Here is my issue, when the motor gets hot after running around town it will develop a stall at very low speeds and or at stoplights. Then it will die, in neutral or in gear, the wierd part is i can turn the key over and it will fire right back up. I was going to change to a phenolic spacer rather than aluminum to disipate some more heat. It seems to only do this when the outside temp is 75 or above. I dont get it, i have adjusted the mixture screws and the timing both advanced and retarded and havent been able to fix this problem. I feel a bit embarrased. Any help would be greatly greatly generous. Thank you



350 olds 30 over

holley 670 street avenger (floats adjusted) choke working properly
1 inch aluminum carb spacer
HEI summit dist (vac ad 20 mech 10) inital timing w/o vac line hooked up 16. I have messed with timing trying to get my problem to cease.
edelbrock performer
ported polished #5 heads
9.7:1 forged pistons
Lunati voodoo 60802 219/227 @.050
New fuel pump (mechanical stock)
New water pump(stock)
Running 93 octane
4 core aluminum radiator
2400 stall w/built th305
Motor has just under 1k all new plugs wires ect.

 

Had a similar problem thought it was electrical turns out maybe running to rich. Have you pulled your plugs mine were so bad that I think it was affecting the spark, and thats after 1000 miles on a rebuild. just a thought.

 

First thing that I find odd is your mechanical advance only being 10 degrees...and then 16 initial. Never mind the vacuum advance, you only have 26 degrees TOTAL timing at WOT...should be more around 35 with the cam you describe. You would probably notice an improvement in performance with a 21 or 23 degree bushing in your distributor and run 12 -14 INITIAL...and IMHO get rid of the vacuum advance I'm sure someone will disagree with me but for simplicity and performance I like to get rid of the inconsistent little bastards lol!

That out of the way, are you running gauges? What is your water temp when the car runs like that?

 

Distributor degrees are doubled so 10* in the distributor is actually 20* plus the 16* initial equals 36* total. Many don't state that anymore but it's the correct way of doing it. If it is indeed only 10* then you have a problem but that wouldn't lead to your stalling problem. You would notice a lack of power though.

Is it a pre 74 car? Do you have a full 12v going to the HEI? Warm temps and less than 12v will cause an HEI to lose power and shut down. It can not use a resistor wire to supply it's power.

 

However, with your math and the vacuum adv hooked up and cruising with lite load, then his total advance would be 56. His engine would sound like a can of marbles rolling down the street! I don't think his timing is what he thinks, the math just does not add up for an out of the box dist.
I agree with ahpilot, he needs to get his dist. recurved. Also I would suspect that he has the 12vdc there as that would affect his performance no matter what the temp is!!

My next question is what is your idle speed and where is your vacuum adv connected?


My other idea is your fuel line routing possibly causing vapor lock.

 

HEI or any type of electric components do not like heat. Less than 12v and high temps will definitely cause higher resistance and they will stop working. I've had it happen to me and seen it many times. I do not think it's a carb problem at all. 75* outside temperature is nothing. Plus he states he has a '4 core aluminum radiator'? Are you running a thermostat?

We still haven't heard if there is 12v going to the HEI or how it's powered. Also not sure why you're running a carb spacer or is it just an adapter because the manifold is a spread bore design?

 

Vacuum advance at part throttle cruise is normally in that 50 degree area. You have to think, a STOCK car and distributor at part throttle cruise is probably in the 2000 RPM range, thus the full mechanical advance has not yet come in full swing. So you're left with the intial+some mechanical+vacuum...based on load. 50 degrees isn't alarming at PART throttle cruise on a stock-ish car.

The problem comes in with rear end gears, aftermarket distributor curves, and engine build. When you throw all that in the mix, an engine may be spinning 3000 RPM at cruise because of the gears, then the aftermarket curve allows mechanical advance weights to move out at a lower RPM, so at part throttle CRUISE you've got initial+full mechanical+vacuum...this is usually when you notice that ping, especially under load. Getting rid of the vacuum advance on a PERFORMANCE engine adds consistency at the track, and protects your investment while cruising down the street.

I agree with you that this could be a fuel problem...the only thing is that he's got a new Holly? And Trip could be right about the resistor wire going to the distributor, when that resistor gets hot its "resist" property is exaggerated and you will barely get any voltage through it. Sort of like heat soak on a starter.

 

If his vacuum advance is hooked to manifold vacuum, at idle, he will be running 36 deg, or more, depending on which setting we run with at idle. It will go into a very lean condition with the carb. The hotter the temp the worse it will get. If his idle speed is up to the point where the throttle plates are barely opening and or metering rods not seating back in the idle circuit, then he will get an off idle dead spot, that also could be exagerated by temp.

I agee with you that cars performing on the track do not need vacuum advance as it does not operate at WOT. However I've found that the vacuum advance gives you a bit more efficiency for normal everyday driving.

The voltage is a simple check and I agree should be accomplished before moving on to other items.

 

^^^^ Agreed...but I would hope he has it connected to the carburetor port.

Have you ever noticed how someone will post a question and then several members will have theory debates on the original post and we will NEVER see another post from the post originator? I love it! Maybe he'll see our rantings and try a few things, who knows.

 

It says it was posted yesterday evening, so he might not even see this until tonight!

I do like to hear back from the people who post, as to what they did to correct the offending issue!

 

I guess you're right...I forgot it was just posted last night. Why can't everyone have time to post to CO all day long? Geez, life just isn't fair

Hey OldCutlass, have you ever gone to the Veteran's Day car show in Bastrop TX? We go every year and usually we have around 20 Oldsmobiles...it's the one show where Oldsmobile outnumbers the big 3. Pretty cool. I'll have my car there this year (I hope).

 

I've not yet gotten this heap reliable enuff to venture that far yet! I've been playing with it for about 2 years, and I trust it around here within a 60 mile radius to be safe. Hopefully within the next 30-45 days I can perform the necessary heart transplant, with a few other items, and she will be good to go.

I do follow the local Olds clubs news letter, so one of these days I'll meet up with you, Richard, and a few of the other guys from up here. If they can stomach a non-olds engine swap!

 

I sure can, I've been thinking about a '72 Supreme bodied racer with a ZZ572 in it for a long time. When I'm done with my current project I may make it happen. I'll have to let the Mrs. claim the 470 ci Supreme so I can build the monster

 

Oh my!!!!! I'll meet up with you when I get my 468/ T400 installed!

 

hey guys sorry for the delayed response, i only have access to a computer during my work day at this time. So i would beleive that i have my timing backwards, i woul'd say more like mechanical advance is 20 and vac is 10. I didnt curve the dist i had it curved by a local speed shop and he had my cam card and motor specs. The car is 69 cutlass s. I will check the voltage to the resistor wire, it only has one hot lead going into it (summit HEI) similar to the pertronix with the coil in the cap. As far a vacuum it is hooked to the full vac port on my carb however it does also have a small dead spot right off of idle. Thanks everyone i will be checking in on this thread through the day i appreciate all the responses.

 

OK then, I would connect it to ported, raise my idle speed back up, and reset my curb idle air/ fuel mixture. I bet your will find most of your issues will be gone!

However there are other trains of thought about running full vacuum! I've found that I would have to retard the timing back at the curb idle setting, and really lean out my air/ fuel mixture to get it to idle correctly!

 

I am going to track down the hot wire to the hei, i am very curious about an inline resistor. I remember when i switched there were two wires one from the starter coil and then the other......which sounds like maybe there is a resistor inline i didnt pay attention too. Im going to check it after work i will update if i find anything.

 

went out to check with it during my lunch break. So there is a white wire coming form the starter and then a black wire coming from the fuse block on the fire wall. They are intertwined into a end connecter and then connected to the power tab on the HEI. Dont see a "resistor" of any sort, anything i should look for? Dont have a resistance meter with me at the time.

 

The wire itself is the resistor (if it truly is). The wire provides resistance. The only to know is by a meter. Been there done that

 

You need to check the voltage with the key on and make sure you have 12v there. If its less than you need to run a new wire from the fuse box to supply 12v only when the key is in the on position, no 12v at the accessory position. There is not a physical resistor there. It is resistor wire!

 

that sounds promising, i will get my meter out when i get home and check it out. I more than likely will not be able to reply back to you guys tonight after 6 or so, dont think i ditched out on you! Thanks again i hope this works!

 

One last quick question before i head out after work, so if one of the wire happens to be less than 12v. Is there a good/better place to run a full power wire from? and how big of a wire should i need?

 

I mentioned that here^^^^^^^^^^^^! good luck!

 

Either remove the resistor wire from the plug in the fuse block and replace it with a regular wire, or go for the big pink wire that comes out of the ignition switch.
I think the wire to the HEI is about 12ga.

- Eric

 

Well i suppose we can scratch that idea ive got 12.58 volts right to the HEI. Hmmmm....

 

Had the same problem at one time.

Turn everything on ,A/C, lights, etc. with the tranny in drive position with the car parked.

Reset your hot idle speed to spec and make sure you are not stuck on the high idle choke cam.

Make sure the dashpot is working . It is supposed to prevent the symptom you describe.

Good luck, Dave

 

make sure your idle speed and idle mixture are set correctly. it's a cat and mouse game on my 72 cutlass i found if i richend up the idle., it idled in drive better with less idle screw but more fuel., also vac, adv. setting have some play in this every engine is diffrent mess with it some like full vac. port some like ported vac. source depends on your build and and cam etc. etc.

 

Sorry i didnt respond earlier, no computer at the house yet. So as an update, saturday morning while driving. Had the same symptom but now it is consistant. I can barely get the car to idle at all. Pulled the carb to see if it had picked anything up and it was clean. Checked to make sure fuel pump was working correcty, its getting plenty of fuel. I did richen it up a smidge which allows it to at least idle roughly. But if you go even part throttle it sounds like its only running on 6 cyliners. Is it possilbe that something is wrong in the HEI cap? Is there a way to test the coil in the cap? I will try adjusting idle tonight and check my timing for the millionth time.

 

I dont know if you guys heard or not but from what they said at the Olds meeting there wont be a veterans day Bastrop this year.... i was excited for it too to bring my car out. Hopefully its not true though

 

Sicky...I am emailing Bill Slezag to find out what the deal is. He heads up the Bastrop car show. I'll let you know.

 

Another plan all shot to hell, huh! I'm sure possibly we can all get together at the zone show, I am going to try and make it there!!

 

Update! I beleive the problem has been solved. Even though the voltage read 12.5 at the dist, i decided to pull it off and rewire from a different source as many of you said. Bota-bing-bota-boom......she fired up and is running great. So anyone know why my Fluke meter would read 12.58 at the power wire to the distributor and not appear to be true? Thanks again for all the help you guys are awesome!

 

Was the engine running, or was the ignition switch on, but the engine not running?

I'm not sure about HEI, but some electronic ignitions can draw very little if the engine isn't actually going, which would result in the voltage being high after the resistor, because there was essentially no draw.

And, thank you TripleDeuces for providing the correct answer!

- Eric

 

I'm a smart imbecile sometimes, I was going to ask about whether it was running or not when checked but I guess that's been solved now. Only reason I knew the answer was because I've been there. Electrical components just do not like heat and that's what it sounded like. I've seen it with Mallory Unilites, Pertronix and HEI. Any high energy ignition requires a full 12v or you get symptoms exactly like what was described. It's not always a resistor wire either. My 65 Riviera had a resistor ignition switch (key switch). Showed full voltage with the key to 'on' but while running it reduced it so as not to burn up the points. I'm not sure if any Olds had this arrangement but if you don't see a resistor wire I'd be looking at the switch.
I'm glad you found the problem and happy motoring

 

Yeah the key was in accesory mode, was not running when i checked. Well this has been an awesome learning experience for me. Im sure there will be more questions down the road. Thanks again TripDeuces.

 

Accessory position?!?

There should be NO power to the coil in the accessory position.

You need to check your wiring - who knows what else may be lurking there...

- Eric

 

you need 12v during CRANK, not just IGN on..

you might be losing your 12v during crank, so confirm while the key is cranking that you have 12v feed to the coil.

 

Steve, although what you say is true, he's having a problem with RUNNING, not STARTING, and he fixed the problem by connecting with a different wire, so starting is not the problem.
If he wasn't getting enough voltage at Start, he wouldn't be able to start the car and tell us that he fixed it.

- Eric

 

granted! this is what i get for jumping to the end of the thread to post! LOL

 

We all do it .

- Eric