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Grinding Noise Directly After Starting Engine
#1

Hey gang, 

 

so my 968 manual coupe is making a new noise and it's disconcerting.  When I turn the key, the starter engages, and the engine fires up.  Directly after I let the key turn back, there is a loud grinding / whirring noise which lasts for 1-2 seconds and then disappears.  It is currently happening about 1 out of every 2 starts, and doesn't seem to be linked to being hot or cold, or any other factors I can think of.  It happens whether or not I have the clutch depressed.

 

My first thought was that it could be the starter temporarily failing to disengage from the ring gear on the flywheel.  I'm not sure what to do in this case, other than replacing the starter.  I did some googling about lubricating the gear, but it appears popular opinion is that this is not a good idea.

 

Anyone have a similar experience?  I'll try to take a video and catch it happening.

 

Cheers

Phil

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#2

I suspect you are right about the starter not disengaging. Why not drop it out to see if something has got in there and is fouling the movement. Get some jump leads, secure the starter in a vice .... or with your foot on your garage floor .... and activate the starter. It is two stage so you will need two +vs ...... one to pre-engage the solenoid and the other to spin the starter.



The job itself is quite is straightforward, the difficulty is getting on too the top nut if, like me, you work with axle stands ..... knuckle sockets are very helpful.
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#3

Agree with Roboman, just drop the starter and disconnect from the wiring. Shure you can test it, but the result may be always good just because it has nothing to engage too. Just take it apart and replace the parts that needs to be replaced if any (carbon brushes for instance). Clean the axles and gears from the starter motor and lubricate what needs to be lubricated with the right grease again. After putting it back together your problem should/could be solved. It's a few hours job when you take it easy.

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#4

Thanks for the response guys.  I'll pull it this weekend and have a look.  I looked around for info on what type of grease, and where to put it, but most of what I found was saying to just replace the unit with a factory refurbished unit.  Any tips?  I have a few special Porsche greases from replacing the clutch system, and then a few run of the mill bearing and lithium greases.

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#5

Gummy Starter Syndrome. It's a thing! Pull it, lube it and maybe replace the brushes while you are in there and you will be good to go. Check the contacts on the back of the solenoid, sometimes they get pitted and will stick, file them and the contact ring smooth and all will be well.

 

These are sturdy units, you don't have to replace them often if you know how to do basic maintenance and can clean and lube them as needed.

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#6

For greasing the bendix some say to use a few drops of oil only, I just greased with some bell-ray waterproof grease.

The oil they say has everything to do in picking up less dirt then grease, well I have no idea if this is true.

 

But it's an straight forward job, so whenever it becomes dirty again in lets say 10 years time you only have to spend a few hours to clean and replace the parts needed if you see some.

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#7

you can buy all the parts in the UK for a starter

 

new bushes

new bearings

new brushes

most important a new Bendix gear, which is the bit that gets stuck

 

I have rebuilt about 15 so far,

 

Its not a hard job if your a bit handy
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#8

Alright, I'm armed with knowledge!.  I might just pull it and see if a little cleaning and grease gets the job done  If the brushes and bendix gear need replacing, I'll get them on order.

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#9

I pulled the starter and disassembled it.  Everything seemed to be in working order other than a bit of excessive friction when the gear moved in and out of the starter.  I cleaned all the parts and put a thin coat of grease on the shafts and put it all back together.  After buttoning everything up, I did about 10 starts and a test drive.  The noise is gone, and there is also less noise when the starter is cranking the motor.

 

The hardest part of the whole job was getting the metal cover over the ring clip on the main shaft, took me over an hour to finally figure out a solution involving two wrenches and a hammer.

 

Nice to turn the car on without the embarrassing grinding noise!  Another small victory, thanks all for the advice.

 

Cheers

Phil

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#10

:clap:

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#11

Good fix but it wont be long till the noise is back
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#12

Well done Phil, hope you used the wrenches and hammer carefully.
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#13

Well done .     Helpful info, from the precise description of the symptoms to the diagnosis, to the fix.     Heard about gummy started syndrome for many years, but never knew how it manifest itself and if there was a fix ( other than buying another starter ) .  



 
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#14

Quote:you can buy all the parts in the UK for a starter

 

new bushes

new bearings

new brushes

most important a new Bendix gear, which is the bit that gets stuck

 

I have rebuilt about 15 so far,

 

Its not a hard job if your a bit handy

 

I am intrested in getting the parts , and rebuild mine , it has lost some of its speed over the years .

 

Where and what part nb'r do i need  Waylander ?

 

 
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#15

Oh I have a big list of starter parts

 

Brushes Bosch 2004336240
 
Brushes Woodauto EC47023
 

Pinion/Drive Assy SDV38150

 
Shaft/Gear Assy BOS1006200034
 
Armature WSA5858
 
C/E Bush BUH6363

 
Solenoid SND12584

 
Lever EC4550

 
 
Field Coil BOS1005001913
 
Aux Coil EC4727
 
C/E Bracket BOS1005851097
 
Gearbox Bush BUH6354

 
 
Tiptronic / 944
 
Bosch 0 001 110 080
 
 
Pinion/Drive Assy SDV32195
 
D/E Bush BUH6354
 
Field Coil BOS1005001913
 
Aux Coil EC4727
 
Armature WSA5858
 
Brush Holder EC47025
 
Brush SBR5635
 
C/E Bracket BOS1005851097
 
C/E Bush BUH6363
 
Lever EC4550
 
Kit/Misc 1 EC35827
 
Solenoid SND12584
 
 
Solenoid Screws BOS2003429072, EC41569
 
The ones in red are what you really want, the brushes you need a big arsed soldering iron for, as I could not by a complete brush box
 
the parts come from WoodAuto
https://www.woodauto.com/
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#16

Thanks  Waylander
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#17

Quote:Thanks  Waylander
vliegwielolaf1234, you can buy all these parts in Holland too!!!

There is a shop in Haarlem where they rebuilt Bosch startermotors (and alternators etc.), they have all you need.
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#18

It’s been a very long time since I replaced mine, but as I recall,  starters are (  or at least used to be ..) quite inexpensive so why would anyone put up with buying all those parts and repair / rebuild a starter instead of buying one which you can just  “ plug & play “ ?  

Unless of course you enjoy doing all that … masochists !   Rolleyes  Tongue

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#19

+1. Generic piece of kit and J's source in Haarlem probably does a swap.



Waylander, I know you're not a car yard, did you do " core replacements " ? I guess that would require you having a pile of starters unless you only did 968s.
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#20

Quote:vliegwielolaf1234, you can buy all these parts in Holland too!!!

There is a shop in Haarlem where they rebuilt Bosch startermotors (and alternators etc.), they have all you need.
 

Oke ,can you give me Name and Adres ?

 

Had a local shop before , a one man company  , but he quit a year ago .

They all start to dissapear , these days , not good 
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