VW Beetle engine 1/5 scale

Arild · Dec 5, 2024

Hi!
I'm trying to build a VW/Porsche engine in very small scale. The crank is ready. I found it challenging to make the cylinder's tiny ribs. they are - as the original - made in cast iron. The HSS cutting steel is only 0.5mm wide, and so are the ribs (max cutting depth is 3.5mm). The cutting steel snaps off often, so it takes times to grind a new one. But, 3 of 4 are made.. I deside to cast the connecting rods in bronze instead of steel or aluminium, so there is no need to make small bearings as this would make the con.rod larger. Now its got bearing directly.
I also deside to leave the crank as is without milling down the sides to make it ligher. I think now it will work as a part of the flywheel!

Regards, Arild (Norway)

Ruant33 · Dec 5, 2024

WoW That is amazing work.

GreenTwin · Dec 5, 2024

Nice casting and machining work !
Cool project.
.

timo_gross · Dec 5, 2024

Would it be a good idea to use a "life tool" on the toolpost and make those small ribs with a slitting saw? Just a thought, no idea if that would make any sense.

Arild · Dec 5, 2024

Hmm

timo_gross said:
Would it be a good idea to use a "life tool" on the toolpost and make those small ribs with a slitting saw? Just a thought, no idea if that would make any sense.

-yes, It's been in my thoughts too! I'll see. But now its "just" one cylinder left to make..

scottyp · Dec 5, 2024

I grew up around bugs and such and would like to do a project like this at some point. Nice looking work.

Arild · Dec 6, 2024

Making a camshaft "blank". It's made of SS316 from a bolt - should be strong enough I guess.. Next up is to make bearing for it.
Tons of works left!

ddmckee54 · Dec 6, 2024

Arild:

The case looks to be sand cast, did you do that too? If so any more pictures of that, and or machining the case? It's looking good so far, looking forward to seeing the heads.

50+ years ago, the very first vehicle I owned was a '59 VW Deluxe micro bus. Really wish I could go back in time and tell myself NOT to get rid of it.

Don

Arild · Dec 6, 2024

ddmckee54 said:
Arild:

The case looks to be sand cast, did you do that too? If so any more pictures of that, and or machining the case? It's looking good so far, looking forward to seeing the heads.

50+ years ago, the very first vehicle I owned was a '59 VW Deluxe micro bus. Really wish I could go back in time and tell myself NOT to get rid of it.

Don

Hello Don! Yes, it is sand casted. I build a small shelf in our garden beside the woods - only about 4square meter. (We live in an area with many houses around, but beside me there is a forest) So, I can do casting outdoor even in the winter time, with a lot of snow already. I use this "red" sand (sticky). So far I have done casting a bronze cannon from the US Civil war that weight around 2kg. It makes a great "bang" at the right occations (soon at New Year!)
I'm educated in electronics and mechanic, so I can make the ignition as well. But so far, no combution engine - only steamengine and rockets!

. I started to melt aluminium and bronze just 5 years ago, even its been a "dream" since I was a boy! (now I'm 55)

Arild · Dec 6, 2024

Now working on CAD (SolidWorks) to figure out how to make the lifter stem "protection". Originally there is a kind of foldet steel to act as a spring. I can not replika that, so try to make a stem with springs at both end and - you see pic #3 how its put togheter. (without the head).

I must admit, that I wanted to be a gold smith or watchmaker when I was younger.. But no money in that my dad said, so I did something else. Still no money in being a gold smith (I work at something else), but as a hobby its fun!

Arild · Dec 6, 2024

I was reading about carburator not so long ago on this forum. "How large (or small) it should be". Where do I found it? -My engine is about 3,6ccm x 4. Does it matter how many cylinder there is, or are we simply looking at one cylinder when we talk about the size of the opening?

scottyp · Dec 6, 2024

I can’t answer that question, but a dual carb setup would be awesome and would make the intake manifold(s) simpler if that is a direction you would be interested in. Something to think about as you go along.

Arild · Dec 6, 2024

scottyp said:
I can’t answer that question, but a dual carb setup would be awesome and would make the intake manifold(s) simpler if that is a direction you would be interested in. Something to think about as you go along.

Yes, it got advantages, that it is the first I was thinking - no need for a large intake tube... But what size? I've seen a lot of engine made by some incridible people in this group, and I'm amused at how small carb. they used! (compared to a real engine it seems to be much smaller)

Tom-AMS · Dec 7, 2024

Arild said:
I was reading about carburator not so long ago on this forum. "How large (or small) it should be". Where do I found it? -My engine is about 3,6ccm x 4. Does it matter how many cylinder there is, or are we simply looking at one cylinder when we talk about the size of the opening?

I can't help with locating the previous post about carburetors, - however, I can say that the VW Solex 30-PICT-1 carburetor used on a 1500 cc engine (83mm bore X 69mm stroke) has a 24mm venturi. Stock rocker arms have 1.1:1 lift ratio, stock intake valves were 35.5mm dia. with 8mm stem; exh valve 32mm with 8mm stem. Stock cam lift ~7.65mm int / ~7.24mm exh. Cam valve timing (@ 0.050" lift) is Int. open 1° BTDC / close 30° ABDC. Exh open 36° BBDC / close 4° BTDC. Cam lobes are tapered to cause cam follower (aka lifter) to rotate. Lifters are "domed", not flat, with ~1400mm radius. Lifter "face" diameters varied over the years, from 28mm to 31mm. The most common used in the 1500 and 1600 cc engines were 29mm and 30mm. The smaller face diameter was used to reduce effective cam duration, increase dynamic compression, and increase low RPM torque. I have 60+ years reanufacturing VW air-coled engines, plus building many hi-performance versions. On our Superflow 600 flow bench a stock VW single port head (casting # 311-101-373A; p/n 311-101-353A) flows ~96 CFM at 8.4 mm valve lift at 28" H2O. A stock Dual port head (casting # 043-101-375A; p/n 043-101-355A) flows ~102 CFM, with same lift and 28" H2O. With a prpoer valve job and some port work, we can get stock DP heads to flow 250 CFM. You may be able to use the above info to "scale" your model carburetor.
The pushrods and pushrod tubes (with corrugated flex ends) angle upward toward the cyl. head, and also angle front to rear. The front to rear angle varies for each pushrod and tube is not equal. It varies progressively from 0° for one pushrod, ~1.5° for the 2nd pushrod, ~4° for the 3rd pushrod, and ~5.5° for the 4th pushrod.
Looking forward to seeing more of your fantastic VW engine build.

cwelkie · Dec 7, 2024

Great progress on your build. It is great that you found a way to express your creativity!

An idea for your pushrod tubes might be found in Chenery's Aeronca design (a horizontally opposed twin). I've attached a photo that shows the ones I made for my example and an excerpt from the drawings. Hopefully you can zoom in to see enough detail.

Arild · Dec 7, 2024

Tom-AMS said:
I can't help with locating the previous post about carburetors, - however, I can say that the VW Solex 30-PICT-1 carburetor used on a 1500 cc engine (83mm bore X 69mm stroke) has a 24mm venturi. Stock rocker arms have 1.1:1 lift ratio, stock intake valves were 35.5mm dia. with 8mm stem; exh valve 32mm with 8mm stem. Stock cam lift ~7.65mm int / ~7.24mm exh. Cam valve timing (@ 0.050" lift) is Int. open 1° BTDC / close 30° ABDC. Exh open 36° BBDC / close 4° BTDC. Cam lobes are tapered to cause cam follower (aka lifter) to rotate. Lifters are "domed", not flat, with ~1400mm radius. Lifter "face" diameters varied over the years, from 28mm to 31mm. The most common used in the 1500 and 1600 cc engines were 29mm and 30mm. The smaller face diameter was used to reduce effective cam duration, increase dynamic compression, and increase low RPM torque. I have 60+ years reanufacturing VW air-coled engines, plus building many hi-performance versions. On our Superflow 600 flow bench a stock VW single port head (casting # 311-101-373A; p/n 311-101-353A) flows ~96 CFM at 8.4 mm valve lift at 28" H2O. A stock Dual port head (casting # 043-101-375A; p/n 043-101-355A) flows ~102 CFM, with same lift and 28" H2O. With a prpoer valve job and some port work, we can get stock DP heads to flow 250 CFM. You may be able to use the above info to "scale" your model carburetor.
The pushrods and pushrod tubes (with corrugated flex ends) angle upward toward the cyl. head, and also angle front to rear. The front to rear angle varies for each pushrod and tube is not equal. It varies progressively from 0° for one pushrod, ~1.5° for the 2nd pushrod, ~4° for the 3rd pushrod, and ~5.5° for the 4th pushrod.
Looking forward to seeing more of your fantastic VW engine build.

Thanks for the useful information. In my cam design, the cam lift 2.3mm, so according to the original that is to much (should have been 7.65/5 =1.5mm), but I guess it won't hurt? However a scale down doesnt neccessary have to - or can be the same as volume decrease by 125 and not 5 (the engine I build is scale 1:5, and the volume is then 125 times less). likewice my valves has a 2mm stem (not 1.6 as in scale), valves face diameter is 7 and 8mm, so that is pretty close to the original!
I'll adjust my cam degree according to your description!

Arild · Dec 7, 2024

cwelkie said:
Great progress on your build. It is great that you found a way to express your creativity!

An idea for your pushrod tubes might be found in Chenery's Aeronca design (a horizontally opposed twin). I've attached a photo that shows the ones I made for my example and an excerpt from the drawings. Hopefully you can zoom in to see enough detail.

Thanks! Yes, it's looks similar to my idea, and yes, of cause I only need it in one end!

But, did you do that casting by your self? It looks professionaly!!

cwelkie · Dec 7, 2024

Arild said:
But, did you do that casting by your self?

No, I’m not that talented or well equipped. The castings were acquired many years ago from the original designer’s son. Sadly and like many other casting sets, these are no longer available (to my knowledge).

Arild · Dec 7, 2024

cwelkie said:
Great progress on your build. It is great that you found a way to express your creativity!

An idea for your pushrod tubes might be found in Chenery's Aeronca design (a horizontally opposed twin). I've attached a photo that shows the ones I made for my example and an excerpt from the drawings. Hopefully you can zoom in to see enough detail.

The way I do casting, is to do make(or download) a original drawing - scale it down - 3D print it, and then make necessary slip angle to make a useful sand-cast- I have done a lot of mistake in that process, but after some trial I succeed! The 3D model after some modification and smoothness are then put into the sand! If you have some drawings, I can probably help you!

Arild · Dec 7, 2024

Yes, I kow, I updated my "A" to a Ferrari picture,, I bought that 10 years ago as a damaged car. Spend a lot of money on engine, but did the most of the work I did by my self.... I tried to make a 1:4 replika of that engine. Ive'made the crank and one sylinder head, but gave up the block, so over to the VW!

VW Beetle engine 1/5 scale

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