Home | Classifieds | History | Technical | Links | Store | About Us | Email
Topics Topics Edit Profile Profile Help/Instructions Help Member List Register  
Search Last 1|3|7 Days Search Search Tree View Tree View  

J.B.'s Rod Bearing Pouring and Machin...

Old Marine Engine » One and Two Cylinder Gas Inboards » J.B.'s Rod Bearing Pouring and Machining Process « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

richarddurgee
Senior Member
Username: richarddurgee

Post Number: 1157
Registered: 11-2001


Posted on Sunday, June 18, 2006 - 02:03 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

J.B.'s Photos

Rod bearing pouring and machining process

1.Damaged Rod

1

2.Starting

2

3. Tinned Cap

3

4.Centering Pin

4

5.Pin in Place

5

6.Saddle Plates

6

7.Plates Installed

7

8.Shaft Installed

8.

9.Pre Heating

9

10.Skimming Dross

10

11.Pouring

11

12.Poured

12

13.Shim Jig

13

14.Peelaway Shims

14

15.Rod Boring

15

16.Finished bearing

16

17.Testing Fit

17
Top of pagePrevious messageNext messageBottom of page Link to this message

jb_castagnos
Senior Member
Username: jb_castagnos

Post Number: 143
Registered: 07-2002
Posted on Monday, June 19, 2006 - 10:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

We poured rod bearings for David Prejean Saturday,took some photos to show the procedure. L-A and Nadler used an insert type bearing, I made a mold for these but soon realized that most of the rods were no longer a true machined bore. The rod in the first picture was run against the crank without a bearing. The rods and caps are blasted and tinned with an acid core paste to help the bearing "stick". The centering pin is a pin machined to fit the OD of the rod and stepped to the size of the rod journal, in this case 1 5/8" with 1 3/8" on each side. The saddle plates are two pieces of flat bar, they were placed back to back on the flat in the 4 jaw chuck, the edges faced off, and then they were tacked togehter to form a square plate as seen in the 6th picture. A 1 3/8' hole was bored, then it was counter bored to form the flange area of the rod bearing. It's not critical that the hole be dead center of the split. The rod cap is tightened against the centering pin and the saddle plates are tightened in place against the pin, the gap between the cap and rod with the pin in place is the amount of shim you should start with. The centering pin is removed and the shaft is inserted, this crank is undersized so the shaft is turned in the middle. If you didn't want to bore the finished bearing the shaft would be turned to match the crank, in this case it was smaller. All holes in the rod were sealed with rtv silicone, no need to wait for it to dry. One of the most important steps to pouring babbit is to preheat the parts, have the babbit hot enough, and pour it fast. If you pour it slow, it will freeze before going all the way around. I use two pieces of square stock on the sides of the rod to give a better pouring target and to give the babbit some head pressure, you also have a reserve in case it leaks a little or shrinks. The shim jig holds a stack of shim material, it's drilled then routed with a pattern tracing bit in the router. These are peel away shims, .002" per layer, Dickie Gibbens introduced me to these, used in the helicopter industry. McMaster Carr has sheets available. The rod is bolted together with the shims, placed in the boring jig, centered and squared up, and bored to size. I usually leave .003 to .004" clearance. I learned the hard way not to build them to tight, was having bearing failures on a good fitting bearing when I realized that most of the engines taken apart were worn and sloppy but kept running. I think 2 cycles experience the same thing as compressors that lose a check valve. If a compressor loses a check valve and continues running, it usually burns a rod brg and or wrist pin. The problem is known as non rod reversal, it stays loaded one way and doesn't allow oil under the bearing. Two cycles are always loaded in one direction, with out a little play the bearing is easily starved. I use a 1/8" radius router bit to radius the ends of the bearing. David ended up pouring three of the four bearings, did most of the filing and fitting and routing, he was a good student.
Top of pagePrevious messageNext messageBottom of page Link to this message

richarddurgee
Senior Member
Username: richarddurgee

Post Number: 1161
Registered: 11-2001


Posted on Tuesday, June 20, 2006 - 02:43 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

JB

I want to say that I appreciate your technical and machining abilities and the extra effort you go to photgraph the almost lost processes of restoring these old marine engines and sharing it here on line, I go over the photos often to really understand how its done ! I have now figured out how to get this quality of work or (art form) on my Lockwoods--

Step 1. Take connecting rods, pistons , cyls,crankshafts, crankcases etc and wrap them very well and put in box .

Step 2. Fill out and attach shipping label to
Donaldsonville, LA % JB

Great stuff Thanks Richard
Top of pagePrevious messageNext messageBottom of page Link to this message

peterogborne
Senior Member
Username: peterogborne

Post Number: 148
Registered: 09-2002
Posted on Wednesday, June 21, 2006 - 07:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

I also was impressed with the whole procedure,the photos were great .The shim is interesting ,what is the material?
Top of pagePrevious messageNext messageBottom of page Link to this message

jb_castagnos
Senior Member
Username: jb_castagnos

Post Number: 146
Registered: 07-2002
Posted on Wednesday, June 21, 2006 - 09:18 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only)

Thanks Richard & Peter.
Go to http://www.mcmaster.com/ in the shearch box enter laminated shims. I use the aluminum .002", it's easy to cut and trim with the router.

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Password:
E-mail:
Options: Automatically activate URLs in message
Action:

Administration Administration Log Out Log Out   Previous Page Previous Page Next Page Next Page

Home | Classifieds | History | Technical | Links | Store | About Us | Email
&copy 2005 OldMarineEngine.com, P.O. Box 188, Forest Dale, VT 05745-0188 • Phone: 802-247-4864 • All rights reserved.
   Marine Engine Seloc Repair Manual Lookup Tool

marine gas engine repair and restoration