planning rebuild

[cknoll]

Hello,

Okay this is a long one… Basically looking for some guidance here:

I have a '77 911S with a 2.7 that is in need of a rebuild for, what looks like, an uncommon issue. The timing gear on the crank shaft is completely loose. I can reach through the porthole for the distributor drive and move the gear side to side and back and forth with my finger. When I turn the crank it turns about 8’ before the gear engages and turns the intermediate shaft. Has anyone encountered this before?

That’s the issue, now to why I am considering rebuilding instead of replacing the engine:

No other issues (no smoke, head studs are all good, good compression etc). The engine actually runs great, which surprises me given the loose timing gear.

The engine has: ’74 exhaust, Mahle cylinders (I think Nikasil), pressure fed chain tensioners, eleven blade fan, basically every recommended upgrade except for the front oil cooler (the car is from Seattle).

After looking into it my thought is that this engine has already been rebuilt and the wrong timing gear was put on. I’ve owned the car for 14 years and it is now up to 140k miles. Is it possible to do a second rebuild? Is there any sure way to tell if an engine has been rebuilt?

Thanks to everyone for your help and knowledge.

[afterburn 549]

Well to put all logic aside and look through the key hole of what will truly be the "case" there ..
Once you split the case halves...usually a monetarily minded octopus reaches out and starts grabbing 100.00 dollar bills, your credit cards and the like.
Nothing wrong with that, but Tobe forewarned is to be...forewarned ! BTDT
Has it had the Mag case updates ? Really silly not to do them if it is apart as it will bite you if you don't

[cknoll]

I'm not sure about the case updates. I plan on having them done if it hasn't. Yeah, plenty of people have warned me. I've been reading up on rebuilding these engines for so long now that I'm actually looking forward to it. Thanks for advice.