S4 Crankshaft/engine block

donistook · 07-27-2002, 11:21 AM

I am freshening one of our race motors and I thought you guys might like to see a few things. You will note on the crankcase picture that the S4 uses four bolt main bearing caps, as does the RS4. The 2.8 A4 engine only uses two bolt main bearing caps. this gives a stronger, higher reving capabilities to the engine. If you look at the top of the picture, you will see the crankshaft rod journal bearing surface is offset between opposing cylinders, i.e., cylinders 1 and 4 oppose each other, but they use the same rod journal on the crankshaft. If you look, you will see that the rod journal surface is offset, allowing the rods to run at different angles.

The link is to a picture of the lower end of the forged connecting rod showing you how the rod is cracked versus machined where the upper and lower section of the rod comes together. This "Crack" gives a stronger surface to bite onto when the rod ends are mated together and torqued...allowing for less movement.

Don Istook

http://pictureposter.audiworld.com/1510/mvc-380s.jpg

donistook · 07-27-2002, 11:34 AM

I am freshening one of our race motors (we have three of them) and I thought you guys might like to see a few things. You will note on the crankcase picture that the S4 uses four bolt main bearing caps, as does the RS4. The 2.8 A4 engine only uses two bolt main bearing caps. The four bolts give stronger, higher reving capabilities to the engine. If you look at the top of the picture, you will see the crankshaft rod journal bearing surface is offset between opposing cylinders, i.e., cylinders 1 and 4 oppose each other, but they use the same rod journal on the crankshaft. If you look closely, you will see that the rod journal surface is offset, allowing the rods to run at different angles.

The link is to a picture of the lower end of the forged connecting rod showing you how the
rod is cracked versus machined where the upper and lower section of the rod comes
together. This "Crack" gives a stronger surface to bite onto when the rod ends are mated
together and torqued...allowing for less movement.

Don Istook

http://pictureposter.audiworld.com/1510/mvc-380s.jpg

System_S4k · 07-27-2002, 12:37 PM

s4what? · 07-27-2002, 12:43 PM

Singletrack · 07-28-2002, 12:41 PM

07-27-2002, 11:21 AM	#1
donistook Junior Member Account #: 1510 Join Date: Mar 2000 Posts: 660	S4 Crankshaft/engine block I am freshening one of our race motors and I thought you guys might like to see a few things. You will note on the crankcase picture that the S4 uses four bolt main bearing caps, as does the RS4. The 2.8 A4 engine only uses two bolt main bearing caps. this gives a stronger, higher reving capabilities to the engine. If you look at the top of the picture, you will see the crankshaft rod journal bearing surface is offset between opposing cylinders, i.e., cylinders 1 and 4 oppose each other, but they use the same rod journal on the crankshaft. If you look, you will see that the rod journal surface is offset, allowing the rods to run at different angles. The link is to a picture of the lower end of the forged connecting rod showing you how the rod is cracked versus machined where the upper and lower section of the rod comes together. This "Crack" gives a stronger surface to bite onto when the rod ends are mated together and torqued...allowing for less movement. Don Istook http://pictureposter.audiworld.com/1510/mvc-380s.jpg

07-27-2002, 11:34 AM	#2
donistook Junior Member Account #: 1510 Join Date: Mar 2000 Posts: 660	Re: S4 Crankshaft/engine block I am freshening one of our race motors (we have three of them) and I thought you guys might like to see a few things. You will note on the crankcase picture that the S4 uses four bolt main bearing caps, as does the RS4. The 2.8 A4 engine only uses two bolt main bearing caps. The four bolts give stronger, higher reving capabilities to the engine. If you look at the top of the picture, you will see the crankshaft rod journal bearing surface is offset between opposing cylinders, i.e., cylinders 1 and 4 oppose each other, but they use the same rod journal on the crankshaft. If you look closely, you will see that the rod journal surface is offset, allowing the rods to run at different angles. The link is to a picture of the lower end of the forged connecting rod showing you how the rod is cracked versus machined where the upper and lower section of the rod comes together. This "Crack" gives a stronger surface to bite onto when the rod ends are mated together and torqued...allowing for less movement. Don Istook http://pictureposter.audiworld.com/1510/mvc-380s.jpg

07-27-2002, 12:37 PM	#3
System_S4k Elder Member Account #: 23081 Join Date: Jul 2001 Posts: 18,116	Mmmmm.... Car porn. :) __________________

07-27-2002, 12:43 PM	#4
s4what? Member Account #: 30356 Join Date: Jan 2002 Posts: 2,303	Love it - keep it coming __________________ Engine Simulator Dahlback Stage 3, other stuff If you live in the NYC Metro area you NEED aftermarket security - if you don't have it WILL be stolen

07-28-2002, 12:41 PM	#5
Singletrack AudiWorld Super User Account #: 25380 Join Date: Sep 2001 Posts: 16,037	Cool! I've never seen that before - thanks. __________________ 2008(9?) S5 - ordered 3/29/08 2004 Subaru Impreza WRX STi 2000 A6 2.7T - Sold "On the run from Johnny Law; ain't no trip to Cleveland."

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