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need help understanding case through bolts

IowaRV9Dreamer

IowaRV9Dreamer

Well Known Member
This is a picture of the case of my O-320-E2A. It was originally carb'd 150 HP and I want to build it for 160 HP with fuel injection. I plan to send the case to Divco - and was thinking of having new through bolts installed.

I think only the center bolts two are free floating - the remaining four appear to be fixed, with two in one side and two in the other. Do I have that correct? If so, I would want Divco to remove and replace them, correct?

Thanks for any info!

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Yah. If the front ones don't have a big 3/4 nut & maybe spacer that means they are threaded. If the case gets surfaced & line bored they pull those automatically. They can inspect all your studs too.
 
Thru bolts

Dave: These style thru bolts use the fat center section as a press fit alignment mechanism. Divco will inspect and replace as necessary. My guess is it will come back re-certified with the studs just like they are now. My B1A has the same fixed rear thru bolts as you but the middle and front ones are free floating with the fat middle part.

Don Broussard

RV-9 Rebuild in Progress
 
If the front through studs don't have nuts on the outside of left half of the case. then the middle and rear ones are not floating but are also screwed into the other case halve.
Good Luck,
Mahlon
 
mahlon_r said:
If the front through studs don't have nuts on the outside of left half of the case. then the middle and rear ones are not floating but are also screwed into the other case halve.
Good Luck,
Mahlon
Click to expand...

Now you have me curious. Mahlon, what you said seems inconsistent with the OP statement. He said that the front studs have nuts on right side only. But the middle ones are floating, with nuts on both sides.

????
 
Mahlon (and all) thanks SO much for the help!

The rear studs certainly look screwed in to the right case half. This is what it looks like from the outside:
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For the front studs, - I'm not so sure. They are flush but the case looks like maybe it has been machined for a nut. Perhaps they are just not pushed through enough:
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they are all screwed into the case at some location on this case. The one with nuts on both sides..the nuts hold the cylinders on but the stud is anchored in the case by being screwed into it. The ones with nuts on one side, the nuts hold the cylinders on, but the stud is anchored in the case by being screwed into it.
Floating thru stud type cases have a nut securing the front set of studs on the left hand part of the case and the stud is not screwed into the case as depicted in the one in this post. It has a press type fit at the bearing parting surface The center studs on that type of case are not screwed into the case halves at any point but are a press type fit at the center main parting surface. and those studs are secured bu the nuts that hold the cylinders on on both sides of the case. The rear stud on the floating type case are still screwed into the case just as the ones depicted in this post.
Hope this helps.
Good Luck,
Mahlon
 
mahlon_r said:
they are all screwed into the case at some location on this case. The one with nuts on both sides..the nuts hold the cylinders on but the stud is anchored in the case by being screwed into it. The ones with nuts on one side, the nuts hold the cylinders on, but the stud is anchored in the case by being screwed into it.
Floating thru stud type cases have a nut securing the front set of studs on the left hand part of the case and the stud is not screwed into the case as depicted in the one in this post. It has a press type fit at the bearing parting surface The center studs on that type of case are not screwed into the case halves at any point but are a press type fit at the center main parting surface. and those studs are secured bu the nuts that hold the cylinders on on both sides of the case. The rear stud on the floating type case are still screwed into the case just as the ones depicted in this post.
Hope this helps.
Good Luck,
Mahlon
Click to expand...

Ah, yes, I understand now. Thanks. Hope that makes sense to the OP also. Thanks again, great to learn more about the guts.
 
Thanks Mahlon, I understand now. To get any of the 6 studs out would require them to be unthreaded from the case. A job best left to Divco. Thanks!
 
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