Babbitt

[petehoovie]

Few people on the Flathead V8 Forum (where I normally post) know about Babbitt bearings as most of the Flathead V8's have insert type bearings. The engine in my '34 has Babbitt bearings. I'm curious to know more about Babbitt and decided to pose my questions here thinking that Babbitt bearings in the Model A engine is more common.


Is Babbitt as durable and long lasting as the more modern type insert bearings? Does Babbitt require any special care or treatment to preserve its longevity? One guy told me that a ZDDP additive to my oil would help to protect the Babbitt, his reasoning being that the zinc in ZDDP is a sacrificial metal that will coat the bearings. Is this valid? Any other information you can provide about Babbitt is appreciated....

 

[J Franklin]

Just use good oil and keep it clean. Also keep the clearances within tolerance. Babbit is used on many insert bearings as well as in jet engine fans.

 

[BRENT in 10-uh-C]

In a nutshell, the longevity will be equal to insert bearings if the babbitt is properly installed and machined. Therein lies the biggest issue in that the bad reputation comes because inferior grades of babbitt and poor casting methods result in inferior jobs that prematurely fail. Remember that early diesel engines successfully used the same type of cast babbitt bearings however in those application the compression ratios and the power-levels were nearly double that over the pre-LB Ford V-8 engines.

 

[Synchro909]

Isn't the thin silvery grey layer of metal on an insert in fact babbit? If that thin layer lasts so long, wouldn't you expect an all babbit bearing to do at least as well?

 

[BRENT in 10-uh-C]

a) Isn't the thin silvery grey layer of metal on an insert in fact babbit?


b) If that thin layer lasts so long, wouldn't you expect an all babbit bearing to do at least as well?

a) It used to be but often times there are different materials used today, but yes in theory you are correct.


b) Two or three things factor in on that theory, and the biggest one is the thicker the cast metal is does not necessarily correlate to being the same density. Less dense will not hold-up as well. Also, the ability to transfer heat away from the spinning crankshaft factors in on wear. Again, density factors in on this too as to how well it can transfer the heat into the main web or cap.

 

[jhowes]

Might I suggest that you tell us where you are. We might be able to direct you to a shop that does good bearings and machining. Jack

 

[30 Closed Cab PU]

If my memory is correct have read here an advantage of poured Babbitt over Inserts is the thickness of the Babbitt. Inserts only have a thin layer of Babbitt when compared to the original poured Babbitt bearings.


Inserts are OK until something goes wrong, they wear through quickly to the underlying material, and can damage the crank. Poured Babbitt gives you more warning, and is much more forgiving since it is thicker. You should also be very vigilant about not lugging the engine with Inserts, they are less forgiving to lugging.


One disadvantage of poured Babbitt is that it takes high skills/knowledge to do properly when compared to inserts. When done properly many consider poured Babbitt to be a better choice to Inserts.


Many recommend converting an A to a pressurized/filtered oil system when using Inserts.


If you do a search here in the A forum on Babbitt and Inserts, you will find tons of info/opinions.


I am unsure about the ZDDP info, hopefully others can answer, I know it has been discussed, perhaps do a search here.


Others please correct me if I misunderstand.

 

[Purdy Swoft]

The only advantage that I can see for using insert bearings is the ease of replacement . Usually when the thin layer of babbitt or aluminum wears off the insert it usually damages the crankshaft .

 

[katy]

IIRC, the early Ford V-8s, the rods used floating insert bearings that were made of bronze, and poured babbit on the mains.
Pls correct me if'n I'm wrong.

 

[Joe K]

Insert bearings are at their best when used with pressurized lubrication. Babbitt bearings CAN be configured for PL, but were not done so with Ford - and most since then perhaps even less.

A rebuilt Sears engine of my experience which was rebabbited without oil grooves comes to mind.

One thing which Ford did on the original engines was "superfinish" the cranks. My experience with modern crank grinders is they're working to surface roughness standards which have been common since the rise of PL.

In PL, the crank journal rarely if ever actually touches the bearing. So there is no real need for superfinish. In a babbit bearing engine it does matter - and hence the need for superfinishing. Were more crank grinders capable of superfinish is my lament.

I once asked my Model A mentor what one could expect for engine life of a "standard" Model A engine. His reply "60K miles if all attended to in timely manner." He was a professional restorer of some minor note in Central Massachusetts. And he didn't specify superfinishing as a constructive option as in the 1980s few had even given it a thought.

I myself had a 26K mile AA chassis which was used as a portable platform for an industrial welder. Purportedly (according to the original owner) that engine had never had the shims changed. It still ran, was horribly loose, but seller and I did get it up to 40 mph in a test run. (no floorboards!) Perhaps the difference in soldiering on in this original engine is in the original superfinishing?

Well, it (the 1930s) was a different age. So one then expected the cars would continue to soldier on for 80 years.

Joe K

 

[Jim Brierley]

I have a Model B engine that I run on the Bonneville salt flats. The engine has been run for many years, is still using the babbitt main bearings that were installed in the 1960's. Last run in 2013 at 167 MPH. Babbitt is great for mains and good for rods but not quite as good. Engine is full pressure oiling and full flow filter.

 

[petehoovie]

Thanks for the replies, guys....

 

[Jeff/Illinois]

This may be of help. I had heard that Ford started going to insert mains in 1936....................

http://www.themotorhood.com/themotorhood/2015/9/22/the-history-of-fords-iconic-flathead-engine

 

[Kohnke Rebabbitting]

1935 Ford V-8 Pictures, Original Type of Oil Grooves in Bearings.

 

[Chuck Sea/Tac]

Brent : I was talking with friends regarding the diesel Babbitt, and someone asked”yeah, but how much bigger were the bearings?” Meaning of course, that the higher compression was spread over larger bearing surface. Any thoughts or info on that?

 

[roy green coupe]

Is the rear seal on the v8 block the same as the model a? I see the same style drain tube.

 

[Railcarmover]

Diesel engines run 18 to 1 compression ratio and compression pressures of up to 400 psi.Inserts are fool proof,the risk to a jobber is way lower than babbit,which as stated above is dependant of the skill of the mechanic.Pressurized oil insert bearings are designed to be kept clean under oil pressure,and will destroy the journal they bear if the babbit layer fails.Pick your poison,Id rather run a 1600 dollar counterweighted crank on babbit than inserts,odds are my crank wont be junk if the bearings wear.

 

[Purdy Swoft]

I've never had a problem with the original uncounter weighted model A crankshaft . I think that Ford added weights to the late 32 or early 33 BB engines . A lot of the trucks were hauling heavy loads at full throttle . then the BB crank wit pinned weights was introduced . The model A crankshafts must have been good for so many of them to survive for all these years. The heavy crankshafts DON't make the engines run any faster . Many that have used the heavy crankshafts say that it really didn't cause the engine to run any smoother . I know that a heavy rotating assembly hurts throttle response and acceleration. I cruise my model A's at 50 MPH and have never had a crankshaft failure in over 50 years . I can usually buy a barn find model A's for less than $1600 hundred dollars . I don't expect my model A's to be as smooth as a modern car . Mine are just fun cars that are not used for primary transportation . I figure that most model A's are used in the same manner. If I was doing some racing I would prefer the unbalanced model B crank with the main bearings turned down to model A size . The larger rod bearings would give more strength where it is most needed without as much added weight .

 

[katy]

Railroad cars used to run babbit journals on the axle shafts. The ones I remember seeing were about 8-9" long w/a shaft diameter about 4-4&1/2".

 

[40 Deluxe]

Railroad cars used to run babbit journals on the axle shafts. The ones I remember seeing were about 8-9" long w/a shaft diameter about 4-4&1/2".

These Babbitted axle journals were a high maintenance/high problem item. When/if they ran out of oil, the resulting friction and heat was called a "hot box" and would sometimes set the boxcar on fire. So a lot of time and effort was spent looking for a hot box before it caused trouble.