Case inspection, align bore or not |
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Case inspection, align bore or not |
930cabman |
Oct 16 2022, 05:52 PM
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#1
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Advanced Member Group: Members Posts: 3,144 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States |
Recently I had my local good guy machinist make a steel inspection shaft to pickup the main bearing bores leaving a thou or so clearance. Seems to make sense, similar to installing the crank with new bearings and making sure the crank spins smoothly (easy). The next part of the plan would involve fabricating another gauge to pickup the cylinder mounting surfaces. Sure this can all be done with indicators, but I am trying another tack with this process. Thoughts?
I also use Plastigage to check actual (after crush) clearances Working a 2.7 911 cases I have found the main bearing bores become elongated due to many heat/loading cycles. This is very common to this magnesium case and keeps guys like Ollies in business. Is this elongation also common to our VW/914 cases TIA |
Superhawk996 |
Oct 18 2022, 11:49 AM
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#2
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914 Guru Group: Members Posts: 5,891 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Regarding crush: the other post you posted to is 12 years old. Not sure you’ll get the answers you seek there.
I couldn’t find a good Mahle document quickly but this covers the basics. Crush is normally taken into account when you specify oversize bearings and the machine work is done to OEM oversize bore spec. Usually will have to contact bearing supplier if going Outside the normal specs. Likewise, engine builders develop their own preferences based on application. https://www.kingbearings.com/wp-content/upl...ce-bearings.pdf |
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