Urgent technical note: Regrinding of 2L Fiat/Lancia cranks

Crank, rods, sealing, pistons, block, flywheel etc
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Guy Croft
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Urgent technical note: Regrinding of 2L Fiat/Lancia cranks

Post by Guy Croft » Mon Oct 12, 2009 11:58 am

As I have emphasised over_and_over you must NEVER regrind the 2 liter Fiat Lancia cranks from any model!

If you do all the nitrided layer will be removed and the relatively soft core material En40B will be exposed. Minute debris will embed in the bearings and tear the crank to pieces.

I have just such an example in my works at_this_time and in less than 1000miles since build (not by me..) the crankpins are worn way under bottom limit and the mains too. In fact the centre main has suffered catastrophic bearing failure and thismay well be the cause since it is the most highly loaded of the main journals. This can happen way quicker than 1000 miles, I have seen it happen within hours.

Time and again I have demonstrated at GCRE while the client is watching how it is possible to file the journal in that soft state with needle file - something not possible on the crank in its original state.

Regrind? Never_never-never!

Not to fit 'Chevy rods' or non OE sized bearings or as part of a routine overhaul or for_any_other_reason.

These cross-drilled cranks MUST be unplugged and oilways cleaned out after even light carborundun polishing or grinding/drilling during balancing because the risk of entrained metallic debris (dust etc from metal removal) in the sludge in the oilway connecting the mains and crankpins is unacceptably high. The only exception might possibly be cleaning the crank with fine Scotchbrite but that is IT!

If you're crank is worn undersize your only option is to get hold of a good used one and if you, dear reader, have any I am constantly in need of them week after week.

See also relevant article at: http://guy-croft.com/viewtopic.php?f=13&t=2027

GC
Attachments
crank sludge.jpg
This is what's in there - or some of it anyhow - consistency of graphite - and yes, that IS a magnet and the sludge is highly magnetic so I'll leave you figure out what it consists of ...
crank sludge.jpg (118.49 KiB) Viewed 6802 times

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