2021 23:50:42
101 forum posts

Re-grinding a crankshaft is a real art. The absolute skill lies with the man on the grinder.

Having watched the re-grinding of an over 6 foot long fully nitrided 8 throw crankshaft, the sight of the pins being ground and the whole shaft swinging off-centre is really impressive. The care that has to be taken to ensure that the metal is not overheated and cracked at the transition from the soft newly ground surface into the hard nitrided fillet radius is not for the faint hearted.

Depending how much the undersize was, sometimes the fillet radii would need to be re-formed as well.

Having successfully avoided creating heat cracking, the shaft could then be re-nitrided and be fit for further use. In the 1980's and 1990's re-grinding a crankshaft was undertaken on a regular basis. It has to be said though, that not every shaft was successful, but at a cost in excess of £15000 pounds for a new shaft at the time, it was worth the effort.

All I had to do was put the numbers on the drawing, that was the easy part.


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