Question about a re-babbitting process

[Wheelmang]

I have a recommendation from a well respected company that has a babbitting process. Rather than re-babbitting the rod bearing inserts the recommendation it to eliminate them and pour the rods themselves. I trust this company but have not heard of this process so am inquiring if others have had this done and what is the success or hopefully lack of failure. Thanks all for your feedback.  

[dictator27]

What engine?

[Spinneyhill]

You might have to p.m. @herm111 asking for a response!

[Wheelmang]

The engine is a 26 DB 6 Volt. Herm is the one who is recommending the process, I just have not heard of it being done and am curious about others who may have gone through the process.

Thanks  

[keiser31]

So....are you saying that the poured rods would be all babbit material?

[Wheelmang]

It is my understanding that the bearing inserts normally on the rods are replaced with babbit not the entire rod assembly. I guess I need to speak more with Herm to get a better understanding. In looking at the rods the inserts are actually a little wider than the rod so that creates the question of what is done to fill the lateral space created by removal of the insert. 

[JV Puleo]

The process Mr. Kohnke recommends is probably better than the original process. It allows better dissipation of heat from the rod journal thereby making the bearings run cooler. It was used in period, albeit not usually in as perfected a form. A lot of engines had the Babbit poured directly into the rods. Often enough this was to avoid the complicated and expensive process of making bronze shells. However, most, if not all expensive cars used the bronze shells. In the day when just about every mechanic and machinist was familiar with pouring Babbit, they were much easier to reline.

[Wheelmang]

JV - Thanks for the feedback. What you say makes a lot of sense and looks like the way to proceed. Herm is a least 3 months lead time on the process but it sounds like his reputation is worth the wait. 

Paul

[JV Puleo]

I think so... in fact, I have an engine in my shop that belongs to a friend that I plan to call him about. Actually, until I read one of Mr. Kohnke's posts on the subject I didn't know he made that type of bearing. The one possible drawback that I see is that, with a one-piece shell, the main bearing thrust is also taken up by the Babbitt bearing. In my own, Mitchell engine, which had thick Babbitt bearings poured directly into the crankcase, the thrust is worn paper thin. But, I suspect the Mitchell bearings were made that way because they were cheaper to do at the factory, not because they were better.

 

I'm confident Herm understands that and has no problem adopting to it. In the case of high end original engines, with bronze shells, the thrust was taken on the bronze. That would have been much easier for a general mechanic to work with, he would only have to have been concerned with the actual diameter of the journal so it is understandable that they would have continued to use the bronze shells even if they understood that there was a slightly better alternative.

[herm111]

On ‎6‎/‎26‎/‎2018 at 12:20 PM, JV Puleo said:

I think so... in fact, I have an engine in my shop that belongs to a friend that I plan to call him about. Actually, until I read one of Mr. Kohnke's posts on the subject I didn't know he made that type of bearing. The one possible drawback that I see is that, with a one-piece shell, the main bearing thrust is also taken up by the Babbitt bearing. In my own, Mitchell engine, which had thick Babbitt bearings poured directly into the crankcase, the thrust is worn paper thin. But, I suspect the Mitchell bearings were made that way because they were cheaper to do at the factory, not because they were better.

 

I'm confident Herm understands that and has no problem adopting to it. In the case of high end original engines, with bronze shells, the thrust was taken on the bronze. That would have been much easier for a general mechanic to work with, he would only have to have been concerned with the actual diameter of the journal so it is understandable that they would have continued to use the bronze shells even if they understood that there was a slightly better alternative.

Mr. JV, I haven't had time to play on the computer for a while.  Ok, lets start with cam bearings. We do build cam bearings, as in your old ones. We spin pour them, at 1200 RPM's, and machine them about .100-00 under the cam size, for them to be align bored in your block.

 

Rods, the reason we don't Babbitt rod inserts, is because when done, and put in the Rods, they have to be , or should be a 100% fit to the I.D. of the rod. If not, they can move in and out, say if there was a small space between the insert, and the rod surface, of a .000-50 thousandths, and as the crank is pushing at the top, and bottom of each stroke, it can fracture the Babbitt in a short time, so the Babbitt gets a bad name. Inserts, when poured, will distort, and have to be brought back to uniformity, and some can't be trued, to a 100%. We can pour them, but we can't guarantee them. So the easy, and better fix is pouring them solid. As Mr. JV said, there is  better Heat transfer, as oil that is between the insert, and rod, is not a good conductor of heat, and if with inserts, they didn't Shims, we normally put in .006 thousandths shims, on either side, and cut with the Babbitt, or if not wanted, we wouldn't.

 

Now, for the mains.  The mains hold a crank that just turns in a merry circle, with out the rod thrust, so main inserts work very well, of course if done right, as with anything.  Bearings are all the same when it comes to Babbitting,  just different size, material that the shell is made of, and oil grooves.

 

If say your main thrust is wore, weather, a Bronze, Steel, or Babbitt shell, we leave about .050 on each side, so the Align Bore man can fit the thrust on the crank to spec's. On the part lines,  we leave  about .006 thousandths to fit the bearing, so as to make sure you get the bearing crush you desire. 

 

That's all I can think of, any more questions, let me know. I am always glad to tell you More then I know !

 

Thanks,

 

Herm.