OK, then, anyone who can explain WHY max vacuum isn't the best setting? It just seems to me that it should be.
OK you carb experts
- Thread starter Romer
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When I used Vacuum to set my timing, it idled great but ran like crap. I backed it off and it runs fine. I set it (DUI) to 13 deg advnace (Bubble being 7deg). Thats what the DUI instructions also recommended.
Pighead said:
Yes, it causes pinging. Is that because when you are under load the vacuum advance of the carb/dizzy advances the timing too far and then you predetonate? (Thinking I just answered my own question, here
)
PabloCruise
SILVER Star
Sounds like all this is similar to the lean drop method - also in FSM
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- #26
I adjusted the varb per Mike and Dave's instructions above and it does seem to run better. I had my idle set a little high before, and now it seems to be in spec. Runs great warm. I'll let it sit overnight and see how it is cold. I know I'll need some choke until it warms up.
Also adjusted the tailpipe with a crow bar and pointed it down more, left it coming out the back end. Didn't notice any smell while driving, but I only drove for about 4 miles.
Thanks Guys - Its always great being able to tweek here and there and improve things
Ken
Also adjusted the tailpipe with a crow bar and pointed it down more, left it coming out the back end. Didn't notice any smell while driving, but I only drove for about 4 miles.
Thanks Guys - Its always great being able to tweek here and there and improve things
Ken
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bump. I just had to bring this up again for someone on Pirate who asked about it. Good stuff. 
I went with a Holley 350 2 bbl because I live at 2300 ft, but hunt at 9000 ft, and the stock TY carbs could not handle it. I tried both the single barrel and the 2 bbl, with the same result. The Holley has a 2 stage power valve which gives me power up to about 10000 ft.
They have a tendency to flood in rough terrain unless set up properly, but I've been running mine for 5 years now, with no problems. It has ported vacuum, so it works with the TY distributors.
They have a tendency to flood in rough terrain unless set up properly, but I've been running mine for 5 years now, with no problems. It has ported vacuum, so it works with the TY distributors.
treerootCo wrote up an excellent guide.
I'd like to add that a vacuum gage can be used for much more than just setting idle. It's also an excellent diagnostic tool for checking vacuum leaks, plugged exhaust systems (like a clogged catalytic converter), broken valve springs, etc.
I equip most of my older vehicles with a vacuum gage so I can adjust them, watch for problems, and try to get the best fuel economy (highest needle reading during cruise). They're also good for selecting power valves. In addition to a gage somewhere on or under the dash, I also have one in my toolbox so I can hook it up in the engine compartment to make adjustments easier. In my racing days, I had one mounted in the engine compartment.
Here are a couple of websites with good charts. The second link is especially good.
http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm
http://www.earlycuda.org/tech/vacuum2.htm
I'd like to add that a vacuum gage can be used for much more than just setting idle. It's also an excellent diagnostic tool for checking vacuum leaks, plugged exhaust systems (like a clogged catalytic converter), broken valve springs, etc.
I equip most of my older vehicles with a vacuum gage so I can adjust them, watch for problems, and try to get the best fuel economy (highest needle reading during cruise). They're also good for selecting power valves. In addition to a gage somewhere on or under the dash, I also have one in my toolbox so I can hook it up in the engine compartment to make adjustments easier. In my racing days, I had one mounted in the engine compartment.
Here are a couple of websites with good charts. The second link is especially good.
http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm
http://www.earlycuda.org/tech/vacuum2.htm
how much does a Jim c Rebuild cost? does it compare to just slapping the weber on?
No comparison. A properly rebuilt stock carb will outperform the Weber and get better mileage at the same time.
PM JimC for a price. A bit over 3 Benjamins I should think. http://www.marksoffroad.net did a bang-up job on mine for around that price too.
Guys pleas post a pic of where you fit the vacuum gage, is it between the dizzy and the carb, i have no clue here
ok, no worries, i found it using the search
was around $300. will outperform the weber by far! weber's are not a great carb to begin with. jim takes a good carb and tweaks it to make it better.
Catching Neutral
GOLD Star
Gary,
Get a vacuum guage from NAPA, or any auto parts store. Got one from advanced auto. It works great and I have had it hooked up quite a few times to check things out.
Get a vacuum guage from NAPA, or any auto parts store. Got one from advanced auto. It works great and I have had it hooked up quite a few times to check things out.
