| Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278291] |
Sun, 24 May 2015 12:04  |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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I still am at a loss to my drop in vacuum and stalling after engine has been running for 15 minutes. I have since replaced both mufflers and have no restricted exhaust. I have an ignition module being shipped for future installment. I have solved other problems but just can't seem to nail this one. Choke pulloff and idle screws could be the culprit ??? Anyways vapor lock could be it??? Thanks for any input
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
[Updated on: Sun, 24 May 2015 12:06] Report message to a moderator |
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278299 is a reply to message #278291] |
Sun, 24 May 2015 13:59  |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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I didn't have the symptom right away after I did the heads and intake manifold. My intake was bathed and didn't see any cracks though I hear sometimes they are hard to see with the naked eye. I did the exhaust block off plates and that is supposed to keep the intake cooler I heard. Anyway, I tried plugging the vapor line before the cannister and it ran the same attached to cannister and off and plugged. I have made headway on other issues and I suspect choke pulloff and high speed idle screw are the next things to try to study and understand. Let's hope my intake is fine... Might have a sticky exhaust valve??? thanks
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278316 is a reply to message #278299] |
Sun, 24 May 2015 19:26 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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budworks521 wrote on Sun, 24 May 2015 14:59I didn't have the symptom right away after I did the heads and intake manifold. My intake was bathed and didn't see any cracks though I hear sometimes they are hard to see with the naked eye. I did the exhaust block off plates and that is supposed to keep the intake cooler I heard. Anyway, I tried plugging the vapor line before the cannister and it ran the same attached to cannister and off and plugged. I have made headway on other issues and I suspect choke pulloff and high speed idle screw are the next things to try to study and understand. Let's hope my intake is fine... Might have a sticky exhaust valve??? thanks
Larry,
We haven't had temperatures in Michigan for vapor lock yet.... Unless maybe you still have winter fuel in the tanks.
I can pretty much guaranty you don't have a sticky exhaust valve. If they stick open, they burn out almost instantly. If one sticks closed, it will trash the valve gear also instantly.
It's a 74, do you still have points in the distributor? If yes, try a new condenser. They are cheap and they fail a lot like this.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278322 is a reply to message #278316] |
Sun, 24 May 2015 20:52 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Matt Colie wrote on Sun, 24 May 2015 19:26budworks521 wrote on Sun, 24 May 2015 14:59I didn't have the symptom right away after I did the heads and intake manifold. My intake was bathed and didn't see any cracks though I hear sometimes they are hard to see with the naked eye. I did the exhaust block off plates and that is supposed to keep the intake cooler I heard. Anyway, I tried plugging the vapor line before the cannister and it ran the same attached to cannister and off and plugged. I have made headway on other issues and I suspect choke pulloff and high speed idle screw are the next things to try to study and understand. Let's hope my intake is fine... Might have a sticky exhaust valve??? thanks
Larry,
We haven't had temperatures in Michigan for vapor lock yet.... Unless maybe you still have winter fuel in the tanks.
I can pretty much guaranty you don't have a sticky exhaust valve. If they stick open, they burn out almost instantly. If one sticks closed, it will trash the valve gear also instantly.
It's a 74, do you still have points in the distributor? If yes, try a new condenser. They are cheap and they fail a lot like this.
Matt
If the condenser failed...sure as hell the points have pitted. Look at the points, if they are badly pitted, new points and condenser are now in order. JMHO
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278334 is a reply to message #278291] |
Sun, 24 May 2015 23:42 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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budworks521 wrote on Sun, 24 May 2015 10:04I still am at a loss to my drop in vacuum and stalling after engine has been running for 15 minutes.
Is the vacuum dropping at idle or are you having to give it more throttle to try to keep it running. If the throttle is still at idle, I would think the crack theory could be a good theory.
If you are having to give it more gas to try to keep it running, then I would look to ignition. Coils also break down in heat as well as modules and perhaps condensers.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278336 is a reply to message #278291] |
Mon, 25 May 2015 00:06 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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budworks521 wrote on Sun, 24 May 2015 10:04I still am at a loss to my drop in vacuum and stalling after engine has been running for 15 minutes.
I was thinking of a test for a crack in the manifold. Here is my shade tree method:
Start with a cold engine. Disconnect the hose from the PCV valve from the carburetor, and plug the port on the carburetor. Pull the breather off the other valve cover. Make sure the oil fill is closed tightly and the dip stick is in firmly.
At this point a normal engine at idle should have a small amount of blow-by vapor whiffing out of the breather.You can put a baggy or plastic bag over the the breather to see if there is a vacuum or positive pressure.. Hang On To It! (When we did this test on a 403 with a bad intake gasket the baggy was almost sucked into the valve cover.)
As it begins to loose vacuum, the crack will begin to suck air from the valley. To make sure this is happening, take the baggy and place it over the breather again. Again, hang on to it. If the crack is opening and air is getting into the intake, causing the vacuum to drop it will create a vacuum in the block.You will see the baggy sucking in the valve cover.
Constant breather vacuum at all temperatures can mean an intake port gasket is leaking on the valley side of the intake. I doubt this will be the case as vacuum drops and the engine warms.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278349 is a reply to message #278291] |
Mon, 25 May 2015 06:30 |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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I have the HEI ignition and have a new Delco module being shipped to replace. It still acts like a slow steady decline in vacuum and then a stall. My vacuum to start once idling is fairly steady and at 17. Probably for 10 minutes and temp at 195 degrees. I did some adjustments to the idle screws again, the choke, and fast idle screw to no avail. My plugs are showing MUCH better burning except number 1 was a bit sooty and number 5 was a bit gassy/oily but overall they improved dramatically compared to before. It is tough for me to study the guide/manual and fully understand all the moving parts associated with the quadra jet. I wonder if since I redid the heads and intake and dropped the distributor in is it possible that my timing mark says 12 degrees tdc but I could be at a different location based on where the piston was in the cyclinder. If the piston wasn't in an exact spot to start off maybe I am getting a bad read on my timing. ??? New module coming and we'll see. Besides the coil in the HEI is there other stuff to look for in the cap. The cap and rotor are new. Thanks gentlemen
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278399 is a reply to message #278291] |
Mon, 25 May 2015 18:55 |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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Senior Member |
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It showed up mid stream after the work. It was running fine after initial repair and as I was trying to seal a few minor leaks all hell broke loose on various front. I have made outstanding progress but just a few minor things to get it right. Thanks
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278429 is a reply to message #278322] |
Tue, 26 May 2015 09:02 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Larry wrote on Sun, 24 May 2015 21:52Matt Colie wrote on Sun, 24 May 2015 19:26Larry,
We haven't had temperatures in Michigan for vapor lock yet.... Unless maybe you still have winter fuel in the tanks.
I can pretty much guaranty you don't have a sticky exhaust valve. If they stick open, they burn out almost instantly. If one sticks closed, it will trash the valve gear also instantly.
It's a 74, do you still have points in the distributor? If yes, try a new condenser. They are cheap and they fail a lot like this.
Matt
If the condenser failed...sure as hell the points have pitted. Look at the points, if they are badly pitted, new points and condenser are now in order. JMHO
An it is every bit as valid as anybody else's, but I have had two condensers that would short when hot. So the points looked great, but no spark at all. When it cooled off, the engine would run fine. I want you to think that I found this right away and didn't stumble around replacing parts and tearing my hair out in tufts.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278541 is a reply to message #278291] |
Wed, 27 May 2015 13:39 |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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Senior Member |
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Well it wasn't the module. Gosh dang thing sounds great until it bogs and quits. Oh boy 12 minutes in idle and great and then the big bummer. I am thinking of getting a vacuum pump and start pumping on it to see if the vac goes back up once it starts stalling. It could be the coil maybe. What the hell is that round thing next to the module hookup close to driver's side? Do HEI have condensors located in the cap???I guess I need to study more stuff on the internet! Thanks for the input guys
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278560 is a reply to message #278541] |
Wed, 27 May 2015 17:00 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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budworks521 wrote on Wed, 27 May 2015 11:39Well it wasn't the module. Gosh dang thing sounds great until it bogs and quits. Oh boy 12 minutes in idle and great and then the big bummer. I am thinking of getting a vacuum pump and start pumping on it to see if the vac goes back up once it starts stalling. It could be the coil maybe. What the hell is that round thing next to the module hookup close to driver's side? Do HEI have condensors located in the cap???I guess I need to study more stuff on the internet! Thanks for the input guys
Right after it stalls, look down the carburetor and pump the gas. Do the accelerator pump jets squirt? I assume it won't restart after it bogs down. Might try dumping a bit of gas down the carburetor and seeing if it will start. This would at least separate out the fuel vs. spark. If it runs a bit it still could be the intake leaking, but I am beginning to doubt it. 12 minutes of idle is not much time to build up heat in the intake.
Another spark angle: Pull off the rotor and flip it over. Look carefully for signs of spark leaking through the ridge in the underside. Look on the weights to make sure spark is not jumping to the weights from the ridge in the underside of the cap.
If by round thing you mean the small steel tube, that is a condenser. I think it is for radio static and not part of the module ignition.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278587 is a reply to message #278584] |
Wed, 27 May 2015 21:58 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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JohnL455 wrote on Wed, 27 May 2015 19:17Your sig file says 74
You say you have HEI
HEI started in 75-76
Someone did a conversion
Did they run a hard 12V ign switched power to the HEI?
Or is it running off resistance wire for pionts??
As wire heats up voltage drops till it dies is my theory.
This is a good one. Good thinking, John. Check the voltage at the HEI Batt terminal on the little conning tower. Should be straight battery voltage.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278632 is a reply to message #278291] |
Thu, 28 May 2015 13:10 |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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Senior Member |
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It has the thicker wire connection to the distributor. I did a systems check by the door and it said 13 volts on the panel. That means the battery/alt are in snyc. I seems like my number 7 plug is a bit oily/gassy but the rest are burning fine. I did notice on a cold start my primaries don't shoot enough gas to start it. It seems like 4/5 cranks and throttles need to start it. How long do you guys think the 455 would run on one float bowl worth of gas. Maybe my fuel delivery is the culprit or the pump/float which should be ok since it was worked on three times. I will consider the gas in carb when stalling to see if helps eliminate the questions. I can just get a small container of gas and slowly pour it in as it starts to bog. Great idea. Thanks
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278634 is a reply to message #278291] |
Thu, 28 May 2015 14:38 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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Air sucking in from the tank switch and starving is what mine ended up.even though I have 76 455 option I did even change the wire to a bigger one straight to 12.in my car the resistor wire is still there and an additional 12 v as well.Remember only 12 volts when cranking and down to 7/9V when running.Are both tanks full of gas?One half full and the other empty no matter what can suck air too.That switch and filter underneath sometimes sees a lot of weather.Mine also has electric pump on there for the vapor lock trouble here in the heat.If your at a light too long and try to pull off she starts to stall,I hit the switch and a few extra psi for gas and running down the road.
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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| Re: Vapor Lock more prone to original turkey tray or crossovers blocked??? [message #278681 is a reply to message #278291] |
Fri, 29 May 2015 21:28 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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How long does it have to sit before it acts right again?
budworks521 wrote on Sun, 24 May 2015 13:04I still am at a loss to my drop in vacuum and stalling after engine has been running for 15 minutes. I have since replaced both mufflers and have no restricted exhaust. I have an ignition module being shipped for future installment. I have solved other problems but just can't seem to nail this one. Choke pulloff and idle screws could be the culprit ??? Anyways vapor lock could be it??? Thanks for any input
C. Boyd
76 Crestmont
East Tennessee
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