Hoglet

[bobden72]

Hi I am building the Hoglet V twin and about to start on the con rods. On the drawings it shows no bearings in the small end. I intend to fit a bronze bush here as its running on a steel gudgeon pin. The big end forked rod is a press fit on the bearing thats fine. The other which runs on the bearing I intended to fit a steel liner to run on the bearing. This seems good practice to me, what have other builders done.

Bob

 

[Jasonb]

If you use the 2024 as specified that tends to be OK for bearing on steel and is often used in much higher reving glow and diesel aero engines with no additional bearings.

J

 

[bobden72]

If you use the 2024 as specified that tends to be OK for bearing on steel and is often used in much higher reving glow and diesel aero engines with no additional bearings.

J

Thanks for your thoughts but I really like real bearing materials. Tried con rods running on aluminium on my Edwards Five and had to redo and fit bearings after about 20 hours running.

 

[johnnyo]

Bob
I'm about to start my rods and redrew them to accept small roller bearings, a little tight to the clearance with the brass flywheel lip and bottom of slot in rod. I think I ended up with a 3/8x5/8x5/32 sealed bearing. RC bearings from fast eddy website. Made rod ends .157 thick with .188 slot in fork. Will bush 1/8" dowel wrist pin with 1/32 wall bronze bushing. Have to figure out the rest myself.
Good luck
Johnny O

 

[bobden72]

That sounds good I have made mine to the external dimensions but bored out the small ends to 5/16" and put a bronze bush in reamed to a 1/4". The blade big end I again bored it over size and put in a silver steel bush a running fit on the main bearing bronze again. The Forked main bear in is a press fit on the main bronze bearing. All worked out well so far.

 

[petertha]

Thanks for your thoughts but I really like real bearing materials. Tried con rods running on aluminium on my Edwards Five and had to redo and fit bearings after about 20 hours running.

Your comment got my interest as I'm about to embark on similar engine. Can you elaborate:
- what was the symptom, wearing the aluminum ID out of tolerance?
- by redo 'bearings', you mean the ID bearing surface of link rods?
- what alloy of aluminum did you use?
- from what I could see of the Edwards plans, there are no diagonal oil bleed holes or saw slit in link rod ends like some other (methanol/oil) 4S radials I've come across. OTOH, The Edwards has an oil pump vs premix oil in fuel. Anyway, did you happen to do an oil passage hole mod like that on your own, or you followed the plans?
- what did you end up using for a bushing material that worked better?
Thanks!

 

[bobden72]

The small ends reamed ID wore so I machined them out and fitted phosphorus bronze bushes. No did not do any modifications built as the drawings. The oil pump seems to work well as judged by the return oil to the tank, I also add a bit of castor oil to the fuel mainly for the smell, I love it.