Big end / Con rod bearings

pmlmbigpondcom

G'day All,

Does any one have comments re replacing the poured and bored big end bearings with shells / slippers ?
34 / 35 splashie

Thanks

Phil

Frankvintagefullflowcom

Hmmmmm. "Splashie". Is that what they call 'em there?
Conversion of a pre '38 rod to inserts is not advisable and isn't practically possible in my opinion, due to the thinner section of the rod forging where the flared portion of the rod beam meets the big end area, and the use of shims in those earlier rods. If you wish to convert, you should find a '38+ set (6 or 8). They were thickened in that area and shims were no longer used. (obviously the 175 rod isn't in this group).
Resizing of the big end does reduce the cross section of that area back to ~ pre-38 dimensions but I don't think it has ever been an issue. For what it's worth, the parts book advises, by inference, that you replace the early (44704-5) rods with the later 166241-&2 (L&R).
There are a few things of which to be very watchful when doing this mod and I'd need to write a short book here to explain them, so I'll leave it here unless you are still interested in pursuing that project.
Frank

Geoff

Phil, I have done this on several engines, and none of them have been successful in the long run, so I recommend you retain the original babbitted rods. I know of others who have tried, and also failed. Even with the later precision rods ('38 onwards) you have to bore out the tunnels to such an extent that you have to relieve down the sides of the replacement shells to give room for the bolts. And the hardness of most modern shell bearings means you will suffer premature crankshaft wear.
Geoff

Frankvintagefullflowcom

G,
I'd be interested in an estimate of how many miles I have left to enjoy mine.
It's true that one must provide clearance for the rod bolts but it's a very minor job to do so, particularly if the rod has been correctly prepared for conversion.
Correct me if I'm wrong, but the issue of hardness is related to the particle embedment qualities of the softer poured Babbitt bearings, so I vote to keep the particles out of the oil in the first place. Only time and miles will tell, but our 212 is doing very well with insert-converted rods......so far. Would you care to describe the nature of the "failures" attributable to that modification?
F

Geoff

I have used three different types of inserts, white metal (babbit), lead bronze, and lead indium. There are several different makes of inserts can be used, Isuzu, Continental C4 (used in fork lifts), and Willys Jeep. The best I had were the Continental bearings, but even with these the crank was worn over .006" out of round after 15,000 miles. The cost of boring out the rods, modifying to take the inserts, filing the sides of the inserts, do not stack up against a good re-metalling job, which should last over 50,000 miles without resorting to filtering. There was no scoring of the bearings or shaft, just plain over-all wear of the journals. Conversely, I have had over 100,000 miles from the white-metalled rods in my Essex motor, with very little crank wear or scoring of bearings. The major thing is t goet as much oil circulating through the bearings as possible, through wide and deep oil grooves, and these have to be cut in the inserts as well, adding to the cost of conversion.

pmlmbigpondcom

G'day All,
As usual, thanks for comments
Certainly helps with decision making
I'll keep on with the poured big ends

Thanks

Phil

Frankvintagefullflowcom

It's true that there are a great many mistakes that can be made in the process of doing the insert conversion and I'm sure Geoff made non of them. It's not a project for anyone or any shop that isn't properly experienced or equipped and I'd agree that it would be an expensive alternative to poured Babbitt if you had to hire it done, and then you would have little control of the outcome. However, I have seen catastrophic results from having them re-Babbitted as well. It's a dying art.

I can't lay claim to a successful conversion since I haven't driven the car enough miles to constitute a true test of the mod but I'll not admit defeat before I'm defeated. Unfortunately, we won't know anywhere in my lifetime, but so far, so good.
I must also admit that I have "resorted to filtering".....just as every automaker on the planet had done decades ago. Granted, it's not as effective in the "Splashies" (I like that term!) due to the nature of that beast, but no one can deny that it's a step in the right direction.
Frank

terraplane8

Frank, how does your system work?

Frankvintagefullflowcom

T-8
Great!
Nothing special here. It simply places a filter in each discharge line from the pump....one front, one rear. I knew I'd need to fend off the naysayers so I did some pretty thorough pump testing before letting anyone know it exists. I'd need to write a book here to explain all and I've already done so in our local chapter newsletter. If you'd care to read any of that I'd be happy to get it to you. As usual (for me) I tend to get pretty windy, so you'll need to set an hour aside to wade through it. None of that material appears on my website since it's not really a part of the Vintage Full Flow project.
It should be noted here that there is no interconnection between front and rear circuits even though it doesn't appear that way in the photos. There must not be any intermingling of those two flow paths!
Frank

terraplane8

Frank, I would like to read exactly what you did please! HETpaloma@slingshot.co.nz, drop the HET.

Thanks in advance.

Frankvintagefullflowcom

T-8,
Will do. If you print it, don't use glossy paper 'cause it's hard to wipe with it.
F

Frankvintagefullflowcom

T-8,
I tried to send info via the email address you gave (less the HET) but it came back as undeliverable. I did a "copy & paste" so it wasn't a typo.
?
Send a note via the "contact" page of the vintagefullflow.com site and I can respond thru that.
Frank

ivanz62

I also would like to read what you have done Frank. My email is ivanz62@comcast.net.
The old school American way to convert was to use Hudson Jet rod bearings in a Hudson 8 and to hard chrome the rod journals to make them tough enough for seven the usually available aluminum bearings we get today. Lead/Indium and Lead/Bronze are getting very hard to find.
Ivan

terraplane8

Frank, thanks will do so. That email box has a small capacity.

Frankvintagefullflowcom

Ivan,
It's getting tough to find Jet bearings these days and they are substantially narrower than the bearing surface yielded by the original poured Babbitt units. I have used a grooved 1.229" width shell that is a steel-backed, copper intermediate layer, Babbitt faced bearing. It yields a width equal to the poured type.
Heat transfer, as Geoff says, is a critical part of the equation in a splash-lube engine. Achieving the correct housing bore diameter for correct bearing crush and a proper housing bore finish are important to a successful retro-fit.
I "enhanced" the grooving to improve oil flow to carry away as much heat as possible....I hope. All of the deep, wide grooves in the world won't improve flow unless the oil has a way out (of course they must be adequate). If you have arrived at a .0005"-.001" vertical clearance or even a bit more, there's little annular space for flow through the bearing. What can't flow out, won't flow in, IMO.
Frank

ivanz62

Insert bearings do not have a fully round inside diameter when properly fitted to a con rod. They are thinner at the parting lined creating the exit that Frank correctly says it required.
Measuring the installed bearing size, one can easily measure the difference. On my Railton racer con rods, to flow more oil through the bearings we have followed Australian Hudson man
Frank Kleinig and Gibson's technique of putting an exit groove on the rod and rod cap next to the bolts. Been working well since 1997 using 5500 RPM at each shift on the race track.

Frankvintagefullflowcom

An exit groove at the parting line was the groove "enhancement" to which I referred. I could see little or no downside to providing a path for additional flow to aid in cooling.
I was curious as to what rods or rod modifications you had used in the Railton, knowing that you routinely pushed it to 6000 ish. Are they stock in all other respects? I added a top oil hole at the gudgeon pin end (like the Jets rods) figuring it certainly couldn't hurt. ?
Frank

pmlmbigpondcom

Hello Ivan
I am interested in how you have gone about this and would appreciate some details
Still leaning towards poured, but always ready to listen to your efforts which seem to have worked
Thanks

phil

ivanz62

Will look for pictures of rod work to post.

Frankvintagefullflowcom

Ivan,
In re-reading your post I see that I misunderstood the nature of the exit groove you have utilized. I simply enlarged the chamfer at the inside edge of each insert where they mate. Of course, to escape, the oil must pass out through the so-created groove and past the thrust face of the rod/cap assy. I judged that there was sufficient clearance between rod thrust face and crank throw to allow some increased flow.
Frank