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Valve reseating
#1
I need the valve seats recut and new inserts fitted in my Austin big7 engine block. Can anyone recommend a workshop to do this please.
Many thanks[Image: huh.png]
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#2
Where are you, P J?
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#3
(13-03-2018, 02:21 PM)P J Quinn Wrote: I need the valve seats recut and new inserts fitted in my Austin big7 engine block. Can anyone recommend a workshop to do this please.
Many thanks[Image: huh.png]

I know of 2 Austin Eight blocks which are available. Could it be that they are the same? Surely someone knows, but I have never had a Big Seven or an Eight.
Robert Leigh
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#4
As I mentioned in an earlier post, the pistons of the 'Big Seven' and the 'New Eight, CR 6.8 to 1' - 1937 to 1948 are the same - Hepolite RS7665 with a bore of 2.235". Without knowing for certain having similarly not owned either model, it's possible the blocks are the same. Robin Taylor of Austin Big 7 Spares would presumably know if they are - robin.e.taylor@talktalk.net
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#5
(13-03-2018, 05:28 PM)Robert Leigh Wrote:
(13-03-2018, 02:21 PM)P J Quinn Wrote: I need the valve seats recut and new inserts fitted in my Austin big7 engine block. Can anyone recommend a workshop to do this please.
Many thanks[Image: huh.png]

I know of 2 Austin Eight blocks which are available. Could it be that they are the same? Surely someone knows, but I have never had a Big Seven or an Eight.
Robert Leigh
I have an Austin Big Seven and have just done a valve grind and recut the seats- quite easy if you have one or buy a cutter. My valve springs were all different lengths so bought a new set. Inlet valve stems were also worn so bought a new set but originals are not available so Robin supplied the nearest alternative and I had to have the width turned down a bit.if the engine is in situ it's a real pig to get the collets back in position. Had to glue them to a pair of wire strippers in the end.
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#6
(13-03-2018, 02:21 PM)P J Quinn Wrote: I need the valve seats recut and new inserts fitted in my Austin big7 engine block. Can anyone recommend a workshop to do this please.
Many thanks[Image: huh.png]

PJ, Where about are you? I know a good engineering workshop in the south east that does them cheaply but not much help if you're miles away in the north or west!!
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#7
Wondering why the original poster is considering valve seat inserts? assuming that's what he means.

If the problem is just that the valve seats are sunk into the block, a light skim will narrow the seats quite markedly without the risk of the pistons coming out the top of the block if the block is as it left the factory.  A skim should be a lot cheaper than the installation of a set of hard inserts.

The seats form  the hypotenuse of a virtual triangle, so every 10 thou' off the block  face will be just over 14 thou' off the seat width with any 45° valve setup- Certainly can't see that hard seat inserts would be necessary in any low revving motor with relatively light valve seat pressure.
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#8
(20-03-2018, 11:18 PM)Stuart Giles Wrote: Wondering why the original poster is considering valve seat inserts? assuming that's what he means.

If the problem is just that the valve seats are sunk into the block, a light skim will narrow the seats quite markedly without the risk of the pistons coming out the top of the block if the block is as it left the factory.  A skim should be a lot cheaper than the installation of a set of hard inserts.

The seats form  the hypotenuse of a virtual triangle, so every 10 thou' off the block  face will be just over 14 thou' off the seat width with any 45° valve setup- Certainly can't see that hard seat inserts would be necessary in any low revving motor with relatively light valve seat pressure.
Worth remembering that valve seat recession is unlikely to be much of a problem when using modern non leaded fuel.....no lead in the fuel back in the day! Damage or other degradation will need re grinding or cutting of course.
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#9
(21-03-2018, 09:35 AM)David.H Wrote: Worth remembering that valve seat recession is unlikely to be much of a problem when using modern non leaded fuel.....no lead in the fuel back in the day! ...

But don't forget, once upon a time regrinding the valves was a regular maintenance routine; my father reckoned on doing it twice a year when he was doing around 10,000 miles per year!
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#10
(21-03-2018, 10:28 AM)Mike Costigan Wrote:
(21-03-2018, 09:35 AM)David.H Wrote: Worth remembering that valve seat recession is unlikely to be much of a problem when using modern non leaded fuel.....no lead in the fuel back in the day! ...

But don't forget, once upon a time regrinding the valves was a regular maintenance routine; my father reckoned on doing it twice a year when he was doing around 10,000 miles per year!

I'll remember that as I clock up 10000miles this year!!
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