Custom Lifters

Hi there,

I need 4 (four) custom lifters made for a 1930s motorcycle I'm restoring. More is fine for cost benefits. The two I have are badly pitted and in rough shape and I need two more. I can provide a drawing if needed of overall dimensions as well as the samples I have, one full and one cut open. I'm not sure how they were originally made but they appear to have been casted, ground and then hardened. At least that's what the internal geometry leads me to believe. Otherwise, the cam surface has been welded on and then obviously the whole lifter finished-machined and hardened? The lifter is hollow with a wall thickness of 2mm all around. The outside diameter is 25mm. I have new adjustment screws so I just need the body.

Anyways, I don't know anything about lifter technology and so I was wondering if these can be made alternatively by just machining and then hardening. I don't know how weight affects performance or operation so I'm not sure how to proceed but my alternative thought to casting is to just drill out the center to the hole tap size leaving a slightly heavier lifter.

I included some pics. Thanks for any help

The weight of the lifter and how it'll affect operation all depends on the valve spring stiffness and the velocity of the lifter as it opens and closes via the cam and it's rpm. Chances are you don't want it much heavier than the original if you can avoid it.

Bmw 494? R11?

Any reason you couldn't have these hard plated in the necessary spots and reground?

Edit: How bad are they pitted? Does it change them dimensionally?

mdshunk said:

Bmw 494? R11?

Any reason you couldn't have these hard plated in the necessary spots and reground?

Edit: How bad are they pitted? Does it change them dimensionally?

Click to expand...

It is a BMW R11. The problem is I only have 2 of 4 lifters and I've been looking for over 2 years to find them. If I find 2 more then I would have them hard chromed and ground.

contact some one like APT that does semi custom and custom performance parts.
they make some odd ball lifters or tappets.
it will cost you unless they already make one wouldn't be surprised if they were $100 to $200 per

they need to be roughed out on a lathe then ground to size and finish then case hardened really hard
the face that rides on the cam has to very hard to hold up.

some one has probably made some check the BMW forums see if you can find the factory specs

anyone could make these, not sure what material they are made from, but i bet they are softer than the cam.

72bwhite said:

contact some one like ATP that does semi custom and custom performance parts.
they make some odd ball lifters or tappets.
it will cost you unless they already make one wouldn't be surprised if they were $100 to $200 per

they need to be roughed out on a lathe then ground to size and finish then case hardened really hard
the face that rides on the cam has to very hard to hold up.

some one has probably made some check the BMW forums see if you can find the factory specs

Click to expand...

72bwhite said:

contact some one like ATP that does semi custom and custom performance parts.
they make some odd ball lifters or tappets.
it will cost you unless they already make one wouldn't be surprised if they were $100 to $200 per

they need to be roughed out on a lathe then ground to size and finish then case hardened really hard
the face that rides on the cam has to very hard to hold up.

some one has probably made some check the BMW forums see if you can find the factory specs

Click to expand...

Unfortunately, no has made these and there are no factory specs to reference. I talk regularly with guys who have the same engines and no one knows the specs. It amazes me honestly. Obviously people work on bikes this age but no one keeps detailed notes.

pull out the good lifter, and measure the specs, then you will have the specs, do many other BMW motorcyclists need these lifters made?

dBDawg said:

Unfortunately, no has made these and there are no factory specs to reference. I talk regularly with guys who have the same engines and no one knows the specs. It amazes me honestly. Obviously people work on bikes this age but no one keeps detailed notes.

Click to expand...

It is not likely going to be high rpm or a daily driver and the materials of the day were not of today...

So one should be able to fashion one from some drop material and call it good.

It needs to be softer than the cam as that is not replaceable and should be able to resist wear.

Looks to be a simple part that can be easily made to close enough.

Hard part is final fit to a likely worn hole that is not to size and each may be different.

But given low rpm and maybe low expected running hours that may not be critical.

This looks like lawnmower duty not race duty...

Can Do PM sent
spaeth

Based on some old time automotive knowledge, keep in mind that the big face of the lifter may have a slight crown to it, that also may be offset fron the centerline, so the lifter will slowly rotate.

The amount of valve spring tension on the valve/lifter is going to influence hardness specs on the lifter and cam lobe faces.

Have the surface that runs on the cam of one of the lifters you have hardness tested.
that will give an idea of range you need to be hardness wise.

funny thing rub 2 soft parts together and you get galling make one of the hard
add a little oil and they stop galling and don't wear as bad.

the material is most likely chilled iron might be phosphate coated or not.

if the large diameter section is hallow the it's probably made in 2 parts.

keep in mind those were low production parts compared to say a model A Ford
so they would use tighter tolerances and some times more complex manufacturing methods
not like a lawn mower engine more a fairly high performance engine for it's time.
50 to 60 Rockwell Rc wouldn't be a huge surprise.

depends on how long you want to be able to run the engine also
a piece of 1018 turned to shape case hardened with something like cheery red
would hold up for a little while.

the material wont be an exotic could be iron or a carbon steel

Dave5605 hit on a very good point that the flat probably isn't really flat
it looks like a simple part but the devil is in the details.
defiantly can be done but it's not a 1 hour job either

dave5605 said:

Based on some old time automotive knowledge, keep in mind that the big face of the lifter may have a slight crown to it, that also may be offset fron the centerline, so the lifter will slowly rotate.

The amount of valve spring tension on the valve/lifter is going to influence hardness specs on the lifter and cam lobe faces.

Click to expand...

I've been told the cam grinder wheel has a slight angle dressed on the face of the wheel, making one side of the cam lobe slightly higher than the other; this is what makes the lifter rotate. Anyone else know anything about this?

I haven't made a lifter, but i can share a few things. Yours may be made of chilled iron, that's cast iron that is cooled quickly resulting in a hard surface. That will be hard to make in small quantity. Working on flathead fords taught me that they need the lifters to be at least 55RC hardness. Your motor has similar spring loads and speeds so the parameters needed are probably comparable. Flat tappets are crowned slightly and the cam lobes are tapered slightly to rotate the lifters in operation, at least during break-in. The ford spec for the crown is 96" radius, that's only about .0002" on a 1" lifter. We're not sure Ford had an accurate method to create that radius or to measure it. At any rate, I'm told some manufacturers just grind a taper on the face instead of a crown. In theory that may be better because the contact between a radius and a taper is a point, while the contact between two tapers is a line, and a line has lower contact load, inspecting your cam lobes may shed some light on what would be appropriate to use on the lifters.

If I had to make those lifters I'd probably make them in 2 pieces, I'd make the lower half of the body out of a tool steel that can be easily hardened and was pretty stable during heat treat, others here are better experienced in that area of material choice. I don't think material strength is going to be an issue, just the hardness. I'd make that lower body like a cup open at the top, then make the top half press fit into the cup, then grind the body after assembly.

There are custom cam grinders around the country who will resurface lifters, one of them can put the crown/taper on the face of your new lifters if the shop that makes them for you can't do it. Here's one grinder I've heard of who will do that - Delta Camshaft

You can stop by a supply house with a square and check the bottom of the lifter.

Ran a cam grinder many years ago for a very short time and they do angle the wheel so the face of the cam is angled to cause lifter to spin.

But the engine in question was built way back when these things were still being worked out.

One could look at the wear pattern on existing parts to see if they indicate any tapers.

I can't help but to wonder if the minor pitting you can visually see might actually be beneficial in terms of oil retention at the cam/lifter interface. I might be full of crap, but I still wonder that.

Couple other things come to mind.
Keep the weight equal to, or less than the original lifter. As the weight of the lifter goes up it will have more of a tendency to float at higher (whatever higher is) rpm. The lifter banging into the cam won't be a good thing.

Also the lifter appears to be (should be?)adjustable so you need some kind of 'locker' for the adjustable part.

Lastly, the end that interfaces to the valve stem will need some compatible hardening too.

Is the part clean and able to be 3d scanned? Can the part be machined from the reverse model? Meaning there isn't any complicated surfaces that have tight tolerances? If you need it reverse engineered, we can do that.

Where the idea comes from that they don't need to be hard baffles me, my old Norton had stellite faces on the lifters? Automotive lifters were flat on the bottom and ride on a lobe that had a slight angle that rotates the lifter as it turns. Now it seems the norm is to have rollers on the lifters and sometimes the rocker arms. The technology changed a lot as engines developed and many things were tried; It seems smart to thoroughly check those parts and try to replicate them exactly as best possible.
Dan

Lifters do have a convex surface to rotate the lifter in the bore to help reduce friction and keep the lifter from wearing in one place only.

The camshaft lobe is hardened and is ground. If you put a lifter back on the wrong lobe and not the one it came off it is used your asking for trouble.

They develop very specific wear patterns for each lobe lifter set.

New lifters on an old cam is a bad idea.

The lifters can eventually wear concave and still work if they are on their original lobe.

The better idea is to bush the lifter bore and grind that lifter to fit the new bore for the lobe it came from.

It will still not match up perfectly like it was but if you do your best to do so it will likely last longer.

If you have lost a lifter or something and cant get a replacement I can likely help you out by modifying an existing lifter rather than making a new one because of the carefully ground convex surface and hardness

But a new lifter on a very old worn cam wont last a long time.

If it just needs to run once in a while that's not a big deal.