What is the correct way to time my carbed 2.7?

I had the mechanic index the flywheel at tdc and at 35 btdc so I wouldn't have to use the mirror trick or cut a hole in the firewall.

IIRC, someone said the motor has to be spinning at 6k.

Seems awful high for an unloaded motor.

The specs are for 35-38 degrees BTDC at 6krpm. However, according to the curves I've seen, all of the timing is in by 3500rpm on many 911 distributors.

6K is the standard, and they've used it since 1965 with great success. 906 motors, and some 904s, too, are timed at around 10K. THAT'S scary! The Cap'n

I indexed my flywheel during the rebuild and time it at 6k, but the timing sets up way before it reaches 6 grand, probably around 4k.

Dion

I putzed around with it a little by my self and it does look like 3500 - 4000 will do it. Anything above that doesn't seem to affect it.

The spec is 6K.
I'm sure the factory had a reason for that...

how come the captain doesn't get the respect he deserves?

brant

He has nothing but respect from me. I think he's a freaking walking factory manual...


BTW, what kind of oil should I use on the little felt pad in the dizzy?

I just use straight (30 or so wt.) weight motor oil in a oil can with a hand pump that I keep around. think the tin man in the wizard of oz.

I would think that a lighter weight would be fine too.

brant

if all the advance is in by 4k.... what is the difference in timing it at 5k, vs 5k vs 10k....

the advance is already done... so in theory, it dont matter?

Not sure anyone was disrespecting the Cap'n. I've just been wondering why the 6k requirement myself for a long time ever since I tried to time a 6 for the first time. I still do it, but don't know why....

I don't always buy the argument....well, the factory gods say it is so no matter what therefore I must do it that way too...

Dion

The reason that I was given many many moons ago by an ancient old p-car mechanic was to make absolutely sure that the timing was never advanced too far.

At 6k you are pretty sure the distributor won't advance any more.

I am pretty sure it is a throwback to crappy distributors, but there arent too many fossils left that can remember back that far....

I would Guess that its possible the timing really isn't fully advanced at 4K

I don't mislead myself or claim to know 911 motors well enough to prove that.

but My mechanic, and race builder does know the motors well enough and insists upon the 6K practice.

I personally trust his advice and try to share good advice when I can

(hell.. if your going to end up with 5K, 10K, or 20K into an engine, does this really seem like a detail you should try change just because you feel like it...? Not with my motor anyways. )

I would agree that there are many things practiced 30 years ago that have changed. for example 12 one-off race cars with metal lines that were probably only intended to have a 1 year lifespan.... yes materials have changed. Physics have not.