Ausmini
It is currently Thu Mar 28, 2024 10:09 pm

All times are UTC + 10 hours




Post new topic Reply to topic  [ 10 posts ] 
Author Message
 Post subject: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 9:55 am 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39621
Location: near Baulkham Hills, NSW
I bought a new GT40 R coil over the counter a few years ago but never used it.
The other day I checked the primary resistance, expecting it to be around 1.5 ohms.
But it measures 3.1! Yes I checked my meter.
Unless these coils are made funny I guess Mr Bosch put the wrong label on it. Rumour has it they are made in China now.
It says GT40 R, use with resistor.... :-/

Worth checking resistance, when buying a coil. Not years later. :wink:

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 10:30 am 
Offline
1098cc
1098cc

Joined: Wed Sep 30, 2015 9:38 am
Posts: 1493
Location: Brandy Hill, NSW
Are you saying that a Mini won't run unless resistance is around 1.5 ohms?

I ask because I can't get my Mini to start using a new coil and resistance is 9 ohms.


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 11:16 am 
Offline
religious status
religious status
User avatar

Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39621
Location: near Baulkham Hills, NSW
No I'm not saying that. I bought it as a 1.5 ohms and it's not. Some electronic ignition performs better with a 1.5 ohm. Fatter spark.
3 ohm coils are for ignition points systems. Which I'm not building.

Re your 9 ohms resistance, if that's measuring across the coil only, it's buggered.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 12:25 pm 
Offline
1098cc
1098cc

Joined: Wed Sep 30, 2015 9:38 am
Posts: 1493
Location: Brandy Hill, NSW
It's a points system car and is 9 ohms across - to main and + to main and it's brand new.


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 1:40 pm 
Offline
848cc
848cc
User avatar

Joined: Mon May 06, 2019 5:29 pm
Posts: 441
Location: Sunshine Coast QLD
cooperess wrote:
It's a points system car and is 9 ohms across - to main and + to main and it's brand new.

Just check the resistance of your meter leads and probes alone, whatever that comes out to will need to be deducted from the reading from the coil. Shouldn’t be much, maybe 0.2 or 0.3 but worth checking.


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 3:32 pm 
Offline
848cc
848cc
User avatar

Joined: Fri Oct 18, 2019 5:11 pm
Posts: 382
Location: Brisbane Northside
cooperess wrote:
Are you saying that a Mini won't run unless resistance is around 1.5 ohms?

I ask because I can't get my Mini to start using a new coil and resistance is 9 ohms.


Are you sure it isn't 0.9 ohms. 0.9 ohms is for a lot of electronic ignitions and will burn out points very quickly.

Minis with points ignitions should be about 3.0ohms. about 1.5ohms if a ballast resistor is fitted.

Electronic ignition varies depending on the manufacturer/model.

_________________
1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 8:16 pm 
Offline
1098cc
1098cc

Joined: Mon Nov 06, 2006 8:54 pm
Posts: 1785
Location: Hunter NSW
Ac dodd spoke about tis on YouTube


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 8:42 pm 
Offline
998cc
998cc

Joined: Sun Nov 06, 2005 5:41 pm
Posts: 844
Location: Adelaide
The standard non ballast coil as used on the late UK Mini with factory electronic ignition for use with 65D distributor is 0.9ohms (from the UK Minispares site).


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 8:43 pm 
Offline
1275cc
1275cc
User avatar

Joined: Sun Apr 29, 2012 1:19 pm
Posts: 4336
Location: Wollongong, NSW
Goldbrocade_62 wrote:
Ac dodd spoke about tis on YouTube

He does lots of helpful videos on minis

Coils


Distributors

_________________
Image


Top
 Profile  
 
 Post subject: Re: Bosch GT40 R coil..
PostPosted: Wed Jan 25, 2023 10:07 pm 
Offline
1098cc
1098cc

Joined: Wed Sep 30, 2015 9:38 am
Posts: 1493
Location: Brandy Hill, NSW
Thank you timmy - very helpful.

Think I may have solved this. I need to learn how to use my multimeter.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 37 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

cron

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.