Idle too high

[Sam D.]

Does any one have any advice on the following: I have a 1964 365 hp car. Original engine never rebuilt. Original rebuild Carb. new fuel filter. I had compression check, valves tuned, distributor timed, Low mileage car. about 58k. runs good but wont idle low. I have to keep the idle at about 11000 rpm or she will die when sitting. But only when I run it a bit. If I go around the block a few times she runs fine. I put some of the store bought octane boost in and she seam to Idle a bit lower. I was going to try Wild Bills octane today! Could it be the vacuum advance, or fuel pump? Or any other trouble shooting areas?

Thanks,

Sam

[Joe C.]

Re: Idle too high

What was done, exactly, before the symptoms presented? It could be a lot of things. Since the engine idles AOK when cool, I would not suspect valve lash. I'm thinking fuel percolation. It happens when hot, and if your carb was recently rebuilt, the floats may be set too high. The octane boost MIGHT be raising the flash point of your fuel just enough to prevent flooding, but that's a stretch.
Give us the chronology first.

Joe

[Sam D.]

Re: Idle too high

Bought the car about over a year ago. Had the symptoms then. found out it had a service carb on it. found an original correct dated one from Bob Kunz auto. Referred through the NCRS problems is still there! Bob said he tested the carb several times and I even sent it back to him after running it for a few month. After I got it back the problem is still there.

[Clem Z.]

make sure the advance weights in the distributor

are not sticking in the advanced position at idle. are valves set at .030?

[Sam D.]

Re: make sure the advance weights in the distribut

I am not sure regarding the 0.30 but I can check into that?

[Greg S.]

Idle too high

Check the archives for discussion on vacuum advance cans for SHP engines. Many incorrectly have a vacuum advance that works at 12-16. SHP engines need a can that starts to pull advance at 8 . The 12-16 inch cans can cause the idle to dither. I am no expert but the archives have detailed discussions about this problem.

[William C.]

Re: make sure the advance weights in the distribut

Make sure you have the proper vacuum advance can on the distributor also. Much discussion on this item in the archives.

[John D.]

Re: Idle too high

Sam, You can tell the boys are getting old. I mean not one of them caught the fact that you are idling at 11,000 RPM. That baby must scream for sure. I mean even JR doesn't go that high but hopefully he will this afternoon.
Yea old Clem is slipping. Just kidding. Hope you solve the problem. Sorry for the sarcasm but I just couldn't resist. I will let Clem know at the next lunch club get together. (if I can get a word in that is).
I doubt very much if fuel or anything you put in the fuel will solve the problem. It's probably time to check out the carb rebuilt job and or the distributor for sure.Check the base of the carb& the gasket. Don't forget the obvious such as a weak accelerator return spring. Hopefully you have an original accelerator pedal because some of the repros will make your idle hang up for sure. Learned that one the hard way. Hinge on the pedal is sometimes the culprit. Have to massage the pedal with brute force so it's not the blame for idle hangup. Watch out for some of the repro accelerator return springs also. Work good for a short period of time and then they aren't worth a crap. Good luck, John

[John D.]

Re: Idle too high

Sam, Vacuum advance should be a 236-16 I believe. If you have one that says B something look out. Chevy sold one that was a reboxed Standard and the spring was way too strong for sure. Should be at least a B28 or weaker for a 30-30 cam. Napa sells them. Like Clupper says go into the archives as there were a 100 posts on this important subject.John

[Duke W.]

Re: Idle too high

A vacuum leak is a prime suspect. Old VACs can be a source of vacuum leaks, or often they don't work. Check all vacuum devices/hoses/connections including the power brake booster, if equipped, and check that the PCV inlet fitting on the carb has the proper restrictor.

A Mighty Vac or equivalent is an excellent tool to check if vacuum systems/devices hold vacuum. You should also check the physical configuration and spark advance map to be sure they conform with the CSM/AIM/AMA specs.

Most C2s only have a handful of vacuum systems, so it doesn't take much time to check all.

Duke

[Clem Z.]

he said he has a F-1 engine and they idle high

like 9000 RPM. john,that is the trouble with you "experts" you want to pick some poster to death with details.

[Duke W.]

Re: he said he has a F-1 engine and they idle high

In the slowest second gear corners at last week's French GP, telemetry showed the engines were down to about 6000 revs - sounded like they were barely running.

Revs are limited to 19,000 by the rules, and with gear spacing of about 10 percent (compare that to about 30 percent for a vintage close ratio Corvette gearbox), the normal through-the-gears rev range is about 17,000 to 19,000, so power delivery is effectively constant during acceleration. No waiting for the engine to "come on the cam or boost" or falling on its face on upshifts due to too wide gear spacing!

Duke

[John H.]

Re: he said he has a F-1 engine and they idle high

And a closed-loop 2,000-psi nitrogen system with actuators to close the valves instead of springs.

[Sam D.]

Re: Idle too high

Just to up date all of you for your responses yesterday. I went ahead and put a bottle of the Wild Bills octane boost in a full tank of gas. The idle dropped from 10.5 rpm to 8.5 rpm with out touching anything! The car ran pretty good for about 8 miles, then she started to spurt a bit. I Turned the idle up to about 9.5 / 10000 rpm. and she ran great all day! no problem on two long trips. Temp was great as well. Since I had the car it has never run better! Can these Special High performance engines run on just normal 93 octane fuel. I don't believe mine can. Should I continue to try and get the rpm down to 8500 / 9000?

Thanks,

Sam

[Sam D.]

Re: he said he has a F-1 engine and they idle high

Just to up date all of you for your responses yesterday. I went ahead and put a bottle of the Wild Bills octane boost in a full tank of gas. The idle dropped from 10.5 rpm to 8.5 rpm with out touching anything! The car ran pretty good for about 8 miles, then she started to spurt a bit. I Turned the idle up to about 9.5 / 10000 rpm. and she ran great all day! no problem on two long trips. Temp was great as well. Since I had the car it has never run better! Can these Special High performance engines run on just normal 93 octane fuel. I don't believe mine can. Should I continue to try and get the rpm down to 8500 / 9000?

Thanks,

Sam