To avoid these ads, REGISTER NOW!

First attempt at making a set of connecting rods!

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
8e4415ad1d7ad7219e3452491bed7d22.jpg

Blocking up some aluminum.

189bf58bc7a8de1067a0920f153bf7fd.jpg

Hi tech engineering drawings

87c775809d1d901733e7b7aa51565664.jpg
7e30d592234070f7e00daa1ac887195e.jpg

Roughing and finishing the rod bores.

4cc487d7c99dfbc87c0dcf6fd31e780f.jpg

Some detail roughed in.

c07eae1fa4bb3250b2b03d7c3eb548e7.jpg

First one profiled in.

Will have some more to share tomorrow when I'm back at work.
 
To avoid these ads, REGISTER NOW!
OP
J

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
Ill Be the 1st to say that's AWESOME... What are they for ?
Nothing too exciting, it's for a 2 stage air compressor I'm rebuilding. One of the stock rods galled on the crank and went egg shaped and scored up the crank. I had to polish the crank undersized, so stock rods would have been too sloppy, so I'm making new ones to suit and I will have bronze bearings on the crank rather than just having the aluminum rods riding on the crank.
 

Movover

Well-known member
Joined
Jan 14, 2015
Messages
585
Location
Central Maine
While you are there add 10mm and stroke it ;) Not that is would do anything.

Its nice to have the tools to make things like that..
 

PWC Repair

Well-known member
Joined
Dec 27, 2012
Messages
3,165
Location
Arkansas
While you are there add 10mm and stroke it ;) Not that is would do anything.

Its nice to have the tools to make things like that..

Ya, and mill the head, clean up the valve pocket area, free flow muffler....................oops, what were we talking about?
 
OP
J

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
Hopefully I can get all the initial work done tomorrow and get the bronze inserted into the big end. By the end of the week they should be ready for installation.
 

astroracer

Well-known member
Joined
Jun 22, 2005
Messages
3,001
Location
Mid_Michigan
Just a comment I hope you are aware of. In the blank you have the big ends sized to fit the bronze bushings, right? What happens to that size when you saw cut the cap off? The "hole" will be egg shaped, missing the material the saw removed. When you bolt the cap back on, with the bronze bushing in place, it will keep the cap from clamping to the rod.
You may be planning to make the cap separately but, from the way you are machining the whole rod, I don't think you realize there will be a problem. Making the cap separately, bolting the pieces together boring and THEN sizing for your bushing will make it right.
This is the way automotive caps and rods are sized.
Mark
 
OP
J

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
Just a comment I hope you are aware of. In the blank you have the big ends sized to fit the bronze bushings, right? What happens to that size when you saw cut the cap off? The "hole" will be egg shaped, missing the material the saw removed. When you bolt the cap back on, with the bronze bushing in place, it will keep the cap from clamping to the rod.
You may be planning to make the cap separately but, from the way you are machining the whole rod, I don't think you realize there will be a problem. Making the cap separately, bolting the pieces together boring and THEN sizing for your bushing will make it right.
This is the way automotive caps and rods are sized.
Mark
The bushing will pressed in, then brazed to the aluminum, then the cap will be cut off, milled flat, drilled and tapped for the bolts, put back in the mill and the bronze will be bored true again.
 

Flat-rate

Well-known member
Joined
Nov 21, 2013
Messages
637
Awesome. If only you could make con rods for small engines. The mini-bike guys would pay a small fortune for a billet Tecumseh rod.
 

BonzoHansen

Well-known member
Joined
Jun 24, 2005
Messages
1,729
Location
NJ
That pic is from my old techumseh snow blower engine. The governor broke and she raced. You can see it bent before it broke.
 
To avoid these ads, REGISTER NOW!
OP
J

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
dcd9c799f51857a2aad7035bae7e9686.jpg
Both rods profiled all the way through.

85adfb072c6c2e988e1809a8ffde23e3.jpg
extracted from the block, bronze bearings shown as well.

e75aab209f262808ff9199858825175d.jpg
side by side with the original cast rod, still lots of material to deck down and finish the detail on the other side.
 

DocsMachine

Well-known member
Joined
Sep 16, 2006
Messages
1,844
Nice work, but I gotta ask: How, exactly, are you planning to braze the bushings to aluminum rods?

Doc.
 

C_F

ALLIANCE MEMBER
Joined
Jan 21, 2005
Messages
9,675
Location
Utah...SNOW BLOWS!
I assume you are going with smaller diameter rod bolts? Just curious, because the ears for the rod bolts are much smaller on your aluminum ones.

Looks like a fun project, I'm interested in seeing how much horsepower you get out of this! :lol:
 
OP
J

Jim Johnstone

Well-known member
Joined
Apr 11, 2011
Messages
1,841
Location
Brantford, Ontario
I assume you are going with smaller diameter rod bolts? Just curious, because the ears for the rod bolts are much smaller on your aluminum ones.

Looks like a fun project, I'm interested in seeing how much horsepower you get out of this! [emoji38]
Believe it or not, there is clearance for the same size bolts. Not a ton of clearance, but it's there.
 

aka Larry

Well-known member
Joined
May 2, 2012
Messages
8,009
Location
Eastern, NC
Are you planning to use ARP rod bolts? If you're going to go to all this trouble, you might as well go all the way right?
 

aka Larry

Well-known member
Joined
May 2, 2012
Messages
8,009
Location
Eastern, NC
It is the 21st century, fuel injection is the only way to go :D

I know, but I thought he wanted it to be purely mechanical for the old school look. Seriously, I'm surprised nobody had thought to use a carb for an air compressor intake, just because it would look cool!

To the OP, looks good man. Nice work! :thumbup:
 
To avoid these ads, REGISTER NOW!
Top Bottom