1937 Aprilia 38-1427

[williamcorke]

I've had this car since 2009 (bought on eBay from Portugal) but it has sat in a barn since then, gathering dust and surface rust on unprotected surfaces (bolt ends mainly, thankfully not bodywork).

It arrived as an unfinished project:
- body done (nice paint, good gaps, well protected underneath). The only questionable area I've found is at the top of the A pillar above the drivers door where the paint is bubbling. Not sure what's underneath...)
- Incomplete interior, but I got a set of early front seats from Ron Frances to have re-trimmed.
- Most of the electrical parts missing (fuse and connecting boxes etc, not dynamo / starter motor though). Thankfully the wiring loom is pretty simple.
- Engine rebuilt, supposedly. It has clean oil in it, turns over, and was clearly run post rebuild, so I'm slightly optimistic.

Having been through a saga rebuilding a front suspension unit (https://www.lancia.myzen.co.uk/forum/index.php?topic=9253.0), I have now moved the car into the workshop and started going through it from front to back. Everything needs to come off to be checked and in most cases re-finished before being put back on the car.

This is a great way to learn the car; certainly necessary as I've not worked on a Aprilia before. So far it's been a real pleasure, and a fascinating comparison to the 1950 Aurelia B10 I've rebuilt over the past few years.

I'm going to have to ask a lot of questions, as the information available from publications (whether contemporary to the car's production or more recent) don't always make things clear. Probably some mechanical knowledge and technical approaches that were lifeblood and so assumed as known in the 1930s are anything but today. Certainly they seem obscure to this self-taught mechanic!

Before I ask a technical question about Marelli dynamo bearings, here are some photos of the car:
- when I bought it (photos from eBay listing)
- in my barn before its recent extraction
- In the workshop
- An example of the surface rust issues - on the hand throttle / choke assembly. No question of not taking things apart when it's got like this.

[williamcorke]

So here's my first question, which relates to the fettling of the Dynamo.

The unit seems to be in generally OK condition, but on disassembly, it's clear that the front bearing needs to be replaced as there's scoring and pitting on the outer race.

As a side note, all the bearings I've so far encountered on have had congealed and discoloured 'hard' grease. My method for cleaning them for re-fitting - if they run smoothly without play - is to;
- scrub the grease with a soft brush under the flow from a parts-washer's nozzle.
- wash off with brake & clutch fluid and dry
- re-pack with new grease

Back to the dynamo. It was easy to remove the rear bearing, but the process to remove the time-expired front one is not obvious to me.

1. The outer race, mounted in the front face casting of the dynamo, appears to be, as far as I can see, screwed in. But how would you get any purchase on it to screw it out, or in, in the first place?

2. Below the outer race there's a dark metal insert (?) with quadrants recessed with some kind of felt material in them. What is this? A thrust bearing of some kind?

3. What are the semi-circular cut-outs either side of the outer bearing race in the front cover for (seen in photo 1)? Could they be used to lever the bearing out?

4. The inner race and its associated dust shield seen to require a special puller to remove. None of the ones I have will act on the  bearing without distorting shield. Ideally I'd install a sealed bearing once I've got the old one off, so perhaps the damage wouldn't matter, but you never know when you might need to re-use something....

Thoughts and suggestions please.

W

Photos:
1. Outer race, with thrust bearing (?) with quadrant recesses
2. Inner race, dust shield

[Mikenoangelo]

Looks like a circlip which can be tweaked out with a small screwdriver pushed into the semi circular hole.

Mike Clark

[simonandjuliet]

Be careful, there looks as if there is a crack in the carrier/backplate already - I will have a look at a spare one to see how best to do it - but I do have a spare backplate if you have a problem

[williamcorke]

Thank you both.

You're right Mike, that does look like a circlip, I just hadn't spotted it (cameras beat eyes these days, sadly).

Simon, I think you're also correct, it looks like someone has over-tightened one of the long bolts that hold the front and back plates together. I'll assess the severity of the crack when I'm back at home later in the week and might take you up on the offer of a better replacement, thank you.

[simonandjuliet]

I have been mulling this over for a couple of days and actually bought a puller that I thought may work

The puller worked for the rear bearing but not the front one. I just couldn't get it to grip.

My solution was to drill 2 holes that lined up with the cage and then tap the cage out with a drift. There is no circlip

Because I have several very tired units I didn't feel too guilty giving it a try and it worked very well. Indeed, I will thread the holes so that in another 85 years it will be possible to put a small bolt in and push it out again !!!

[simonandjuliet]

Just to complete the dismantling ...... I used some "U" shaped spacers under the bearing and pulled off with standard puller

[williamcorke]

Thanks Simon, that's a real step forwards.

I managed to remove the inner race of the front bearing (as seen in your final photo above) by 'popping off' the ball race and then clamping the puller over the centre part of the race (smaller diameter) in a vice. Harsh, but it worked.

I will try to drill holes accurately in the front cover and drift the outer cage. I spent some time trying to remove the fugitive circlip, so it's good to know why I failed!

The rear bearing was straightforward to remove, but looking for a replacement has raised some questions. I clearly need to learn more about bearing types.

Dimensions for the rear bearing are:
- OD 35mm
- ID 15 mm
- Width 8mm

Simply Bearings (usual supplier) only stocks what are called 'Magneto Bearing' in this size.

"Magneto Bearings: The inner groove of magneto bearings is a little shallower than that of deep groove bearings, the outer ring has a shoulder on only one side and may be removed. This can be advantageous for mounting. In general, two bearings are used as a pair. Magneto bearings are small bearings with a bore diameter of 4 to 30 mm and are generally used for small magnetos, gyroscopes and instruments."

it seems to me that the front bearing of the dynamo is probably a bearing of this type - the inner and outer can be popped apart quite easily. If this was not the case, it would be a lot harder to dismantle the unit and remove the front cover.

Any insight on bearing types and what's appropriate or correct will be much appreciated.

[simonandjuliet]

I did a bit of research about this and came across a great site by " The Magneto Guys" with a wealth of info about bearings and set up - they have a Lambda in some of their photos

Looking at the bearing sizes and refs, it looks as if the rear bearing is readily available (E15) , but the front isn't . However there is a slightly narrower bearing (L17) that could be shimmed to fit

As I understand it, "magneto bearings" are open to enable easy dismantling, and need the end float carefully setting. I wonder if you couldn't fit a standard bearing on the front (easy availability) and then the "magneto bearing" at the rear

On the bench with standard press the front bearing is easily fitted/removed bearing and you still get the easy-fit armature/front plate into the centre block and rear bearing

Hope that makes sense ....

[lancialulu]

I did a bit of research about this and came across a great site by " The Magneto Guys" with a wealth of info about bearings and set up - they have a Lambda in some of their photos

Looking at the bearing sizes and refs, it looks as if the rear bearing is readily available (E15) , but the front isn't . However there is a slightly narrower bearing (L17) that could be shimmed to fit

As I understand it, "magneto bearings" are open to enable easy dismantling, and need the end float carefully setting. I wonder if you couldn't fit a standard bearing on the front (easy availability) and then the "magneto bearing" at the rear

On the bench with standard press the front bearing is easily fitted/removed bearing and you still get the easy-fit armature/front plate into the centre block and rear bearing

Hope that makes sense ....

I think that is what I did when rebuilding the Marelli dynamo on my B12 - seems to work famous last words

[williamcorke]

The rear bearing is E15, but my measurements of the front one suggest it is an E17 (17 x 44 x 11mm) and available as a Magneto bearing (as originally fitted) from Simply Bearings. One of each - front and rear - are on the way to me and we'll see if the fit is correct.

The approach of drilling holes in the front cover and tapping through worked perfectly, thank you Simon. I considered tapping the holes so small nuts could be used as plugs and removed for future replacement (in 85 years time!), but am now leaning towards plugging them with solder. Any thoughts on the approach welcomed.

[davidwheeler]

Worked for me.

[simonandjuliet]

Glad both are available ..... my error came from using the RIV bearing book that I now see is incorrect - It gives the bearing as 40mm exterior

Should have gone out and measured it !

[williamcorke]

Itsa Bitsa!

Encouraged by the Aprilia discussion on the forum recently, I'll post some more questions on my ongoing S1 project here.

Having now got the front part of the drivetrain out of car, I'd like to understand better exactly what is in the car, so if people more familiar with with part numbering can shed some light, that would be much appreciated.

1. Radiator

Marked Tipo 439, which I think means it is from an SII 'autotelaio per carrozzieri' (not a standard Berlina).

2. Engine

Marking on the rear RH engine support 'MOTORE'... but the number below isn't readable (7 7 ).
There's an Aprilia engine for sale on eBay.co.uk at the moment that has a different marking (3rd photo). Which is the earlier (S1) type of marking? MOT, or MOTORE? UPDATE - the 3rd Photo 'MOT' is a '97' engine, which is S1, so 'MOTORE' seems likely to be later.

On the rear of the block there is the number '26677', upside down (4th photo). What does this signify?

The Portuguese  registration documents (from the '50s and '70s) have the engine number listed as 97-682.

3. Head (5th photo)

20 8806
15 6 49

Second number - means this is a post-war head? Are the heads different SI vs SII?

4. Gearbox (6th photo)

438 (top cover)
16589 (bellhousing)

Does the 438 number mean the 'box is an SII Berlina unit?

Finally, the clutch. Is this an SII unit? UPDATE - parts books tell me this is SII. (Tav 13a). No 'hairsprings' around the edge, just a large central single concentric one.

Lot of questions, sorry about that.

[simonandjuliet]

To answer some of your questions - 439 does suggest a rad from a 2nd series chassis car

The engine should be a MOT 97 1234 - it looks as if it has been erased in the photo. I have also seen F 1234 as well - from French Ardennes

The other numbers are , I think casting numbers apart from the dating numbers

The 438 on the 'box suggests S2, but that could be that the top has been swapped - is there an air vent/grill on the top of the bell-housing ? If yes S2

I can't remember the different clutch plate diameters off the top of my head but the S2 has a larger diameter than S1