X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m23.mx.aol.com ([64.12.137.4] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1020841 for flyrotary@lancaironline.net; Fri, 24 Jun 2005 17:16:57 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.4; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m23.mx.aol.com (mail_out_v38_r1.7.) id q.2b.75d6aa0b (15862) for ; Fri, 24 Jun 2005 17:16:07 -0400 (EDT) Received: from mblk-d47 (mblk-d47.mblk.aol.com [205.188.212.231]) by air-id06.mx.aol.com (v106.2) with ESMTP id MAILINID61-3df642bc781722d; Fri, 24 Jun 2005 17:16:07 -0400 Date: Fri, 24 Jun 2005 17:16:07 -0400 From: wrjjrs@aol.com Message-Id: <8C74719120C3BF4-B54-2F99@mblk-d47.sysops.aol.com> X-MB-Message-Source: WebUI X-MB-Message-Type: User Received: from 66.127.99.234 by mblk-d47.sysops.aol.com (205.188.212.231) with HTTP (WebMailUI); Fri, 24 Jun 2005 17:16:07 -0400 X-Mailer: AOL WebMail 1.1.0.12781 Subject: Engine Rebuilds and turnover torques Content-Type: multipart/alternative; boundary="--------MailBlocks_8C74719120C3BF4_B54_300B_mblk-d47.sysops.aol.com" MIME-Version: 1.0 To: flyrotary@lancaironline.net X-AOL-IP: 205.188.212.231 ----------MailBlocks_8C74719120C3BF4_B54_300B_mblk-d47.sysops.aol.com Content-Type: text/plain; charset="us-ascii" Ok Group, Most engines have a predictable torque for turnover in a "like-new" rebuild. We should check with Mazda to see if they have a suggested new engine turnover torque. When I was building racing engines the manufacturers had VERY specific suggested torques, and if your engine didn't meet spec they (cosworth in this case) suggested you tear it back down to find out what the problem was, or risk engine damage. !!! Warning Anecdote alert !!! One of the engines I regularly rebuilt for racing was the Kawasaki Z1-B 903cc 4 cylinder. I was helping a friend using this engine in his D-sports racing car. He was a very competent mechanic and often did portions of the build (it was his car) so I would only do the critical stuff, like cam timing for instance. We had finished one of these 2-man rebuilds and I turned over the engine BY HAND without the plugs installed. These engines used a roller bearing crankshaft so turnover torques were usually very low. Most of the revolution was easy but at TDC there was just the slightest "tick". The owner wanted to start the engine but I refused to let him. I pulled the cams and the cylinder head. It turned out that he had installed ALL the pistons backward With the cutout for the intake valve in the exhaust position and vice versa. The pistons had oversize valve cutouts and the intake valve was just touching the exhaust cutout. If standard pistons had been in there it would have bent the valves on the first rotation. As it was there was no harm done. Just some embarrassment on the owners part. It we had started that engine it would have destroyed itself within seconds! The point here is to be very careful when you do a rebuild and if you feel a "tight spot" or simply have to exert too much force to turn the engine over, Take it back apart and find out why. Thankfully Ed didn't destroy his new rotors, but he might have. This is one of those classic pay me now or pay me later scenarios. Glad you made it back Ed. Lets learn from this incident everyone! Bill Jepson ----------MailBlocks_8C74719120C3BF4_B54_300B_mblk-d47.sysops.aol.com Content-Type: text/html; charset="us-ascii"
Ok Group,
 Most engines have a predictable torque for turnover in a "like-new" rebuild. We should check with Mazda to see if they have a suggested new engine turnover torque. When I was building racing engines the manufacturers had VERY specific suggested torques, and if your engine didn't meet spec they (cosworth in this case) suggested you tear it back down to find out what the problem was, or risk engine damage.
!!! Warning Anecdote alert !!!
 One of the engines I regularly rebuilt for racing was the Kawasaki Z1-B 903cc 4 cylinder. I was helping a friend using this engine in his D-sports racing car. He was a very competent mechanic and often did portions of the build (it was his car) so I would only do the critical stuff, like cam timing for instance. We had finished one of these 2-man rebuilds and I turned over the engine BY HAND without the plugs installed. These engines used a roller bearing crankshaft so turnover torques were usually very low. Most of the revolution was easy but at TDC there was just the slightest "tick". The owner wanted to start the engine but I refused to let him. I pulled the cams and the cylinder head. It turned out that he had installed ALL the pistons backward With the cutout for the intake valve in the exhaust position and vice versa. The pistons had oversize valve cutouts and the intake valve was just touching the exhaust cutout. If standard pistons had been in there it would have bent the valves on the first rotation. As it was there was no harm done. Just some embarrassment on the owners part. It we had started that engine it would have destroyed itself within seconds! The point here is to be very careful when you do a rebuild and if you feel a "tight spot" or simply have to exert too much force to turn the engine over, Take it back apart and find out why. Thankfully Ed didn't destroy his new rotors, but he might have. This is one of those classic pay me now or pay me later scenarios. Glad you made it back Ed. Lets learn from this incident everyone!
Bill Jepson  
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