HELP! I-5 crankshaft end-play problem

[Cody]

Thats almost exactly what I was going to say. Our race motors get rebuilt every 20 hours, but can go about 40. Much past that and you are pushing the rod bearings and better pray you don't spin one. Even at the 24 hours of Daytona last weekend in 24 hours, 1 minute, 47.035 seconds the winning car ran "only" 1,873 miles. Add in maybe an hour on the dyno to break it in. Thats an acomplishment for a race car, but does that sound special in a street car? Last season the Champion R8 actually re-used a motor after a 24 hour race. They actually ran the same motor at Le Mans as they did at the following race in Atlanta (a 3 hour which they won). After the race at Atlanta though I watched the Audi engineers were doing thier post race inspection (always fun to watch them dissasemble the thing halfway to the nare tub!) and found the motor to be shot. One of them remarked to me that he was surprised that it actually lasted. Race motors are race motors, street motors are a different ball!
 game. 

My opinion sticks with sanding coating of of bearings is bad, but if you want to try it out it's your descision. This is definately going to be a situation where once you get this in a car running you are going to want to do a proper break in and change the oil early. When you change the oil that first time look super close for copper shavings in the oil. Steel is after all harder then copper, especially the alloys used for a crank, so I would say if anything is wearing on anything it would produce a bit of copper shavings.

-Cody Forbes
Black Forest Racing
http://www.500tq.com
'86 5ktq
'87 5ktq EFI/K27
'88 80 4cyl
'88 90 4cyl


---------- Original Message ----------------------------------
From: Kneale Brownson <knotnook at traverse.com>
Date: Thu, 05 Feb 2004 06:17:10 -0500

>Isn't a "race" engine, as in an Indy car for example, something that gets
>rebuilt after 500 or so stressful miles?  I sure wouldn't use "race" engine
>building practices as the way to go in a car I want to drive 100K miles.  
>
>At 11:37 PM 2/4/2004 -0500, Ameer Antar wrote:
>>Thanks for responding guys. I too am normally on the cautious side, 
>>especially since I have no real experience rebuilding bottom-ends. I took 
>>the bearing shells over to the race shop and talked with the owner. I told 
>>him how everything now has the perfect clearance, but my concerns over 
>>having the copper showing. He told me he sands the thrust bearing shells for 
>>all the engines he builds. He's been in the race engine business for over 20 
>>years and never had a problem with that. He even showed me a race engine he 
>>was building that had the copper showing on the thrust surfaces of the 
>>bearing shells.
>>
>>At first, I was a little worried myself, but now with all his assurances and 
>>experience, I'm going to go with it as is. I figure if a race engine, which 
>>will see much more rpm's than mine ever will, can handle sanded bearings, 
>>mine will too. Now that I think about all those metals, copper is a bit 
>>harder (not much) than the babbit coating on the shells, and the original 
>>thrust washers are some sort of steel, so actually the OE design dictates an 
>>even harder surface than babbit or even copper. I guess that means w/ the 
>>new design there will be more wear in the bearing shell thrust surfaces than 
>>the crank's. I guess thrust surface wear is not a huge issue... certainly 
>>not as big an issue as journal surface wear which directly affects oil 
>>pressure. I hope everyone knows I only sanded the thrust surfaces on the 
>>side and not the journal surfaces of the bearing. The shop owner did the 
>>machining on the bottom-end, and he's guaranteeing it. So, doing this is 
>>sorta like doctor's order
>> s. I'm planning on running the motor in this body for a while, then 
>>transplanting it to a nice clean quattro shell (if there is such a thing) 
>>when funds and a good opportunity turn up. So I guess I'll found out how 
>>much difference in wear there is then. I really appreciate all the advice 
>>and concern; really shows people care on this list... I'll be sure to let 
>>you know of any future troubles.
>
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