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Sat Apr 21, 2012 1:04 am

1914, 94 bore, cb magnaspark digital distributor, cnc then hand ported los panchito heads, 1.25 rockers, 44 webers horizontal spray bars, 38 elongated vents, been through mains from 135-175, idles 50-75, airs 170-210, pump jets 50-55. right now it idles perfect, no air leaks, all barrels sync'd at idle. currently have 175 mains, 75 idles, 170 airs, and 55 pump jets. revs great to 3k then stops, like there is a rev limiter. the digital distributor has a built in rev limiter that is curently set for 6500. timing is set at 15 btdc per the distributor install directions. if I retard it to 7.5 btdc, it will not run. im at a loss at what can be left. HELP!!!!!!!!!!!!!!!!

Sat Apr 21, 2012 1:08 am

Whats the advance set to? were did you set the valves?

Sat Apr 21, 2012 6:16 am

What camshaft do you have in it?

My random guess would be there is something funky going on with the “digital” distributor.

Sat Apr 21, 2012 7:27 am

the advance is set at 15 degrees btdc, valves are .015in cold, and the cam is engle 110

Sat Apr 21, 2012 11:23 pm

BillyBobsRaceShop wrote: the advance is set at 15 degrees btdc, valves are .015in cold, and the cam is engle 110 Pleas tell me that was A miss type..........................
I know nothing about the dizzy your running and what the advance needs to be,, but figered that would be useful info for some one to help.. but on the valves you need to be somewhere between "0" and .004-.006 depending on your set up..

Sun Apr 22, 2012 4:05 am

I agree with vw_hank, I hope your valve gap is a typo?

Also, can you tell us how is your advance kicking in? At 15 btdc at idle where does that leave you when the engine is revving up around 3000rpm? What is your total advance?
Even if your distributor was not advancing at all, you should still be able to get it idling at 7.5 btdc. Are you using a degreed crank pulley?

Sun Apr 22, 2012 7:17 am

BillyBobsRaceShop wrote: the advance is set at 15 degrees btdc, valves are .015in cold, and the cam is engle 110

.006in is .015mm so that must be a typo.

Also...OP....I'd try posting your problem in the Performance Engines/Transmissions forum as your build sounds pretty elaborate and someone on there might have experience with it.

Sun Apr 22, 2012 10:34 am

if it feels like a rev limiter - it probably is the rev limiter

Sun Apr 22, 2012 10:54 am

does it stop AT 3 or AROUND 3? Is it a slow deceleration to there or is it go go go stop? If its go go go stop, its probably the limiter.

Sun Apr 22, 2012 12:12 pm

I looked at the distributor on CB’s website, seeing how I know nothing about it. https://secure.cbperformance.com/catalog.asp?ProductID=1855 Is that the one you have? If yes then it has a two step rev/rpm limiter… Maybe the first ‘step’ is set and kicking in at 3000? You said it feels like a limiter is kicking in. I couldn’t download the instruction sheet.

Koeppler wrote: I'd try posting your problem in the Performance Engines/Transmissions forum For sure or contact CB about setting up the distributor. That engine should rev over 3000 even if the valve lash, jetting and such are out of wack. If I were you I would borrow/install a known good plain old stone age centrifugal advance distributor if you don’t know all the in’s and outs of the digital distributor and see if that helps.

Sun Apr 22, 2012 4:03 pm

ok, so the lash was a typo, was set at .015mm, the distributor set to advance all out to 32 btdc by 2700rpm, but is fully programmable. got the degree pully, just went through and swapped the dist and coil for a pertronics 2 as well as a bosch 009 dist and blue coil, to no avail. also rebuild the carbs to see if any blockage was occuring. swapped from f11 emulsion tubes to f2 and nothing. could it be the dual valve spring setup is causing something?