Re: MASH\'S APEX 550 STROKER
The metal sheath that is installed over the front of the crankshaft is called a crankshaft sleeve. It’s there to create a better and tighter seal of the front oil seal, and we use them all the time. It’s a perfectly acceptable way to ensure the best seal possible, and it did cover the extended portion of the keyway. The crankshaft was not defective and the crankshaft sleeve was not negatively affecting performance or reliability one bit.
A few hours ago, I got off the phone with two different Extrude Hone technical representatives. According to both Rick Miller (Extrude Hone-Pennsylvania) and Ed Melendez (Extrude Hone-California), the Extrude Honing media is like silly-putty with salt in it. The putty is pushed through under high pressure, in effect carving out the inside. The process does not produce metal shavings. Instead, it produces small metallic particles that are absorbed into the media and suspended in it, even as the media is removed.
They both said that Extrude Hone’s cleaning procedure is extremely stringent. As with other parts, they clean the Viper manifolds using high-pressure air blasts with solvent, and they haven’t had issues with residual media. In fact, they even check every manifold inside with boroscopes, which surprised me. Because the media is recycled, 99.9% of it is reclaimed from the part that they’re honing, and they monitor that percentage carefully. And both of their opinions are that if a small pocket of residual media were to be trapped somewhere, it would be blown out the exhaust valves almost immediately upon fire-up (i.e. in the first two minutes), as it doesn't stick to the metal. There would definitely not be enough left to cause scoring of the cylinders, especially after as many miles were put on the motor.
I emailed them the pictures I received, and after viewing them, they said they were inconclusive. They also said that because the engine had been opened up twice, there would certainly be reasonable doubt, and it would be impossible to say exactly what did cause the scoring. And each of the reps said that you all are welcome to call them to verify what they told me.
We’ve Extrude Honed probably 100 Viper and Mustang manifolds in the seven years we’ve been in business and haven’t seen any mentionable residual material from the extruding process.