If there was no rubber cover on the PVC hose at the carb, it’s a 3/8” opening, there is no engine that could run or idle for sure. If it could run it would be so lean you would melt a piston quickly.
Ken, jimmy six is saying that IF THE CARB IS METERING PROPERLY, having an open port for the PCV is going to run very lean. You are saying that even with that large vacuum leak, IT'S RICH and runs better than with a PCV in the hose. You are both in agreement with Moriarity now. Carb is dumping fuel and causing driveability and adjustability issues. I'll also mention that someone coming on asking what's wrong might not be the best judge if it's rich or lean. Let the people try to help.
Oh buddy I wasn't trying till be a smart a$$... Trust me I appreciate all of the input!... That's why I hate texting and emailing because alot could be read into just text... Sorry if it came out that way..lol
Too much fuel pressure?? What fuel pump have you got? Have you got a regulator? Do you know what the pressure is at the carb?
90% of the cars I get in the shop, for running problems are due to ignition timing being all wrong. Then the carb gets all jazzed up in their attempts to make run better. So its then a combination of both. And too many of them have that damn GM HEI big cap distributer that I hate. Where is the idle timing at? I know you said you set the initial timing at 12 degrees. Is the vacuum advance hooked to ported or manifold vacuum? At 950 RPM idle speed, the throttle plates are probably open enough to be generating a ported vacuum signal of some amount, which can be hard to keep idle timing consistent. If its on manifold vacuum, you should be seeing 25 degrees or more of idle timing with the vacuum advance hooked up. If its that way now, then disregard the rest of the post. Mechanical advance should also not be starting to come in at idle speed. A degreed balancer or timing tape is really a must, to know just where and what the timing is doing. I think the timing is way retarded at idle, specially if its at 12 degrees at idle. To get a base line of what the engine wants, what I would do is to hook vacuum advance to manifold vacuum, start the engine and advance the timing. If the engine speed goes up, its telling you it wants more timing. The increase in engine speed, is telling you the engine is producing more power at idle by burning the fuel more efficiently. Then lower idle speed and advance some more, until it starts to break up, then back of somewhat. Now look at the timing, bet its at 25 degrees or more. Now unplug vacuum advance and see where the initial timing is at, for the baseline timing. Most engines are happy at around 25 degrees of idle timing, 40 degrees or more at low load highway speeds, 36-38 degrees at wide open throttle and mechanical advance starting to come in close to right off of idle. Now you engine may have trouble starting, if the timing is too far advanced and will have to find a happy medium, with your setup. Rarely if ever, do I run ported vacuum advance, due to I run into way too much wide open throttle timing. Some engines react poorly with manifold vacuum advance, depending on the vacuum signal it makes (engine doesn't make enough vacuum to fully deploy the vacuum canister at idle) and can also have off idle stumbles that are hard to get around, cause the timing retards too much as soon as a load is put on the engine. In those cases, I run only mechanical advance, with as much initial timing, the engine will not crank over hard with, and set up the mechanical advance for the rate and total timing of around 38 degrees or so. These engines will have a rougher and richer idle. The only way around that is to have a timing retard to start the engine, so you can get the idle timing up, to idle better. Bill
With it idling, put a hand over the top of the carb, like you were trying to snuff out my stepmother... If the idle picks up, you have a vacuum leak, it it tends to stall, you don't. This is the acid test that I swear by. Was there a torque converter recommendation for the cam you used? Mine was from Lunati and I followed what they recommended, my car is a manual.
I appreciate all of that bud... Will definately check it all out.. .Im just going to throw on a new carb since this is a 2nd hand "supposedly new" that I threw on... I will set this off to the side as a spare after I go through it.. I will run down your recommendations.. Thanks a bunch!
HAHA.. Snuffing out your stepmother.. LMAO.. The cam shows that a stock converter will work.... I ran the same cam with a stock th350 and torque converter in a big block I ran and had no problem.. .Im almost positive it is in the carb now..
sounds like time for an AFR to give additional data for confusion or maybe even some clarity in troubleshooting
Oh hell... Don't want to or shouldn't have to go that route... Just wanting a driver... Not turning 9's in the quarter.. LOL.. .
Slightly wet... Nothing severe... Pretty sure it's the carb.... New one will be here tomorrow... I'll slap it on and check everything out again.
Sounds good. I will say that Powerglides tend to have tighter stock converters than TH350s. I've had the 'great in Park, dies in Drive' on more PGs than any other trans. It's just a matter of getting things right and balanced.
Yeah.. .If it wasn't for the vacuum issue with the carb I would lean towards the converter. When it shuts the motor down if you plug up the 3/8 port on the front of the carb.. .
If it makes you feel any better, here's one from the archives. Old guy comes in with his 10 year old Caddy. It barely runs. We do the full tuneup, even rebuilding the carb. It's purring when done. He comes back later and after a back and forth, it turns out his complaint is that before, when he braked to a stop, he could let off the brakes and it would just sit there in gear and not creep forward.
I've had similar issue with mine, a couple of times in the past. Pulled idle mixture screw right out, and blasted with spray carb cleaner. Cleared up. Next time, that didn't work, sprayed carb cleaner through the tiny air bleed? holes in top of carb body, near the metering rod hold downs. Sorry, going by memory, not at home to confirm on my car.
Could have too tight of a torque converter for your cam is a possibility as others have said. You have not said what kind of distributer it has, or what kind of vacuum you have connected to it. Are you sure the reason it wont die in gear with the vacuum cap off (vacuum leak, which is going to raise idle speed due to more air into the engine) isnt because the idle speed increased? Have you tried to set the idle speed at 950RPM with the vacuum cap on the carb and put into gear? If you have and it still wants to die in gear, put the timing light on it, look at the timing at idle in neutral and then have someone put it in gear and see if the timing retards. It shouldnt. If it does, you are already into the mechanical advance curve at that RPM at idle, so not only will you loose the around 200RPM or so from puting it in gear, you also lost timing, and RPM may go low enough to stall the engine. This is easy to do, don't cost nothing but a few minutes of time and and will rule out a possibility if its not the issue. Bill
As said having no plug on a 3/8” PVC fitting or a correct PCV valve with a direct hole to the intake manifold an engine will not idle; that’s too much air. There is a carburetor problem. After you change carburetors as you said you are going to do; I would plug the fitting on the PCV hose and get your replacement carb idling correctly for mixture and rpm then attach the PVC hose with the valve and readjust the mixture and idle if needed.
Will do... I appreciate the input... I'll let yall know if I commit myself if this carb isn't my problem.. LOL... May be a 67' 327 for sale.. LMAO
As a general rule, the Thumpr cams need a lot more initial timing to idle correctly. They have a tight lobe separation so that means a lot of overlap that needs plenty of fuel along with plenty of air to counter the exhaust dilution at idle in order to idle in gear. I also agree you need to check that the mechanical advance isn't already active at your idle speed and dropping timing when the idle slows in gear. Get the initial timing up to around 18° for that Dumpr cam. Just for a test, set initial timing at say 24-26°, reset your idle speed....then see how it reacts to being placed in gear. Don't run it hard this way, timing will be way too high for that at WOT and loaded, but just see how it reacts at idle.
Carb was crap!... swapped for another and she runs decent now... doesn't die in gear... thanks to everyone's input... I advanced timing about to 25 initial... she likes it i think.. I'll drive her tomorrow and see what she does
Glad to hear it's running right! 25 is probably going to be too much, but let the engine tell you what it wants. I used to connect a vacuum gauge and bring up the timing until it got highest vacuum. Then roll the timing back until it dropped 2 inches of vacuum from highest. 20-18, 15-13, etc.
With this cam I'm not going to be drawing a bunch of vacuum... but I will definitely toss that gauge back on... hindsight I wonder if my problem was not enough vacuum woth a Edelbrock This engine will only draw about 14 With this cam I can only draw about 14 max on the vacuum... but will throw the gun and gauge back on tonight and find a happy medium.. I appreciate all the help!
I'm sort of wondering if the type of carb was the problem or the carb itself was messed up... It was an Edelbrock AVS "Air Valve Secondary"... I wonder since this 327 with the cam isn't pulling enough vacuum.. .LOL.. hell I duno.. I know she runs now with a standard mechanical choke 600cfm now.. .
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