Conn Rod Bearing Inserts: Yea or Nay?

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules

Topic author
Dave Loving
Posts: 20
Joined: Sun Oct 20, 2019 6:42 pm
First Name: David
Last Name: Loving
* REQUIRED* Type and Year of Model Ts owned: 1910 Touring; 1911 Torpedo; 1923 Roadster
Location: Mansfield, MA

Conn Rod Bearing Inserts: Yea or Nay?

Post by Dave Loving » Mon Feb 06, 2023 3:11 am

My 1911 Torpedo needs new conn rod bearings, should I go with Inserts rather than conventional Babbitt?
Thanks,


Kerry
Posts: 1297
Joined: Mon Jan 07, 2019 2:42 pm
First Name: Frank
Last Name: van Ekeren
* REQUIRED* Type and Year of Model Ts owned: 1916 touring, 1916 pick-up, 1924 coupe, 1926 touring, 1927 touring
Location: Rosedale Vic Australia

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by Kerry » Mon Feb 06, 2023 4:27 am

Nay is the word if no oil pressure crank, I fitted some years ago for a fellow club member and never had any feed back on how they lasted as the engine was sold from his estate. Now your talking a 1911 block. Don't experiment with it, scat crank if you can afford it with the lighter babbitt rods or a EE thats crack tested and ground, fit babbitt rods, that will last for a long time and many miles. The inserts do not fit the DB or Ford original rods also no longer available is STD unless using the scat rods on scat shaft. Another option is measure your old shaft stick in some fresh babbitt rods and hope the old crank dosen't break and take out your block.


TXGOAT2
Posts: 6400
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
* REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by TXGOAT2 » Mon Feb 06, 2023 9:47 am

I don't believe that inserts would offer any advantage in a stock or near stock engine. I assume an insert installation would be non-adjustable. Modern-style insert bearings would wear at about the same rate as original type bearings in a stock T engine, and they would lack certain capabilities of original style bearings, such as high embedability and high conformability and adjustability. Conformability is important in an engine with a flexible crankshaft and wide tolerances and no oil filter. Insert bearings will perform well in a modified T engine with a modern counterbalanced crankshaft and full pressure lubrication with a modern type oil filter.

For an early T engine, I'd want to install aluminum pistons, modern rings, and the best crankshaft you can obtain, and balance everything. A counterblanced crankshaft will run much smoother and hold bearing alignment under stress better than a stock crankshaft. Aluminum pistons with modern rings and a counterbalalanced crankshaft will improve smoothness, power, durability, economy, and longevity while offering a wider safe RPM range without altering the original block.

User avatar

TWrenn
Posts: 3372
Joined: Sun Jan 06, 2019 10:53 am
First Name: Tim
Last Name: Wrenn
* REQUIRED* Type and Year of Model Ts owned: '13 Touring, '26 "Overlap" Fordor
Location: Ohio
MTFCA Number: 30701
MTFCI Number: 24033
Board Member Since: 2019

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by TWrenn » Mon Feb 06, 2023 9:55 am

Dave Loving wrote:
Mon Feb 06, 2023 3:11 am
My 1911 Torpedo needs new conn rod bearings, should I go with Inserts rather than conventional Babbitt?
Thanks,
I'm no expert as I always say, but having watched several of my engines being rebuilt by an expert, I think I can at least say if you're needing new rod caps, then you no doubt need new rod babbit also, and well...it just expands from there. Do your engine a favor and do the whole thing.


TXGOAT2
Posts: 6400
Joined: Sun Feb 14, 2021 10:08 pm
First Name: Pat
Last Name: McNallen
* REQUIRED* Type and Year of Model Ts owned: 1926-7 roadster
Location: Graham, Texas
MTFCA Number: 51486
Board Member Since: 2021

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by TXGOAT2 » Mon Feb 06, 2023 10:12 am

Crank pins tend to wear unevenly. A "flat" crankshaft with out of round crankpins will not give good service with any type of bearing. Be sure that the crankshaft is in good condition. If the crankshaft is in good condition, your rod bearings may only need adjustment. The oiling system needs to be working correctly.


Erik Barrett
Posts: 460
Joined: Mon Jan 07, 2019 12:32 am
First Name: Erik
Last Name: Barrett
* REQUIRED* Type and Year of Model Ts owned: 1913 speedster 1924 touring 1925 dump truck
Location: Auburn, Ca.

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by Erik Barrett » Mon Feb 06, 2023 1:31 pm

Insert bearings like filtered pressurized oil. They are very intolerant of debris in the oil. With all the trash generated by the starter drive and transmission, they are not a good choice for stock T’s.


Norman Kling
Posts: 4041
Joined: Tue Jan 08, 2019 1:39 pm
First Name: Norman
Last Name: Kling
Location: Alpine California

Re: Conn Rod Bearing Inserts: Yea or Nay?

Post by Norman Kling » Mon Feb 06, 2023 4:42 pm

Babbitt is the way to go. If you use inserts, it would be best to also have a pressurized oil system, but to do that, you would need to drill the crankshaft. The bearings on a T crank are also small and the drilling would weaken the already weak crankshaft. With a new Skat crank, the babbitt bearings would wear for a long time and only need small adjustment from time to time to keep it going for years.
Norm

Post Reply Previous topicNext topic