Home Model Engine Machinist > Showing Them > Photos and Videos > Opposed 4 cylinder 4 stroke
Reply
 
Thread Tools Display Modes
Old 08-12-2011, 01:05 PM   #1
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Opposed 4 cylinder 4 stroke

Hello, this is my first posts to the forum but I have been reading, admiring and learing by reading here sense Ive started machining.

This is my 2nd IC build. 400 hours work over the last 7 months and about 400 parts finally came to life and I got it running reliable yesterday.

It currently runs on glow fuel but I would like to eventually convert it to gas and fit a CDI ignition.

I dont have any build pics, just pics of the parts as they where completed.

The engine is a 120cc 4 cylinder 4 stroke. The plans are from Germany. I did a fare amount of modifying and redesigning the parts. More to experiment then to fix problems. Also to convert all the metric dimensions to imperial as thats the only tooling I have.

Here is where I found the plans. They have many aero motors and that is my real passion.
http://www.cad-jung-shop.de/epages/62479729.sf/en_GB/?ObjectPath=/Shops/62479729/Categories/Bauplane


2nd test run 600 rpm idle 5200 rpm at 3/4 throttle.



The pistons and rods are 2024, intake and exhaust is 304, cast iron cylinder sleeves, valves are 416 and bronze on the valve cages and bushings.

The exhaust tubes where filled with lead bent using a custom made bender then the lead was melted out.

I made a custom valve seat cutter that I learned about from this forum and it worked perfect, only a light lapping was needed.

The valve springs are wound on the lathe using a technique I found online. They are then stress relived in a toaster oven. They where easy to make but tricky to make all the same.

The rods have needle bearings in the big end and bronze bushings in the other.

The roller rocker arms are 6061 with hardened W1 rollers and roller shafts.





Attached Thumbnails
flat4 (2).jpg   flat4 (4).jpg   flat4 (5).jpg   flat4 (6).jpg  
__________________
geoff_h is offline  
3
People Like This 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:10 PM   #2
lazylathe
 
lazylathe's Avatar
 
Join Date: Aug 2009
Posts: 1,285
Liked 24 Times on 24 Posts
Likes Given: 2

Send a message via MSN to lazylathe
Default Re: Opposed 4 cylinder 4 stroke

Looks great so far!

Judging by my poor eye you have a CNC machine at your disposal??
All the parts look great!

How about an intro post in the Introductions section?
Tell us a bit about you and what you do!

Andrew



__________________

The best part about procrastination is that you are never bored, because you have all kinds of things that you should be doing.

Time is money, money is the root of all evil, and knowledge is power. Therefore, procrastination is the key to world peace.

lazylathe is offline  
 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:13 PM   #3
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

The head gaskets are turned from .005 copper shim stock in aluminium jigs the other gaskets from .020 copper.

The rings are cast iron and made using a technique from SIC where they are turned to size then heated on a mandrel to hold the new shape.

The fuel splitter is brass and silver solidered

The brass intake and exaust couplers are free to turn on the 304 tubing and have brass flanges silver soldered in place to hold them into the ports. This allows them to be set to any position then the coupler is tightened to hold them in place.

Attached Thumbnails
flat4 (8).jpg   flat4 (11).jpg   flat4 (12).jpg   flat4 (10).jpg  
__________________
geoff_h is offline  
 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:23 PM   #4
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

Quote:
Originally Posted by lazylathe
Looks great so far!

Judging by my poor eye you have a CNC machine at your disposal??
All the parts look great!
Thank you.

Everything was made manualy on a 13x40 Import lathe and 9x46 Wells Index mill.
__________________
geoff_h is offline  
speedyb Likes This 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:28 PM   #5
cfellows
 
cfellows's Avatar
 
Join Date: Aug 2007
Posts: 3,770
Liked 653 Times on 429 Posts
Likes Given: 3

Default Re: Opposed 4 cylinder 4 stroke

That's a great looking engine. Runs very nice. I especially like how low it idles.

Do you have any pictures of the crankshaft? I'd be interested in seeing how you hold it together.

Chuck

__________________

So many projects, so little time, not enough energy...

cfellows is offline  
 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:33 PM   #6
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

This was the first crank built to the original drawings. Its turned from 1144 and the rod journals are hardened shaft. There is a splined connection to allow for 2 bearings in the middle of the crank. Everything is held together with machine screws.

The crank proved to be weak and in the first runs the front crank sheared at the bolt that pinches the rod shaft.

Attached Thumbnails
flat4 (13).jpg   flat4 (15).jpg   flat4 (17).jpg   flat4 (18).jpg  
__________________
geoff_h is offline  
 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:42 PM   #7
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

Here is the 2nd version of the crank and rods. Crank is again 1144 and the rods are 2024 with bronze bushings in the small end. the big end is reamed and held together with 2x 2x56 screws. The crank is made in 2 parts and turned between centers. Not shown is the coupler that holds the center joint. Its just a tube with the id the same as the bearings to be a firm slide fit onto the crank halfs and holds them together as 1 removing any side play from the bearings.

The 2nd set of pics show how the crank is supported in the case. 2 bearings in the nose, 2 in the middle and 1 in the back.

The holes in the bottom of the case allow oil into the cam housing and are countersunk for o-rings to seal them.

The drive key is custom made.

Attached Thumbnails
flat4 (38).jpg   flat4 (23).jpg   flat4 (25).jpg   flat4 (28).jpg  
__________________
geoff_h is offline  
 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:51 PM   #8
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

The carbs are standard RC carbs with new throttle arms made.

The first cam was made of W1 but when hardened twisted and was not usable. All part of the materials learning curve I guess. The 2nd cam was redesinged and made of O1 and was thicker diameter between the lobes to try and allow it to be more stable when hardened. It is 270 intake 270 exhaust and 110 degrees between the lobes

Attached Thumbnails
flat4 (19).jpg   flat4 (22).jpg   flat4 (29).jpg   flat4 (30).jpg  
__________________
geoff_h is offline  
JaamieG Likes This 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:56 PM   #9
geoff_h
 
Join Date: May 2010
Posts: 21
Liked 12 Times on 9 Posts

Default Re: Opposed 4 cylinder 4 stroke

Everything put together and ready to run. Now the real fun starts, to try and refine it.

Attached Thumbnails
flat4 (33).jpg   flat4 (34).jpg   flat4 (35).jpg  
__________________
geoff_h is offline  
JaamieG Likes This 
Reply With Quote Quick reply to this message
Old 08-12-2011, 01:57 PM   #10
dieselpilot
 
Join Date: Jan 2009
Location: Chicagoland
Posts: 1,184
Liked 86 Times on 78 Posts
Likes Given: 1

Default Re: Opposed 4 cylinder 4 stroke

Beautiful. I'm going to guess, die maker?



__________________
dieselpilot is offline  
2
People Like This 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
2-stroke, 2-cylinder engine? Jerd Questions and Answers 41 03-04-2013 02:03 PM
(OT)Hybrid 2-stroke / 4-stroke engine with glass cylinder Jan Ridders Finished Projects 13 07-20-2012 08:17 AM
4 stroke - 4 cylinder Boxster flyingtractors1 Finished Projects 4 04-09-2012 02:01 PM
Opposed 4 Cylinder Air Engine cfellows Plans 55 06-06-2011 03:05 PM
Four Piston Two Cylinder opposed engine design bearcar1 The Break Room 1 02-23-2011 03:42 AM




- Top - Member List