Hi, Doing a dynamo to alternator conversion on a 72/73 late bay with a heritage (from distant memory) kit I purchased a long time ago. just fitting the new alternator and backing plate on to the fan and wondering if there's a starting point for number of shims and which side of fan to put them? I've also found the backing plate is utter turd fit wise, this the norm?! I've seen a YouTube video showing to use 2 shims (look like the thicker ones) in the hub then the fan. Do I try to fettle with the back plate until this fits and doesn't rub? The pic below shows the shims I have. Any help much appreciated. Any other tips would also be useful! I've got leccy fuel pump and fuel block off plate so not too worried about that aspect.
Look in your Haynes, there isn't a set number of shim - if there was they wouldn't be needed at all if you see what I mean. You have to put enough to get the recommended clearence between fan and backing plate. 1mm I think, or is it 2mm?
I'm not sure whether it's the same deal for ALT swaps as it is for flywheel/crank pulley shims Personally, I'd make sure the fan has sufficient clearance in the doghouse front and back, bolt the backing plate on and see where the rear face of the fan belt pulley lies in relation to the crank pulley...shim from there....more or less as needed. Zed's just beat me to it
Zed, Vanorak, cheers for the info. Just after a "starting point" as such really. I understand the shims are there for tweaking etc.. I don't think the Marmitee backing plate is helping my cause. I just persuaded it into a position that looks ok, so i'll give that a go and see how i get on with fan shroud clearance etc. cheers again
The backing plate should bolt on (with two nuts on studs?) and sit firmly in place. What did you have to do to persuade it? Spin the fan and straighten it if you need to. When that's straight you can check the gap all round is constant and bend the backing plate a little if needed to until it is. Now you can finally measure the gap and adjust to spec with shims. You might need a few, you might not, so there is no starting point. If you have no gap chuck a few in and see. Nothing's as straightforward as it sounds is it?
When you finally get it all together and installed, put a straight edge across the crank pulley and check the alt pulley is lined up.
I was told to change the push rod under the fuel pump when changing from dynamo to alternator , not sure why.
Only if you also changed the fuel pump because your existing didn't fit with the alternator. The pumps commonly sold fit with both dynamos and alternators and as most buses have already had the pump swap usually you need to do nothing to the pump/pushrod.
I've got leccy fuel pump and fuel block off plate so not too worried about that aspect. The holes needed drilling out a little to ensure the alternator sat centrally on the plates and the sheet metel moulding around the fixing holes needed a slight beating with hammer and punch to get the everything to sit flat. after that the plate was sat wonky so as you said bent it slightly to sit flat to the fan. All back together now and looking ok. Next thing... oil filler out of existing stand...funny how the tool to remove this isn't mentioned when buying the kit?
old oil filler neck out of old generator stand and in to the new stand...that's right isn't it, assuming it's a straight swap?
Are they different (may well be - I've never done a conversion)? Yes, you will need the tool if you want to swap the filler.
make one out of a bit of flat bar...or two flat end screwdrivers gaffered together with a socket inbetween the shafts
