Dynamo pully and backing plate same as alternator?

[dublicious]

Hi guys,

Looking at doing an alternator conversion and wondering if the pully and backing plate are the same for each? I already have the stand coming and alternator (Bosch remanafuctured). Output has been tested some fingers crossed.

Take care,

J

 

[K@rlos]

Pulley is the same, backing plate isn't

 

[K@rlos]

You'll need a different fuel pump too

 

[dublicious]

Cheers dude, will start looking for back plate. I replaced my fuel pump some time ago, which one is needed?

 

[K@rlos]

The alternator needs the fuel pump which is angled and I think it has a shorter pushrod too

 

[starbiscuit]

The OE pulley off my dynamo would not work with my alternator conversion; it fouled the alternator casting.

I didn't pack it out because it moves the centre-line of the drive belt and I didn't fancy the risk of increased wear or losing the belt.
And I didn't fancy grinding clearance on either the pulley or the alternator.

The replacement pulleys available from the usual places are all universal now, I think, so will fit alternator or dynamo.
At least, there was only one type on offer when I had to buy one, and it fitted the alternator fine.

You will know if yours fits or not because it will be difficult to turn by hand and will make a grinding noise

Yes, you need the later angled fuel-pump and shorter push rod.
You also need an alternator-specific pedestal, or take a grinder to the dynamo one, because the alternator casing is much bigger diameter at the pulley end than the dynamo.

Again, I think the replacement ones are universal.

 

[dublicious]

Many thanks guys work is underway

 

[dustrat]

I changed from dynamo to alternator on my Ghia and on other key start engines that I have built with no problems apart from changing pedestel and fuel pump.I did not change back plate or any of the fan bits. It has been stated that back plate has got to be changed, no it does not ,it is the same .If you doubt this check on Heritage or any of the other suppliers web sites.
Robert

 

[Clem]

I've fitted Bosch alternators to my van and Ghia and in both cases just swapped alternator units, pedestals and fan belts.

 

[Peter Good]

The 38 Amp dynamo back plate may be different to accommodate the extra 11mm in length. The 30 Amp dynamo is the same length as the alternator, hence the same back plate.
Peter Good

 

[dustrat]

Sorry Peter, I dont know where you are getting information about 38 amp dynamo being 11mm longer (thats 0.43inch,nearly half an inch) as dynamo or alternator are all same over all length. If they were not you would not be able to line the crankshaft pulley and generator pulleys up to put fan belt on. The fan housing will not go any futher back !! Just to make sure I have got my facts right I phoned 2 of major VW suppliers and they confirmed that length of all dynamo / alternators are the same .
Robert

 

[matt-me]

Peter probably got his information for the fact that he used to sell this type of electrical equipment. Things may have changed now but when i did an alternator conversion some 5/6 years ago i bought the kit, but thought I could re-use the OG backing plate too. I did try as it was much better quality than the piece that came as part of the kit. There was a slight dimensional difference in the front to back plane, only millimeters, but the OG one definitely did not work/did not line up correctly. Maybe things have moved on as i did think it was odd that they basically looked exactly the same but were very slightly different....

 

[sparkywig]

Peter probably got his information for the fact that he used to sell this type of electrical equipment. Things may have changed now but when i did an alternator conversion some 5/6 years ago i bought the kit, but thought I could re-use the OG backing plate too. I did try as it was much better quality than the piece that came as part of the kit. There was a slight dimensional difference in the front to back plane, only millimeters, but the OG one definitely did not work/did not line up correctly. Maybe things have moved on as i did think it was odd that they basically looked exactly the same but were very slightly different....

I had the exactly same issues on the last two conversions I did.
The OG backing plates are in a box in the store.

 

[Peter Good]

I have absolutely no problem in anyone asking where my information comes from. In this case I was the junior in the drawing office that created the information using the standard DO kit available in the late 60's for certain of the piece parts that went to Bosch and others for generators and starter motors. I was very careful to state 38 Amp dynamo, as the 30 Amp unit is indeed the same length as alternator. I doubt any supplier still has a 38 Amp dynamo on the shelf, as they largely disappeared some 10 maybe 15 years ago hence giving rise to stock reply statement they both (the 30 Amp dynamo & alternator) are the same length.
As can be seen from the various statements of factual witness in this thread, there are not just one, but a small number of components that differ to the 30 Amp/alternator in order to take up the 11mm difference.
However, with benefit or otherwise of receding grey hair can I say, life is as it should be, a life-long learning process where we never stop learning.
Peter Good