Camshaft thrust plate

[Andrew1967]

The camshaft thrust plate I’ve bought does not have ‘white
metal’ side to it as per OE, that would normally bolt to the front plate and face the cam. In other words it just looks like a plain metal plate.

Are these ok to use ?

[Dearg1275]

Andrew, I would not want to use a plain steel plate, but are you sure it’s the same material both sides? Scratch it and see if there is a difference in hardness between the sides. The last one I used looked like one material but wasn’t. Where did you get it? You could ask the supplier.

D

[ricardo]

They should have a soft bearing coating on one side, you'll see it if you try to scracth them (near to the bolt holes).

They only fit one way, so its easy to see which one is the thrust side.

[Andrew1967]

Good idea David.

It does look the same material but maybe not as obvious as the OE type.

I’ll check tonight as you suggest.

Thanks also Ricardo

[Andrew1967]

Hmmm, the plate does not have a soft surface and as said, only goes one way round anyway.

I found a very good used one in the garage and will use that but also bought a NOS OE spec one off eBay for the next build.

[whistler]

I've recently bought a new triangle plate from Minispares and both sides look the same. One side has the part number stamped on it.

[Exminiman]

Not something, you would want to take a chance on, notice KAD actually mention the “bearing surface” https://kentautodevelopments.com/produc ... rust-plate
Its two quid more, but cheap insurance....

[Andrew1967]

Not something, you would want to take a chance on, notice KAD actually mention the “bearing surface” https://kentautodevelopments.com/produc ... rust-plate
Its two quid more, but cheap insurance....

...and you can see the bearing surface in that picture which you can't on the one I got that came from the other usual source - not Minispares .

[winabbey]

Out of interest here's the BMC Australia engineering drawing for the camshaft thrust plate. Note the reference to babbitt face.

A simple Google search produced this description.

babbitt metal
/ˈbabɪt ˌmɛt(ə)l/
noun
a soft alloy of tin, antimony, copper, and usually lead, used to line bearings.

AYG0010 Camshaft Locking Plate wm.jpg

[Exminiman]

Out of interest here's the BMC Australia engineering drawing for the camshaft thrust plate. Note the reference to babbitt face.

A simple Google search produced this description.

babbitt metal
/ˈbabɪt ˌmɛt(ə)l/
noun
a soft alloy of tin, antimony, copper, and usually lead, used to line bearings.


AYG0010 Camshaft Locking Plate wm.jpg

Thats useful drawing to keep on file, can check any locking plates are in tolerance..

[agricola]

I have just bought the minispares one. If you look at it sideways you can see a line and thus clearly see the side that has the bearing surface

[bwaminispeed]

You guys do realize that the Cam gear rides against the front of that same plate, steel on steel contact, with no issues whatever.........

I just checked half a dozen of my plates, and, they all have about the same amount of of wear front and back....

Pretty sure using plain steel both sides is a none issue.......

TR6 engines use a very small straight piece of plain steel that engages in a groove around the front cam bearing, it has only about 10% of the contact area of the Mini one, never any issues with that system........

[GraemeC]

It doesn’t generally - the thrust from the angle cut on the cam lobes and the dizzy drive pushes the cam towards the plate, and therefore the gear away from it.

[bwaminispeed]

Yet still, the wear marks are about even on the backs and fronts of most of my plates........

With only 3-5 thou clearance, I'm pretty sure the cam rattles back and forth pretty good giving about equal thrust loads on both sides, not to mention all the harmonic vibrations from the timing chain/gear assembly.......

[Spider]

You guys do realize that the Cam gear rides against the front of that same plate, steel on steel contact, with no issues whatever.........

If the Cam is actually ground correctly, it will only ride on the Cam side of the plate, hence why the factory only had the babbitt on one side only.

[AndyPen]

Cheers - very helpful

[Exminiman]

You guys do realize that the Cam gear rides against the front of that same plate, steel on steel contact, with no issues whatever.........

If the Cam is actually ground correctly, it will only ride on the Cam side of the plate, hence why the factory only had the babbitt on one side only.

Interesting, Spider, do you know what causes the cam to bias to the cam side?

[Spider]

You guys do realize that the Cam gear rides against the front of that same plate, steel on steel contact, with no issues whatever.........

If the Cam is actually ground correctly, it will only ride on the Cam side of the plate, hence why the factory only had the babbitt on one side only.

Interesting, Spider, do you know what causes the cam to bias to the cam side?

The Lobes should have a Taper on them. This is to 'match up' with the radius ground in to the followers. The tapers all go the same way.

Every factory Cam I've checked has this as do those from APT and my own local Cam Grinder. This in part, is what makes the difference between a good and poor cam.

You can always pick these crud grinds as after short use from them having a bur on one side of the cam lobes.

Here's some info from Isky on the subject, with a diagram of a worn or poorly shaped follower.

[agricola]

Spider perhaps the distributor skew gear a little too?

[Spider]

Spider perhaps the distributor skew gear a little too?

I can't see that and the Distributor Drive having must influence here as it's the Valve Spring Pressure on the Cam Followers and then to the Cam Lobe Taper that gives the Cam is Thrust bias.