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-   -   SC engine won't hand turn after cylinder install (http://forums.pelicanparts.com/911-engine-rebuilding-forum/1175839-sc-engine-wont-hand-turn-after-cylinder-install.html)

Stunistu 04-03-2025 05:42 AM

Thanks to Dpmulvan for catching the bolts being installed upside down. Great catch. I'm the builder working with mike 491.

boyt911sc 04-03-2025 10:50 AM

Connecting Rods Orientation…………
 
Quote:

Originally Posted by Stunistu (Post 12439989)
Thanks to Dpmulvan for catching the bolts being installed upside down. Great catch. I'm the builder working with mike 491.



Stunistu,

Did you install the connection rods with stamped # all facing the same direction when all are hanging down on the crankshaft? Did you use stretch bolts? Thanks.

Tony

Stunistu 04-03-2025 01:19 PM

Yes, all numbers are in properly. I'm using ARP bolts.

brighton911 04-05-2025 03:37 AM

Lucky you can re-use the rod bolts, not so lucky that the cases have to be split to correct the issue. I would look carefully at the rod bolts and mating rod surface to ensure no damage has been done to either.

Dpmulvan 04-05-2025 04:40 AM

Quote:

Originally Posted by Stunistu (Post 12439989)
Thanks to Dpmulvan for catching the bolts being installed upside down. Great catch. I'm the builder working with mike 491.

It’s an easy mistake to make, most connecting rods have the nuts on the bottom.

Henry Schmidt 04-05-2025 09:16 AM

The connecting rods should be resized when installing ARP bolts. If they were rebuilt without the ARP bolts, they should be. If the were resized with the errant install they should be resized.

87m491 04-14-2025 04:59 AM

Reinstalled new rod bolts in the correct orientation and reinstalled case half. All turns nicely and pistons and cylinder hopefully next weekend. You can see, we should have seen, how well the anti rotation ears on the bolts seat perfectly in the recesses when on the correct side! Also can see what I think are gouge marks (north/south in the middle of the picture) in the case where the rod nut scraped the case when improperly oriented.

Doh! But not too expensive a lesson.
https://i.imgur.com/LT10Irkm.png
https://i.imgur.com/ksfnnnpm.png

ahh911 04-14-2025 07:35 AM

Take the engine all apart again and start over with the specs in hand. Have a good study of the Bentley repair manual, check all clearances, every bearing you've had off. If this was missed, what about the other details? Spend the time now not later.

87m491 04-14-2025 09:48 AM

Quote:

Originally Posted by ahh911 (Post 12446944)
Take the engine all apart again and start over with the specs in hand. Have a good study of the Bentley repair manual, check all clearances, every bearing you've had off. If this was missed, what about the other details? Spend the time now not later.

To be fair, the engine doesn't really get much more "all apart again" than down to the bare crank.

mikedsilva 04-15-2025 12:33 PM

Quote:

Originally Posted by 87m491 (Post 12447036)
to be fair, the engine doesn't really get much more "all apart again" than down to the bare crank.

:)

Turbo_pro 04-15-2025 03:36 PM

Did you really just reverse the rod bolts without resizing the big end? I think as Henry said, that is a mistake that could cost you a spun rod bearing early during the break in period.


Quote:

Originally Posted by Henry Schmidt
The connecting rods should be resized when installing ARP bolts. If they were rebuilt without the ARP bolts, they should be. If the were resized with the errant install they should be resized.


gsxrken 04-16-2025 05:13 PM

While I did have my rods resized with the ARP bolts (because in my 40 years of doing this stuff that’s what you do), I do wonder how necessary it really is in the OP’s case. Is the marginally higher torque value of the ARP bolts (5 ftlbs, maybe?) going to distort the cap to such a degree that it might shorten the life of the bearing? I’m skeptical- but have no data to support that. And I have never gambled on my hunch for any of my 5 or so various engine rebuilds, so it’s not a strongly held one.


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