Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 01-27-2020, 07:25 PM   #1
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

My thrust clearance quadrupled after a 75 mile drive. Itís about .030 now.
D3BE41CA-292A-4E10-98DD-C4C1D412D918.jpg
97DDED91-6BF4-45BC-8AA5-6A40236D5614.jpg

I picked up this bronze Model A Ford Rear Main Thrust Plate & Oil Seal
40D8A27B-79CE-42B4-9637-83316E46BF72.jpg

I searched for info on the install, but I havenít found anything. How do I remove the Babbitt thrust portion of the rear main? I was thinking of just scraping it off with a sharp scraper. There must be a better way.
ghalperin is offline   Reply With Quote
Old 01-27-2020, 07:43 PM   #2
J Franklin
Senior Member
 
J Franklin's Avatar
 
Join Date: May 2010
Location: oregon
Posts: 4,094
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Read here- https://www.fordbarn.com/forum/showt...=bronze+thrust

There was a better step by step pictorial write-up on the barn but I couldn't locate it. Maybe someone else knows where it is hiding.
J Franklin is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 01-27-2020, 09:42 PM   #3
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Quote:
Originally Posted by J Franklin View Post
Read here- https://www.fordbarn.com/forum/showt...=bronze+thrust

There was a better step by step pictorial write-up on the barn but I couldn't locate it. Maybe someone else knows where it is hiding.
Thanks for the link, itís very helpful.
ghalperin is offline   Reply With Quote
Old 01-27-2020, 10:36 PM   #4
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Tonight I pulled the crankshaft and started whittling away. It took about 30 minutes with a breakaway utility knife. It almost looks like the end thrust was poured separately from the main bearing. Thereís a dirty section in the center that looks like it was not bonded well with the thrust bearing part.

979C26C0-F9F1-4AB4-8676-164FCF16DF45.jpg

Anyways, the bronze part fits perfectly. Iíll check the end play after I get everything cleaned up.

7D14046D-0E50-4D2F-B91B-29E33ACCDE3F.jpg

Iím replacing the rod nuts with ARP nuts. Should I do the same with the main cap nuts?
ghalperin is offline   Reply With Quote
Old 01-28-2020, 08:03 AM   #5
Mulletwagon
Senior Member
 
Mulletwagon's Avatar
 
Join Date: Jan 2019
Location: Florida Panhandle
Posts: 290
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Interesting post; please continue the story and photos. Thanks.
Mulletwagon is offline   Reply With Quote
Old 01-28-2020, 09:38 AM   #6
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 10,975
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

I know this might be a touchy subject but I was curious about who did the babbitt bearing work?
rotorwrench is online now   Reply With Quote
Old 01-28-2020, 09:42 AM   #7
Dave in MN
Senior Member
 
Dave in MN's Avatar
 
Join Date: May 2010
Location: Jordan, MN
Posts: 1,217
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

ghalperin,
I have used over 150 of these combination thrust and seal in rebuilding A engines with insert bearings. To avoid a leak, bed the combination thrust and seal with a sealant. Permatex #2 works well.
Good Day!
Dave in MN is offline   Reply With Quote
Old 01-28-2020, 06:37 PM   #8
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Quote:
Originally Posted by rotorwrench View Post
I know this might be a touchy subject but I was curious about who did the babbitt bearing work?

The engine was rebuilt in the '70s, I doubt if they're still around. The car was in Napa for decades.
ghalperin is offline   Reply With Quote
Old 01-28-2020, 06:38 PM   #9
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Quote:
Originally Posted by Dave in MN View Post
ghalperin,
I have used over 150 of these combination thrust and seal in rebuilding A engines with insert bearings. To avoid a leak, bed the combination thrust and seal with a sealant. Permatex #2 works well.
Good Day!

Thanks for the tip, I plan on it.
ghalperin is offline   Reply With Quote
Old 01-29-2020, 01:12 AM   #10
redmodelt
Senior Member
 
redmodelt's Avatar
 
Join Date: May 2010
Location: Portland OR
Posts: 4,885
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

When doing new Babbitt, MAKE SURE THE THRUST FACES ARE AS SMOOTH AS THE JOURNAL ON THE CRANK. That means both ends. If they are not will act like a file and remove material same as a file would.
__________________
I know the voices aren't real but damn they have some good ideas!
redmodelt is offline   Reply With Quote
Old 01-29-2020, 04:50 PM   #11
Nosetime
Senior Member
 
Join Date: May 2017
Location: Huntington Beach, Calif
Posts: 233
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Glen, when I put mine back together I used ARP rod nuts and headstuds, like Jim suggests in his book. I also bought the modern sealed main bolt kit from Brattons or Snyders.
Nosetime is online now   Reply With Quote
Old 03-24-2020, 03:34 PM   #12
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

After completely disassembling, adjusting all the babbett's and reassembling, it still knocked. I sent the rods out to have the wrist pin bushings changed. When I was cleaning it up for reassembly, again, I noticed a small mark on the center of the combustion chambers and matching marks on two pistons. I only had .019" between the piston and the head. I had .020" shaved off the tops of the new pistons and all is good.
E08FB0A4-CF1B-42E0-A743-406AEBF8B41E.jpg

2668442A-6592-4623-8B2F-792AA4279682.jpg

That little tit on the bottom side of the piston was expanding just enough to kiss the head.

53C74471-0D36-4CCB-840B-FBC924E040B9.jpg
ghalperin is offline   Reply With Quote
Old 03-24-2020, 04:14 PM   #13
MikeK
Senior Member
 
MikeK's Avatar
 
Join Date: May 2010
Location: Windy City
Posts: 2,842
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Quote:
Originally Posted by ghalperin View Post
. . . Thereís a dirty section in the center that looks like it was not bonded well with the thrust bearing part.
That dirty looking section is actually torn apart alloy from internal porosity and shrinkage. Caused by a combination of dissolved gas from a lot of remelt in the heat, overheated alloy resulting in loss of nucleation points, and failure to immediately and properly compact the poured shells by peening after pouring. That caused the thrust face to easily compact in short order when the engine was run.

If it all happened in just a few miles as you state I question the integrity of all three mains, and not just the side faces. If the same guy did the rods you may be in for more problems.

As for your desire to change from stock nuts with cotters to ARP nuts, I'd call that overkill unless you're planning some serious mods and racing.
__________________
Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.
MikeK is offline   Reply With Quote
Old 03-24-2020, 05:33 PM   #14
ghalperin
Member
 
Join Date: Nov 2015
Posts: 38
Default Re: Bronze Model A Ford Rear Main Thrust Plate & Oil Seal installation

Quote:
Originally Posted by MikeK View Post
That dirty looking section is actually torn apart alloy from internal porosity and shrinkage. Caused by a combination of dissolved gas from a lot of remelt in the heat, overheated alloy resulting in loss of nucleation points, and failure to immediately and properly compact the poured shells by peening after pouring. That caused the thrust face to easily compact in short order when the engine was run.

If it all happened in just a few miles as you state I question the integrity of all three mains, and not just the side faces. If the same guy did the rods you may be in for more problems.

As for your desire to change from stock nuts with cotters to ARP nuts, I'd call that overkill unless you're planning some serious mods and racing.
Sorry to be misleading in my initial post. The engine has not been apart since the '70s. I was driving it a little too hard on the toll road and afterwards is when I noticed the nocking. All of the babbitt clearances were very close to .0015". I only ended up adjusting a couple.
ghalperin is offline   Reply With Quote
Reply

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

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 10:44 AM.