[Staowners] Alpine Engine Questions

[Bob Hamilton]

Hi Joellin,

Good to hear from you again and that you are still working on the Alpine.

I totally agree with what Ian just wrote and confirm the interference 
fit of .0003" at the small end to the pins. I have accomplished 
fitting the rod, pin and piston by using a hair dryer to heat the 
parts up (well oiled) instead of an oil bath as suggested in the shop 
manual. Definitely do not press them together cold.

Another important point is that there is a very small oil hole on the 
big end that is there to spray oil onto the thrust side of the 
cylinder wall. Other than this oil hole, the rods are symmetrical and 
it is possible to assemble them 180 degrees out with this oil hole 
lubricating the wrong side, as I did 10 years ago and just corrected 
last December. I knew it was assembled incorrectly about a week after 
doing it in 1996 but chose to run the engine this way for the past 10 
years and it hasn't adversely affected the engine as far as I can 
see. The thrust side is the right side of the cylinder wall if you 
are sitting in the car.

There are no liners in these engines but there were (are?) oversized 
pistons available in increments of .010" up to a maximum of .040".

Hope this helps.

Later,
Bob



At 10:20 PM 2/15/2007, Captain Ian L. Moist wrote:
>Joelin
>
>I  rebuilt A Mk III  motor and an Alpine Special Motor  back in the 1970's,
>And owned and ran 5 STs over a period of  about 15 years.
>
>The connecting rods are made of duralumin which is basicically an alloy rod.
>
>The little end bore in the rod was precision reamed in manufacture to  render
>a three thousandth of an inch interference fit on the gudgeon pin in 
>the piston.
>
>Because the coefficient of expansion of the duralumin rod  is above 
>that of the steel
>gudgeon  pin, it is a 'pinch' when cold, but as the engine warms up 
>to operating
>temperature, (  170 F)  it becomes a free sliding fit with oil fed 
>under pressure into the
>'X" swirl-ways.
>
>If the gudgeon pin can be pushed into the conrod when cold, it may 
>well give rise
>To little end knock when the engine is assembled  warmed- up, and  under load.
>
>The old way of assembly and de-assembly was to heat the piston and rod up
>In a bath of oil and slide the gudgeon pin into place.
>
>Some bolt butchers have bashed the pin in or out when cold, and that does
>not do such a fine piece of engineering any good.
>
>I have never seen a liner fitted in the 2,267 cc motor . The engine 
>is very sturdy
>And virtually unbreakable unless it runs out of oil or water. 
>Probably the weak
>Point of the bores and the limit to what can be achieved, is the amount of
>Metal existing between  bores  1 & 2  and  3 & 4. Like other Rootes motors,
>The original design usually ended up being progressively bored  in manufacture
>As new models were introduced to give that little extra.
>
>Hope this gives you some perspective.
>
>Ian L Moist. ( Aus)
>
>
>
>
>----------
>From: staowners-bounces at sunbeamtalbot.info 
>[mailto:staowners-bounces at sunbeamtalbot.info] On Behalf Of scoobyjo at comcast.net
>Sent: Friday, 16 February 2007 7:57 AM
>To: staowners at sunbeamtalbot.info
>Subject: [Staowners] Alpine Engine Questions
>
>I'm starting to work on the engine for my '54 Alpine and have a few questions.
>
>Aluminum Connecting Rods
>1)  How duable are the aluminum rods?  I don't know the history of 
>the engine, so I'm not sure how many miles are on it.
>2)  Can the rods be checked and reused?  Or am I better off replacing them?
>
>Cylinder Liners
>3)  Can the cylinder liners be bored or do they need to be 
>replaced?  If they can be bored, what is the maximum?
>
>Replacement Parts
>4)  For those that have already rebuilt their engines, do you have 
>any suggestions regarding replacement parts?  Suppliers?  Alternatives?
>
>I appreciate any help you can provide.
>
>Joellin
>_______________________________________________

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Robert (Bob) A.C. Hamilton, Waverley, Nova Scotia, Canada
Sunbeam Talbots - Alpine, Drophead and Saloon, 1953-1954
Sunbeam Talbot Web Page: www.sunbeamtalbot.info (or .org)
E-Mail: hamilton at accesswave.ca or robertach at ca.inter.net
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  

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