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  #1  
Old 06-29-2008, 11:16 PM
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Location: Dallas, TX
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Weekend Wrenching

This weekend was pretty interesting. Friday started with the lady who is managing the estate of a deceased SLC 5.0 enthusiast calling me up. I bought three cars from her in the past. A 450SLC 5.0, 500SLC and a 450SLC parts car.

She had sold the house where one of the other cars was stored, it was a partially disassembled 500SLC which was lightly hit in the front when the owner accidentally smashed it into the garage.

She needed to get it out of the house on Friday so she made me an offer that I couldn't refuse so I bought it.

Now I'm up to 15 and i have to aggressively sell some cars including the 76 6.9, silver blue 500SLC, the 59 Ford F100 and the Triumph GT6.

The 500SLC that's going up for sale is now being stored at a friends shop because I can't keep it and the inca red car in the same place.

The Inca red car while disassembled, is in pretty good shape. The paint is fantastic and all the rubber and glass looks new. It will take some serious effort to put it back together so I need to decide what to do here.

On Saturday, I worked on the 6.3. The fuel pump seemed to be out and the car had not been run for some time so I took the tank off and drained it. The gas that came out looked like red varnish and was obviously bad.

We washed the tank out with acid and removed the strainer that needs to be replaced. The next step is to clean the injection pump and replace as much of the fuel lines as possible.

Sunday was spent working the MG with a friend. I had the engine and the carbs rebuilt but the car does not seem to run right. Jimmy who rebuilt the engine and carbs put that right. But it still has a fuel delivery problem. I suspect that it's got to do with the aftermarket fuel pump. I seems to be pushing out too much fuel. Today I placed a fuel pressure regulator on the fuel line but it seems now run lean at times. I'm not sure what the deal is yet but I think I may go back to the original SU fuel pump and see what happens.

The rest of the day was spent working around the house, washing the 6.9 and listing some W108 and R107 parts on Ebay. If anyone is interested, this is what i have for sale.

http://shop.ebay.com/merchant/aalabbasi

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With best regards

Al
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  #2  
Old 06-30-2008, 10:08 PM
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Location: Atlanta, GA
Posts: 591
Al, regarding your MGB, check what kind of valves and seat your rebuilder put in the carb. Those HIF carbs are sensitive to float settings, plus the floats and needles can easily be sticky/misalign if they are new. Problem is you can't see it unless you take them all off. If rebuilder has not put in Grose Jet valves, then get those first. Moss Motors sells them: part number "386-340 $11.95 GROSE-JET, superior relacement for std. needle & seat"

Next, I would knock out that fuel pump and put a regular SU back. As I mentioned in a previous post, I had an aftermarket rotary pump like that on a 1973 MGB and it regularly blew open the float needle/shut off, causing fuel to pour into the cylinders. Putting Grose Jet float needles and fuel pump kill switch between ground and fuel pump solved it (but not after having been stranded a couple of times on I-45). If your problem is a sudden lack of power and VERY rough running, that's what happens - valve does not shut off and fuel blows in cylinders. Weak mixture can also be caused by sticky needle valves.

Good luck,

Bert
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  #3  
Old 06-30-2008, 11:31 PM
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Bert

I tend to agree, I think the SU fuel pump is the way to go.

All the best

Al

Quote:
Originally Posted by sjefke View Post
Al, regarding your MGB, check what kind of valves and seat your rebuilder put in the carb. Those HIF carbs are sensitive to float settings, plus the floats and needles can easily be sticky/misalign if they are new. Problem is you can't see it unless you take them all off. If rebuilder has not put in Grose Jet valves, then get those first. Moss Motors sells them: part number "386-340 $11.95 GROSE-JET, superior relacement for std. needle & seat"

Next, I would knock out that fuel pump and put a regular SU back. As I mentioned in a previous post, I had an aftermarket rotary pump like that on a 1973 MGB and it regularly blew open the float needle/shut off, causing fuel to pour into the cylinders. Putting Grose Jet float needles and fuel pump kill switch between ground and fuel pump solved it (but not after having been stranded a couple of times on I-45). If your problem is a sudden lack of power and VERY rough running, that's what happens - valve does not shut off and fuel blows in cylinders. Weak mixture can also be caused by sticky needle valves.

Good luck,

Bert
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Al
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  #4  
Old 07-05-2008, 01:02 PM
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Location: Lansing, MI
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Well Al, you have made me feel much better. Just when I thought "Gee, I already have 3 MB's, I better not look for anymore", you show me that it's impossible to have too many
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Old 07-05-2008, 01:26 PM
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Quote:
Originally Posted by alabbasi View Post
Sunday was spent working the MG with a friend. .................................. I suspect that it's got to do with the aftermarket fuel pump. I seems to be pushing out too much fuel. Today I placed a fuel pressure regulator on the fuel line but it seems now run lean at times. I'm not sure what the deal is yet but I think I may go back to the original SU fuel pump and see what happens.
..........................

http://shop.ebay.com/merchant/aalabbasi

I have found that the following will help with hot restarts and potential flooding due to heat soak.

Back in the 60's an old tech' showed me how he stopped heat soak flooding.
Some carb' systems already employ this, so if yours is, maybe the return is plugged/restricted.

At the carb inlet, multi or singles, install a tee piece with a restriction orifice
of about 1mm in size in the return leg. Run this returned fuel through the OE return line or install a return system to the tank. I use the tank filler neck as it is often easier to remove and to install a bulk head fitting for the return line.

This will allow the system to depressurize after shut down and stop heated fuel expanding and over powering the float needle . If the fuel vaporizes, the return allows liquid fuel to arrive at the carb's quickly on restart as the electric pump will circulate fuel through the return with cooler fuel.

The orifice is small enough to not steal pressure from the carb's and any pump has sufficient volume to work the system.

I find that 2 psi is enough for SU's and 3 for Stromberg's. SU pumps come in different flavours too...there is a engine mounted pump and a tank area mounted pusher pump, this latter pump is usually set to 4 psi. Using a tank pump near the carb's will result in flooding.
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  #6  
Old 07-05-2008, 10:06 PM
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Gang

Thanks for the tips on the MG, There is something very suspect with the universal fuel pump. I think it's giving uneven flow and hence I plan to go back to the SU pump set up that came out of the factory. I've spoken to some people and they say that the SU pump is the only way to go.

This weekend, I spent working on the 6.3. I bought a new fuel strainer and installed it and the fuel sender in the newly cleaned tank. We also pulled the fuel pump out because it was seized. I took the top off and the impeller was locked up. Spraying it with parts cleaner removed a whole pile of crap. After soaking it for a while, the impeller freed up. The rubber o-ring was completely flat and lost any sealing ability so a trip to ACE hardware found a substitute o-ring that fit perfectly.

We also drained the oil from the MFI pump. It was dirty and way low. As Art said, getting to the dip stick was a huge pain in the neck. Once it was off, we drained the oil by sucking it through the dip stick. Then added new oil the same way. The whole process took a couple of hours.

Once that was done, we replaced as many of the fuel lines as possible and put everything back together again and added gas to the tank and cranked the engine..... nothing. Removing the fuel line from the fuel pump showed that the pump was not pumping. After a bit of investigating, it appears that the outlet from the fuel pump has a nut shaped strainer or regulator that appears to be blocked. Once we removed it, the pump began to work. It's now soaking in parts cleaner while i search for a replacement part. I hope to be able to crank this fella next week. Any words of wisdom would be gratefully appreciated.

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Al

Last edited by alabbasi; 06-29-2009 at 02:12 PM.
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