Author Topic: Build pictures of GB 4 cylinder overhead value engine  (Read 1060 times)

Offline gldavison

  • Full Member
  • ****
  • Posts: 173
  • Tarkio, Mo.
Build pictures of GB 4 cylinder overhead value engine
« on: August 17, 2020, 02:49:16 AM »
Some members wanted to see a build thread on my construction of Geroge Britnell's 4 cylinder overhead value engine. I did not take any pictures of actual machining setups. So here you go with what I have so far.


This is the first group picture I took.
     


The con rods are bronze. I just happen to have a section of bronze bushing stock 3"OD X 1-1/4" ID left over from repairing a dozer years ago. I cut a slice off and milled to the proper thickness. Then I draw a 3" circle in cad with id of 1-1/4" and placed 4 rods and caps in that circle. The code was generated in Fusion360 and they were cut on my home made CNC router. You can see that machine here. http://www.gldpages.com/CNCRouter.htm

 

 
After they were cut out I used a rotary table to do the profiling.
    


The rocker arms were constructed in same manner as the rods and profiled on RT.
    
 

Here is the value and tappet cover.
   

And here we have the spark plugs.


This is the last group picture I took.


The timing gear cover and distributor cap were also CNC'd on my router.

Offline nj111

  • Full Member
  • ****
  • Posts: 129
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #1 on: August 17, 2020, 08:02:14 AM »
Very nice, you are getting on well with that project.
Nick

Offline Johnmcc69

  • Full Member
  • ****
  • Posts: 717
  • Erie Pa., USA
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #2 on: August 17, 2020, 03:41:09 PM »
 :ThumbsUp:
WOW! Nice work!
 :popcorn:

 John

Offline ddmckee54

  • Full Member
  • ****
  • Posts: 369
  • We're having fun now --- or so I've been told.
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #3 on: August 17, 2020, 06:51:12 PM »
Gary:

I like your CNC router.  What are you using to control it and what kind of travel speeds can you get out of it?

I'm currently working on a CNC router that will be similar in size to yours'.  The design for my router is very loosely based on the MPCNC and I am curious about the performance of your machine.

FYI - I tried the link on your homepage to your CNC foam cutter, but it didn't work.

Don

Offline tvoght

  • Full Member
  • ****
  • Posts: 943
  • Indiana
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #4 on: August 17, 2020, 10:08:34 PM »
That looks great Gary. Been wondering how you are doing. Pretty good I'd say.  --Tim

Offline gldavison

  • Full Member
  • ****
  • Posts: 173
  • Tarkio, Mo.
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #5 on: August 18, 2020, 01:07:49 AM »
Well, I guess since some fellows got me posting, I just as well keep it up until this project is finished. Today I finished the exhaust pipe flanges. Here I m profiling on the RT.



And the finished product.


Offline gldavison

  • Full Member
  • ****
  • Posts: 173
  • Tarkio, Mo.
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #6 on: August 18, 2020, 01:10:35 AM »
Hi Tim,

All's well here. Looking forward too Rapid City.

Offline gldavison

  • Full Member
  • ****
  • Posts: 173
  • Tarkio, Mo.
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #7 on: January 05, 2021, 03:56:52 PM »
Time for an update on this little engine. I decided not to make a radiator when I found this on Walmart's website. $27 and free shipping, just couldn't turn it down. Its for a 4 (120mm) computer fan.




As you can see, there is no fill neck. So got out my radius gauges and measured the radius on the tank. Then I drew up a model in a 3D CAD program.



Machining the fill neck.


And the radius



Next we need a radiator cap.




I use coarse sandpaper to sand the paint off of the tank at the top and proceeded to a fix the aforementioned part with J-B Weld. After the JB cured out, drill a hole  thru the new fill neck into the tank. And the finished product.





I 3D printed the fan shroud.



Offline Admiral_dk

  • Full Member
  • ****
  • Posts: 2086
  • Sften - Denmark
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #8 on: January 05, 2021, 08:46:53 PM »
Great conversion of the radiator - I really like the transformation  :cheers:

Have you assembled the engine yet ?

Per

Offline crueby

  • Full Member
  • *****
  • Posts: 12019
  • Rochester NY
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #9 on: January 05, 2021, 10:14:46 PM »
Love the look of the radiator, never knew they made ones that small.

Offline Art K

  • Full Member
  • ****
  • Posts: 1515
  • Madison, Wisconsin USA
Re: Build pictures of GB 4 cylinder overhead value engine
« Reply #10 on: January 06, 2021, 02:15:46 AM »
Gary,
Glad to see that you are doing well and being productive as well. The engine looks great.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King