Alusil machining and refinishing
08-17-2009, 01:29 PM
#1
Man of many SIGs
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Alusil machining and refinishing
I contacted the manufacturer who developed the Alusil process for the automotive industry in the hopes that they could provide me with detailed machining and finishing info to supply to a machine shop. The company is Koebenschmidt in Germany. http://www.kspg-ag.de/index.php?lang=2 They offer a detailed manual for machinists on the proper proceedure for Alusil machining and refinishing. It is pretty inexpensive and I'm sure there are some here who need the info. It is available at http://www.christiani-tvet.com/produ...ds/powersearch
Your welcome
Your welcome
08-17-2009, 01:57 PM
#2
Rennlist Member
Just use one of these. It makes it a little easier. I just apply some silcon spray when im done. 
I contacted the manufacturer who developed the Alusil process for the automotive industry in the hopes that they could provide me with detailed machining and finishing info to supply to a machine shop. The company is Koebenschmidt in Germany. http://www.kspg-ag.de/index.php?lang=2 They offer a detailed manual for machinists on the proper proceedure for Alusil machining and refinishing. It is pretty inexpensive and I'm sure there are some here who need the info. It is available at http://www.christiani-tvet.com/produ...ds/powersearch
Your welcome
Your welcome
08-17-2009, 01:59 PM
#4
Rennlist Member
Im kidding! But the engine that was subjected to this light abuse for a few revolutions of the "destroyer", was perfect after a year of racing! (dodged a bullet, as it could have been a BIG problem)
(dodged a bullet, as it could have been a BIG problem)
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08-17-2009, 03:01 PM
#8
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"I contacted the manufacturer who developed the Alusil process for the automotive industry ..."
While this is perhaps technically correct, Koebenschmidt developed "Alusil", not the process of using high-silicon alloy to cast aluminum blocks. Alusil is a proprietary alloy developed mainly to avoid paying Reynolds royalties on Reynolds 390, the original alloy jointly developed by Reynolds and General Motors for Bruce McClaren's CanAm engines, then later used in the Chevy Vega engines.
"If the cap on the Washington Monument and the engine block of the Wright Brothers' first flight at Kitty Hawk are the two most significant aluminum castings ever produced, the engine block of the Chevrolet Vega represents the most significant series of aluminum castings ever produced. In 1969, General Motors introduced the Chevrolet Vega, which had an all-aluminum block with no cast-iron cylinder liners. The block was diecast using the Acurad process. The alloy was 390 (developed by Reynolds) with 16-18% Si, 4-4.5% Cu and the balance aluminum. The high Si content increased wear resistance by allowing primary crystals of Si to precipitate. Two-and-a-half million Vegas were produced during the car's life cycle. The Vega block was different from all the earlier cast blocks in that it had no liners. The success of the Vega block still is under review today and has led to further work on aluminum alloy engine blocks. "
While this is perhaps technically correct, Koebenschmidt developed "Alusil", not the process of using high-silicon alloy to cast aluminum blocks. Alusil is a proprietary alloy developed mainly to avoid paying Reynolds royalties on Reynolds 390, the original alloy jointly developed by Reynolds and General Motors for Bruce McClaren's CanAm engines, then later used in the Chevy Vega engines.
"If the cap on the Washington Monument and the engine block of the Wright Brothers' first flight at Kitty Hawk are the two most significant aluminum castings ever produced, the engine block of the Chevrolet Vega represents the most significant series of aluminum castings ever produced. In 1969, General Motors introduced the Chevrolet Vega, which had an all-aluminum block with no cast-iron cylinder liners. The block was diecast using the Acurad process. The alloy was 390 (developed by Reynolds) with 16-18% Si, 4-4.5% Cu and the balance aluminum. The high Si content increased wear resistance by allowing primary crystals of Si to precipitate. Two-and-a-half million Vegas were produced during the car's life cycle. The Vega block was different from all the earlier cast blocks in that it had no liners. The success of the Vega block still is under review today and has led to further work on aluminum alloy engine blocks. "
08-17-2009, 06:38 PM
#11
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I worked in a large Chevy service dept from '72 to '82. A Vega 'tune up kit' was 2 front fenders and a short block. I'm not kidding. I have no idea why our 928's are seemingly imune to the Vega affliction, but they seem to be. There was a field procedure for honing the blocks, but Chevy had so little faith in it that they paid for short blocks (in many cases, depending on lots of variables). It started with a head gasket failure - the block scored and the oil consumption reached one quart per 300 miles or so (with smoke). Once the gasket went they needed a block. The head was iron, BTW. The scores were easily seen and felt. I have no idea what the piston deal was as they never came out - blocks went in a shopping cart and back in parts for warranty return. The cars were OK by the standards of the time - nice steering wheels, shifted OK. Odd note - when originally shipped they were vertical, hence the new style batteries. This caused a strange problem on the '71's where a carb problem related to this vertical shipping caused a recall (little before my time, don't know details). It's a wonder to me that our cars are as good as they are considering the free standing bores and all.
08-17-2009, 06:43 PM
#12
Nordschleife Master
I would guess a big probelm with Vega was iron head combined with aluminum block. The different expansion coefs etc.
I worked in a large Chevy service dept from '72 to '82. A Vega 'tune up kit' was 2 front fenders and a short block. I'm not kidding. I have no idea why our 928's are seemingly imune to the Vega affliction, but they seem to be. There was a field procedure for honing the blocks, but Chevy had so little faith in it that they paid for short blocks (in many cases, depending on lots of variables). It started with a head gasket failure - the block scored and the oil consumption reached one quart per 300 miles or so (with smoke). Once the gasket went they needed a block. The head was iron, BTW. The scores were easily seen and felt. I have no idea what the piston deal was as they never came out - blocks went in a shopping cart and back in parts for warranty return. The cars were OK by the standards of the time - nice steering wheels, shifted OK. Odd note - when originally shipped they were vertical, hence the new style batteries. This caused a strange problem on the '71's where a carb problem related to this vertical shipping caused a recall (little before my time, don't know details). It's a wonder to me that our cars are as good as they are considering the free standing bores and all.
08-17-2009, 07:55 PM
#14
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Tuomo is right, the iron head was the big problem- Every other engine using high silicon aluminum blocks with aluminum heads worked fine. The cylinder-finishing procedure developed by Reynolds is still the primary method in use for re-finishing today. I believe the manufacturers use a chemical etch because its much quicker procedure, but not easy to duplicate in a machine shop.
