Building Whittle V8

[byawor]

I have started this engine and have some questions. First the plan calls to modify the glow plugs from 1/4-32 to 3/16 40 dont like that. I will try to modify the head to accept standard plug. To do this I will try the following. Plan calls for the plug hole to be drilled .125 from the face of the head. I will drill it at .160. This will break into the combustion chamber and not break into bottom of the face. Second there is no provision for bronze sears. Dont like the idea of the valves seating on aluminum, so I will try to make the seat and guide all in piece and press fit into the head. Any thoughts?
Bob

 

[stevehuckss396]

3/16-40 is the same as #10-40 and is a standard size. They are available by rimfire. Should be no issues.

 

[gadabout]

3/16-40 is the same as #10-40 and is a standard size. They are available by rimfire. Should be no issues.

Steve, he needs glow plugs , do Rimfire make glow plugs?
Cheers
Mark

 

[xpylonracer]

Plenty of info for the Whittle on this iO Group.
https://groups.io/g/WittleV8

 

[Peter Twissell]

I built this engine last year.
Modifying the plugs was a lot more straightforward than I imagined it might be.
At this scale, seating the valves directly in the heads is not a problem. The forces are very small and the biggest issue with heat is keeping it in, rather than moving it away.
I did make a few modifications to the design, including the head gasket arrangement.
Pete.

 

[indian]

3/16-40 is the same as #10-40 and is a standard size. They are available by rimfire. Should be no issues.

Sorry Steve but these two threads are not the same on two counts. 3/16 is 0.187 and no 10 is 0.192. 3/16 x 40 is 55deg and no 10 x40 is 60 deg. not much but in these small sizes VERY important.

 

[Peter Twissell]

Definitely join the group https://groups.io/g/WittleV8
One of the first parts to make is the crankcase. The original drawing is incomplete and there are files on the group which show the missing dimensions.

 

[stevehuckss396]

Sorry Steve but these two threads are not the same on two counts. 3/16 is 0.187 and no 10 is 0.192. 3/16 x 40 is 55deg and no 10 x40 is 60 deg. not much but in these small sizes VERY important.

I was speaking to the interchangeability of the 2. One could be used in place of the other as they are only a few thousands apart.

I miss took the intention of the thread change and assumed it was to change from glow to plug. My apologies.

 

[byawor]

Thanks for the link, I have never seen that website and have trouble navigating it. Can someone explain how to find the file with "revised" drawings
Bob

 

[Peter Twissell]

Hi Bob, look in the files section, among others, there is a sub section titled errata.
Cheers,
Pete.

 

[xpylonracer]

Bob, use this link: https://groups.io/g/WittleV8/files/Errata