aquartlow

This is my first time posting on this forum and I appreciate any information anyone could afford me. My father purchased a '62 Starfire about a year ago and we need some tips on how to tune it correctly. It has a 394 cu. w/ auto 4bbl carb. point type ignition. The original carb has been replaced by a remanufactured one (exact replacement), the points, condensor, coil, cap and wires have been replaced. The ignition timing has us stumped. We removed the vacuum line to dist. at base of carb.(manifold vacuum) and set timing to 5' BTDC and it runs smooth, checked dwell at 30, everything seems fine but once vacuum line is reconnected to dist. the engine bucks a little and you can hear it misfire out the exhaust. The timing has gone from 5' BTDC to 33'-35' BTDC and once the mechanical advance is figured in we have almost 50' at 2200-2500 RPM. This doesn't sound correct to us. I will admit I am new to Oldsmobiles and GM products in general, I mostly work with Fords, but my father owned a few Oldsmobiles and it has been some time since we dealt with non-electronic ignitions so we may have missed a step in the tuning procedure. The carb was a Holley remanned Rochester?? and before installing it we looked at it closely and used part numbers to match it when we ordered it so it looks to be the correct model. There is a manifold vauum line at base of carb but no timed vacuum port, this seems to be where we are getting confused. The manifold vacuum is advancing the dist too much causing the misfire but no other vacuum port exists for the dist. Please help if possible we have done everything two or three times but still end with the same result of course to see if we missed something. Sorry for the long post just want to give as much info as possible. Thank you, Todd

tpawlik

I think your initial setting is too low. Does your car have A/C? The timing is a couple of degrees different for cars with A/C. Try advancing the timing a little to see if it smooths out. When I get home I will look at the shop manual and can email you the timing info if you need it.
I never checked the timing in any car once the weights in the distributor took over to advance the timing.

aquartlow

Thanks TPAWLIK, for the response to my inquiry. Please check your manuals, I do not have any written reference on tuning this vehicle. I have checked online and it states for this model it should have a base timing setting of 5' BTDC, hopefully this is where the problem lies. The '62 does not have A/C, but has an auto trans. Thanks again for the help, Todd

tpawlik

You are close. The manual says:
1. Disconect vacuum advance line from carburetor and cover fitting with tape.
2. Adjust engine speed to 850 RPM
3. Set timing at 5 degrees BTD for regular fuel engines and 7.5 degrees for premium fuel engines. (Starfires had the high compression engine requiring high octane)

If you still need additional info from the manual, just let me know.

Jakespeed63

Read all the posts, and I still do not understand why his car AND mine run all this timing advance. Mine is a 1964 Starfire 394 4bbl. Engine completely rebuilt. Was having driveability issues as well.I recurved(swapped out vaccum diaphram) my distributor to give a total timing of 28 degrees, initial of 12 degrees with 18" of vacuum. Before it was base 5 and total of 40!

Still want to trash that 4GC carb and retro-fit an Edelbrock I have on the bench. TV linkage on trans makes it a bit difficult. Keep in mind I am a purist, but have owned this car for almost 25 years and sick and tired of being sick and tired.

JT

trackz man

Have you set the dwell to 30 degrees- or as the manual states 28-32 degrees???

aquartlow

We set dwell to 30 degrees as well as set initial timing to 5 degrees BTDC and it runs well until we re-attach the vacuum line to the distributor. My father has fiddled with the dwell and advance alot to get the car to run better but after checking his by "ear" tune-up it shows about 50-60 degrees of dwell. I would probably need a factory diagram for the vacuum and/or the lay-out of the engines vacuum lines. We do not know if the vacuum advance on the distributor was ever replaced, it does work, just too much at idle it seems. Thanks Trackz Man for the inquiry. Todd

speedwrench1973

It sounds like you have a timing misfire from too much advance. Some vacumn advance units are adjustable with an allen wrench in the vacumn port. You may have to swap out the unit. Also check the ground wire on the breaker plate. If it is loose,you will loose point ground when the plate rotates. Hope this helps.