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Fuel Pump - Scratching my head


James_Douglas
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Ok,

 

I did the valves and opened them up to .009 and .012. I check all the bolts in the engine.  All are tight.  Let the car sit in the driveway for 45 minutes with a towel over the front of the grill.  Got it to 190F.  Shut it down for 15 minutes so it can heat soak.  Then started it up and started driving around the neighborhood.  It has been in the low 70F here.  After about 30 minutes of driving it started cutting out again.

 

I pulled the Tip-Toe-Switch grounding wire (for the downshift) from the coil.  No effect.

I put a clamp on the vacuum line to the booster.  No effect.

I changed the Tip-Toe-Shift resistor.  No effect.

 

I took the car home and put it in the garage.  Late in the day, I pulled out the distributor to check the governor weights and the vacuum advance. Once in my Sun 500 Distributor machine, the same one I used to set it up 1100 miles ago, I noticed that the points were not making their usual sound.

 

Now keep in mind that the car started and ran fine until the problem started.  No miss, strong, and the like.

 

I shut down the machine and turned the cam to raise and open the points.  They looked WAY to close.  I pulled a feeler gauge of 0.020 and it would not go in.  Down to 0.015 and it would not go in.  Down to .010 and it would not go in.  They were at .006!

 

The next thing I noticed was that the rubbing block looked like it was 1/3 the height I would normally see. 

 

My working hypothesis is that the rubbing block pre-maturely wore down and the point gap dropped from .020 to .006.  When the engine gets good and hot the expansion of the steel causes the points to close down to near closed. 

 

I went to Napa and got a new set of points and condenser and it is all set up.  The thing is at 35 degrees of dwell, the lobes are within +/- 1 Degree of 60 Degrees and the mechanical and vacuum advance is on specification. 

 

I plan on pulling it out in a minute and letting it get good and hot and then taking it for another ride.

 

James

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:confused: I am very surprised it would start easily and run decently with that small a gap.

When I still had points in my trucks distributor it seemed fairly sensitive to this setting. After several hours running time it became harder to start and when I checked the gap had narrowed to around .016". I reset it to .020" then it was easier to start. I really felt the rubbing block was wearing too rapidly so I switched over to a Pertronix module. I am not suggesting you do this......only bringing it up because the construction quality of points sets seems to be a variable.

 

Jeff

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Ok,

 

With completely checked out distributor, the problem still happens.  I took the carburetor off of the 1947 Desoto which is running fine.  I put it on the '49 and the problem is still there.

 

I pulled all the spark plugs and did a dry then wet comp test. 

 

100-105-80-85-105 105   Wet made little difference.

 

Now, one thing I did not mention is that I am loosing a "little" water over time. I suspected that it was the original honey core radiator weeping a little. Now, I am not so sure.  I am wondering if I have a sealing problem between 3 and 4 cylinder.  

 

After lunch I will rig up an air chuck to blow into each cylinder and see if I can hear anything coming out the cooling system.

 

I do think the head may have to come off.

 

One frustrated guy.

 

James

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James;

Didn't you just go through this engine? I was under the impression that you just had the head off.....etc.

If so certainly you checked it for warp....? If you do pull it again you really ought to check the manifolds closely for cracks and warp.

I know when I had my manifolds off the mating surfaces required a fair amount of work to true and clean them up.

 

Jeff

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James;

Didn't you just go through this engine? I was under the impression that you just had the head off.....etc.

If so certainly you checked it for warp....? If you do pull it again you really ought to check the manifolds closely for cracks and warp.

I know when I had my manifolds off the mating surfaces required a fair amount of work to true and clean them up.

 

Jeff

Jeff, Different car.  That was the 1947 Desoto that had the carb high speed piston stick closed and ate #5 cylinder then it went lean.  That car is running fine now.

 

This car is the '49 Desoto.  The engine was rebuilt by my dad in 1964 (Automotive Engineering) then the car was parked in 1966, then sold to a collector in 1970, then pulled out by me 36 months ago.  When I had the engine on the floor, I took it down to the short block. Everything looked good so we cleaned it up, surfaced the head, put in all new gaskets and ran with it.

 

James

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Evening update:

 

I pulled the head.  The cooling system has OIL in it.  Emulsified and in the entire cooling system.  Hard to tell how much, maybe a pint or so.

 

The cylinder head and the pistons have way too much carbon on them for 1400 miles. Everything was perfectly clean when we started it up.

 

The really big question is:

 

How in these engines can you get oil into the water but not have any water showing up in the oil ?

 

James

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Sorry James;

I forget that some of you guys have more than one of these. :huh: Thought we were still on that other one.........

 

I am not all that familiar with the oil passages on these engines......but it if I had to venture a guess I would look very closely around the valve ports for a small crack. 

 

Jeff

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Perhaps a head gasket leak allowed oil blow by from weak rings in cylinders 3 and 4 to slowly get into the water passages in the head. High pressure pushed oil into the low pressure cooling system. Low pressure coolant could not come the other way, not against 85 PSI. This leakage may be a secondary problem with the engine. I can not explain how this leak would cause so much power loss after going uphill under load for a while. Still a mystery.

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Perhaps a head gasket leak allowed oil blow by from weak rings in cylinders 3 and 4 to slowly get into the water passages in the head. High pressure pushed oil into the low pressure cooling system. Low pressure coolant could not come the other way, not against 85 PSI. This leakage may be a secondary problem with the engine. I can not explain how this leak would cause so much power loss after going uphill under load for a while. Still a mystery.

Interesting idea.  Numbers 3 & 4 may have gotten water in them and caused issues with the rings...then then I torqued the heads some months back, remember some oil in the water when she was first driven, then went away with the re-torque?  Perhaps the water in the oil got stopped by the re-torque, but the leak stayed from the cylinder to the water jacket.  Then as you point out the pressure pushed the oil back into the water system.

 

I like it.  We took the plug out of the oil gallery on the side of the block and put 60 PSI in it with the head off.  We had topped off the water so it was at the top of the holes in the block.  When pressurized, I heard the air blow the oil back down into the pan.  We did not see any bubbles of any kind in the coolant holes.

 

Well, I guess I will clean everything well and put a new gasket.  Button it up and see what happens.

 

James

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James;

The fact that the loss of power does not happen until it has been running for quite a while seems to point towards it being a valve or valves sticking open or not seating properly. If it were me I think a close examination of the valves on the offending cylinders would be in order before I put the head back on.

Again a temporary vacuum gauge should give an indication of when and what is happening.

Jeff 

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Well,

 

It just get uglier and uglier.

 

With the head off, I spent the morning cleaning everything.  The cylinder is junk and there may be a crack in the block.

 

See the photos.  My machinist looked at the head and confirmed what I already new.  The odd thing is that nobody can figure out how the head got hot.  The head had been milled you can still see the cuts in it.  The cylinder with the worst coloring is also the spot at which the bulb goes in for the temp gauge.

 

We tested the gauge with a pot of water and a calibrated instant read thermometer.  It is within a 3 degrees at 190F.

 

So, how the hell did the head get discolored.  If you look close you can see the cracks.

 

I have two old heads I need to pull.  Take a look at the block photo.  This is between 7 & 8.  If you look close it looks like a hairline crack between the cooling passage and the valve seats.  May cause a problem or may not.

 

James

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James;

Sorry to hear this. :(

Discoloration and cracking like this usually comes from running with a very lean condition. Just a guess..... but I suspect you had an air leak on that branch of the inlet manifold at some point. Inlet valves probably hung open under extreme load causing the lack of power.

With the mass of these engines being what it is problems like this probably get "masked" from easy detection. In a lighter modern engine it probably would have shown up as a spike in engine temperature.

 

Jeff

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Update July 3rd.

 

What a F&$#ing mess.  The oil in the water created a perfect emulsion and coated like a pasty glue everything inside the cooling system.  I spent all day taking everything apart and cleaning it. 

 

The intake-exhaust manifold was removed.  There was no sign that the unit as not sealing.  We have no idea what caused the heat up in the rear 3 cylinders the heat coloring is worst on # 6 and gets less on #5 and less again on #4.

 

What the hell is the root cause? 

 

My choices at this point are"

 

1. To to mill the manifold to make sure it is ok, put the replacement head on and put everything back and try it.

 

OR

 

2. Pull the hood and everything else and pull the engine and take it all apart.  The block would have to not only be magnafluxed but pressure tested in the oil galleries and then rebuild the whole thing.

 

Time to get a drink and ponder.

 

James

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Did you flush the block with the welch plugs pulled to see that you were getting good flow around the back of the block?  Since you have the head off you could fill the block with water to see that it is flowing through the rear passages.  For the rear cylinder to get the hottest sounds like a flow problem.  Most people comment about all of the gunk that comes out of the welch plugs holes in the back side of the engine, especially the one by the starter.when they flush the block. 

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There's not a lot of sense putting the head back on and thinking the oil is not going to get into the water again.  There are no oil passages in the head so it's entering from the block, probably where the oil galley runs alongside the water jacket.  I'll guess it had water in it and froze at one time in it's life or simply rusted through the jacket.  I'll also guess the head heating is due to a plugged or broken water distribution tube.

 

Sad to say, you might just as well pull the motor and hunt up another block.

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Sorry about what you have found.

I guess it could have been caused by blockage in that part of the cooling system ? I am a bit surprised that you did not see high temperature readings on the gauge to go along with all this but I suppose it could have been localized and did not show. ? Also it is hard for me to imagine that a hole between the cooling passage and an oil gallery would not have allowed a bit of coolant into the oil pan at some point. You would think that after shut down some coolant would have made it's way into the oil. :confused: I am relatively new to these engines so I will defer to those with more knowledge on the subject.

 

Either way I think it is a good idea to true up the mating surface of the intake manifold if you are going to reuse it. It has a fairly small mating surface and an air leak at one branch might not show up as anything visible to the eye. Years ago I had an small OHV 4 cylinder engine with a similarly configured intake manifold develop an air leak at one branch. Before I was aware of what was happening the heat caused by this leak removed a pie shaped section of the exhaust valve just as neat as a lazer. When I nursed it home and pulled the head the discoloration and cracking around the exhaust valve looked very similar to your photos.

 

Jeff

Edited......was thinking exhaust but typed intake. :rolleyes:

Edited by Jeff Balazs
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Did you flush the block with the welch plugs pulled to see that you were getting good flow around the back of the block?  Since you have the head off you could fill the block with water to see that it is flowing through the rear passages.  For the rear cylinder to get the hottest sounds like a flow problem.  Most people comment about all of the gunk that comes out of the welch plugs holes in the back side of the engine, especially the one by the starter.when they flush the block. 

I did not pull the core plugs as there is no way in a 1949 (smaller engine bay) to get them back in without taking the block out.

 

I did however pull out the drain cock and with the head off was able to check the water jacket.  Other than the oil, everything is clear.  Keep in mind that the block was cleaned out well 1500 miles ago when I had the engine on the floor.

 

This engine on the inside is one of the cleanest I have ever seen for a used flathead six. 

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There's not a lot of sense putting the head back on and thinking the oil is not going to get into the water again.  There are no oil passages in the head so it's entering from the block, probably where the oil galley runs alongside the water jacket.  I'll guess it had water in it and froze at one time in it's life or simply rusted through the jacket.  I'll also guess the head heating is due to a plugged or broken water distribution tube.

 

Sad to say, you might just as well pull the motor and hunt up another block.

Dave, in the end you may be correct.  However, this is a "known" engine.  It was rebuilt in 1964 by Automotive Engineering, driven by my mother for a couple of years, then sat in the garage in Sebastopol, CA.  That garage never saw below 35F.  Then in 1970 the car was sold to a collector across town.  He pickled it and stored it until I got it back 36 months ago. The water was drained. 

 

Given that it was in indoor storage in the same town and it gest below 32F only for a couple of hours once or twice a year if at all, something odd is going on.

 

The block is completely clear (save the oil) and the water distribution tube is perfect.  There is little to no rust in this block.  It looks better than any I have seen, that is why this is a real mystery. 

 

At this point it is about a days work to put another head on and see what happens.  It is a week or two work to pull the engine put it back with a few weeks waiting for it to be rebuilt or a replacement rebuilt.

 

I think I will stick it back together and see what happens. I will monitor the water every time I run it.  If any oil starts to show up then I will park it and start looking for a replacement engine to rebuilt. 

 

At least if I can move it under its own power I can move it around.  Here in SF I have very little space as some on this forum can attest from their visits.

 

James

Edited by James_Douglas
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  • 3 weeks later...

Update:

 

Well,

 

We just got in from the 59th Annual Hillsborough Concours d’Elegance.  The 1949 Desoto Convertible made it.

 

After the saga for a month and a half trying to find out why the car was cutting out...and finally coming to the conclusion that it was a cracked cylinder head.  It was nice to take it out for a drive.

 

We still do not know if the problem was due to the head in its entirety. I used TSP, auto parts cleaner, and lots of water to flush the cooling system.  But, there is still some residue and so it will take several weeks to a month of driving and checking to see if I am still getting oil in the cooling system.

 

With a good head, that was not milled, all the cylinders came up at 80PSI +/- 5.  The car runs good, although at max RPM like 3500+ it is cutting out a bit.  May or may not be a related problem.

 

The car showed well at Hillsborough although since it is not quite done it did not win anything.

 

The next few weeks will tell if there is a crack in the block.  If that is the case, then I will source a 265 and rebuild it for the 9 passenger 1947 Desoto and take that 251 and put it in the convertible.

 

Wish me luck.

 

James

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James,

You were there too? Was so busy there, I would have loved to check the car out, but never got the chance!

Update:

Well,

We just got in from the 59th Annual Hillsborough Concours d’Elegance. The 1949 Desoto Convertible made it.

After the saga for a month and a half trying to find out why the car was cutting out...and finally coming to the conclusion that it was a cracked cylinder head. It was nice to take it out for a drive.

We still do not know if the problem was due to the head in its entirety. I used TSP, auto parts cleaner, and lots of water to flush the cooling system. But, there is still some residue and so it will take several weeks to a month of driving and checking to see if I am still getting oil in the cooling system.

With a good head, that was not milled, all the cylinders came up at 80PSI +/- 5. The car runs good, although at max RPM like 3500+ it is cutting out a bit. May or may not be a related problem.

The car showed well at Hillsborough although since it is not quite done it did not win anything.

The next few weeks will tell if there is a crack in the block. If that is the case, then I will source a 265 and rebuild it for the 9 passenger 1947 Desoto and take that 251 and put it in the convertible.

Wish me luck.

James

Edited by nonstop
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  • 7 years later...
On 5/27/2014 at 5:21 PM, James_Douglas said:

Hi Guys,

 

I just got a call from the support people at Federal-Mogul.  They are supporting the Carter products for six more months and that is it for them.  The new group that purchased Carter...who knows.

 

Apparently and to his surprise is that the published data (which Speedway, Jegs, and all the rest use) of Up to 73 Gallons an Hour and 6 PSI are all "Free Flow" numbers.  Worthless to measure for car guys. The support man said that the engineer told him that...

 

The 6 Volt Carter pumps with a fuel pressure gauge stuck on the output of the pump is 2 to 3 PSI.  The volume is 25-30 GPH or 3.3 to 4 pints per minute.

 

I got 3.25 PSI at the carburetor and a little less than 3.0 pints in a minute.  With a fresh filter, one without junk in it, I will see what I get.  It looks like however that the pump is fine.  I was correct that the specifications were odd and misleading.

 

James

Free flow: That's what I found on another web site.  When you mention Carter are you talking about the 4259?  I ordered the Airtex E8902. Jeesh - I read the whole post. When I think I have problems with the crank bolt. 

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