Supercharge it ...

How to upgrade your Austin...and further......
Big Daddy
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Re: Supercharge it ...

Post by Big Daddy »

Countryboy wrote:Should a centre bearing strap help prevent this ?
Yes definitely :!: 948 block is not very stiff so centre main strap or complete steel main cap help considerably. But modification is still worthwhile on a 1275 block :thumbs:
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gazza82
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Re: Supercharge it ...

Post by gazza82 »

Already sorted then ... :D
"If you're driving on the edge ... you're leaving too much room!"

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Cars: "Project 757" '59 A35 2-door bought in 1971 & Subaru BRZ SE LUX Auto plus "family fleet": Alfa MiTo, Peugeot 206, (Ex '98 Alfa Romeo 156 2.0 TS)
Chris T
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Re: Supercharge it ...

Post by Chris T »

My only two crankshaft failures both occurred in the last millennia in 948 engines while just cruising at fairly modest constant speeds - with fully warmed engines and sufficient oil - on dual carriageways. I'd have been travelling at around 65-70mph, so below 4,000 revs with the 3.9 diff fitted at the time (a 12G295 head provided some oomph to mitigate the apparent ratio mismatch).
I was able to limp the 30 miles home on the first occasion at tickover revs, but not the second. The first was found to have sheared across the webbing allowing the crankshaft to noisily continue its rotation.
On the second, I seem to recall that the engine would run, but without driving the flywheel, so a recovery truck took me home. On strip-down, the rear big-end journal was found to have ripped itself away the webbing. This was a recon crank and it was noticed that the journals had not been radiused at the webbing when cut undersize.
I presume that there was some sort of harmonic imbalance in the drivetrain to cause these failures, though I never got around to exploring that further.
Chris T.
400,000+ A30 miles in 40 years
Austins <=> sustAin
Big Daddy
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Re: Supercharge it ...

Post by Big Daddy »

Chris T wrote:This was a recon crank and it was noticed that the journals had not been radiused at the webbing when cut undersize.
Basic error which seems typical of so many machine shops... :roll:
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Hurtzberg
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Re: Supercharge it ...

Post by Hurtzberg »

Countryboy wrote:Should a centre bearing strap help prevent this ?
Less than a year ago you refused a strap-on but I see curiosity is getting the better of you.... :whistle:
Andrew

1957 A35
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David Swain
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Re: Supercharge it ...

Post by David Swain »

:rol:
David Swain. Member No. A1743
Contact for 'The Suffolk Group'.
Contact Email suffolk@austina30a35ownersclub.co.uk

A30 van 55 'R.G. Swain', A35 4 Door 59 'Little Gem', A35 2 Door 59 'The Rev' '+1'
Chairman
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Re: Supercharge it ...

Post by Chairman »

Jason Warren has a Shorrocks supercharger on his 1098cc twin carb A35 known as Jinxy....been on it for a few years now....however He is meticulous with thoroughly warming up his engines before giving them any welly and is fussy with his oil changes too.....
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Countryboy
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Re: Supercharge it ...

Post by Countryboy »

Hurtzberg wrote:
Countryboy wrote:Should a centre bearing strap help prevent this ?
Less than a year ago you refused a strap-on but I see curiosity is getting the better of you.... :whistle:
If you think I would be receiving one of those you are some kind of crank ! :lol:
Rest Home for rusty vehicles
Big Daddy
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Re: Supercharge it ...

Post by Big Daddy »

Countryboy wrote:If you think I would be receiving one of those you are some kind of crank ! :lol:
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