Author Topic: cracked lower case  (Read 619 times)

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Offline maddog63

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cracked lower case
« on: July 23, 2016, 07:42:40 AM »
 I have a 75 400f. I was tighting  the lower motor mount bolts and I cracked the case right on the oil gallery just below the oil filter. I am a welder so I'm going to try and weld it.  Has anybody else done this? What is the proper way to bolt the engine in? Does it matter which bolts you tighten first?

Offline DaveBarbier

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Re: cracked lower case
« Reply #1 on: July 24, 2016, 11:16:33 AM »
Shouldn't matter which bolts are tightened first. Upload a picture so we can see the damage. It could probably be TIG welded. I've heard of people welding the cases from chain damage and collisions. All it takes is a competent welder and cleanliness.

Offline calj737

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Re: cracked lower case
« Reply #2 on: July 24, 2016, 11:23:16 AM »
The motor mount bolts should only be tightened to their torque spec, never above. Your cases are cast aluminum, so the metal bolts are much stronger. Clean and preheat the area to help purge the impurities before welding. And clean the area with stainless brushes to remove the oxidation, even if TIG welding. The outcome will be much better. I'd also tack it in place, then install the bolt, gently tight, then finish welding it to avoid distortion.
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Offline maddog63

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Re: cracked lower case
« Reply #3 on: July 25, 2016, 12:20:32 PM »
will do thanks.

Online scottly

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Re: cracked lower case
« Reply #4 on: July 25, 2016, 01:45:35 PM »
Please post pictures of the cracked case, with the motor still in the frame. Tightening the mounting bolts shouldn't have damaged the case, unless something was incorrectly assembled.
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