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| Surge under Acceleration https://slantsix.org/forum/viewtopic.php?t=16336 |
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| Author: | Slantedbrain [ Sun Feb 26, 2006 9:21 am ] |
| Post subject: | Surge under Acceleration |
1971 Engine, 77k miles, 1bbl Holley. Engine, and myself, experiece a surge under accerlation. Once we're at WOT though, it seems to go away. Sounds like a vacuum problem-o. I'm too tired and depressed right now to add more. Ask if you need more info, or let me know what I should hit real hard with a hammer. |
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| Author: | Slant6Ram [ Tue Feb 28, 2006 12:49 pm ] |
| Post subject: | Still Running |
How much have you done since I last looked at the car? I bet the valves are needing a fine tuning again. Might not have anything to do with the surging though. Good to hear it's still going for you. If you ever want to trade to a good running 2 door, let me know. 
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| Author: | Dennis Weaver [ Tue Feb 28, 2006 2:03 pm ] |
| Post subject: | |
I always hear this and that about lashing the valves here at this site. I've had many cars with slant sixes, 273's and pot-belly 318's (mechanical cams, all) in all sorts of states of prior use and abuse (read-worn out and lack of maintenance), and besides some clackety-clack, never had an issue with valve adjustment besides noise and maybe a little bit of a rough idle. Should you lash the valves periodically? Yes, but some of you just seem to be super anal about it! Unless the lash is so loose that the valve is barely opening, OR alternatively if they are TOO TIGHT, you really won't notice that much of a difference with a lash "fine tuning"... Not saying it's a bad idea, just saying I doubt it's an issue. D/W |
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| Author: | Slantedbrain [ Tue Feb 28, 2006 3:01 pm ] |
| Post subject: | 12 Lashes for your insolence |
Sorry, just sounded silly. Umm, as for how much I've done, not a whole lot. Just basic maintenance, changed the oil, used SSD's engine cleansing milkshake, used good gas and such. As for the setting the valve lash, phoo, on mine, yeah....it made a huge difference. I'm gonna have to give you a call some time and get my white.....car over there and have you help me find the fun problems on it, that and i believe i owe you some money for an intake/exhaust gasket, seeing as I'd like to get those problems fixed and upgrades done sometime. |
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| Author: | Jeb [ Tue Feb 28, 2006 5:54 pm ] |
| Post subject: | |
Sounds like your carb is running way to lean. The reason whay it goes away at WOT is because the power valve is open, covering the lean spot. You may need to jet up a notch. What size jet does your carb have in it now. Or it may be the infamous metering block problems that plague a lot of Holley 1920s. |
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| Author: | Slantedbrain [ Tue Feb 28, 2006 6:49 pm ] |
| Post subject: | Oh goodie. |
What jet size does it have? No idea, i've never torn into to it to find out. but it wouldn't really surprise me at this point. I'll just be happy when i can get the super six setup i have sitting in my garage on it. [size=x-small]Thanks Phil[/size] It really wouldn't surprise me, like i said, if this wonderful piece of holley-rific fuel delivery engineering has finally bit the dust. |
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| Author: | Slant6Ram [ Wed Mar 01, 2006 7:02 am ] |
| Post subject: | What's with the funny sayings? |
Dennis, several months ago we adjusted the valve lash for the first time in this car's life. All of the exhaust valves where extremely tight, indicating badly worn or burnt conditions. It ran MUCH better after the adjustment. I just don't know how much the adjustment will change as the valves re-seat. I'm sure the head should be rebuilt. I've got a couple of cores if he wants to send one out for rebuild and eventual swap. I still have a couple of those gaskets when you are ready to do an intake swap. When they run out, I'll get more. I've got 2 or 3 old holley 1920 carbs in a box. When I was still using one, I had several extra jets, but I'm not sure what sizes. If you buy a rebuild kit for the carb, we could tear into it and clean it out and see what size jet you've got. I should have a bigger jet in the ashtray of my truck still. I bet you've got a vacuum leak causing some of that surging. If you pulled all of the spark plugs, you should be able to 'read' the color to see if one is leaner than the rest or if any are fouled. A lean plug would look white. If they are all lean, then it's the main jet. |
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| Author: | Jeb [ Wed Mar 01, 2006 8:51 am ] |
| Post subject: | |
Might be a worn throttle shaft. See if you can wiggle the shaft any. Also look for fuel stains on the shaft. |
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| Author: | Dennis Weaver [ Wed Mar 01, 2006 9:14 am ] |
| Post subject: | Re: What's with the funny sayings? |
Quote: I bet you've got a vacuum leak causing some of that surging.
I'll concur with that. Wasn't meaning to jump on you personally, either Slant6Ram, and obviously adjusting the valves the first go around solved some problems for the two of you. My point was just that miniscule little valve adjusments (I'm talking in the big scheme here, not just this specific case) are not going to make a big difference.D/W |
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| Author: | Dennis Weaver [ Wed Mar 01, 2006 9:17 am ] |
| Post subject: | |
Quote: Might be a worn throttle shaft. See if you can wiggle the shaft any. Also look for fuel stains on the shaft.
Jeb, a worn throttle shaft usually causes idle problems. By the time the air gets flowing, the air leaking past the shaft is such a small percentage of overall air flow thru the carb that it doesn't make much of a difference. It could make it just a wee lean if it was really shot...D/W |
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| Author: | 70valiant [ Wed Mar 01, 2006 3:56 pm ] |
| Post subject: | |
Hey SlantedBrain I have a carter BBS sitting in the garageI am never going to use that I would let go cheap, PM me if you want it. the guy my brother in law got the engine from said it ran fine. Also I have a rebuilt head that just needs 2 studs extracted. shipping would be awfull but I could bring it to Carlisle in July or Pittsburgh in August, again I would make you a deal you cant pass up. P.S. your welcome on the SS |
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| Author: | Slantedbrain [ Thu Mar 09, 2006 6:42 am ] |
| Post subject: | The surge is gone! |
Its fixed, turns out it was a massive vacuum leak caused by.... The carb, actually the carb mounting bolts, they were loose, so everytime i hit the throttle it would pull the carb around making a nice vacuum leak at the bottom of the carb, tightened it down and Voila! its fixed. Many thanks to Slant6Ram for helping me out with this. |
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| Author: | Slant6Ram [ Fri Mar 10, 2006 2:41 pm ] |
| Post subject: | Good clean fun |
Quote: Might be a worn throttle shaft.
While checking the throttle shaft, I noticed the entire carb moved. the nut on the engine side of the carb took two full turns before it hit the carb. We knew we had found the problem instantly. Also got the oil light to go out by replacing the sender. All in all it was a pretty good wrenching session. Love that car! Sure you don't want to trade for one of my 2 door models?
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