Click on image for the lowdown. 
====
| | |
7 members (jay d, Bill Hanlon, RaNfLaS, GMCJammer51, DadsFirstPickup, Tyler Watts, Steelonsteel),
94
guests, and
3
robots. | | Key: Admin,
Global Mod,
Mod | | | Forums66 Topics128,048 Posts1,055,663 Members48,426 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Aug 2011 Posts: 835 Shop Shark | | Shop Shark Joined: Aug 2011 Posts: 835 | Have you checked to make sure your vacuum advance is working? You can check this by looking at the distributor with the engine running, and reach over and goose the throttle. You should see the whole distributor rotate 10 or 12 degrees. If it doesn't rotate, you may have a blown diaphram in the vacuum advance. This will affect your performance, and will cause a vacuum leak.
I would also check your gauge and make sure it is reading zero when it is not connected. Your altitude will affect the reading. It should have an adjustment to set it to zero.
Good luck!
Kurt | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | CASO,
Took a run at 3:00 PM. 8 miles.
Start Vacuum at idle 18-19" Rpm 1050 Temp <100
Return time 3:18 PM Vacuum at idle 18-19" RPM 1050 Temp 170
On run vacuum fluctuated 6" to 23". Step on gas vacuum drops. Let off gas vacuum is easily 22-23" Climbed that 1/2 mile long hill and vacuum drops to 0-6" about half the way up and Lucille is losing power and cut out twice. When I let off the gas she kicks back in immediately and vacuum is 10-15". Eased up on acceleration for the last half of the hill to get her to the top. What does that mean?
Thats the latest story.
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | that means that the fuel pump was the problem [as suggested way up this thread], and you need to learn how to use the choke properly, and get a higher thermostat - when it's not up to proper operating temperature it needs some choke, and 'proper operating temperature' is 180+ .... fergit the vacuum, the more you push the gas, the more the vacuum drops which is as it should be .... figure out how to operate the beast and just drive'er
Bill | | | | | Joined: Jun 2007 Posts: 134 Shop Shark | | Shop Shark Joined: Jun 2007 Posts: 134 | Haven't seen anyone mention it yet, but could there be a restriction in the exhaust? That could cause the vacuum to drop to zero. See Scenario 14 here: http://www.secondchancegarage.com/public/186.cfm | | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | situation seems more scenario 2 with the engine too cold, from the descriptions the vacuum doesn't stay at zero or drop with increasing throttle ..... but might help David to study that page
Bill | | | | | Joined: Feb 2012 Posts: 84 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2012 Posts: 84 | Forget vacuum, its fine, start looking at other things. I agree, a 180 thermostat is a must. You might have a partial fuel blockage somwhere as well. I had a quite similiar problem, pulled the top of the carb bowl and found what looked like a wheat hull paritaly blocking the float valve inlet. (Carter W-1) Starving the engine at peak demand. WOT, reduced flow can't keep up, bowl empties, engine starts cutting out. Let off, bowl refills, runs fine.
Last edited by Drydock; 03/15/2012 10:00 PM.
| | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | red58 and others, The thermostat point is well taken! As you can see by my previous post I hardly ever got to 180 degrees. I takes too long to get there. So, maybe I've either got the wrong thermo or I'm not patient enough to get her warmed up. It takes forever, it seems, to get to that temp. Maybe my fuel/air mixture is too rich. The only way you get a hot flame is with a lean mixture and the right amount of air. So, if I'm running under 180 degrees I may be running too rich, right? Does that make sence?
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | you're over thinking it all, just get it the way it should be, the reasoning was done by the Generals engineers 70 years ago - the ol 6 will run best warm but it has to be forced to warm up, and until it gets there use the choke when loading it, that's why they put it there .... my experience has always been that the 6's with a stock cooling system tend to run too cool with a stat less than 180, if you only get to 170 in 15 minutes you've got a 160-165 stat or a defective one that doesn't close properly
Bill | | | | | Joined: Feb 2012 Posts: 84 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2012 Posts: 84 | Read back, you've got a new filter just ahead of the carb, Have you ever had the thermostat housing off? You'ld be amazed how many folks just leave the dang thing out! | | | | | Joined: Jan 2010 Posts: 4,263 Shop Shark | | Shop Shark Joined: Jan 2010 Posts: 4,263 | Once you get the proper stat installed and engine warm, set your Carter per the steps below idling Adjustment steps 1-5 ignition timing steps 1-3 | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | First, I myself and a whole bunch of viewers greatly appreciate all of those who contributed to this thread and their knowledge about these old technology machines. I think there are many folks viewing that, like myself, who just don't know or undersatnd how these machines were designed to operate during that period of history. 1930's - 1960's. I think my thread has struck a nerve as seen by the number of folks viewing. If I can help others by my constant inquiry about performance issues that many have then I have learned alot and so have others. This is why Stovebolt.com is so successful.
I will switch out my thermostat to a 180 degree one. I had installed a new thermo 4 years ago when I got the truck, however, I don't recall what the rating was. I also didn't know at the time that 180 degrees was the appropriate temperature for a 216. I kind of thought at the time (and what do I know) cooler was better. Another example of old technology info that people aren't aware of.
DADS50, thanks for pointing me (and others) to some important steps for idle and timing adjustments. I'll try and knock them out next after I install the correct thermostat.
Once again, thank you all for your input. I couldn't do this alone without you.
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Feb 2000 Posts: 5,200 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 5,200 | Here is some more to think about,
Before changing the thermostat, drill a 1/8" hole in the edge of it to let air out of the head as you fill the coolant system. You can also force the stat open and slip a aspirin in the opening, as coolant enters and air exits, the aspirin will melt shutting the t-stat.
Forget the vacuum gauge, you can never get a steady reading while driving. Its doing what it should be doing. As for being low, who knows, it might be right for your engine, not all are the same, age, wear and tear all make a difference. Driving with a vacuum gauge is for fuel milage, try to keep it as high as possible and you will get the best fuel milage. That will mean a very tender foot on the accelerator.
Advancing the timing will bring up the vacuum at idle, its a good way to adjust the timing if you don't have a light. The idle speed will also increase as the timing is advanced, so back it off as you advance the timing to keep the mechanical advance weights in a closed position. As the engine speed increases, the timing should also advance from the mechanical weights being thrown outwards. You can check this with a timing light, slowly increase the throttle opening and the timing should slowly advance. In 1937 the distributor is designed with 46 degrees total advance @ 3500 rpm with 17 more degrees of vacuum advance. Our modern day fuels are much better then when the truck was being used, and your compression is way low compared to a modern engine, so more timing will have no damaging effects on the engine. If it helps great, if not return it back to where you started.
You carb is not running rich or it would climb hills. You have something wrong in the carb that is not letting the power circuit kick in. Engines require more fuel under a load such as climbing hills, so the carb is designed to increase the air to fuel ratio as the throttle is opened farther and farther. Get a shop manual and read up on the power circuit of the carb you are using, then pull yours apart and fix the problem! Reading my '37 manual, the original carburetors have a moving metering rod which adds fuel the higher its pulled out of the jet. Its a stepped rod with the power mode at the tip. If yours is not working or is adjusted wrong, it will never get to the power circuit thus causing your hill climbing problems.
Idle adjustments only effect idle. Once the throttle is open, it bypasses the idle circuit.
Vacuum advance will also not effect the power circuit since the vacuum drops to zero when the engine is accelerating. Vacuum advance is good for fuel milage, it pulls in a bunch more timing at light throttle or cruise when there is little or no load on the engine. As the load increases, the vacuum drops and the timing retards back to the original setting. Just make sure its working, theres no vacuum leak, and your timing is set a few higher then stock.
Joe | | | | | Joined: Jun 2008 Posts: 1,388 Shop Shark | | Shop Shark Joined: Jun 2008 Posts: 1,388 | How about the exhaust riser valve? Is it functioning? I don't recall seeing it mentioned it above (but I could have easily missed it). | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | Thanks for all the input folks!
As of right now I have pulled my carburetor and went back and reviewed what I did when I rebuilt it in 2007. There is only 1200 miles on that that carb, but I did notice that I had made a note about some missing felt washers in the rebuild kit. They were little felt washers that were suppose to be slipped over each end of the throttle shaft. I can see that there was leakage there on the outside. Finding a tiny felt washer to seal the leak around the throttle shaft would be impossible, so, I made my own out of leather. I took 1/8" thick leather, cut it to a 1/2" square and punched a 5/16" hole in it so it would slip over the throttle shaft. Then I split that little piece of leather in half to get two 1/16" thick leather washers and installed them. After putting the whole carb back together I put a little 3and1 oil on those leather gaskets. Worked like a champ!
I totally understand "Joe H's" comment about the power circuit. I didn't break down the carb this time because I've already been there on a rebuild and I didn't want to screw up all the gaskets. So, I'm gambling that they supplied me with the correct parts to preform a decent rebuild and are functioning correctly.
I'm really glad that I had to pull the carb again just to address those two little seals, because I was shocked what I found when I disconnected the gas line! Earlier on this thread we were going through and trying to figure out if the fuel pump was "the problem". "Hotrod Lincoln" gave me some very good info on fuel pump inlet vacuum and outlet pressure. Well, I tried to check the outlet pressure of the old fuel pump with my pressure/vacuum gage. On the positive side of the pump I had disconnected the gas line just before the carb . I inserted the plastic tapered fitting on my tubing connected to the gage into the gas line to try and get a reading. To shorten this story, the gasoline attacked the plastic and it broke off inside the gas line steel tubing. I wasn't aware of that until today. With the new fuel pump installed it pushed the broken off plastic tapered tip forward enough so that I was able to extract the plastic piece out that was hampering the fuel flow to the carb. WHAT ARE THE ODDS??.
Today I also installed the 180 degree thermostat, however, not without, "silly me", forgetting to install a "new" thermostat housing gasket. A run down to NAPA solved that "airhead" moment.
I've got one more thing I want to do before I take Lucille on a run. Just an annoying "leak" (4 letter word) from her tranny. I used a non-seize bolt material on the threads of the drain and filler plugs and the gear oil is leaking past this material. Gonna drain the tranny and put some leak proof sealant on the threads of the plugs and refill the tranny. Don't want to screw up my tranny!!
Once again, I'M EXHAUSTED OVER HERE!!
Oh, BTW, tomorrow I promised my wife that I would get away from Lucille and give her (my wife) a little attention. Like getting out for a "little Sunday lunch"!
On Monday I'll give you all a performance report. Hopefully "climbing hills" is not an issue any more!!
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Oct 2002 Posts: 4,066 Bolter | | Bolter Joined: Oct 2002 Posts: 4,066 | install you a hemi with 560 gear.. that baby will go up hill then Redryder pixMy HotrodA veteran - whether active duty, retired, national guard, or reserve - is someone who, at one point in his or her life, wrote a blank check made payable to The 'United States of America', for an amount of "up to and including my life."I am fighting cancer and I am winning the fight | Pain is part of life; misery is an option. | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | Now that's really funny right there!!!
Then I'd have to change her name to "Screaming MAMA", or "Hemmingbird" and she'd be flying over Texas in a heartbeat!!
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Feb 2012 Posts: 84 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2012 Posts: 84 | I kept thinking, it sounds like fuel starvation! Glad you found it!  | | | | | Joined: Oct 2002 Posts: 4,066 Bolter | | Bolter Joined: Oct 2002 Posts: 4,066 | Redryder pixMy HotrodA veteran - whether active duty, retired, national guard, or reserve - is someone who, at one point in his or her life, wrote a blank check made payable to The 'United States of America', for an amount of "up to and including my life."I am fighting cancer and I am winning the fight | Pain is part of life; misery is an option. | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | I don't know what to say, jeez....I'm tearing up over here...where has she gone...
I thank you for your heartfelt compassion.
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Jan 2010 Posts: 4,263 Shop Shark | | Shop Shark Joined: Jan 2010 Posts: 4,263 | Might want to do a carb rebuilds anyway. Sounds like the piece of plastic was past the filter. Any little crud in the carb will cause problems.
I find the accelerator pumps in the carbs don't last me long at all. I had to replace 2 last year.
Enjoy your Sunday with the family. | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | "Houston, we have lift-off!"
Man-o-man, what a difference! I finally have POWER!! Climbing hills is not a problem any more!! Amazing what a new fuel pump and unrestricted fuel lines will do. I should have done this first thing when I got the truck. Only thing is, she had soooo many problems with her that it was, OK, which one do I attack first??
Anyway, I'm glad I won the battle!! Thanks to all of you who helped me conquer this problem.
Oh, one other detail I did this morning was to get Lucille and new throttle control spring. The old one didn't have enough strength to it especially since I installed those new leather seals on the throttle shaft of the carb.
Now it's time for some cruising!! Ha, ha!!
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Jun 2011 Posts: 1,901 Shop Shark | | Shop Shark Joined: Jun 2011 Posts: 1,901 | thanks for the up date...  so in the end can we safely 'guess' that it was a partially plugged fuel passage that was the culprit causing the 'original' lack of power complaint and every thing else that got fixed was really just required normal maintenance we can all expect to encounter sooner or later? Truth is I think these types of issues are half the fun (if you can call it that) of owning one of these rigs. No, "where do I plug the computer in?" here.... just good ol scientific method at work coming up with theories and testing them for validity.
Give me ambiguity or give me something else
| | | | | Joined: Jul 2005 Posts: 946 'Bolter | | 'Bolter Joined: Jul 2005 Posts: 946 | Whoo hoo! It's great when it's something easy. You fixed the fuel leak on the carb too, right?
| | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | CASO, Your close! The real problem from the get go was the fuel pump. I don't know how old it was, but it was shot! The diaphram was plain worn out. Sometimes you can tell from the outside if it looks like its leaking. In my case there were no tags attached to show anyone it's age. You would think that it would be date stamped. So, I thought I could try and take it apart and "monkey" with it to get it to perform better, but that turned out to be a waste of time. Just buy a new one!! I paid $44.00 for one at NAPA.
The blockage was my creation. As I said before, when I went to try and check fuel pump pressure on the "old" pump I inserted a tapered nozzle like probe into the gas line just ahead of the fuel filter which was just ahead of the carb. The gasoline attacked the plastic and degraded the fitting. Lesson learned, don't stick plastic probes into gasoline!! Some plastics can handle gasoline and some can't. I should have had a hose connection on the "outside" of the gas line to check the pressure. Oh, and BTW, this engine analysis kit I have is from the '70's. A good friend of mind gave it to me one day when he found out I had aquired and old truck. So that little plastic probe in that old kit just wasn't compatible to be exposed to gasoline.
Anyway, I would suggest everyone check their fuel pump and if it isn't delivering the correct fuel rate, get a new one right off the bat!! End the drama and frustration!
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | | | | Joined: Oct 2007 Posts: 397 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 397 | jomichael, Yep, the leak at the throttle shaft is gone!
"Lucille" ..... Proud Member of the "Southern Stovebolts" David Wolff 1946 Chevy 1/2-ton In the Gallery | | |
| |