Bentley 4 1/2 litre Blower in 1/12th scale - may contain Airfix.

[nick]

18 hours ago, Dancona said:

Hi Nick,

 

There are some useful photos of assorted Bentley bits on this website, plus a four and a half sump, it looks to me as if the blowers used a sump that looks as if it may be off a standard 4.5l car.

 

http://vintagebentleyblog.weebly.com/45-litre-engine-page-1.html

Thanks, I already picked that one dry! I’ve made something up now, pictures later for critique.

 

regards,

 

Nick

[nick]

Here's where I'm up to:

 

 

 

Still got the detailing to do on the hose clamps, but I think the shape of the inlet and blow off valves is near enough now. Hopefully the shape of the cam cover is a bit better now too?

 

As to the sump

 

 

The general arrangement is about right, but I have no idea what goes on under the the three flange plates in the last image? anyone? can't find a single picture of this anywhere.

 

 

Regards,

 

Nick

 

 

[Malc2]

Here are some more pics of GF3372's sump I took at Goodwood back in 2008, hope they are usefull!

A lot of current day Blower Bentleys were not built as blowers, so I am sure modern photos are going to be misleading or diferent in the details.

The good news is that the history of each car is well known, I believe GF3372 is a bitsa car, the Beaulieu car is also a conversion to a Blower.

Malc, 

Edited September 25, 2021 by Malc2

[nick]

5 minutes ago, Malc2 said:

Here are some more pics of GF3372's sump I took at Goodwood back in 2008, hope they are usefull!

A lot of current day Blower Bentleys were not built as blowers, so I am sure modern photos are going to be misleading or diferent in the details.

The good news is that the history of each car is well known, I believe GF3372 is a bitsa car, the Beaulieu car is also a conversion to a Blower.

Malc, 

Brilliant. Thank you Malc.

[Malc2]

No problem, I have sent you a link few more from GF3372.

 

M. 

[nick]

OK here is a problem. I based my engine on the airfix item so it would fit the kit and also as it looked about the right shape and geometry. However at this late stage, I think I've stumbled on a major cockup. Now I'm drawing the boost pipe from the supercharger to the inlet, it won't fit and fouls the crankcase like this:-

 

 

the circle is where it should end up to pass through the hole in the chassis cross member centrally. The supercharger side (the front face of the cross member) IS Central, the rear isn't.

 

This is about the only photo of the real thing that I can find and it looks centered to me

 

 

This is what Airfix did

 

 

Hard to believe this is correct. Equally I don't know how I'm going to correct this either. I assume the error is in the crankcase shape.

 

Any input, thoughts, images to help anyone?

 

Regards,

 

Nick

 

[Malc2]

Without access to the real thing for measurements you will never be sure!

I see you have these options:-

1 Quick and dirty is to put a flat on the pipe and snug it up to the crank case as close as possible

2 Narrow the crank case, put the pipe in the correct location to center on the circular feature in the crossmember

3 A bit of both above

 

Malc.

[Jo NZ]

Is the airfix crossmember correct?

 

[nick]

56 minutes ago, Malc2 said:

Without access to the real thing for measurements you will never be sure!

I see you have these options:-

1 Quick and dirty is to put a flat on the pipe and snug it up to the crank case as close as possible

2 Narrow the crank case, put the pipe in the correct location to center on the circular feature in the crossmember

3 A bit of both above

 

Malc.

How about this then? the proof is in the printing, but I think I have it.

 

 

it requires a tweak to the crossmember, but the airfix one isn't right (surprise, surprise) anyway, so no sweat.

 

Nick

[nick]

this is a better render to see what's going on:-

 

Nick

[Malc2]

Looks great, what did you do in the end?

 

M.

[nick]

10 minutes ago, Malc2 said:

Looks great, what did you do in the end?

 

M.

A bit of everything, changed the curve profile slightly, reduced the tube diameter a bit, tweaked the crankcase and took a look at the chassis crossmember.

[Brandy]

On 9/25/2021 at 11:40 AM, Malc2 said:

the Beaulieu car is also a conversion to a Blower.

Not quite true. It was originally a blower, but a road car not a race car, that is where the differences lie.

 

Ian

[Brandy]

On 9/25/2021 at 4:08 PM, nick said:

Hard to believe this is correct.

Damn it, I just checked mine and you're absolutely right. I hadn't even noticed! So on that note, I will not bother to correct it - if I hadn't noticed before, it doesn't need correcting now!

By the way. the lug at the bottom front of the crankcase, which you have now removed, is the mounting point for the front of the engine onto the crossmember, and also the mounting for the supercharger. Also, re your pic of "the real thing" above, the Birkin cars did not have the thermostat in the cooling system so the water pump outlet on the right of the pic should be blanked off, also no fan.

 

Ian

[nick]

I’ve got some paint on the first print now, a few print issues to correct, but we’ll, you’ll see soon 😎👍

[nick]

 OK a lot wrong, cam cover shape has lost the plot, schoolboy errors handling uncured paint. Etc, etc, but maybe if we can look past that on my over-excited prototype?

 

 

three versions from now, ie, tomorrow, it will be right. 
 

thanks for looking,

 

Nick

 

 

[Malc2]

54 minutes ago, Brandy said:

Not quite true. It was originally a blower, but a road car not a race car, that is where the differences lie.

 

Ian

Yes, sorry you are right, the body was changed from a Vanden Plas Tourer to an open Birkin type, so the chassis/powertrain should be similar to the Blower race cars.

[Dancona]

Looking excellent in every respect Nick, except if I'm going to get really niggly the front of the cam cover, its still not quite right. 🥴

[nick]

38 minutes ago, Dancona said:

Looking excellent in every respect Nick, except if I'm going to get really niggly the front of the cam cover, its still not quite right. 🥴

Thanks, yes I know, I made it worse! next on the list, it's a bloody odd (and ugly!) shape to be honest, I'll figure it out in the end.

 

Nick

[nick]

Finally got the chrome right on the Knock-offs. Wheels are pretty much ready to go now. Just printing a few more sets to check consistency 

 

 

Nick

[nick]

You might recall I said I wasn’t going to model the valve guides, well here they are

 

 

 

these castings are now as close to the real ones as possible, even though it will be almost entirely hidden - if it’s there, why not model it?
 

I’ve also finessed the detail on the crankcase now

 

its printed really badly, so I need to mess about with the orientation but I can easily fix that

 

ill take some proper pictures tomorrow too.

 

thanks for looking,

 

Nick

 

 

 

[nick]

Been playing with my prototype Bentley engine today. I'm stupidly pleased with such a simple thing as a spark plug - I can't tell you why.

 

They may not look very sharp. However, they are quite small

 

 

I've learnt to make things like this in two pieces - why? well it's the best way to get super-sharp demarcation between things - 'porcelain and steel' in this case! it just works somehow.

 

I'm also pleased that my bolts can be made to work with wire locking, this is a prominent feature on this engine so I'm glad it's possible.

 

 

 

 

Still ironing out bugs, but coming along nicely I think.

 

Here's some shots of the wheels, just got the manuals to produce now and then they will be on sale.

 

 

Regards,

 

Nick

[albergman]

A one-man production line!    Glad you added  that pencil for scale Nick.

[nick]

I think I've finally got the shape of the cam cover correct:-

 

 

What was throwing me was that the Airfix one is too flat and square, the real thing is more rounded so it;'s impossible to get from the flat-topped geometry of the airfix thing to rather ugly (to my eye) bulbous nose of the real thing.

 

When there's more curve to the lid, it works. Like to see what the experts think though?

 

Been refining my spark plugs and wire locking today too, fotos tomorrow.

 

Regards,

 

Nick

[nick]

Easier to see in a render:-