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Z320

BMW fan for TR 4 cylinders

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Hi Marco,

I did not follow this thread in detail, but when I saw this picture it looks like you are working on one of your nice creations again:)

A couple of thoughts:

Galvanising will add a bit material on the shaft and in the bore, so you will have to measure tolerances and machine before pressing together. For a good press fit, I would prefer the base steel anyway, as the zinc is very soft.

I hope you can limit run-out to say less than 0.05 mm, since rotor assemblies (the core) are best made from one single piece.

Gruesse,

Waldi

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3 hours ago, Waldi said:

Hi Marco,

I hope you can limit run-out to say less than 0.05 mm, since rotor assemblies (the core) are best made from one single piece.

Gruesse, Waldi

Yeah Waldi, I know,

but for this a 7 kg steel bar would be required - to cut down to only 540 gramm!

But I made the construction the way to have the possibility for some adjustment:

drills are both 20 mm deep, only the last 3 mm are pressed, the other 17 mm are glued.

No weld, no solder (bends the tube) and finally I "only" have to beat the Triumph cast iron hunk.

Wird schon schief gehen.

Grüße, Marco

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Hi Marco,
keep them coming. 

Cheers,
Waldi

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Another thing would be a shroud around the fan

to avoid a short circuit of air behind the rad and to reduce the loss of air thrown out radial to the fan.

Today I spent some minutes with a cardboard model on the car and made a clip....

Edited by Z320

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On 1/24/2020 at 11:25 PM, Z320 said:

Hi,

all 3 pieces ready, they will go out tomorrow to get a galvanic zinc coat,

then pressed and glued together with Loctite 648.

P1150448-b.JPG.25d2c55b0ce87389e0a54f122f948ce4.JPG

Lovely project.  Well done.

Peter W

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Hi Peter,

thanks for that, I'm still waiting for the parts back from zinc coating....

While this I made the shroud, ready to get two "crimps" (?, google translator) by a friend to become more stiff.

Ciao, Marco

 

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On 1/12/2020 at 5:29 PM, RAHTR4 said:

Pete,

I think you will find that this fan has an offset hub and thus places the blades closer to the radiator.

The Spitfire fan is the reverse of this and moves the blades away from the radiator.

Regards, Richard 

 

On 1/15/2020 at 11:16 PM, Bfg said:

 

P1330531s.jpg.5efc46d03628a5ea34cbe8d43cf339d7.jpg 

^ Positioning is different to the original in respect that the new fan would mount onto the end of the extension piece, whereas the the original TR4 blades sat further back towards the engine.  Not having a car here, I don't know if the 20mm difference will position it too close to the radiator ?  If so, then someone has suggested using the shorter extension piece off the TR6.

Pete

 

Marco, unless you have shortened the length of your central tube from what it appears in your photograph I think you might want to check the above fan mountings positions.    ..possibly you have already checked the length is correct for your car ? 

    ...my drawing (below) very roughly illustrates the difference in offset between the original / "Old Fan" (Top left) and my "New" TR6 / Gt6  plastic fan (in yellow, bottom left). Perhaps the plastic BMW fan might also hit the radiator unless you shorten your fan extension.

P1330580.thumb.jpg.708f77734d3ff57306c4aa5c58ed2777.jpg

^ the plastic fan (bottom left in yellow) sits further forward than the original steel hub TR4 fan, so it may interfere (hit) the radiator. 

Please note - I say this not as a criticism of your work, only just as hopefully useful observation

Pete.

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Hi Pete,

you illustration of this detail is L-O-V-E-L-Y!!!

Thank you to be in thoughts with me, I realize no criticism.

I already have the BMW fan on the original extension on my 4A, the gap to the radiator is about 40 mm.

So I made my new extension exactly the same length as a spare part (on the photo) from my spare part engine.

I will check double when I have the extension of my 4A off, but I have no worry.

Thanks, Marco

Edited by Z320

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Excellent Marco.  I am glad you are not offended. I only try to help.

You know of course the  early side-screen car's and also the TR6 fan extension look very similar but they are shorter than that of the TR4.  I note this only because the one on your car may have been swapped.?

Otherwise I am relieved that you have good clearance. 

40mm is a lot more than I had been led to believe is normal ..as the following photo (off the internet) implies.

67TR4A00371as.jpg.c964fb8bb8bdab6e1aa456d51f758160.jpg

^  naturally I cannot measure off this but one might visually assess the clearance between the fan blade and the radiator to be 20 - 25mm.  You might also note - there is plenty of clearance between the chassis / suspension cross-brace and the flange which the fan bolts to.

I think with 40mm of gap I would also make a shroud to fit around the fan.   

Best regards,

Pete.

 

Edited by Bfg

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Hi Pete,

my TR fan and my BMW fan on the extension are about the same high and the gap to the rad is also about the same.

You realised the car on your photo is a ruin? The bracket on the right side, holding the rad, is not fixed

and I guess this is because the radiator is tipped backwards because of a to short top rad hose.

But I could be wrong and after 50 years nothing is shure on our cars.

Ciao, Marco 

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The radiator was maybe dropped in to show fan position.

I think the top hose in the photo looks like a Triumph original 129936 fabric covered hose.  

This is the type I had re-manufactured a couple of years ago from OE drawings, but improved with mesh reinforced EPDM rubber and the original stockinette covering. 

 

Cheers

Peter W

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parts are back from galvanic zinc coating, looks like chrom..... 

shroud is also ready, but first get the brake project ready and the car back on the street

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Hi,

I did different things the last weeks, with some Corona free time I glued the parts together yesterday.

First step, 30 minutes later second step.

P1150844-b.JPG.d099b8de201453a2ef0a17dd57da9edb.JPG 

P1150846-b.JPG.94c3acfd1a1ef3984411db879381d0df.JPG

Runs lovely on the lathe. I did not want to do this before I have the extension out of my car to compare.

P1150850-b.JPG.7c05aa6bdf8684b6e905e63dedf6d0de.JPG

Checking the weight, it's about 33% of the original.

P1150856-b.thumb.JPG.76faa0eee61ab612bd0daccebce15c37.JPG  P1150858-b.thumb.JPG.42a33f4010f011fc5e552df9d8f6ca2d.JPG

My typ "20" belt now fits between extension and steering rack, distance is about 13 mm.

P1150863-b.JPG.1ef9409aad8e8c9ed12876403ed3ab1c.JPG 

P1150866-b.JPG.ffb72ecf8e77a97a747b66b23a2e8e81.JPG

Fan is already fitted, ideling was lovely, but a test drive was not possible because of a unsealed heater hose,

I will see what I can find stored at my workshop tomorrow, a 12 mm hose must be anywhere....

Ciao, Marco

 

 

Edited by Z320

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5 hours ago, Z320 said:

Checking the weight, it's about 33% of the original.

instantly gaining 5 HP ;-)

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BE CAREFUL THE ABOVE POST COULD BE SCAM!! DO NOT OPEN THE LINK.

Waldi

 

Edit: I have reported it.

Apologies to sender if not scam but this looks suspect for a first time poster.

Edited by Waldi

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3 hours ago, JochemsTR said:

instantly gaining 5 HP ;-)

Minimum! B)

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51 minutes ago, Waldi said:

BE CAREFUL THE ABOVE POST COULD BE SCAM!! DO NOT OPEN THE LINK.

Waldi

 

Edit: I have reported it.

Apologies to sender if not scam but this looks suspect for a first time poster.

Thank You Waldi,

the post has been removed.

John.

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Thanks John.

Waldi

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Marco

thats a beautiful bit of engineering artwork. 
 

I wish I had the skills and imagination to do things look k this.

thank you for sharing. 

H

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12 hours ago, Hamish said:

Marco

thats a beautiful bit of engineering artwork. 
I wish I had the skills and imagination to do things look k this.

thank you for sharing. 

H

Hi Hamish,

thank you for that, I will go to bed tomight very proud with a tie on (do you understand that?).

Indeed I grow with the challenges, always hoping I fail not with the next one...

Ciao, Marco

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Hi,

a "grumpy old man" (indeed he is a real good fellow) asked me about my glueing by PM.

Well, I did not weld or solder because I expect the construction will be bended by the heat.

Glueing is very safe and solid, depending on the glue. I use 4 different Loctite products.

In this case it is german called "Fügen Welle-Nabe", what I want to translate with "fixing shaft-hub", product no 638.

This is used for example to glue bearing in gearboxes, I did it also with the main roller bearing (crankshaft) of my Norton.

Very solid and fast (!), more solid than it has to be in this case, because the big bolt holds all together in the crankshaft.

Hope this helps, Marco

Edited by Z320

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Hi,

last thing was the shroud, I fitted it today.

Is experementel and look like a §$&%!! spring form pan for baking cakes?

P1150875-b.thumb.JPG.9af9de045a47844812d8835d21777719.JPG 

P1150878-b.JPG.fe68fc897b9259db349e70c0f28339a8.JPG

It will be difficult to come to a objectiv rating about a benefit or not.

My referenz is a situation 2 years ago:  summer, 35°C, full sun in the afternoon, 1 h Stau driving for 25 km, coolant was 110°C hot - but everything was OK.

Will there be any situation like this on 2020? Not the heat - my at the autobahn driving anywhere?

Ciao, Marco

 

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Hi Marco,

nice work. 
In process- and oil industry, cooling fans are quite common, but much larger, up to 5-8 meter in diameter is common. Here the entire “radiator” is provided with a channel to avoid circulation (hot air being sucked to the radiator again, reducing efficiency). Also, the gap between fan tips and shroud are minimised. 

I think your shroud reduces the amount of hot are reversing into the outer areas of the radiator, and promotes axial flow.

Waldi

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Nice job Marco, 

Sure, the shroud is to first impression not so beautiful, but then I've rarely see an electric cooling fan and its brackets look elegant either.  First and foremost the fan has a job to do, and it needs to do it well.  I am sure the shroud will positively contribute to the fan's draw of air through the radiator, so is imo worthwhile. 

Perhaps it would be less conspicuous if your fan extension and the bright plated fastenings were less eye-catching / drawing your eye to them. ie. if they too were painted dull &/or black ?    Anyway, I suspect you'll hardly notice any of it being there after a short while. 

But perhaps the shroud also lessens the fan's wind noise a little ?

I had always intended to do much the same with my own (most likely in fibreglass though) ..so thank you for showing me how to do the shroud's mounting. 

Well done Sir.  B)

Pete.

 

p.s. compared to the welding of the original chassis and its own brackets (bottom photo)  - your work is more noticeable because it is too neatly done ! :D

Edited by Bfg

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Well, it's just an experiment, I don't know what will happen.

Worst case will be a drive during summer, 35°C, full sun in the afternoon, 1 h Stau driving for 25 km, coolant 110°C hot - but everything OK.

That would be a " disappointment"

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