Inliners International Forums General Discussion Engines 235 timing spec

Does anyone know the factory timing spec for a 235 in a 55 1st series 3100? I checked mine after setting the initial timing to the BB and it seems like the advance is very aggressive. I have 0 @500, 10 @ 1000 and 38 @ 2000RPM. Admittedly, I left the vacuum hooked up when I checked this, but even so, it seems like a steep curve. The only factory spec I found was for a 55 2nd series 235. It called for 0-4 @ 750 & 24-28 @3500RPM. I got this from the online manual at chevy.oldcarmanualproject.com. I'm going to rerun the test with the vacuum disconnected, but I'd like to find a reference for comparison. BTW, the truck runs well with no pinging, and idles smoothly.

regards,
Leon

timing is set by lining up the flywheel ball with the pointer with the vac advance disconnected and idle speed around 425 rpms. The ball is about 5 degrees advanced.


Starting in '59, they used the first short vertical line on flywheel clockwise from timing ball.

Yep, got that done.
That sets the initial or minimum advance.
But if the BB is 5 deg advanced then my centrifugal timing curve is even more aggressive than I measured. That would make it 43 @2000 RPM. That seems way out of line. That's why I'm looking for some factory reference data.

regards,
Leon

Leon,

My crusty old Motor's manual shows the following for 53-55 235.

Centrifical advance - 2@375 rpm 13@1750 rpm
Vacuum advance - 10@18 inches of vacuum

So it would seem you should see a total advance of about 28 degrees at 1750 rpm or 18 degrees with the vacuum advance disonnected.

-Ed