MGB & GT Forum
Frayed distributor ground wire sheathing
Posted by AlanR
Topic Creator (OP)
Mar 24, 2017 10:04 PM
Joined 10 years ago
37 Posts
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My car has been sporadically stuttering recently. It seems to happen most when accelerating between 2k and 3k rpm, but does sometimes happen at constant speed. The is no noticeable effect on the tach reading, and the car seems to run happily along otherwise. I had a chance to quickly poke around a bit tonight and noticed that the sheathing on the distributor ground wire has frayed, leaving a section exposed. The wire itself appears to be in good condition. I know little about distributors, and am curious if this could potentially be the cause of my troubles.
For reference, I have replaced the points, condenser, rotor, cap and wires along with the coil in the last few hundred miles. The carbs were recently rebuilt and the timing is set to spec, and the valve clearances adjusted.
Thanks in advance to all who took the time to read my post.
Alan.
For reference, I have replaced the points, condenser, rotor, cap and wires along with the coil in the last few hundred miles. The carbs were recently rebuilt and the timing is set to spec, and the valve clearances adjusted.
Thanks in advance to all who took the time to read my post.
Alan.
Mar 24, 2017 10:19 PM
Top Contributor
Joined 20 years ago
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Being a ground wire it's unlikely to cause problems unless the bare area is contacting something with power. That insulation does tend to come detached and look like yours...have seen many like that with no issues!
Friends talking around a fire is the history of mankind.
Friends talking around a fire is the history of mankind.
dipstick
Kenny Snyder (RIP)
La Center, WA, USA
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1941 Ford N-Series
1958 MG MGA 1500 Coupe "Rosie" 1970 MG MGB GT "Pat's GT" 1971 MG MGB "Gifted To Me" & more |
Mar 24, 2017 11:11 PM
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Probably not the problem. Ace Hardware has liquid insulation that can be wiped on to replace the insulation. The ground wire from breaker plate to body screw appears to be very short, and may be limiting your breaker plate rotation.
Be safe out there.
Kenny
Be safe out there.
Kenny
ohlord
Rob C
A tiny Island off the coast of Washington State, N.W., USA
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1957 Land Rover Series I "EYEYIYI"
1957 Land Rover Series I "OVRLND" 1971 MG MGB 1971 MG MGB "Bedouin 2" & more |
Mar 24, 2017 11:13 PM
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Timing spec is no longer timing spec
It's just a base line at which to begin the process of maximising timing.
Not your problem currently
However can assure you the timing is anything from ideal .
What plugs and gap?
What points and gap
You don't have a quality rotor installed
What weight oil in carb dampers?
Check free travel of breaker plate assembly?
LNDRVR4X4.COM
Home of Project "INCARN8'
1957 Series 1 Land Rover electric VEHICLE CONVERSION
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It's just a base line at which to begin the process of maximising timing.
Not your problem currently
However can assure you the timing is anything from ideal .
What plugs and gap?
What points and gap
You don't have a quality rotor installed
What weight oil in carb dampers?
Check free travel of breaker plate assembly?
LNDRVR4X4.COM
Home of Project "INCARN8'
1957 Series 1 Land Rover electric VEHICLE CONVERSION
FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED
RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972
Mar 25, 2017 01:37 AM
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Rob that rotor is the better black one, not the best red one but not the end of his world.
Michael J. Caputo
'79, '77, '76, '74.5 (rubber dual SU), and '73 owner. Extensive experience in 12v Audio System design and installation. Vendor of Regalia and Promotional Products since 1993. Supplier of Accessories to MOSS. Forum Member since 2009; with a warped sense of humor since birth. Publisher of the annual MGB & GT Calendar, mailed worldwide.
Michael J. Caputo
'79, '77, '76, '74.5 (rubber dual SU), and '73 owner. Extensive experience in 12v Audio System design and installation. Vendor of Regalia and Promotional Products since 1993. Supplier of Accessories to MOSS. Forum Member since 2009; with a warped sense of humor since birth. Publisher of the annual MGB & GT Calendar, mailed worldwide.
Member Services:
Please send photos for next year's calendar to photos25@mgbcalendar.com. If you need help with your Weber downdraft carburetor, feel free to call me at 978-249-5760, USA, Central Time!
dickmoritz
Dick Moritz
Philly 'burbs, PA, USA
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Mar 25, 2017 11:39 AM
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Good advice, as always from Kenny. FWIW, a bottle of nail polish from the Dollar Store has many uses in cars, including such insulation...
Dick
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Dick
In reply to # 3476047 by dipstick
Probably not the problem. Ace Hardware has liquid insulation that can be wiped on to replace the insulation.
Errabundi Saepe, Semper Certi
(Often wrong, but always certain)
Mar 26, 2017 09:03 AM
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Joined 17 years ago
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See the loose crimp on your condenser? I'd start by fixing that.
The ground wire can be bare. Its a ground. But make sure its actually doing its job.
Check your newer vac unit to see if the diaphragm leaks, because the problem you have sure sounds like a lean misfire. I'd thoroughly check everywhere for vacuum leaks. Tighten all intake and carb bolts/nuts. Check and replace every vacuum line to be certain they are extremely tight, including any smog hoses you might have.
jeff@advanceddistributors.com
The ground wire can be bare. Its a ground. But make sure its actually doing its job.
Check your newer vac unit to see if the diaphragm leaks, because the problem you have sure sounds like a lean misfire. I'd thoroughly check everywhere for vacuum leaks. Tighten all intake and carb bolts/nuts. Check and replace every vacuum line to be certain they are extremely tight, including any smog hoses you might have.
jeff@advanceddistributors.com
Topic Creator (OP)
Mar 27, 2017 11:31 AM
Joined 10 years ago
37 Posts
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Thanks everyone. On Jeff's advice I went out and checked the vacuum advance unit and found that the diaphragm has failed. The is pretty frustrating as it is the second new unit that has failed in the past 2 years. Is it possible that I am doing something on my end that is causing the unit to fail? Aside from removing the smog equipment, everything else is standard on my car.
Since I will have to put in an order to exchange the vacuum advance unit, is there anything else I should look at replacing on the distributor at this point? As a reminder the points, condenser, rotor, cap, plug wires and coil are all new in the last few hundred miles.
Since I will have to put in an order to exchange the vacuum advance unit, is there anything else I should look at replacing on the distributor at this point? As a reminder the points, condenser, rotor, cap, plug wires and coil are all new in the last few hundred miles.
HiPowerShooter
James Booker
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Mar 27, 2017 11:38 AM
Joined 9 years ago
7,787 Posts
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If you're buying new Chinese vacuum units...that's the mistake. Find a good OEM used one(or send yours if you still have it) and send it to Jeff to rebuild. It'll last a long, long time...
"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.
"Who do you think you are? I am."...Pete Weber
73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...
"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.
"Who do you think you are? I am."...Pete Weber
73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...
ohlord
Rob C
A tiny Island off the coast of Washington State, N.W., USA
Sign in to contact
1957 Land Rover Series I "EYEYIYI"
1957 Land Rover Series I "OVRLND" 1971 MG MGB 1971 MG MGB "Bedouin 2" & more |
Mar 27, 2017 11:42 AM
Top Contributor
Joined 12 years ago
28,863 Posts
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Have Jeff rebuild it.
He can fix the diaphragm
LNDRVR4X4.COM
Home of Project "INCARN8'
1957 Series 1 Land Rover electric VEHICLE CONVERSION
FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED
RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972
He can fix the diaphragm
LNDRVR4X4.COM
Home of Project "INCARN8'
1957 Series 1 Land Rover electric VEHICLE CONVERSION
FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED
RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972
dipstick
Kenny Snyder (RIP)
La Center, WA, USA
Sign in to contact
1941 Ford N-Series
1958 MG MGA 1500 Coupe "Rosie" 1970 MG MGB GT "Pat's GT" 1971 MG MGB "Gifted To Me" & more |
Mar 27, 2017 01:20 PM
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Joined 15 years ago
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"... is there anything else I should look at replacing on the distributor at this point?"
Yes.
- Given a '72 distributor the centrifugal advance springs are likely stretched causing the advance to be inaccurate.
- The underside of the breaker plate may be worn in the sliding post area allowing the plate to tip.
- The centrifugal advance curve is a factory emissions compromise and not the optimum for your engine.
I suggest sending the distributor to Advanced Distributor (Jeff) to be refurbished.
Be safe out there.
Kenny
Yes.
- Given a '72 distributor the centrifugal advance springs are likely stretched causing the advance to be inaccurate.
- The underside of the breaker plate may be worn in the sliding post area allowing the plate to tip.
- The centrifugal advance curve is a factory emissions compromise and not the optimum for your engine.
I suggest sending the distributor to Advanced Distributor (Jeff) to be refurbished.
Be safe out there.
Kenny
Steven 67GT
Steven Rechter
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Mar 27, 2017 02:13 PM
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Joined 12 years ago
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In reply to # 3476240 by dickmoritz
FWIW, a bottle of nail polish from the Dollar Store has many uses in cars, including such insulation...
Yes exactly. I've used clear nail polish for years for electrical repairs.
It also works well to repair tears in speaker cones.
Mar 27, 2017 09:30 PM
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Joined 17 years ago
19,950 Posts
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Its a problem with both the materials being used and the quality of the assembly. Since the guy making them refuses to use any form of adhesive, they don't last long.
Its inexpensive to rebuild the original and I can usually make them last many, many years by simply using exceptional materials. I can repair the advance curve at the same time to be optimal for your specific engine build as Kenny mentioned.
The same guy who builds those new vac units also rebuilds Lucas distributors. I suspect those last a year or two as well. I've repaired quite a few of them after they didn't work as expected. That's why I suggested you check to see if the vac unit leaks. Its an ongoing issue. When people offer a 2 year warranty, they're telling you how long the part is designed to last. I stand behind my builds for years. I have yet to see a diaphragm fail on a vac rebuild, although a few didn't seal on the first try. I've ironed out those issues with new techniques and tooling.
jeff@advanceddistributors.com
Its inexpensive to rebuild the original and I can usually make them last many, many years by simply using exceptional materials. I can repair the advance curve at the same time to be optimal for your specific engine build as Kenny mentioned.
The same guy who builds those new vac units also rebuilds Lucas distributors. I suspect those last a year or two as well. I've repaired quite a few of them after they didn't work as expected. That's why I suggested you check to see if the vac unit leaks. Its an ongoing issue. When people offer a 2 year warranty, they're telling you how long the part is designed to last. I stand behind my builds for years. I have yet to see a diaphragm fail on a vac rebuild, although a few didn't seal on the first try. I've ironed out those issues with new techniques and tooling.
jeff@advanceddistributors.com
Mar 28, 2017 11:52 AM
Joined 18 years ago
8,982 Posts
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List to what Jeff says, he can be WELL trusted!
1974-1/2 Roadster, "Bumble Bee", Corvette Yellow - in shambles, wire wheels
1976 Roadster, "Virus", Sandglow - "driver" condition (stock + 32/36 Weber DGEV, cast iron header, 25D distributor), bolt on wheels, ON the road!
1974-1/2 Roadster, "Bumble Bee", Corvette Yellow - in shambles, wire wheels
1976 Roadster, "Virus", Sandglow - "driver" condition (stock + 32/36 Weber DGEV, cast iron header, 25D distributor), bolt on wheels, ON the road!
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