timing locked versus unlocked

[cavemod]

I run an hei on a 355 6" rod motor last year it wouldn't idle and towards the end it was missing at almost all rpm .what we found was it sucked an intake gasket on one side and the rotor when mounted wobbled a 1/16" or better caused by the centrifical advance being worn out.we welded it up tight and it spins true again but have no advance system for it now no mechanical and never had vacum to start with.my question is what is a good starting point with the timing?With the distributor the way it was we set the timing at 3000 rpm but with no advance is this still common practice ??we were at 40@3000 at it ran great at first but after a couple night it started acting up and got worse and never did find the problem till the season ended.Any help will be appreciated thanks

[dirty white boy]

with no advance,..you can set timing from just above idle to red line dont matter...probably be a lil hard to crank tho' with no advance...


an you'll get a lotta debate over locked an un locked!! last time this subject came up i believe it was 3-4 pages or reply's in a short time!!

[Egoracing]

Most race engines are run locked. You are lucky it did not burn the engine up by sticking when it was not advanced. Have the car wired so you can spin the engine up before flipping the ignition switch and race it. You are never below the advance RPM on the track anyway unless you are bogged WAY down during a restart but when the advance goes bad or sticks it can get $$$$ quickly.
You will still want to bring the RPM up when setting the timing to get a good stable indication, at lower RPM the engine shakes and can make it hard to set. What kind of engine are you running? 40 is HUGE for most engines.

[Graff Spee]

32 to 37 sounds like a good range to be safe in. 40 is a drag race timing number!

[sj valley dave]

If it is a stock type head, not a fast burn chamber 36* is about it...The better the head, the less timing the head requires to make HP...I totally agree on the locked up deal...Race engines have no need for centrifigal advance, one more thing to go wrong. We never have owned a car where you did spin the engine over on a button, get oil evrywhere and then flip the ignition switch...

[CC57]

All my race vehicles have have been locked and have been set so I could spin the engine, and then connect the ignition circuit and fire the engine.

Worked great on high compression motors, or after a motor got hot.

Even now, in my low compression 602 crate motor, I spin the motor before firing so as to allow the oil to move about in the engine.

If you're runnng MSD, there is also a box that will change (advance or retard I believe) the timing until the engine hits ~1,000 rpm. Nice unit to look into.