Demon V8 (multiplied 1.5)

[Foketry]

second water pump built following the original design, with brass gears
to build the gears I went to a small hobby workshop of a friend of mine

the ball bearings and shaft are made of stainless steel

 

[bluejets]

If the slot in the #100 pic is your delivery then that is more than likely why it doesn't work.

If one looks at the water pump internal build from say, Gerry Howell, one will see the geometry necessary for it to work properly.

On the page below, there are a series of photos down the left side.
If you go down to just past the "cam followers" you will see a plan view of the inside and the geometry I refer to.
https://www.craftsmanshipmuseum.com/HowellV4.htm

 

[Foketry]

Thanks for advice, I know Jerry Howell's pump, I built it for V4 engine, but for Demon V8 I wanted to respect the external shapes of the pump, as per the original design
Without cutwater it didn't work properly and I went back to the project with gears instead of impeller.
in the photos my water pump for V4 with impeller and cutwater

 

[Foketry]

It is time to grind the valves, after having chamfered the seats with the tool drawn by George Britnell , steel 115CrV3 hardened on water

 

[Foketry]

 

[Foketry]

vacuum pump to cheek leaks

 

[petertha]

Foketry, can you tell me a bit more about your valve assembly?
- cage/seat in the head is made from bronze? What alloy?
- about how wide is the contact area on the
- when you did the lapping , did you observe any lapping wear on valve, cage seat or both?

 

[awake]

I'd like to know more about that valve lapping tool attachment. What does it do, exactly - is it a speed reducer, or ??

 

[doc1955]

If it is like the manual one it goes forward about a half turn tthen back about a quarter turn. Kind of like a washing machine. I have a few manual crank ones.

 

[awake]

Interesting - I take it the back-and-forth motion is better for lapping than a continuous circular motion?

 

[Foketry]

Foketry, can you tell me a bit more about your valve assembly?
- cage/seat in the head is made from bronze? What alloy?
- about how wide is the contact area on the
- when you did the lapping , did you observe any lapping wear on valve, cage seat or both?

for the seats I use a common bronze, CuSn12 (B14 old Italian denomination )

the contact area is very small, max 0.1 mm, I have tried on some cage seats to leave a sharp edge, it is easier to obtain a leak-free seal , in the next engines I will not make any chamfer
without chamfer I noticed that a small manual lapping of one minute with silicon carbide 600 and one minute with grade 1000 is sufficient

I build the valves with stainless steel, after lapping a mark remains on the valve cone and the bronze cage seat becomes opaque

 

[Foketry]

Interesting - I take it the back-and-forth motion is better for lapping than a continuous circular motion?

a circular motion is incorrect , the valve leaks , if you look at the valve with the microscope there are circular signs that let air pass through, instead with a small rotation back and forth you only notice small broken lines

 

[Foketry]

If it is like the manual one it goes forward about a half turn tthen back about a quarter turn. Kind of like a washing machine. I have a few manual crank ones.

Exactly, it's like you say

 

[Foketry]

If it is like the manual one it goes forward about a half turn tthen back about a quarter turn. Kind of like a washing machine. I have a few manual crank ones.

Doc, about this engine I have seen all your movies on Youtube several times, for the valve timing I will repeat your method
thank you

 

[kuhncw]

I understand your valve lapping attachment powered by the drill, but what is the tool with the wooden handle used for?

Chuck

 

[Foketry]

I understand your valve lapping attachment powered by the drill, but what is the tool with the wooden handle used for?

Chuck

The wooden tool is the classic manual lapping tool. I glue the head of the valve to the instrument through a small silicone tube to give flexibility.
The gray plastic tool is to be used with the drill, it rotates back and forth through an internal mechanism. This also connected to the valve head via a silicone hose
I have tried both systems ,both work well

 

[kuhncw]

Thanks. I was wondering how you were attaching the valves to the lapping tools.

Chuck

 

[Foketry]

the distributor cap , Delrin material

 

[Foketry]

the central electrode, graphite material from an electric motor brush , whit spring
The brush was originally square, I turned it round on the lathe

 

[awake]

Great idea on using the motor brush. Would there by any advantages to making all the electrodes the same way? (Asking out of ignorance, not trying to suggest that there is!)