I bought an AAZ trying to comp test, what starter to use?

[erice1984]

I have an AAZ, I have an 020 ASF transmission. I tried the stock direct drive starter, worlwide part number 16726, and the gear reduction 16947.

The direct drive (16726) almost stalls when it gets the cylinder near TDC.  This leaves me to believe that it can't generate the RPM's to get good psi reading.

The gear reduction starter (16947) goes pretty good, but I don't think it spins the engine fast enough to get the psi to build.  I haven't fully verified this yet, I am at the parts store typing this and going back home with this starter to actually run it for 15 seconds to see what psi builds up.

Can I use the AAZ starter?  Bosch part number SR0408X with the 020 transmission?

Let me know what you guys think.  Thanks  -Eric

[R.O.R-2.0]

you need a diesel specific starter to crank over a diesel.. they are WAY BIGGER than a gasser starter, physically..

and they have about 3x the power too..

[erice1984]

you need a diesel specific starter to crank over a diesel.. they are WAY BIGGER than a gasser starter, physically..

and they have about 3x the power too..

I understand, but gassers are rated 0.7-1.1KW, while diesels are rated 1.5-1.8KW

Both of these starters are listed as for diesel.  Both the specifications on them 1.8KW.

The only thing I can think of, is that my direct drive starter (16726) is weak from age, and not able to move the larger engine and possibly higher compression numbers because my 1.5 is fairly worn out.

I have no idea why VW offered a gear reduction starter that doesn't spin the same speed as the direct drive starter.

The AAZ starter, SR0408X is a direct drive unit, and spec'd at 2.0KW

I just wondered if anyone else has run into this issue and what solutions they came up with.

[erice1984]

Okay, the gear reduc starter actually does a lot better job starting my 1.5..  Huge difference.  I don't hear the poor starter making the "I'm almost dead" *rrruhha..rrruhha..rruhha* noise while cranking (aka slow crank).

Well I compression tested my engine and it is not good, but I am still going to remain optimistic as it has been sitting for probably over a year.

So I believe it is my engine that is having the problems not the starter.

[R.O.R-2.0]

you need a diesel specific starter to crank over a diesel.. they are WAY BIGGER than a gasser starter, physically..

and they have about 3x the power too..

I understand, but gassers are rated 0.7-1.1KW, while diesels are rated 1.5-1.8KW

Both of these starters are listed as for diesel.  Both the specifications on them 1.8KW.

The only thing I can think of, is that my direct drive starter (16726) is weak from age, and not able to move the larger engine and possibly higher compression numbers because my 1.5 is fairly worn out.

I have no idea why VW offered a gear reduction starter that doesn't spin the same speed as the direct drive starter.

The AAZ starter, SR0408X is a direct drive unit, and spec'd at 2.0KW

I just wondered if anyone else has run into this issue and what solutions they came up with.

all diesel starters ive read specs on, have been in the 2.1+kw range..

[erice1984]

all diesel starters ive read specs on, have been in the 2.1+kw range..

Let me know which ones those are.

[R.O.R-2.0]

the ones that come factory in mk1 and mk2 cars.. you know, the ones that weigh about twice as much as a gasser starter? ive read it a few different places that say the diesel starter is 3x the power of a gasser unit..

[erice1984]

rockauto.com states what the KW rating is.

So does Advance Auto parts

Short of contacting bosch or VW thats where I got my information from.

But yes there is a power difference between gas and diesel starters.  If there was one very powerful starter I could use I would like to know so I can use it!

[Quantum TD]

How bad are the compression numbers? You might try soaking the cylinders with kerosene for a few weeks to  try to loosen up any stuck piston rings. Just be sure to 1) blow out the kerosene thru the injector holes/glow plug holes, don't glow the plugs when cranking, and drain the crank case and refill with fresh oil. If you get better numbers, run it for a short time, and then replace the oil and filter again.

I suggested this trick to someone on vwdieselparts.com and they reported improved numbers all around, and more-even numbers across the board. I'm gonna do it to the 3 turbo diesel motors I have kicking around here.

[erice1984]

How bad are the compression numbers? You might try soaking the cylinders with kerosene for a few weeks to  try to loosen up any stuck piston rings. Just be sure to 1) blow out the kerosene thru the injector holes/glow plug holes, don't glow the plugs when cranking, and drain the crank case and refill with fresh oil. If you get better numbers, run it for a short time, and then replace the oil and filter again.

I suggested this trick to someone on vwdieselparts.com and they reported improved numbers all around, and more-even numbers across the board. I'm gonna do it to the 3 turbo diesel motors I have kicking around here.

Good idea.

I added 1/2 qt of ATF to the oil to loosen stuff up before I tested.  My numbers were 300, 360, 330, 280

I'll try it.

[R.O.R-2.0]

rockauto.com states what the KW rating is.

So does Advance Auto parts

Short of contacting bosch or VW thats where I got my information from.

But yes there is a power difference between gas and diesel starters.  If there was one very powerful starter I could use I would like to know so I can use it!

like i stated, mk1 and mk2 starters are the gigantic, direct drive starters.. they require good cables, and a good battery or else they will not spin fast enough..

any starter is kinda *marginal* for an engine with 24:1 compression.

[erice1984]

like i stated, mk1 and mk2 starters are the gigantic, direct drive starters.. they require good cables, and a good battery or else they will not spin fast enough..

any starter is kinda *marginal* for an engine with 24:1 compression.

I hear ya, I had the battery out of my car, has 800CCA was fully charged.  I was using jumper cables, I think they were 6 AWG or something.  but 12ft long.  I should make a better setup for the next go around (I have 0 and 2 AWG laying around and keep the cables to less than 2 ft).  I had my charger on the battery, it was only pushing out ~6 Amps but I would wait until my multimeter would read 13.0volts and then hit the starter again.

I almost guarantee its because the engine has been sitting for so long and all goo'd up.

[R.O.R-2.0]

like i stated, mk1 and mk2 starters are the gigantic, direct drive starters.. they require good cables, and a good battery or else they will not spin fast enough..

any starter is kinda *marginal* for an engine with 24:1 compression.

I hear ya, I had the battery out of my car, has 800CCA was fully charged.  I was using jumper cables, I think they were 6 AWG or something.  but 12ft long.  I should make a better setup for the next go around (I have 0 and 2 AWG laying around and keep the cables to less than 2 ft).  I had my charger on the battery, it was only pushing out ~6 Amps but I would wait until my multimeter would read 13.0volts and then hit the starter again.

I almost guarantee its because the engine has been sitting for so long and all goo'd up.

hmm, im thinking that you used too small of wire to power the starter.. 6g is small.. and especially such long runs of it..

jumper cables are great for starting a dead car, but not good for connecting a starter to a battery.. they dont handle enough current..

[dieselweasel]

I'm thinking you're right...lots of voltage drop along 6 awg wires 12' long.  Also the small surface area of the clamps contacting the terminals doesn't help matters.  I'd rig up some of that 1/0 you have with proper terminals and redo the compression test...you can then use them for battery cables.  


Any starter I've seen on an AAZ was gear reduction.  

[Otis2]

The AAZ starter, SR0408X is a direct drive unit, and spec'd at 2.0KW

I use that starter in my AAZ-powered Vanagon.  

Good, high compression in the engine, but it starts like butter, even when it's warm and the glow plugs don't glow.

Long stretch of battery cables (gasser cables & battery box position), probably marginal for the task, but the Bosch SR0408X stands up just champion to all the abuse.

Just another data point to be considered.