MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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edwin68
Edwin Velazquez

(4 posts)

Registered:
04/13/2015 05:50PM

Main British Car:


81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: edwin68
Date: April 13, 2015 05:59PM

Hi everyone I inherited my fathers mgb. It has a 3.9 land rover conversion motor in it and the problem the car has is after driving 100 miles the car will stall and won't restart. I keep going thru coils. Now since I didn't build this and the person who did is no longer with us I was hoping someone out can help me. To me it seems the coil is getting to hot it is current installed on the stock location on the right fender right over the right exhaust manifold. What have you guys done to resolve the heat issue from either moving the coil or in replacing the dist. with a coil build into it. what would be the best way to resolve this issue. Thank you ahead of time any input would be helpful ed


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5812 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: BlownMGB-V8
Date: April 13, 2015 06:52PM

Ed, you could relocate the coil and that sounds like it would be a real good idea. Another thing you could look at is the balast resistor. Now some coils are made to run without one so you need to check and see which type it is, but with a resistor it will reduce the current and the coil won't make as much heat. Balast resistors come in several different ratings. The best thing is to match the resistor and coil to a car application that used both.

Jim


edwin68
Edwin Velazquez

(4 posts)

Registered:
04/13/2015 05:50PM

Main British Car:


Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: edwin68
Date: April 13, 2015 08:32PM

I will look into that thank u jim


88v8
Ivor Duarte
Gloucestershire UK
(668 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: 88v8
Date: April 14, 2015 03:12PM

And install the coil so it's upright, not on its side. That way the windings will be permanently immersed in oil.

I second that a ballast coil with a suitable resistor is a good mod.

Ivor


edwin68
Edwin Velazquez

(4 posts)

Registered:
04/13/2015 05:50PM

Main British Car:


Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: edwin68
Date: April 15, 2015 10:38AM

Thanks ivor I plan on working on it on sat won't be able to test drive it till the following weekend being that I have to drive 100 miles to get it to act up


bsa_m21
Martin Rothman
Vancouver, Canada
(205 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: bsa_m21
Date: April 15, 2015 11:01AM

Also check the carb (if you have one) for heat transfer. If it gets too hot the fuel will boil and make it very difficult to start. On the advice of Fred key, I installed an isolator and heat shield. Made a world of difference.

M.


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1077 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: 81 mgb with a 91 3.9 land rover engine stalls when it gets hot need help
Posted by: ex-tyke
Date: April 15, 2015 05:30PM

As a check for correct coil application, your model year should have a ballast wire (WLG) as part of the engine/front end wiring - it follows that the coil resistance across the two ( + & - ) terminals should be about 1.5 ohms.

EDIT: Meant to add...... If your coil measures 3 ohm, it's most likely that extra resistance is developing more internal heat which the coil can't dissipate adequately.



Edited 1 time(s). Last edit at 04/15/2015 05:37PM by ex-tyke.



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