Quote:
If you cannot get the idle screw to affect the idle, I would look at the casket under the carb
I'd say if he finds a casket under his carb, he's probably found the source of his driveability problems! 
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| Author: | turbocuda [ Tue Aug 22, 2006 3:22 am ] |
| Post subject: | Possible vaccum leak? a lil long |
Hey all. Ive got a problem I cant seem to figure out. Ive got a 225 in my 66 cuda and for a few months now its having trouble gettin 20lbs on the vac gauge in the dash at idle when I start it. It used to get about 25. The biggest concern I have is that sometimes if im at a stop light and the cars idling, the vac gauge starts falling gradually and the car starts idling worse and worse. Ive even had her quit on me coming out of a parking lot with my foot half way in it. To me it seems like a vac leak but ive looked everywhere for it and I cannot find it. Its not leakin around the carb or the intake. The hoses are all good. Ive even sprayed some soapy water around everything and nothin came of that. The only thing I can think of is that its leakin around the head because the passager side of the head is about the only thing I cannot get to to spray. I recently switched my stock exhaust manifold for one that I ported and in the process I changed all the gaskets. When I did this the car ran fine. Ran just like it used to. Had more power like it used to. It was holding more vac also. So I drove it around the neighborhood brought her back home and parked it. Next time I went out it started doing it again. Wouldnt want to run sitting at a light. Also the carb WILL NOT tune. Doesnt matter what I do to it. It doesnt change anything at all. I can turn it as far as I want to in any direction and it makes no change. One last thing. I noticed when changing the manifold that the previous owner broke a stud off that seals the intake and exhaust. So it has no nut on it to seal that end. Sorry this is so long but I want to make sure u guys know whats going on. thanks. |
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| Author: | Sam Powell [ Tue Aug 22, 2006 6:38 am ] |
| Post subject: | |
If you cannot get the idle screw to affect the idle, I would look at the casket under the carb for your leak. Too much air is getting through there somewhere. See if the bolts are tight. See if the base of the carb is tight to the body. You must tighten these screws from below on most carbs. Sometimes the base gasket will come apart, and fill the vacuum passages under the carb, thus messing up the internal vacuum signal getting to various parts of the carb up inside. This effects the draw of the fuel up into the ventri as well as the power valve operation. Sam |
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| Author: | RDJ [ Tue Aug 22, 2006 7:35 am ] |
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If you didn't retorque the manifolds to the head after the first time you drove it, you may want to start there. The first time you drive the car with a new gasket, the hot engine will expand, crushing the gasket a little. I know when I changed my intakes recently, the nuts were a few pounds light after the first run. |
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| Author: | SlantSixDan [ Tue Aug 22, 2006 7:39 am ] |
| Post subject: | |
Quote: If you cannot get the idle screw to affect the idle, I would look at the casket under the carb
I'd say if he finds a casket under his carb, he's probably found the source of his driveability problems!
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| Author: | Doctor Dodge [ Tue Aug 22, 2006 7:40 am ] |
| Post subject: | |
What carb do you have, is it the Holley 1920? Have you done a valve lash adjustment? DD |
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| Author: | turbocuda [ Tue Aug 22, 2006 4:20 pm ] |
| Post subject: | |
Sam Powell: Well I havent actually tried to adjust the idle so I do not know if the idle will change or not. The car idles somewhere between 800 and 900 and its supposed to be about 750 for an auto. What I was talking about and maybe u already know this but just to clarify, its when I try to get the air/fuel right and to get the best vac I can. It just doesnt seem to change. RDJ: I made sure to retorque the bolts when I came back and a few were loose but I tightend them back up so they should be fine. But I can try and re torque them and see maybe if theyve come out again. SlantSixDan: Would a casket seal I wonder?  Doctor Dodge: Yes sir its the 1920. Ive done the lash adjustments alot and it doesnt seem to want to stay adjusted. For example I adjusted them here a few months back because they were chattering somethin awful. Well I adjusted them and started the car and it ran great. It idled better and everything. So I adjusted them when they were hot. Well I let the car sit over night and I started it the next day and it was out of adjustment again. So now they are chattering like they were. Perhaps Im just not doing it right I dont know. Thanks guys |
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| Author: | Sam Powell [ Tue Aug 22, 2006 8:45 pm ] |
| Post subject: | |
The valves should quiet down when the car warms up. Dan, can I get a job as your staight man? That was pretty darned funny! Maybe that carb belongs in a casket. Maybe I should wear my glasses when I type on this forum!  The idle I was refereing to is the idle air mix adjustment, which I thought you were fiddling with and not getting any response. This is the small screw which is in the base of the carb. The head sticks out at about a 45degree angle to the line of the engine. When you turn it in, it shuts the air down, and makes the mixture richer. If you turn it all the way in, it should kill the engine. If it does not, then you are getting air in somewhere else. It could be that your idle adjustment on the throttle blade opening is open too far. This can be required if your timing is retarded too much. This is why you have to be able to check your timing too. Retarded initial timing will slow the engine idle down to the point that the throttle blade idle adjustment needs to be opened too far in order to get it to idle at all. Get the books Dan refers to in the other thread about tuning that is running now, and follow the sequence outlined in there for a tune up, and, you will get this right. Sam |
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| Author: | turbocuda [ Wed Aug 23, 2006 3:28 pm ] |
| Post subject: | |
They are out of adjustment cause even when its warm they still chatter. In all actuality I dont know much about tuning carbs but I do know that getting the most vac out of it usually means uve got a decent mixture. At best will pull 17 or 18lbs when hooked to the intake. I used to get 19 to 20 on it. But I know shes pullin air from somewhere otherwise it would idle in traffic. But I do not know how to find out where its coming from. Ive heard that spraying carb cleaner will affect the way the car runs if its sprayed over the place thats leaking. The whole soapy water thing just doesnt seem to work. |
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| Author: | dakight [ Wed Aug 23, 2006 4:11 pm ] |
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Soapy water won't work very well todetect a vacuum because the fluid is drawn into the leak and no visible bubbles will form. Use soapy water to find a pressure leak, not a vacuum leak. |
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| Author: | emsvitil [ Wed Aug 23, 2006 5:36 pm ] |
| Post subject: | |
Use WD40 (or similiar) to find a vacuum leak........ Since it will burn, the idle quality changes when you find the leak. |
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| Author: | turbocuda [ Thu Aug 24, 2006 1:07 am ] |
| Post subject: | |
Well I tried resetting the valves again. I hate doing that. I sounds better than it did. But more than likely tomorrow Ill start it and it will go right back to how it was. The car until its fully warm wants to quit even when making it idle at 2 grand. Once its warm something apparently expands and makes the leak (wherever its at) smaller. Also I dont know if this is normal or not but when I rev the engine I get a different result on my indash vac gauge as to how much vac I have. Ill try the wd40 tomorrow and see if I can find the leak. Thanks everyone. |
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| Author: | turbocuda [ Thu Aug 24, 2006 10:40 pm ] |
| Post subject: | |
Ok well I tried the WD40 and either its not leaking anywhere I sprayed it (around carb and intake and exhaust) or the WD40 thing doesnt work. So I warmed the car up and check the intake and exhaust bolts again. I tightened them fairly tight. Then I started the car again to see if it made any difference and it didnt seem to. So now what Im going to do is replace all the vac hoses and see if that makes any difference. One thing that bothers me though is that the intake thats on this engine is a later model intake so it has alot of vacuum places on it to hook things to. Also has a pcv system on it which I didnt think the 66 models had. The pcv itself on the valve cover doesnt fit real tight and if u shake it, it rattles which ive heard isnt good. So what im trying to figure out is how is this system supposed to work? If it doesnt belong how can I plug it off if I can? |
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| Author: | dakight [ Fri Aug 25, 2006 12:19 pm ] |
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All 66 models came equipped with PCV. I'm not sure when they were standard nationwide; I think it was either 63 or 64 but I know they were by 66. The PCV valve on that model fits into a cap which is held by friction and spring tension onto a chimney atop the valve cover; it's normal for there to be some movement in that setup. The PCV valve is supposed to rattle, if it does not then it is not functioning correctly. |
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| Author: | turbocuda [ Fri Aug 25, 2006 7:31 pm ] |
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I thought a pcv system couldnt work without the correct air cleaners plugs. My biggest concern is that there is oil going through the system and apparently it going into my carb. Which explain why when I rev the engine I get some blue smoke. I know it could be the piston rings as well. The valve seals I already replaced. Im not really familiar with the pcv system but its not supposed be putting oil into my carb is it? |
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| Author: | SlantSixDan [ Fri Aug 25, 2006 8:01 pm ] |
| Post subject: | |
Quote: I thought a pcv system couldnt work without the correct air cleaners plugs.
I can't quite make sense of this, because I don't know what "air cleaners plugs" are. But, for the PCV system to work, what is needed is the following:• Air inlet to the crankcase. Handled by the breather cap, which may be ducted to the air cleaner or may be vented direct to atmosphere. • Air outlet from the crankcase, via the correct-specification, clean, and correctly-operating PCV valve and hose to the fitting at the base of the carburetor. And that's it! Quote: My biggest concern is that there is oil going through the system and apparently it going into my carb.
Ah. Yeah, that's a problem. It's caused either by a whipped (dead-tired) engine, or by the use of an improper valve cover not equipped with a baffle under the PCV valve to keep the valve from sucking up oil and sending it along into the intake tract. You're not running one of those cruddy Chinese chrome valve covers or some other aftermarket cover...are ya?
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