Main Bearing Grove question about Plymouth 4 Cylinder Engines

[johnRFain29U]

Pat,
Recommmend you contact Terry Harkin in South Dakota about the babbit bearing work - his shop has been in the family since 1903 and all they do is babbitt work for old cars.? Terry will be glad to talk to you on the phone and give you advise on what to do.? I had a similar problem a few years back - Terry rebabbitted my rod bearing for $40 and it was a work or art! As for the inserts, Terry could pour them undersized for you and you could then have a machine shop line bore them to fit the crank (after the crank is checked and turned - better do that first though!).

"Harkin Machine Shop, need help re-Babbitting your bearings or engine rebuilding? Our shop has been turning out quality BABBITT work since 1906. Not only is this our livelihood but we thoroughly enjoy helping people get these great old cars running again; contact us with that difficult job.? 903 43rd Str NE, Watertown, SD? 57201 Terry Harkin, Ph: 605-886-7880.

Also, I talked with Terry recently about the groving - he said Chrysler (and Plymouth) only groved the top half.

As for pistons, I would contact Egge. I have not done bussiness with them, but they do make replacement pistons for early Pymouths.? http://www.egge.com/? Phone 866-534-EGGE /

New rings can be purchased from Hastings for about $75.? Hastings Manufacturing Company, LLC
325 N. Hanover St., Hastings, MI 49058
Phone (269) 945-2491 ? Fax (269) 945-4667
Toll Free: 800-776-1088? http://www.hastingsmfg.com

[matchlesspat]

I have this problem with my 29 Dodge DA, the engine had been "rebuilt" before I bought it in South Africa, I used the car for 4 years with good oil pressure and low oil consumption (straight 40 grade), slight fumes from the breather after a run,
  on my way to the Goodwood revival this year it lost a rod bearing, the babbit had completely shattered and lay in the oil pan, anything between dust and pieces you could reassemble if you had enough time, when I stripped the engine I found a mess, the cylinders had new pistons but 1/4" oversize (nash) and the cylinder bores are badly scored lower down, 1" wide 1/32" deep! the main bearing inserts are worn but probably still useable but the crank is scored and needs grinding, I probably need to get the inserts and the rods re babbited and find some standard pistons to sleeve down to, not easy in the UK.

The main problem with replacing babbit with inserts is that most modern inserts come in one basic thickness of about 3/32" or 2mm  (plus undersizes) and the old babbit was often quite thick so when you remove it and machine the rough surface of the rod back to something you could fit inserts into you probably have a bigger gap to fill, especially if the crank has been ground a few times,

I have just replaced the main bearings on a modern engine and they were only groved at the top where the oil is fed, solid on the bottom,

  Pat

[Wm Steed]

I find it to be very interesting that there appears to be so many different opinions concerning babbitted bearings. Carla's lengthy posting was very informative.

David Rainville asked the question about converting babbitted engines to inserts. I can't speak for the Plymouth engines, I do know that other engines are converted to inserts on a regular basis. I use to run a lot of two cylinder Kohler engines in my business, these engines were all from the mid nineteen fifties with babbitted bearings. As the engines needed rebuilding the machine shop that did them converted them over to insert type bearings.

I have a friend that is really deep into Ford Model T's. He regularly converts the 'T's' to inserts, splitting the crankcase to eliminate the common oil system between the engine and trans which requires the fitting of a rear main seal to the crank/block. To this whole mix he adds an 80lb external oil pump so he can get oil up to the Rajo overhead valve head. Of course he has to use an external water pump, however, these pumps were a very common add-on to the 'T's' when the 'T' was a common vehicle. He has built 'T' engines that put out over 300hp....Bill

[David Rainville]

I read Carla's babbitt information with interest. You seem to know quite a lot about babbitt bearings. I have a 31 with babbitt bearings and recently had the engine rebuilt. I asked if it could be converted to insert bearings and was told it could not. I would think that it should be possible, is there a reason you could enlighten me why it's not.

[johnRFain29U]

Wow - thanks!

The engine was rebabbitted 30 years ago in Orlando, FL, so I cannot take it back to be redone.? The car had been in storage for a number of years.? I took it out of soarge in 2003 and got it running - then threw the #1 rod bearing.? I sent the rod off to Harkins machine shop in SD to be rebabbitted.? Tom Hartkin did a beautiful job.? I asked him if he had any suggestions on what i should check as to why the rod bearing failed.? he suggested to check the groves in the bearings. The oil ports in the crank do not always line up with the oil port in the bearing, so a grove in cut in the bearing to improve oil flow thru the crank to the rods.? I discovered the groves were cut backwards.? apparently the machinist measured, then cut the groves on the wrong side.? (Sort of like going in for surgery, and the doc operates on the wrong side.)? I added groves in the correct place, and have not had any problems.? However, I saw some replacement bearings for sale for other engines and noticed the groves go all the way around the bearing.? Mine were only done on the top half.? Now I wonder if I was suppose to grove them all the way around.? However, that may not be necessary.? Just wondering, since I have the engine out now doing some work on it, if I should do the groves better.?

[Carla]

Actually, I have to correct that last paragraph in my earlier comment........there are some engines.....the XK Jaguars for example, which have additional drillings into the oil drillings which feed the rod bearings.......those are so-called 'sludge traps' and are closed with taper thread pipe plugs.

When working on one of those, the 'sludge trap' plugs must be removed before the crank goes out to the specialist firm for re-grinding. After the crank comes back from grinding, and the oilways are cleaned out, the plugs must be put back in with red Loctite, and the thread above the plug deformed slightly, to surely retain the plug from ever becoming loose. One must remember to have the plugs back in before the crank and related parts are sent out to the suitable specialist firm for balancing.

cheers

Carla

[Carla]

John,

If that were my engine, I'd take it back to the shop which did the Babbitt and line-bore work, and ask them to groove the babbitt in the caps equally as the did the Babbitt in the block.

Thats only my opinion, tho........its truly fascinating that many of the people who have done a lot of Babbitt work will have very different opinions and preferences about the best way to do best quality Babbitt work.

There are quite a few different alloys of 'white metal'  bearing metals which are all called 'Babbitt', even tho the name Babbitt, used correctly, refers to only one specific alloy, so-called 'genuine Babbitt metal'.

A look through some of the old catalogues will show such allegedly wonderful materials as 'Selby Diesel Engine Babbitt', 'Magnolia Metal' several varieties of' 'nickel babbitt' and 'copper hard babbitt' (note the small 'b'), and so forth, on and on......down to inexpensive 'lead based bearing metal, for use with light loads and low speeds'.

Different machinists with experience in Babbitting work may have some strong opinions about Babbitt alloys, to be sure.....and there is, indeed, the trade-off between wear and the possibility of fracture under load, or chipping-out in thin sections, such as thrust faces of mains in engines, with the varying percentages of tin and copper......they may have strong opinions about details of technique, as well.....the extent of 'keying' cuts in the iron casting, and 'tinning the casting' before the pour.

Some say that the iron castings must be pre-heated to as nearly bearing metal pouring temp (which varies according to the specific alloy)  as the iron casting will stand without risking warpage or cracks in the iron from uneven cooling, some say that the iron should be pre-heated only mildly, and the keying/tinning is the most important consideration, whilst yet others are strongly in favour of the so-called 'chill pour' in which the Babbitt is poured with the iron casting at room temperature. Those who favour the latter will claim that the crystalline structure of the Babbitt metal is better preserved by rapid cooling.

Likewise, some will say that the Babbitt, once cooled to ambient, must be well and thoroly peened, whilst others will say this step is not only unnecessary, but harmful in that it may tend to degrade the affinity of the Babbitt for the tinned casting, and yet others will say that peening, whilst necessary, should be gently done. with a minimum of force.

Babbitting is slowly becoming a lost art......I haven't done any myself for years and years now, and don't plan to run any more of the stuff. Not only is it a truly unpleasant job, it can be seriously dangerous if you fumble the least bit and spatter molten Babbitt on yourself or a helper.

If you have any interest in the technicalities of Babbitt work, go ask about it on the 'Practical Machinist' internet board. There are quite a few millwrights and machinery rebuilders there who are doing Babbitt bearing work for the industrial applications in which it is still the everyday 'fact of life'.......just don't ask me...... : )

We don't have any engines which use poured Babbitt bearings, and, these days, I would be ever so insecure about owning one and having to pour bearings for it......I'd dare not send the work out, as I've heard too many 'horror stories' about automotive shops these days, who have people doing this work who don't really understand how to do it properly, so the victim engine experiences early bearing failure.

Re the drilled holes in the crank........as a necessary part of any engine rebuild, those holes must be cleaned.....spotlessly clean.....with a suitable rifle cleaning rod, brush, and lacquer thinner or other suitable solvent. You'll see for yourself where the holes go, but, on all the old cranks I've ever seen, they are simple drilled holes between a main journal and the adjacent rod journal. If the crank is ground, be certain that they are correctly deburred, that is, smoothly counter-sunk ever so slightly, to remove any sharp edge.

cheers

Carla

[johnRFain29U]

 ???  The main bearings on my 29 Plymouth were groved to ensure that sufficient oil gets to the rod bearings and in turn the cylinder walls.   The shop that re-babbited my engines main bearings only groved the top bearing half - the groves were not extended around the bottom half of the babbit bearings.  My question is - must the groves go all the way around?

Also - in the crank shaft - does the oil hole from the mains to the rods connect only from one main to the nearest rod, or do all of them connect together?