SC engine won't hand turn after cylinder install

[Stunistu]

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

[boyt911sc]

Originally Posted by Stunistu

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]

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

[brighton911]

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]

Originally Posted by Stunistu

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]

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]

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.

[ahh911]

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]

Originally Posted by ahh911

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]

Originally Posted by 87m491

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

[Turbo_pro]

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.

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]

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.