Idle Issue

[PaulB1965]

My Hurst has a tendency to idle high and go even higher as it warms up , any ideas as to what may be causing it ? The car has sat an awful lot and not benn driven much

 

[MrSony]

I have seemingly found my issue. Advance springs were somewhat weak and were allowing 4* more of advance at idle. I put new springs, not necessarily stiffer but they are new, and a crane adjustable vacuum advance from crane, 99600-1. I need to drive around and adjust the vacuum advance, but it seems to not be hanging up anymore. Whether or not I still have a vacuum leak is TBD, I dropped a spare downpipe and an O2 bung from the AEM kit off at a local machine shop on Friday. It was a Friday at 3PM, so it probably won't be done until Monday or Tuesday.

 

[Turbo Zach]

I have seemingly found my issue. Advance springs were somewhat weak and were allowing 4* more of advance at idle. I put new springs, not necessarily stiffer but they are new, and a crane adjustable vacuum advance from crane, 99600-1. I need to drive around and adjust the vacuum advance, but it seems to not be hanging up anymore. Whether or not I still have a vacuum leak is TBD, I dropped a spare downpipe and an O2 bung from the AEM kit off at a local machine shop on Friday. It was a Friday at 3PM, so it probably won't be done until Monday or Tuesday.

None of your friends have a welder? I know I live over a hour north of you, but if you came over I would fix you up.

 

[MrSony]

None of your friends have a welder? I know I live over a hour north of you, but if you came over I would fix you up.

Nope. One has access, but he's not very good lol.
I'll keep ya in mind next time if I'm ever up there.

 

[MrSony]

Video of it. The timing mark is at 14*, +4* than I had it set at. Changed the springs and lubed the weights as said.

 

[Bonnewagon]

That's a lot of advance for a Buick 350. My '68 used 0° and my '74 used 4°. Is that basic crank timing or are you hooking the vacuum advance to full manifold vacuum?

 

[fleming442]

Go do some burnouts, and see what it does. Video or it didn't happen.

 

[MrSony]

That's a lot of advance for a Buick 350. My '68 used 0° and my '74 used 4°. Is that basic crank timing or are you hooking the vacuum advance to full manifold vacuum?

Base timing is 10*, dist has 22*, 34* all in (no vacuum advance as of now until I get it dialed in), by 2600rpm. Runs pretty good. My 8:1 350 I had at 12*, but never curved it, it was as TA set it with the same 22* of mech. advance but in at 3000.

 

[MrSony]

In general most 9-10:1 SBB can tolerate 10-12*, depending on timing curve and where you have the vacuum advance hooked up. I run ported, always have. Never had that running hot at idle issue that people describe as a reason to use manifold vacuum either.

 

[MrSony]

My Hurst has a tendency to idle high and go even higher as it warms up , any ideas as to what may be causing it ? The car has sat an awful lot and not benn driven much

If your fast idle linkage is sticking it will idle high and get higher as it warms up because warm engines atomize fuel better therefore run smoother with more rpm. let it warm up with the air cleaner off (all vacuum hoses plugged) and see if the choke opens all the way and the fast idle weights drop all the way down.