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1925 engine does not like hills.


dibarlaw
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I have been discussing this with Hugh but it is always good to get other opinions.

 Symptoms.... loss of power on long grade. The first time it happened I was able to downshift but barely was able to crest the hill. Later on the return trip on the same hill I was not so lucky and the engine quit. We had to back down about 75 yards and turn into a farm lane. When I tried to start the engine it would flood. So we played the waiting game and 45 minutes later it reluctantly started. I got over the hill in 2nd and drove the remaining 15 miles home. The engine was running rough. I had checked around the manifold ports with carb cleaner to detect a vacuum leak. No difference. I thought that the heat riser tube may be opening up when the engine was hot. So this was my experiment for today.

 

Hugh:
 I was able to swap out the single manifold fitting for the double. So I can monitor the engine with the vacuum gage while driving. When I was removing the original single fitting, I saw that it was cracked. Boy would that be the ticket to solving the vacuum problem!!    NOPE! image.png.7cd82ac64e17592a10915aef0367e514.png I installed the double fitting and ran the line through the hole near the top of the cowl.
image.png.af12c4295624c651885aca73c928d5dd.png
At idle it was holding over 18 in vac.
image.png.3fdb362df439f07b47005a4909ee3836.png
 The engine was still hard to start. When I first retimed after the new timing gear it would start every time at the 2nd revolution with the spark set at full advance. I remembered you said that your timing of would go off from the distributer shaft setting. So, I retimed the engine again. Setting between 1-6 and 7 DEG. I tried 1-6 but the rotor button would be pretty far off to move it this far advanced. I also reset # 1 valves again since they seemed a bit tight.  .007
 Started much better and after dialing in the carb, it was holding steady at 17.5 in vac. I did about a 5-mile drive. The engine seemed to run much smoother. At 35 mph on level road vacuum was holding about 15 in. Then I tried to take a small grade. Vacuum dropped to less than 5in. So, a long hill would really starve the vacuum tank. At a rolling stop I could pull out in high but vacuum would drop below 5in. Back in the garage vacuum was back at 17.5 in. steady at idle. When engine was revved up vacuum would drop to below 5in. Also noticed that the glass in line fuel filter was not staying full as it usually was.
 Maddening!
 Best Regards:
 Larry
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Larry:

 

It seems to me your engine vacuum profile is normal. As you may remember, I have a vac gauge permanently installed in my 1940, and used them in all of the cars of my wild youth, so I know what normal behavior is, to some tolerance anyhow. As you go up the hill and put pedal to it, the vac will drop, to 5 inches or even lower, especially with our relatively underpowered engines. Try a vac snap test. With the engine idling in neutral, quickly floor it then fully release. The vac should quickly drop to zero and then snap back to 25 inches plus if everything is to snuff.

 

The vac tank holds a reserve for these situations, right? Is it filling properly when you are cruising at 12 to 16 inches? Or maybe the level is ok but you are pulling in more gas than the system was designed for. Is this the rebuilt engine?

 

You could do the old inline elec pump thing and just use it on the grades.

 

Cheers, Dave

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Couple of other quick ideas. With the vac tank at proper level, unhook connx to carb and see how fast it drains. Time it and measure the amount so we can get a rate. Also, if you can, repeat with vac hooked up (maybe use a vac pump? Mine does 85 cfm, might be enuf). Or use a fuel flow meter hooked up temporarily.

 

https://www.amazon.com/Digital-Turbine-Flowmeter-Kerosene-Gasoline/dp/B082P32RC7/ref=sr_1_1_sspa?dchild=1&keywords=fuel+flow+meter&qid=1623650191&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFTTktLNE9VTDJKODYmZW5jcnlwdGVkSWQ9QTAyMDE4MzgyRFM2SEM3QUZKMFNTJmVuY3J5cHRlZEFkSWQ9QTAwNDEyMjMzQVNGS0M2NkVITk5SJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

Cheers, Dave

Edited by Daves1940Buick56S (see edit history)
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6 hours ago, dibarlaw said:

 

 
. Also noticed that the glass in line fuel filter was not staying full as it usually was.
 

 

Might be an air leak in the rubber gasket on the fuel filter. Is your filter mounted upstream from the vacuum tank? If so maybe it's sucking air which is why it's not staying full. If the filter is downstream from the vacuum tank, I can't think of why it would not be staying full.

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6 hours ago, Morgan Wright said:

 

Might be an air leak in the rubber gasket on the fuel filter. Is your filter mounted upstream from the vacuum tank? If so maybe it's sucking air which is why it's not staying full. If the filter is downstream from the vacuum tank, I can't think of why it would not be staying full.

Morgan the filter is downstream from the Vacuum tank between the tank and the carb.DSCF2639.JPG.6fd7d7607f58c73c3ee9942e40e788b7.JPG

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Larry, 

     Glad that you installed the vacuum gauge.  Instrumentation is what we need to help isolate your engine problems.

A few of my notes on vacuum.  At idle, you should be 18-19 mm Hg on full advance.   It looks like you are there as long as that is backed down from maximum achievable vacuum.  Rotating the spark advance to full retard and it should drop to 16 mm Hg.  My idle speed is 380 rpm full advance and 300 rpm full retard.  Leaning out (turning the fuel mixture screw underneath more closed) will raise the vacuum some (as high as 20). - but this is too lean and it will backfire in the intake, so you need a richer mixture.  I am between 3/4 turn and less than a full turn on the fuel mixture screw under the carb.  Adjustments to the fuel mixture may effect the air valve, but that seems to run right when the back of the air valve is flush with the end of the adjustment index tab.   I did notice some differences when I went a few ticks either side of this, so there is some experimentation that can be done.     

    

You may still have some other problems, but this does sound like a fuel delivery problem.  Most fuel filters are made for fuel pumps.  Very few function well in vacuum tank or gravity feed situations.  Consider using just a piece of copper tubing to replace the fuel filter as a test, or using one of these fuel filters that are designed for gravity feed applications.  I also do not know if you have a screen in the float bowl inlet.  Screens typically have less restriction than a filter but they can be clogged.  The pleats in the paper filters increase the surface area and lower the pressure drop, but you can still have too fine a mesh to allow proper flow.   There is very little motive force in a gravity feed application.  

 

Leaks at the banjo fittings could also be a culprit for not drawing enough fuel, but that is a tough one to check the integrity.  Using a 1/2 gallon lawn mower tank is also a good cheap test mule accessory.  Disconnect and plug the vacuum line.    Bring a can of gasoline with you.  The tank feeds directly to the carburetor.  Drive to the base of a hill and see how the car operates with vacuum and fuel delivery issues out of the equation.  

Hugh

 

https://www.amazon.com/gp/product/B00FXWZN16/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

1099934357_fuelfiters-gravityfeed.JPG.7c033a00d0e731f37ac000650888bcff.JPG1150820224_fueltanktemporary.JPG.88dd81cfaaeafb883836ba8963619c18.JPG

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My experience with fuel delivery issues is the carburetor opens for the grade but extra fuel is not metered to match due to a restriction somewhere, but here’s the catch, when I’ve experienced this, the resultant lean mixture pops and bucks.  Larry is just seeing a lack of power.   
 

Also when I had the burned valves, I had difficulties starting. 
 

I also had a cracked cap drive me nuts with all sorts of interesting issues based on temperature and humidity. 

 

just my 2 cents. 

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Posted (edited)

Results of the compression tests. This is about the best I have been able to achieve with my adapted connections for my gage. The only adapter I have is an old 2 piece 7/8" thread plug base but with the 1 1/8 hex the 14mm top thread adapter I can only snug this adapter to the hole with needle nose pliers.

DSCF8727.JPG.e58eb8f9edd429ed6145764019bd9fae.JPG

 Over the last 2 weeks and local low speed easy driving I have #s 1 and 2 plugs getting a bit carboned again. When the car quit on me near the crest of the hill I checked the first 3 plugs to see if they were wet. Dry as a bone and the porcelains were clean and white. Of course that was after a 50 mile drive.

 I will work back from the carb now and check all connections.... AGAIN....

Edited by dibarlaw
spelling (see edit history)
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So what’s going on with #s 1 and 2?

 

I’d look from cap to plug and everything in between.  Those two are not pulling their weight.  On the hill you may only be getting power from the other 4. 

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On 6/14/2021 at 10:04 AM, dibarlaw said:

Results of the compression tests. This is about the best I have been able to achieve with my adapted connections for my gage. The only adapter I have is an old 2 piece 7/8" thread plug base but with the 1 1/8 hex the 14mm top thread adapter I can only snug this adapter to the hole with needle nose plyers.

Those readings look pretty good to me, given the compression ratio.

 

As an adapter to connect 7/8-18 plug holes to a compression gauge, I use the base of a take-apart old spark plug, then tap the inner hole to 14 mm plug thread to accept my modern compression tester which also has an o-ring seal.  (You can make a thread chaser for those 7/8 holes by using a separate take-apart plug base to which you have made four equidistant cuts perpendicular to the thread to allow debris to accumulate.)

 

I have 35,000 miles of experience driving vacuum tank equipped cars, including long upgrades in hot weather and at altitude.  I drive by (1) the motometer and (2) the vacuum tank.  Half throttle on long upgrades as much as possible to keep the vac tank sucking, AND to reduce the amount of heat generated by engine that must be shed by the cooling system.  Stay in the Sweet Spot, even if that means going slower or even downshifting.  If you simply must go past half throttle, be mindful of the capacity of the vac tank reservoir and what distance it gives you--conservatively 5 miles.  Then pull over and run at fast idle to 3-5 minutes to replenish the reservoir.

 

All that said, I'd be looking at some ignition issues in this case.

Edited by Grimy
fixed typo (see edit history)
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years ago I had problem with not getting fuel.  I put an air hose to the fuel tank with about 5 psi and a rag wrapped around it and where it was sucking air it blew gas out.  It was at the banjo fitting at the fuel tank.  Just an easy method of finding a suction leak.

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2 minutes ago, garnetkid said:

years ago I had problem with not getting fuel.  I put an air hose to the fuel tank with about 5 psi and a rag wrapped around it and where it was sucking air it blew gas out.  It was at the banjo fitting at the fuel tank.  Just an easy method of finding a suction leak.

Great thought!  We don't want to put too much Roobus-Doobus (i.e., tightening) on the banjo bolt for fear of splitting the pot metal female threads in the top/lid of the vac tank (ask me how I know), so I use compressible-but-thin copper washers on both sides of the banjo fitting--and keep some spares in the car.

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Larry and I talked about the issues he has last night.  The compression readings look really good - consistent with a freshly rebuilt engine.  We talked about the heat riser tube.  From what I hear about these things, I am glad my cars pre-date these.  The thing that just doesn't make a lot of sense is that on a level road the engine runs fine.  Put it under a load and it wants to go South.  He has had the cylinder head gone through, so that shouldn't really be a problem there.  My 1916 D-Series Reference Manual calls for setting the valves at .005" COLD.  My 1922 calls for setting the valves at .006" - .008" HOT.  Maybe the increasing compression ratio through the years factors into that.  I would think that a bad distributor cap would cause problems whether idling or under load.  Larry tells me that he has heard of folks going through multiple condensers before getting a good one.  Maybe that is something to consider here.  I asked him about the coil.  I am going to run a modern coil on my '16's engine.  I bought a 6 Volt coil from Brillman's down in Virginia.  I was told that this is a HOT coil.  They tell me that this coil puts out 55,000 volts.  That's a HOT coil compared to a 6-Cylinder Chevrolet coil that puts out 25 - 30,000.  It was mentioned that there could be a leak at the vacuum tank banjo fitting.  Mark Shaw and I talked about these connections not so very long ago.  We agreed that I could use either crush gaskets or the Red Fiber Washers.  I think that I am going to go with the Red Fiber when the gas tank and vacuum tank fittings are made up permanent.  I do not want to do anything to put that pot metal tank lid at risk of damage.  It will be interesting for sure to find out just what the problem(s) are.  The way things are now I don't have any issues to deal with.  I can't even get a GOOD 6-Volt battery to put in my car, let alone try and drive it up any hill (sorry 'bout that Larry).

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

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The only difference between going on level ground and up a hill is the car needs a lot more gas going up a hill. A LOT more. My modern car has a MPG gauge and it says 67 MPG going downhill, 23 on level ground, and 7 MPG going uphill. So forget about timing and spark strength and spark plugs. Larry's problem is he starved for gasoline going up hills. Something is limiting the amount of gas getting to his engine. 

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I know for fact that ignition issues can mimic carburetion problems.  My '20 had the original plug wires and if you even touched one lightly you could hear the old rubber insulation crack.  The engine ran halfway decent at times and then at times it seemed like it was all it could do to even run.  I changed out the old wires and it was unbelievable how much better the engine runs - like daylight and dark.  I'm telling this here because it happened to me and it made a believer out of me with regard to the ignition system.  Could something like this be Larry's problem?  I cannot say that with certainty.  He is going to have to eliminate one area at a time.  Sometimes these things can drive a person that drinks a bit to go sober.  As Larry says, it's maddening and I can certainly feel his pain about it - been there and felt that.  I believe that there is something beside a fuel delivery issue going on and that's just my 2 cents.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

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7 hours ago, Terry Wiegand said:

I know for fact that ignition issues can mimic carburetion problems.  My '20 had the original plug wires and if you even touched one lightly you could hear the old rubber insulation crack.  The engine ran halfway decent at times and then at times it seemed like it was all it could do to even run.  I changed out the old wires and it was unbelievable how much better the engine runs - like daylight and dark.  I'm telling this here because it happened to me and it made a believer out of me with regard to the ignition system.  Could something like this be Larry's problem?  I cannot say that with certainty.  He is going to have to eliminate one area at a time.  Sometimes these things can drive a person that drinks a bit to go sober.  As Larry says, it's maddening and I can certainly feel his pain about it - been there and felt that.  I believe that there is something beside a fuel delivery issue going on and that's just my 2 cents.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

 

 

I can't think of anything electrical or ignition that can mimic fuel requirements going up a hill. Cars need a huge difference in fuel going up a hill, I don't think the ignition changes uphill vs. downhill. And when I say fuel I'm not talking about carburetion, I'm just saying it needs a huge amount MORE fuel going up a hill. You burn 2 or 3 times more fuel uphill, even though the spark stays the same.

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Actually, as cylinder pressures go up (more fuel in the cylinder or a greater load on the engine like going uphill) the resistance at the plug goes up, so if your ignition system isn't healthy, the plugs won't fire very well. Cylinder pressures aren't a static thing and an ailing ignition system absolutely will struggle going up hills as loads increase. If there's fuel in the vacuum tank, then that's not the problem. That system is simple. If the carburetor was the issue, he'd have poor acceleration on flat ground as well when using large throttle openings or leaning on it at low speeds in high gear. Now there's always the possibility that the vacuum tank is starving because of the long uphill slog and he's running out of gas, but that's easy enough to eliminate using the techniques others have described. But if the car pulls well through the gears on level ground at large throttle openings, then my gut says ignition might be the most reasonable place to look for issues. But as Terry says, it's going to take some process of elimination to finally narrow down the culprit. Eliminate all the fuel system variables first since they're easier, then move on to ignition. One step at a time.

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I have encountered improper valve adjustment that kills power and causes difficult starting, while hot, two different times over the years. In both cases hot valve lash was too tight. When the engine heated up, the valves were slightly open . Opened the lash up and a perfect running engine came back. I think it was due to valve and seat wear that causes the valve lash to go away. One was on a fairly fresh rebuild the other was a very high hour industrial engine. Each engine started and ran normal when cold. After sustained load, power went down , the engines chocked down and died easily. Wouldn't start when hot. Let them cool 30-60 minutes and engines cames right back to life. At first I suspected old ignition components.

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23 hours ago, raydurr said:

I have encountered improper valve adjustment that kills power and causes difficult starting, while hot, two different times over the years. In both cases hot valve lash was too tight. When the engine heated up, the valves were slightly open . Opened the lash up and a perfect running engine came back. I think it was due to valve and seat wear that causes the valve lash to go away. One was on a fairly fresh rebuild the other was a very high hour industrial engine. Each engine started and ran normal when cold. After sustained load, power went down , the engines chocked down and died easily. Wouldn't start when hot. Let them cool 30-60 minutes and engines come right back to life. At first I suspected old ignition components.

raydurr:

 I think you may have something here. I have reset the lash several times thinking things were a bit too noisy. Still trying to keep at .007 when warmed up but not quite hot. After replacing with another new condenser I had the engine running for about 10 minutes. It had started up quickly cold. I spent some time dialing in the carb to get the best vacuum reading. I shut it down and it refused to start for about 10 minutes after several short attempts.

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28 minutes ago, dibarlaw said:

raydurr:

 I think you may have something here. I have reset the lash several times thinking things were a bit too noisy. Still trying to keep at .007 when warmed up but not quite hot. After replacing with another new condenser I had the engine running for about 10 minutes. It had started up quickly cold. I spent some time dialing in the carb to get the best vacuum reading. I shut it down and it refused to start for about 10 minutes after several short attempts.

If you have yet to touch the lash, can you repeat this, get the no hot re-start and quickly run a compression test?

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Looks like an ignition issue to me. Try checking the KV's across the board. Also check burn time. If the wires run through a loom, suspect that also. Modern plastic fuel filters don't have a place in an early car like that. Get a fuel bowl with a screen for the bottom of the tank, tractor supply sells  ones very reasonable, and it's correct for the era. Just be sure to use 20's fittings. A vacuum tank will pull through modern filters........if you do it that way, hide the filter under the car. NEVER use rubber  for fuel line EVER. On old cars many years go by and no one ever checks them.........and then the resulant fire happens. Looks like a very nice car........why not do it right the first time and be done with it. It's common to have to play with a car 500 miles to get it dialed in perfectly, you will get there. Just don't give up. 

Edited by edinmass (see edit history)
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17 minutes ago, edinmass said:

Modern plastic fuel filters don't have a place in an early car like that. Get a fuel bowl with a screen

 

It looks too small to me. I've never seen such a small filter on a car, it looks like a filter for a motorboat. Maybe when it was new it worked but the first tiny bit of clogging and there is no reserve. Take it off and bypass it temporarily and see how your car runs without it. 

 

I tell you boys and girls, it's a fuel issue. If it were the valves, it would show in the compression test. If it were the spark it would show on flat ground. It could be a clogged high speed jet or an adjustment of the air spring to the high speed jet. You ain't getting up hills on the low speed jet alone. Just because the vacuum tanks works doesn't mean you are getting all the fuel you need for hills.

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Morgan......possible it's a float level issue....but I don't want to confuse the issue. It could be a handful of things....ignition is always most likely.

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Posted (edited)

Thanks all..

Time to take another trial run. I have opened up the lash again. Last night when I talked to Larry Schramm he said to open up to .009 which I did. In the process snapped one of the ball studs. I do have a spare 1924 head which I was able to source another. Of course that meant that the rocker shaft assembly needed to be loosened and lifted to replace. One step forward 2 steps back.

 Ed's recommendation is well taken but I do not have access to the types of diagnostics he has.  Also I have a glass/ metal in line filter with a stone element down stream from the vacuum tank.

 Simple Timing light/Dwell meter is what I have. When Larry S was at my house last year he brought his scope/analyzer unit and confirmed bad wire situation. I replaced the wires with new 9mm fabric covered wires. I had made micarta separator for under the spark plug cover. Afterwards all seemed to be running fine. Most times I run without the cover since these Champions are taller. The block wire clamp is quite a tight fit for these new original style wires. I made a larger replacement so the wires go through somewhat loose also with a micarta insulator from the block.

 After I reset the lash again last night (after retorquing the rocker shaft bolts and nuts) the engine was still not wanting to start. I will recheck timing and dwell again today before another run.  

Edited by dibarlaw (see edit history)
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A leaking heat riser tube would be diluting the charge with inert exhaust gas. 
 

I know you checked it for rust holes but could it be leaking in some other way?

 

And I’m sorry to disagree (still) with all the comments about fuel starvation.  When you lack fuel, for whatever reason, and open the throttle, the excess air/oxygen since there is not enough fuel present to consume it causes an immediate lean mixture and a lean mixture pops and bucks.  It does not provide smooth weak power. 
 

And I still think # 1 and 2 plugs are trying to tell you something as well. 

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Brian, I have gone back and read and reread again everything in this thread.  I cannot find anywhere that Larry talks about the engine popping, bucking, and backfiring from a lean fuel condition.  I am simply saying that I don't know what the heck is going on with this engine.  I'm still thinking that there has to be something goofy in the ignition area on this engine.  That new coil that I got from Brillman's was $37.00.  That might be something to consider along with a good handful of condensers.  That old saying of Patience and Perseverance has never been more appropriate than right here.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

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After reading all this i'm leaning to a weak spark. If it's hard starting and no pull when you have your foot in it. 

Pull off a wire and see how far the spark will jump to ground. Minimum 1/4 inch.  

I agree with Terry. Try another coil and condenser. 

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Done and done... Tried this before and replaced the modern coil with a BIG A epoxy coil. After using it for several years I switched out because I noticed that after a 20 mile drive it got very hot (internal resistance style.) Just about too hot to touch. The original DELCO coils were mounted up under the dash away from engine heat. It was also mounted up under the dash. To me it was too hot to touch. So I went to the Family/Farm Store and bought another Non-Made In USA 6 volt coil. After the recent 35 mile trip on a 90+ degree day it was warm but not too hot to touch. I have replaced condensers at least 5 times over the years to eliminate that possibility as discussed. I had replaced the old pot metal distributer with the later cast iron one years ago. Replaced condenser again several days ago.

 I retimed for 1-6 as suggested by Brian H. (That is what I had been running at before.) I double checked yesterday with my timing light and still had to adjust distributer shaft again. But that also got vacuum up from 17 to steady 19 in vu.

523523366_s-l300(1).jpg.e83be4db0fa5e17c9a5a960e89a1d397.jpg 

 I will take the car out today to get gas as there is a 1/2 mile grade to check performance.

 Stay tuned.

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