Starter motor upgrade?

[fspGTD]

Has anyone researched a starter motor upgrade for VW Diesel?  I'm looking for one that is stronger & lighter than the original Bosch.  I'd prefer a higher quality or better engineered starter motor than the Bosch, IE: with ball bearings instead of bushings, etc.  I am most impressed with Densos quality, however they are a completely different gear reduction design and finding one that fits or can be made to fit to VW 020 transmission and geared and sized properly may prove to be a quite difficult task.

I was looking at the starter on a '01 Golf TDI automatic and was surprised that is was Valeo brand starter motor.  So it seems VW added or switched to Valeo starters at some point.  I wonder if a TDI starter would bolt up... the basic outside dimensions looked like an orbital gear-reduction style just like the Bosch starters found on A2 IDI VW Diesels.  Are the Valeo starters that come on TDIs any better I wonder?

[jtanguay]

would those starters have enough cranking power to turn over the high compression engine though?

[chrissev]

would those starters have enough cranking power to turn over the high compression engine though?

I think the power of the starter has a lot to do with the gear reduction.  Ie, a relatively weak electric motor, properly reduced in speed and increased in torque, can crank over a high compression engine easily.  The main issue you will probably have will be gear mesh problems and starter gear travel problems.  If the gear on the end is not the same as the flywheel gear, you will wreck the flywheel.  Also if the travel of the gear is different when the solenoid pushes it out, then that might be a problem.  There's this little copper bushing in the back of the 020 transmission that the tip of the starter shaft sets into when the solenoid is energized, so the prospective starter's shaft would have to fit in to this.  Perhaps there would be a way to retrofit the end gearing and shaft of an 020 tranny style starter to a newer TDI starter?

[Patrick]

A good starter/alternator shop should be able to tell you. barring that, take a starter with you and go through their pile of "cores" until you find something that looks right, and then check all the things already mentioned. I pulled this stunt on my tractor, which has a 3 cyl perkins and a Lucas starter. Put one on with a matching nose cone and drive, and twice as big a motor. (weight is not an issue.) Should be able to do the same thing the other direction, a good shop will be able to tell you if what you find is capable of cranking that motor. I don't mean a Can Tire or a Wal Mart!!!

[fspGTD]

Here is an aftermarket starter I found listed for lightweight VW watercooled application (about 7 lbs), rated at 25NM torque, however only 1.0kW which I think is some measure of it's output?  That seems like it might not be enough power output for a diesel (the stock Bosch diesel starters in our VWs are rated at 1.7kW, I found)  Does anyone know more about what these ratings describe?  The electrical draw, or mechanical output power (IE: some measure of torque x rpm at the output shaft)?  In the advertisement, I found a really nice graph of all the working dimensions:


http://www.startermotors-alternators.com/Motorsport-Starter-Motors.htm

Notice how this design eliminates the need for the transmission bushing.

The factory starter design by the way always has a shaft engaged in the transmission bushing.  When the starter operates, the drive gear slides out over the shaft and engages the flywheel teeth.  Then the shaft and gear start both rotating, driving the flywheel (that's why lubrication of this bushing is important.)

Some types of starter designs (like the one linked above) seem to not use the bushing - they must have roller bearings inside the starter motor to support the gear instead.

I found a variety of aftermarket starters available, advertised for vw aircooled and vanagon application.  Does anyone know if any aircooled vw starters physically fit the 020 transmission?

[QuickTD]

The Kw rating of the starter describes its output power. Kw and horsepower can be used interchangably, 0.746kw=1hp.  I've never tried a watercooled gasser starter on a diesel, but I did try an aircooled one. The aircooled starter can be made to fit by slotting one of the mounting ears. You may need to watch for solenoid clearance, the engine I tried this on was out of the car so this was not an issue. The gear and shaft fit the trans and flywheel just fine. However, the one I tried bumped the motor about a half turn and could crank it no further. Simply not enough power to get it over the compression "hump". This was a VW bus starter (2.0L?) and the engine was a freshly rebuilt 1.9TD.

 The reason I was messing around like this was to make a lightweight engine starting rig. I tore apart an old 4 spd transaxle leaving just the bell housing. I mounted a starter to it so I could fire up engines on the ground. The only starter I had lying around at the time was the aircooled one. I've since got a diesel starter (a heavy old direct drive brute) and it works good, if a bit heavy.

I think the permanent magnet gear reduction bosch starter is about the lightest thing you will find that will still start the motor. I've never seen any diesel starter quite as small as those.

[srivett]

Maybe a 5 cylinder AUDI diesel starter would work?

Steve

[fspGTD]

Thanks for the aircooled starter info - do you know what application was for the the aircooled starter you were able to make fit?

By the way, I calculated the gear reduction ratio for the gear reduction A2 VW diesel IDI starter, and it's in the range of a 3.625 - 3.8 reduction ratio [Edit: it's exactly a 3.8:1 reduction ratio]

Regarding the aftermarket aircooled starters, there seems to some denso or "denso-like" aftermarket replacement options available.

Here are a couple offset gear reduction starters (says they are made by hitachi, but the design looks denso to me) for a couple different vw vanagon/aircooled applications:
  * Westfalia 68-75 Manual Trans & 72-91 Auto Trans, 2WD


  * Westfalia 76-91 Manual Trans 2WD


(source: http://www.gowesty.com/starter_story.htm )

These style of denso starters seem to be a popular upgrade to retrofit onto older applications with weak starters (available for everything from US-made V8s to old british cars, etc.)

According to denso, there is one technological version of starter motor that offers a little better power to weight ratio than this offset gear reduction family.  The newer better style is called the "PS" ( source: http://www.globaldensoproducts.com/em/s/ps_starter.html ) I can't find it available anywhere though; it is apparently too new to have cropped up in the aftermarket.  I make note that I saw on the web elsewhere a disassembly shot of a valeo starter that had the same surface commutator (not cylindrical).  maybe Valeo's got some good stuff... I would like to check out that Valeo A4 TDI starter a little more closely.

[QuickTD]

I'm no expert on aircooled engines so I really have no idea what engine it came off of. My buddy had it as a spare for his dune buggy. He had quite  a few and they all appeared to be the same, or at least the starters were.

 Those little denso starters do have some power. I've seen that type used on little 1-1.2 litre isuzu and kubota diesel engines used in mobile refrigeration units. They have to start the engine many times a day and seem to hold up well. I'm not sure if they would crank a 1.6l or not. In the PNW you may not need quite the starter that we need here in Canada... About all I can suggest is to give it a try...

[lord_verminaard]

The A4 TDI starters would be worth a shot, in my year of working for VW parts I dont think I ever saw one replaced.  Remember too, that the TDI needs to be spun to at least 750 RPM before she'll kick over- that's a lot of work at 19.5-some odd compression.  

Brendan
84 Scirocco 8v
00 Camaro L36 M49

[fspGTD]

The A4 TDI starters would be worth a shot, in my year of working for VW parts I dont think I ever saw one replaced.  Remember too, that the TDI needs to be spun to at least 750 RPM before she'll kick over- that's a lot of work at 19.5-some odd compression.  

Are you sure the TDI is really getting spun at 750 RPM?  The protraining manual for 1.5/1.6l diesel VW states that the minimum number of cranking RPM that are deemed to be "OK" for the 1.5/1.6 liter IDI diesel is only 150 RPM.  I am now very curious to know if an A4 TDI manual transmission (02J/etc) starter would bolt up to an 020 tranny.  

It is hard to find info on this Valeo-OEM A4 TDI starter.  I did find a reference on valeo's web site that they were as of late, an OEM supplier of starter motor for the VW Golf.

Although it's not from the OEM supplier, I found some info on a starters for a VW Golf TDI application in this pamphlet (scroll down to the 9th page - it includes all the applications for the Golf TDI starter, as well as a picture):
http://www.iskra-ae.com/slo/docs/new_application_september2002.pdf

[QuickTD]

I'm pretty sure the minimum cranking speed for the TDI is around 200-250rpm. Any starter that could spin the motor up to nearly idle RPM would be a winner in my books though.

[fspGTD]

I checked the A4 Bentley manual, and sure enough it lists the A4 TDI / VR6 starter at a 2.0kW rating.  I couldn't find a cranking RPM specification.

This is indeed a little bit higher than the 1.7kW rating of the Bosch IDI Diesel starters (which is the same rating for either the A1 direct drive style or the A2 planetary gear reduction style.)

[subsonic]

Anyone ever find out if the  5 cyl diesel starter would fit?  It must have more power to turn over that extra cyl.  Who is our resident volvo D24 expert here?