TheSamba.com :: View topic

Sun Feb 29, 2004 7:13 am

i own a 66 bus w/ a 1600 sp 009 dist - 31 solex/pict carb, i purchaced a advance timing light gun - the type with the dial on the back, how do i set the timing on my bus, idle? 3000 rpm? my flywheel is stock but its marked tdc my my mechanic.

Sun Feb 29, 2004 9:37 am

30 degrees at 3000 rpm. Let it end up where it ends up when it comes back down to idle.

Sun Feb 29, 2004 5:06 pm

ok, i set the dist. at 30 @3000 rpm's it stayed at 30 from what i guess was 2500 through 4000 rpm's on the nose, and then it fell back down to 6-7 1/5 advance at idle, kinda choppy at idle, but i dont have anything to worry about-right?

Sun Feb 29, 2004 6:01 pm

You've got it.

The reason you set "centrifugal only" distributors for maximum advance, is because there is no load sensing in the advancement. Due to this, you are setting the timing for worst case driving. The engine can often use and benifit from more timing advancement, but only the vacuum advance distributors can make sure timing is taken out of it in situations where the engine cannot take the extra timing.

Sun Feb 29, 2004 6:13 pm

Since you now know the technique, you may try going to 32 max advance and give yourself 8-10 degrees at idle... that is the most I run any engines ( all distribs and engines are a bit different)
IF you DO NOT have any pinging issues when accelerating then it should be fine at that setting ...and may help your " choppy idle "and for sure help if there is any flat spot ( the more initial advance you can safely use the less of a flat spot you may have due to the way centrifical advance distribs work)

but if you hear pinging upon acell with premium fuel then back it off till it quits.

or you may just need to adjust carbs etc to get the idle better and then re- check the timing again.

Sun Feb 29, 2004 6:22 pm

Here is something kind of interesting to read...

http://www.bostonengine.com/articles/009.html

Sun Feb 29, 2004 7:18 pm

thanks guys, i had it at 28 but i could hear a very faint tick at idle,is 28 better for long trips at 55 mph on a bone stock bus? at 32 it should go smooth, but ive heard talk about overheating ,and i live in a hot climate{south florida} should this be a issue-most of the time my bus never goes over 45 mph and less than a 20 min ride, im running 93 octaine

Sun Feb 29, 2004 7:25 pm

the very fait tick i heard was prob because of rough idle, usual engine talk, but i didnt hear the valves rattlin at acceleration, tommorow i'll move the idle up to 8-10 and see if it gives me a 30-32 full advance , hopefully with no faint tick at idle . if it does this and runs smoothly at all rpm's im safe, from overheating issues~ right?