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| Carb issues with my 73 slant 6 https://slantsix.org/forum/viewtopic.php?t=17028 |
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| Author: | andrewhed [ Wed Apr 12, 2006 2:29 pm ] |
| Post subject: | Carb issues with my 73 slant 6 |
I bought a 73 valiant from a little old lady a few months back, 69k miles, always very maintained. It sat over the winter in a garage, and this spring it out and isnt running so hot. runs ok under throttle, but idles rough. Intermittantly it will run ok, but then will return to running rough. I have done the usual suspects, replaced the fuel filter, cleaned the carb with carb cleaner, replaced the plugs, changed the air cleaner and crank pressure filter....run some carb cleaner additive to the tank. Looking at the carb, im thinking that its original. an old holly which came with the car right? So im getting around to thinking thats the issue. But ive heard so many horror stories about these - you cannot just go to autozone and buy one of those remanufactured ones for 94 dollars can you? Should I have this one professionally rebuilt? Any other suggestions i might try? Thanks for any ideas. |
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| Author: | stuggin [ Wed Apr 12, 2006 4:32 pm ] |
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I just rebuilt my carb myself a couple of months back, and even though it was a different make (Carter BBS) it was really simple to do and i can't imagine it would be that much harder for a Holley. So, don't waste your hard earned $$$ on a pro rebuild, just do it yourself. Allen |
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| Author: | Reed [ Wed Apr 12, 2006 4:37 pm ] |
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Hi and welcome to the forum! I agree, you can spend les smoney and rebuild it yourself. It sounds like the carb has siome gummed up internal passages or you have a vacuum leak somewhere. Since the car has only 69k on it I would recommend you do a thorough tune-up and check all your gaskets, vacuum pods (distributor and choke pulloff), filters, cap, rotor, plugs etc... Cars that don't get driven enough get some problems. |
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| Author: | andrewhed [ Wed Apr 12, 2006 5:36 pm ] |
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thanks guys, all the tune up stuff look good and ive done all that stuff. Maybe I will redo the carb, but i thought that particular carb had a problem with the bushings or something and that was why people paid to have them redone, to have the throttle plate or something drilled out and rebushed? Sorry about the terminology, im a fuel injection guy! There is a fellow about an hour from me the rebuileds carbs, famous for doing those painful jeep cj carbs, that will do mine for like 40 bucks. Is a rebulld just new seals and stuff? The only carb ive ever rebuilt was a english stromberg thing that aint like that holly at all, and a merc outboard carb. Dont reall know what im doing. Not that i cannot learn...i just dont have a clue! |
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| Author: | SlantSixDan [ Wed Apr 12, 2006 6:10 pm ] |
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Welcome onboard! You've got lots of good options. If you've successfully survived the ordeal of coping with a Zenith-Stromburg "carburettor", you should have zero trouble rebuilding your Holley 1920. Or, since it sounds like you've got excellent local talent who's offered you a terrific price for the work—the tipoff is that he knows the troubles with the AMC BBDs and, presumably, how to fix them—you'd probably be money ahead to let him go ahead and do it, saving you the cash and hassle of buying dip-type carburetor cleaner and such. Your '73 will run considerably better if you will bypass the OSAC valve. |
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| Author: | andrewhed [ Wed Apr 12, 2006 7:20 pm ] |
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hmm. i think i will have that guy rebuild that carb. whats a osac valve? |
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| Author: | SlantSixDan [ Wed Apr 12, 2006 8:11 pm ] |
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OSAC valve info, see Here. Other posts to read and follow: This one and This one Next time you're due for spark plugs, get NGK ZFR5N ones, and remember, on your '73 the ring gaskets that come with the spark plug (any spark plug for your application) are not used! |
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| Author: | andrewhed [ Wed Apr 12, 2006 8:24 pm ] |
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ahhh! I kept the ring gaskets on my plugs, should i pull em off? is that what those cups that go in the head take the place of? Those cups in my old slant 6 didnt come out if i remember. but these came right out. I should just thread the plug through that cup and then into the head eh? Makes sense. And i was wondering what that stupid setup on my firewall was. I had a 73 before, and it didnt have that. I think it already got ripped off! I had a 74, and it went into the air cleaner like you mentioned. Thats comin off tommorow. and ill pull those plugs. I got cheepo champion. they were 6 dolllars for 6... Maybe time for new plugs now? Thanks for everything Andrew |
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| Author: | SlantSixDan [ Wed Apr 12, 2006 8:58 pm ] |
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Quote: ahhh! I kept the ring gaskets on my plugs, should i pull em off? is that what those cups that go in the head take the place of?
Yepper!Quote: I should just thread the plug through that cup and then into the head eh?
Yes. You may want to replace the spark plug "cup" (actually tube)) seals while you're at it. Fel-Pro ES12794 (set of six plug tube seals) or NAPA Victor-Reinz B45384 (individual spark plug tube seal). These are the rubber O-rings that seal the plug tubes to the head to prevent oil leaking.Quote: I got cheepo champion. they were 6 dolllars for 6...
The NGK ZFR5N plugs aren't all that much more costly. We're not talkin' about those silly $4 and $5 gimmicky plugs here.
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| Author: | andrewhed [ Wed Apr 12, 2006 9:21 pm ] |
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hey thanks, maybe if i put the plugs in right and fix that stupid valve thing it will run right. Maybe i dont need a carb rebuild anywho? The very intermittant nature of the problem led me to think vaccuum right away. Thanks for the reply. |
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| Author: | Charrlie_S [ Thu Apr 13, 2006 3:11 am ] |
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Might I sugest, a valve adjustment. |
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| Author: | SlantSixDan [ Thu Apr 13, 2006 7:40 am ] |
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Quote: hey thanks, maybe if i put the plugs in right and fix that stupid valve thing it will run right. Maybe i dont need a carb rebuild anywho?
You do almost certainly need a carb rebuild.
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| Author: | andrewhed [ Thu Apr 13, 2006 3:51 pm ] |
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Well, took that vac line that goes to that crazy valve off today, and run it stright from the distributor to the carb. Runs a whole lot better with my foot into it. Its amazing what unimpeded vacuum advance does for the car. Still idles like garbage though....time for a rebuilt carb. Gonna replace those spark plugs this weekend with decent ones and not fit those rings. I had a slant 6 in the 80's for a good 5 years, and always put those rings on....whats the logic behind not using them? Andrew |
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| Author: | SlantSixDan [ Thu Apr 13, 2006 4:00 pm ] |
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Quote: Well, took that vac line that goes to that crazy valve off today, and run it stright from the distributor to the carb. Runs a whole lot better with my foot into it
This exact quote has been uttered or typed probably tens of thousands of times since 1973. Down the street from me lives a super clean green 4-door '74 Valiant. 225/auto, original owner. High school math teacher. Very polite and quiet in that uniquely Canadian way. Was talking about his car with him one day a few years ago and looking under the hood, watching the well-tuned 225 idle smoothly and without a hint of tappet click. Noticed the intact OSAC and asked permission to move one vacuum hose under his hood in a completely reversible manner. He consented.Few days later he knocked on the door and said "WOW! I've been living with that hesitation since the '70s, and now it's GONE!" Quote: Still idles like garbage though....time for a rebuilt carb.
Yep, I agree. If you need a short-term stopgap, remove the air cleaner lid, peer down into the carburetor and find the hole facing upward in the inner sidewall of the carb throat that is sized just perfectly to accept the shooter straw on your spray can of carb cleaner. Insert the straw fully into the hole and hit the spray button. This may blast enough of the junk out of the carb's idle circuit that things improve.Quote: I had a slant 6 in the 80's for a good 5 years, and always put those rings on....whats the logic behind not using them?
All slant-6 heads from 1963 to 1974 are designed such that the spark plug tubes themselves are the gaskets. Sometimes the ring gaskets are tough to remove, but that's the correct thing to do. The factory service information is very clear on this point. That said, it's not totally disastrous if you leave them on. The plugs just run somewhat hotter and you are more likely to get pinging under some circumstances.'60-'62 heads are designed such that you are supposed to use the gaskets, while '75-up heads use non-gasket taper-seat plugs. Factory info, see Here. |
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| Author: | andrewhed [ Thu Apr 13, 2006 4:13 pm ] |
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Quote: Might I sugest, a valve adjustment.
Ah do i have to? Its so darn quiet! Then again my vw bus motor was real quiet right before it burnt a valve.... |
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