Slow cranking 6 volt starter

356 Porsche-related discussions and questions.
Post Reply
Message
Author
Alan Close
356 Fan
Posts: 36
Joined: Mon Jul 25, 2011 1:03 pm

Slow cranking 6 volt starter

#1 Post by Alan Close »

My 56 coupe has a 1720 engine and starting is a problem. When cold, I pump the throttle a few times leave my foot off ant it cranks verrrry slowly but it will start. When hot with the throttle open it will crank fast enough. Is there a remedy for the slow cranking?

Alan Close, El Cerito, CA

User avatar
Wes Bender
356 Fan
Posts: 4861
Joined: Wed Aug 27, 2008 10:54 am
Location: Somewhere in the Gadsden Purchase, USA

Re: Slow cranking 6 volt starter

#2 Post by Wes Bender »

(edited to delete first comment.)

As for slow cranking, open the throttle a bit and that should speed it up a bit. Best bet is to check all the ground straps and battery connections and make sure the contact areas are clean and the connections tight.
Last edited by Wes Bender on Fri Dec 14, 2018 4:12 pm, edited 1 time in total.
Some days it's just not worth chewing through the restraints.....

User avatar
Mike Wilson
Classifieds Monitor
Posts: 11490
Joined: Tue Apr 15, 2008 4:37 pm
Location: SW Los Angeles

Re: Slow cranking 6 volt starter

#3 Post by Mike Wilson »

As Wes advises, check all the components including a load test on the battery, all grounds, the ignition switch, the starter itself and the starter bushing, etc.

Mike
Mike Wilson
Lomita, CA
'63 B coupe

User avatar
Greg Bryan
356 Fan
Posts: 3692
Joined: Sat Oct 04, 2008 1:05 pm
Location: San Pedro, CA 90732; Fallen Leaf, CA 96150
Contact:

Re: Slow cranking 6 volt starter

#4 Post by Greg Bryan »

Also check the ground strap between the trans and the body
Greg Bryan

User avatar
Doug McDonnell
356 Fan
Posts: 6061
Joined: Sat Apr 05, 2008 8:21 am
Location: Augusta,Michigan

Re: Slow cranking 6 volt starter

#5 Post by Doug McDonnell »

Alan My favorite can of worms. It literally can be dozens of thing. Including a little of this combined with a ;little of that with a dash of Geez Louise added. I recommend: http://www.cyberwerkstatt.com/Members_O ... ooting.htm I had the same problem after I restored my 65 C coupe including transmission rebuild with new starter bushing. New Bosch Premium rebuilt starter new wiring harness and battery. Literally new everything. Ended up being the Premium rebuilt starter!! Replaced it and no problems since. That said, battery,wiring,grounds, ignition, starter and it's bushing - all can be the cause. That is why I think it is best to use the flow sheet.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

User avatar
Jim Alton
356 Fan
Posts: 1772
Joined: Sun Mar 30, 2008 12:11 pm
Location: Los Angeles County

Re: Slow cranking 6 volt starter

#6 Post by Jim Alton »

A bit less than 40 years ago I got an "A" in electrical machines (motors and generators) en route to earning an electrical engineering degree. I've done pretty much nothing with with motors and generators since.

But, a friend who's was a VW-Porsche mechanic almost as long as I've been alive points out that you can have a bad starter. Maybe the windings on one pole of the rotor are bad. That's why Zims sells $ 180 Bosch-remanufactured starters and $ 420 Zim Premium-Rebuilt starters.

You should certainly try the cheap stuff first,
  • Clean all the connections,
  • Change the starter bushing
If the cheap fixes don't do the job, maybe you should try either getting a "Premium" starter or send your starter to a good rebuilder. Some folks on this forum recommend ABC Partswerks LLC; there are surely others.

Please note that HARD START RELAYs won't help this problem. Those relays are to make sure the solenoid in the starter actuates--a different problem.

My 356A has similar problems and one of these days I'll get a better starter or better rebuild.
 
Jim Alton
Los Angeles County, CA
1958 Porsche 356A Cabriolet
1965 Porsche 911 Coupé
1966 Volkswagen Type 2
2003 Porsche 986 Boxster

User avatar
Jon Schmid
356 Fan
Posts: 1797
Joined: Thu Jun 26, 2008 4:32 pm
Location: La Mirada, CA

Re: Slow cranking 6 volt starter

#7 Post by Jon Schmid »

If you have a lead acid battery, check the electrolyte level.

Dan Epperly
356 Fan
Posts: 1139
Joined: Thu Apr 01, 2010 4:35 pm

Re: Slow cranking 6 volt starter

#8 Post by Dan Epperly »

The rebuilt starters I get at the local Autozone or Pep Boys, VW units,which work on my Bs, as well as my various VWs, all come with used solonoids. They usually work out of the box, but a good number after a while do what you describe. I have tried everything toisolate the trouble and it always ends up being the starter, specifically I believe the old used solenoid.
Usually after a few switch outs, they are guaranteed for life, I find a good one that last.
I wonder of the Bosch rebuild units come with new solonoids for that price?

User avatar
Al Zim
356 Fan
Posts: 4307
Joined: Thu Mar 27, 2008 12:37 pm
Location: FT.WORTH/DALLAS TEXAS
Contact:

Re: Slow cranking 6 volt starter

#9 Post by Al Zim »

The simplest way to increase your cranking speed when cold is to put the car in neutral (so you will not crash into the garage wall) and push in the clutch. Disconnecting the transmission reduces the load the cold oil puts on the starter. The second thing you can do is put a Regular (read it gets hot) light bulb on top of the engine a few hours before you are starting the car or overnight. Make sure it is touching the aluminum on the engine. Everything will be warm. If you have the black regulator you can check the voltage at 2500 rpm it should be 7.25 volts. If not read your shop manual and it will tell you how to increase your voltage so the battery will be stronger. A three year old battery (even an optima) is near the end of its life. zim 2018/12/15
www.allzim.com 
356 Parts and Services
www.facebook.com/ZimsAuto/
www.instagram.com/zims_autotechnik/

Geoff Fleming
356 Fan
Posts: 1972
Joined: Sun Jan 31, 2010 6:50 pm
Location: Union, New Jersey

Re: Slow cranking 6 volt starter

#10 Post by Geoff Fleming »

Al's advice on depressing the clutch is good...especially important in colder weather, otherwise you are adding the viscous drag of the trans. to the work of the starter motor. It is important to open the throttle when starting from cold, to bring in sufficient air. Trying to start an engine equipped with carbs requires some throttle opening.
As I mention in another thread, go over the condition of the battery cables and cut back any corroded wiring, use a new or clean clamp on the positive. Remove the ground cable and carefully clean the area where it attaches to the body. Even a degree of voltage loss, due to corrosion, can seriously slow the cranking ability on a 6 volt car.

Post Reply