31 Bearings

[Guest 1956Packard]

Rather than hi-jacking another post (Opinions about #8 Rod bearing failing on 39 320CI super 8) I too would be interested in hearing about everyone's experiences replacing babbitt bearings with bearing shells / inserts.

As you know my 31 came with babbitt bearings. It has been suggested putting bearing shells in is the way to go. I think I have found that is easier said than done. Has anyone here actually done that with this vintage engine??? I'll I've heard is anecdotal info and stories about a rather old article. I know this has been discussed before, but not sure much was resolved (plus we've got new visitors).

Geoff

[Guest 1956Packard]

I'll assume silence means that no one has experience in this....

Geoff

[Restorer32]

We have rebuilt several '31 and '32 (as well as several '36-'37)Packard engines. On 1 of the '32s we had the rods changed to inserts. I believe '56 Plymouth rod bearings were adaptable. We've always had the mains babbitted, always with good results. If you think about it, what is an insert bearing other than a babbitted shell? I suggest you contact Paul's Rod and Bearing and discuss your problem. He uses the same babbitt material as used in modern engines. I suspect he can educate you as to the pros and cons of babbitt vs. inserts.

[Tom M]

Also give Harts Machine a call. They are located in Cecil, Ohio. I had my rods rabbited by them. I have not re-installed them yet since they have my lower half right now cleaning it up. Plus car is in a Zillion pieces.

[Dave Mitchell]

If you ask 20 Packard guys this question, you will probably get 20 different answers. Everyone seems to have some magic formula. (Most are more trouble than they are worth, some only survive because the owner only drives the car on and off the trailer) In this case you are getting two similar answers - send them to Paul's Rod and Bearing. They have done 4 sets for me in the last year, and I can't even count the total number of sets for 8s, V12s and V16s that they have done for us. I have over 20,000 miles on one V12 that they did for me and I have never had a problem with them. You can tell them that I recommended them. I am not sure it will get you anywhere, but they are helping out one other person from the forum at my request.

[Owen_Dyneto]

If you're willing to accept the limitations on engine speed that the highway conditions of the day imposed, and your crankshaft is round and without defects, you should have no apprehension about having your rods rebabbitted by someone with the requisite skills, and I support the recommendation of Pauls Rod & Bearing, I've used his work in my 34 Packard Eight (320 engine) with tens of thousands of miles of trouble-free driving. But if you want to go flog your car down interstate highways at modern speeds (which no one should recommend, given 70+ year old brake design, suspension, wheels, lights, etc) then I'd say consider a more suitable rear axle ratio and perhaps an insert conversion.

[Ed Miller]

I've replaced the connecting rod babbit with inserts on my Packard '33 Twelve and '34 Super Eight and '32 Cadillac V8. All are driven especially the Cadillac and '34 Packard. If you are going to tour extensively, inserts is the way to go.

[Guest 1956Packard]

Thanks for the response guys. I was expecting to re-babbitt, but wanted as many opinions as I could get - even knowing that each opinion would vary from the next.

Ed:

Where did you have your inserts installed? One of the possible issues with placing inserts into the Packard engine is that there is not enough material on the rods to machine in order to accept the inserts without interferring with the bolts. One source indicates that the rod bolts would have to be 'shaved'. Not something that I would welcome.

Also, this may be a silly question, but what about mains? Anyone ever heard of them being replaced with inserts? Is that even possible?

Geoff

[Packard enthus.]

I would think that ANYONE who advocates the use of "poured babbit" rod bearings for ANYTHING other than a stationary "trailer queen" exhibit, instead of "precision shell insert" type bearings, (except in, say, pre 1918 or so engines with "red lines" of around 800 rpm) would demonstrate their sincerity by writing articles explaining why ALL those engineers for ALL those motor companies, cars, trucks busses, marine, aircraft engines etc., FOR SIXTY OR MORE YEARS NOW... are wrong.

After all...ALL those engineers for ALL those motor companies..trucks..cars, busses, aircraft engines, marine engines ALL OVER THE WORLD...MUST be wrong to waste the mfg's money for the extra machine work to set up for "precision insert" type bearings, when a simple poured babbit bearing would do,... MUST be doing that just to annoy the "experts" in here!

Then, when you get done writing those articles explaining why ALL those engineers, for ALL those motor companies...trucks..cars, buses, aircraft, marine engines, for some sixty or more years now...are wrong...I recommend a reading of John Steinbeck's famous GRAPES OF WRATH, written before World War Two. There are some interesting references of rod bearing failure in that book, showing this was VERY much a part of life with motors, until the curse of the poured babbit bearing was cured forever, with the UNIVERSAL ( as in world wide ) application of the "precision shell insert" type rod bearing in the years that followed.

When you are done reading GRAPES OF WRATH (you should already have read it in your American Literature classes)...really amusing reading can be found in the newspapers covering the celebration of the opening of the first stretches of the Penn. Turnpike in 1938.

While some of the newer cars blasting down the Penn. Turnpike on opening day did have insert rod bearings, and made the trip successfully, many did not. Buick and Chevrolet were the last "hold outs", foisting this primitve concept on their purchasers. Read what happened to then NEW Buicks and Chevrolets when they tried to stay with the "insert" bearing equipped cars that day.

When is the last time you heard of rod bearing failure on a car PROPERLY set up with "insert" type rod bearings ? It just dosnt happen (absent, of course, grotsque abuse). And also remember, modern motors in automotive service have it MUCH easier than the pre-war long stroke engines, which, even at modest speeds, develop MUCH greater "loadings" on their crank pins. And then there is the matter of gearing.

I am not competent to do the math..but I am willing to bet, the loadings on the crank-pins/con. rod bearings on a modern car at 110 mph are far less than that of the typical pre-war motor at 50 mph.

[R W Burgess]

6688, I would think that any vehicle that Restorer would restore would not be considered a "highway blaster" driven at extremes.

His restorations are done for gentleman that would not abuse their vehicles like that. This statement would probably cover most car owners in this forum.

Wayne

[Restorer32]

Actually, some of our cars do get "blasted down the road" and we prefer to use modern insert bearingse possible. We just had a set of rods for a '37 Buick converted to inserts. On the same car we had to have the original factory insert rear main bearing shell rebabbitted because NOS rear mains are unavailable. No problem with the "09 ONLY we're restoring, it has roller mains and rods.

[R W Burgess]

You've got to work with me here, Jeff! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

I was reading Hartmann's post as "almost" racing down the road, if you consider 100 mph a high load factor. I can't imagine any of your customers driving like that? Am I close? <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" /> <img src="http://forums.aaca.org/images/graemlins/laugh.gif" alt="" />

Wayne

[Packard enthus.]

For Wayne:

PLEASE...PLEASE be assured I was not critisizing Rest. 32. I have no idea who he is. From the little I have seen of his "posts", he seems like a competent guy who wants, as I hope the rest of us want, just to be of service to other car buffs who may not have had the opportunity to have as much contact with old car issues as we have.

I am sorry if my "posts" confused you about relative engine bearing loads. Yes, SOME of the big-engined classics of the late 1920's and 1930's most certainly WILL do 100 mph or better. I never did find out the top speed of our '41 "180" coupe with over-drive !

The point is, what I was trying to illustrate, is the RECIPROCATING loads on connecting rod bearings, not that any of us would try and go 100 mph in our collector cars ! The point I was trying to make, to illustrate how much harder on rod bearings our old cars are with their long strokes and low gearing, is that at 50 mph our connecting rod bearings are being "punished" with loadings probably as great as a modern car, with its short stroke and "high' gearing, would be at 100 mph or better.

THAT is the reason why I strongly recommend "insert" / precision shell bearings when a classic-era Packard (or any other make that was not already factory equipped, as Packard was from 1935 on) as opposed to poured babbit.

As '32 notes, CRANKSHAFT MAIN BEARINGS can be re-poured and work out nicely - both the surface SPEED of the bearing on the "mains", and the RECIPROCATING loadings on the CRANKSHAFT are obviously much lower than what happens out at the crank-pin.

And of course a poorly thought out modern "insert" CONVERSION, like any other "botch job" can ruin a motor. Let me give you an example of what NOT to do. To do this I have to give you a little background.

The ASTM/SAE "standard" for the thickness of the insert shell itself, has changed. Pre-war shells were thinner. For 1935, Packard "stroked" the V-12 out from around 440 cu. in. to just under 480 cu in. They had to come up with a "skinnier" connecting rod - the rod and con rod bolt is ONE chrome moly forging. Because modern insert "shells" are thicker, during restoration, some machine shops made the mistake of "nicking" the rod bolts (again, there are no bolts...the shaft of what would be a bolt on most engines is part of the rod forging itself) when boring out the rod "big end" to take a modern bearing.

That sets up a potential stress area. Bad move. VERY bad move.