Laminated main shims...HUH?

[Thorlick]

Rusty, my 1927 roadster pick-up (L.A.F.D. Mountain Patrol Vehicle), decided that he should have a short vacation whilst I was tasked with a bit of maintenance. Yesterday I dropped the pan maintenance cover to investigate a slight knock which suddenly developed in the #1 rod. This deficit of babbit material in #1 is the first time in over 10 years of using my "Horlick Mountain Pan" that such a problem has developed. One might think that I was running low on oil, but I had topped the oil supply immediately before this drive. The drive was a normal daily drive up the hill to Grass Valley California. The last pitch was about 3 miles of significant up grade... nothing much for here, but perhaps the Himalayas to Michiganer.

Here is a photo of the rod ready for replacement. It seems to be using invisible babbit!

Wiped rod

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In the interest of presenting an honest record I took a photo of the Mountain pan. To my shock I realized (note the greasy hand palm print on my forehead) I had for some stupid reason returned Rusty to stock... no Mountain Pan, no Horlick oiler! Well I could smile in looking at Rusty's originality, but I am back to original style wiped bearings. When I reassemble this you can be sure it will have a Horlick Mountain Pan modification in place.

Here's the pan cover ... stock Ford Not the improved Mountain Pan design.

Stock pan cover

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Here is a photo of the Mountain Pan I thought was in there!

Mountain Pan

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Upon looking at my center main bearing I was shocked to see a time bomb in progress:

Main bearing laminated shims

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My usual build involves torquing the mains and then backing off just far enough to insert a cotter pin. I can't believe how the shims have been forced out the side of the main! I will be replacing these shims!

I was absolutely flabbergasted that I would loose a rod with my Mountain Pan, but now find that instead the improved design is not discredited but seems to be indicated more strongly!

IMHO, TH

[George N Lake Ozark]

WOW Terry !! Keep the oiler for sure. As far as caps, I was always told to go tighter and add cotter. I think you're going to be putting your "Mountain Pan" back on.

[George N Lake Ozark]

OH and I don't know what happened to the shims. Interested in finding out.

[Les Schubert]

I like your dip tray modification. Interesting concept


And that is one of the reasons I use Loktite instead of cotter pins in these applications!!

[Thorlick]

Upon further cogitation I remembered (through the haze of time) that last time I had this engine apart to work upon I found that the pan was no longer perfectly straight. Due to my usual T-guy frugality, I chose not to pay to have the pan straightened since I had another straightened pan ready to go. My mistake (well, one of my mistakes) was to forget to swap in the access cover which has my Mountain Pan dips brazed in place. That will be easily rectified.

Clever Horlick Mountain Pan

This is the Mountain Pan. I will just swap this back onto the engine pan now in use. It is only 1/3 of my mountain set-up but is the heart of the system. It is a totally hidden modification which does the most to save you from spinning off rod bearings in the hills... I wish I had left this in my car! You can easily see the secret of this modification; as you go uphill the rear of the dip keeps the the oil from running back to the bell housing. This is very simple and extremely effective!

This is a long slow job... because I don't heat my garage. Since warm weather is on the way this job shouldn't take too long.

TH

[Wayne Sheldon]

I have done something very similar for years, especially on my speedsters, ever since I lost number one rod on an Endurance Run about 25 years ago (steep hill!). Terry does a much nicer job than I generally do. His pan dams are prettier than mine.

That main set of shims is bizarre. Brass shims should not do that unless the bearing cap was loose to the block. A friend of mine was putting a T together in the middle of the night to make it to a run a couple days ahead. He found he had no shims handy, so he cut some out of aluminum soda cans. He told me about it after the fact, and I commented that I didn't think it was a good idea. He did make it to the races, and completed the day. Then afterwards (partly because of my concerns), he pulled the pan cover and found the soft aluminum had beaten out of the rods and mains. He redid the engine with brass shims and drove it for a couple years before he had the engine properly done.

[Scott_Conger]

I would suggest that as far as the engine knew, the bearing was in fact loose. You don't ever want to stretch the bolt and "squash" the shims and then relieve tension...any amount...Nada...zip...never. Tighten until you're happy and then advance enough to install cotter pins. And looking at the bolt heads, they were either not clocked to easily accept cotter pins or have rotated in use.

[Jerry VanOoteghem]

I guess the moral of the story is; when you loosen your main bolts, the shims can fall out.

[Aarongriffey]

I’m with Scott on this one. Never loosen the nut to put the cotter pin in.
Get a box of Chev V8 rod nuts and forget the cotter pins.
The nuts don’t loosen on modern engines.
If you’re worried that they will loosen then put pal nuts on after the nut is tightened or use locktight.

[Erik Barrett]

T main bolts should run 75 ft lb. torque minimum. Tighten up to align pin, never loosen. If this is a problem, swap nuts around to get something that works.

[Wayne Sheldon]

If I can't advance the nut enough to fit the cotter pin? After several times of trying different nuts to only find the same "not quite"? I just remove the nut, carefully file a small amount off the nut bottom, and replace. It does not take much for the nut to advance one twelfth of a turn. Do try to file straight and flat.

[John Warren]

I’m with Scott and Aaron. Never loosen and don’t use cotter pins. I have never had an issue.

[RustyFords]

Get a box of Chev V8 rod nuts and forget the cotter pins.
The nuts don’t loosen on modern engines.

Which Chevy V8....a typical small block 350?

[Ruxstel24]

[quote=Aarongriffey post_id=15980 time=<a href="tel:1552280105">1552280105</a> user_id=1026]
Get a box of Chev V8 rod nuts and forget the cotter pins.
The nuts don’t loosen on modern engines.

Which Chevy V8....a typical small block 350?
[/quote]

They're pretty much all the same...

One of the first lessons I was taught as a kid,
you ALWAYS tighten to find cotter pin holes. We all can see the results of backing off to align.

[Original Smith]

I think laminated shims are great. The problem is they don't make them thin enough to get an accurate adjustment. .003 is too thick to be able to get.0015 clearance.

[Adam]

All the laminated shims I’ve seen in the last 20 years come apart in .002” laminations.

[Thorlick]

They're pretty much all the same...

Dave, are you saying to use the Chevrolet rod nuts on the Model T main bearing bolts or on the Model T rods?

[Ruxstel24]

They're pretty much all the same...

Dave, are you saying to use the Chevrolet rod nuts on the Model T main bearing bolts or on the Model T rods?

The rod cap nuts...
T main bolts are bigger.

[D Stroud]

Use small block Chevy bolts too. They pretty much fit right on. Dave

[Kohnke Rebabbitting]

Model T main shims should come in .032 thousandths thickness, but the people that have them made use the less expensive, .003. I tried to get them to go to .002, but NO.

To use the .003 thousandths, get some .001, and .002 thousandths, sheet stock.

If you are a adjusting a bearing, and the bearing is to loose, take out one shim of .003, on one side ONLY, and try your clearance, if to tight, with .003 out, put in a piece of your .002 shim stock, or a piece of .001 thousandths. Doing it that you can set any bearing at any clearance you want.

Never take out both sides at the same time, unless it is a long way to go. But if you have to take both sides at .003, you are about in the market for new bearings. Most broken Model T cranks come from an out of alignment situations, in the Bearings, Pan, or crank.

When you try to straighten a crank, and use with out grinding, the center main might indicate straight, but there is no way the crank will be straight. It will flex, and will break at some time.

Model T main bolts should be pulled, with OILED Threads, to 80 foot pounds, then pull the Key hole, if, your using Keys, and forget about them.

We have for 55 years, used New lock washers, and pull 80 foot Pounds

Herm.