Ø90mm Dynamo on 2276 motor

[hunteroval]

Hi All,

Advise please. I have a 2276cc, Webcam 86, 48 IDA motor. ~190hp. I have a welded fan. It has an alternator, I want to run my VW Bosch 11U German 111903021 Ø90mm 12V dynamo. Not sure if this is significant but it is stamped in French ‘importe d’allemagne’.

I understand that dynamos don’t charge as well as an alternator and that they drain hp. Dynamos on big motors look more period and in my opinion, the nuts.

Questions:

1.   My motor will rev to 7,500rpm easily, will the dynamo cope? I see pictures online of other hot motors with what look like early dynamos, are they actually or have they been converted to alternators? Or are they not revving as high? I’m aware I can edit pulley ratio but I can’t neutralize a 100% increase in revs – assuming original 30hp motor did about 3,500 rpm.

2.   Alternator and pulley lined-up perfect with crank pulley. With dynamo mocked-up, I have pulley mis-alignment of about 7mm. Dynamo pulley needs to move towards rear of car to align. I’m certain I can engineer my way round the problem but would like to ask: Has anyone experienced this before? Have I used the wrong combination of parts? I don’t want to be adding spacer rings behind pulleys and increasing leverage on bearings without giving it some thought.

I have an empi engraved pulley and sandseal arrangement which I believe is causing the problem. Crank pulley has been machined to suit, there is little clearance between tin/block so not much more can be removed. I have a 30hp top pulley from Wolfburg west. If I fit the alternator pulley to the dynamo to test, mis-alignment remains very similar. Dynamo is sitting on a 113.101.211 stand. I have an Empi 30hp-style tin with oil cooler dog house.

Thank you for any help you can offer. 

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[Neil Davies]

I can't help at all, but I'm interested in the sand seal set up - does it require machining to the case at all? It might save my 2276 that is damaged there!

[Olaf A./DFL]

A few of our Club Members also have that set-up - you will have to find a matching pulley on the dynamo- there are different types available. You will need the ones that were fitted to the early 34 PS engines and pulley shims to make it fit.

[nicolas]

I can't help at all, but I'm interested in the sand seal set up - does it require machining to the case at all? It might save my 2276 that is damaged there!

yes you need to machine it.

[richie]

I can't help at all, but I'm interested in the sand seal set up - does it require machining to the case at all? It might save my 2276 that is damaged there!

That one in pic is a press in collar that has seal inside it & pulley is spaced off to clear it, but there are seals available that require case to be machined so seal fits inside snout and pulley fits like normal

[hunteroval]

I can't help at all, but I'm interested in the sand seal set up - does it require machining to the case at all? It might save my 2276 that is damaged there!

That one in pic is a press in collar that has seal inside it & pulley is spaced off to clear it, but there are seals available that require case to be machined so seal fits inside snout and pulley fits like normal

Hi, yes my pulley is machined to suit. It's ok but means changing pulley is more involved. Here's my pulley:

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[hunteroval]

Thanks for the replies. It was a bit quiet on here so I did a bit more research and bought a 6v pulley. The offset is perfect and aligns with my crank pulley but I'm not happy with the look. It's a larger diameter than the 90mm dynamo, looking on forums about 109 maybe. The offset creates a big gap behind the pulley too. I'll grab a pick when I'm next in the garage.

[Neil Davies]

I can't help at all, but I'm interested in the sand seal set up - does it require machining to the case at all? It might save my 2276 that is damaged there!

That one in pic is a press in collar that has seal inside it & pulley is spaced off to clear it, but there are seals available that require case to be machined so seal fits inside snout and pulley fits like normal

Thanks Richie, a project for a rainy day I think! Seems a shame to chuck away an otherwise very nice case if it can be fixed.