Elephant foot tappets

Back to the original question...Where did he come up with the elephant's foot adjusters?

Seattle##gs and Fast Eddie

Unfortunately these are hand made custom items Its well thought out technology borrowed from some speedway engine gurus and adapted by a Norton enthusiast with success.

"Tappets are from Andover. De-hardened - ends reshaped using an R3 toolbit - rehardened in warm peanutoil - annealed 2hours 220°C - 'ball' polished.

Feet' are homemade with bottom of cups done with an R3 Toolbit - lapped, polished and DLC coated etc."

That’s a LOT of work Jim! I’d be interested to know if the guy has any real data / evidence regarding the problem he is trying to fix and the benefits of his solution ?

Regarding off the shelf parts, IIRC the common ones folk play with are from Rotax and VW and Mercedes.

I think the VW and Mercedes ones are the same part?

Altering threads is required amongst other faffing around.

^^^ £65.50 wow !

Land Rover ones are only £1.69 each ( BSF thread ) sold singly

Grandad said:

^^^ £65.50 wow !

Land Rover ones are only £1.69 each ( BSF thread ) sold singly

Search Result | John Craddock Ltd

Search results from our catalog of Land Rover and Range Rover parts and accessories

www.johncraddockltd.co.uk

Click to expand...

Come on, they are only £8.19 each!

Why not just use valves with hardened stellite tips like the KPMIs. Cheap and easy to get.

Fast Eddie said:

That’s a LOT of work Jim! I’d be interested to know if the guy has any real data / evidence regarding the problem he is trying to fix and the benefits of his solution ?

Regarding off the shelf parts, IIRC the common ones folk play with are from Rotax and VW and Mercedes.

I think the VW and Mercedes ones are the same part?

Altering threads is required amongst other faffing around.

8mm Elephant Foot Valve Adjusting Screw Set (Tappet) - Type 1 Engines

CB Performance heavy duty Elephant feet adjusters feature a large foor print that covers the valve stem to reduce the chance of mushrooming

www.coolairvw.co.uk

Click to expand...

Imagine trying to tap new threads into the hardened rocker.
The custom ones pictured have the advantage that they are short and can be installed easily with little height difference.
I give the guy an A+ for ingenuity.

Is there anybody that could custom make them for a reasonable price?

seattle##gs said:

Imagine trying to tap new threads into the hardened rocker.
The custom ones pictured have the advantage that they are short and can be installed easily with little height difference.
I give the guy an A+ for ingenuity.

Click to expand...

I certainly agree with the A+ !

But even as someone who has messed with these before, nowadays I am personally of the opinion that hard stemmed valves, or lash caps, just work.

Yes they might seem more crude, less elegant, etc, but they seem to work just fine.

I’m not trying to dissuade anyone else from playing with such projects, just explaining why I don’t (anymore).

I laid out what's happening with the stock tappets (see image). Stock tappets have an approx 9.5mm radius which is just about right (but I would prefer 20mm). The mushroom tappets have a much broader radius but some on this forum have reported breakage at the edges (I personally have no experience to report about mushroom tappets and some may be thicker and stronger at the edges). During rocker arm rotation - the contact point moves all the way from one side of the valve tip to the other because of the wider radius of the mushroom tappet tip and this puts stress on the outside edge of the mushroom.

From my study I found that the center point of the tappet tip slides about .015" on the intake valve tip and about .018" on the ex valve tip. But the wear point also moves from one side of the tappet tip to the other as the tappet tip rotates along with the rocker arm and this is why you have a longer witness mark (but not all the way from one edge of the valve tip to the other).

My experience lash caps has been very good. Hard valve tip surfaces do just about as well.

Does anyone know the actual tip radius of the mushroom tappets?

Below:
the curved red lines are the radiused surface positions of a stock tappet tip when on the seat and at 1/2 lift and also at full lift. The top green line is the valve tip when the valve is on its seat, middle green line is at 1/2 lift and bottom green line is lift at .400"

Just found out that mushoom tappets have an 11mm radius. Stock is 9.5mm See image above.

I haven't found many off-the-shelf Norton valves (other than Black Diamonds) that come with hardened tips. Just bought stock 650 valves from RGM, and I don't think they have hard tips, can't see a parting line. A couple years back, a guy with 650 replacement valves posted he had wear issues, I think even with mushroom tappets.

Therefore will probably run the JSM lashcaps on mine, if they'll fit a stock retainer. That way, the wearing part becomes easily replaceable.

The parts house UK-made valves are just rebuilder valves, no stem coating treatment, no hardenned tip. Designed with planned obselesence in mind, not to be any better.

I believe only Maney stocked hardenned UK-made Norton valves.

I've been using mushroom head tappets with black diamond valves with great success. No wear at all on the valve tips and I put many miles on the engine which is now down for a rebuild.
There are two types of mushroom head tappets that I have found. One type is thinner at the mushroom head and slotted for a flat screwdriver to make adjustments. The other that I purchased was from BCS which has a copper coating and has an Allen key adjuster top. This has the thicker mushroom head (more meat). I think Comnoz mentioned that he had problems with breaking the edges of the mushroom head on the thinner type. Not sure if it was a bad batch or type of cam used, but mine went on for 80K miles before the rebuild.

these two types:

I put many many miles on my MKIII, commuting and road trips. I found that the caps wore considerably less than the valve-stem tips.

elefantrider said:

I haven't found many off-the-shelf Norton valves (other than Black Diamonds) that come with hardened tips. Just bought stock 650 valves from RGM, and I don't think they have hard tips, can't see a parting line. A couple years back, a guy with 650 replacement valves posted he had wear issues, I think even with mushroom tappets.

Therefore will probably run the JSM lashcaps on mine, if they'll fit a stock retainer. That way, the wearing part becomes easily replaceable.

The parts house UK-made valves are just rebuilder valves, no stem coating treatment, no hardenned tip. Designed with planned obselesence in mind, not to be any better.

I believe only Maney stocked hardenned UK-made Norton valves.

Click to expand...

The lash caps seem to be made of harder material and show very little wear. The Maney valves are made by GS valves, They have hardened tips and thats what I use for my big valves.

CanukNortonNut said:

Elephant foot ???? So what is the advantage?

Click to expand...

There are several advantages.
* No side thrust at valve guides. Particularly guides made of bronze wears due to side thrust. Valves will increasingly rattle in the guides, accelerating wear at both valve and valve guide further. If wear gets really bad, the valve's sealing will be affected.
* It's an incomprehension assuming hardened valve tips will prevent tappets digging in. Valves with hardened stem tips will still wear, though they should resist it significantly better than untreated tips.
* Friction between tappet and valve tip translates to resistance in the valve train, which means (additional) wear at the cam follower and camshaft lobe. The elephant foot tappet eliminates this factor.
* No need to maintain the valve to tappet clearance, contrary to the original design.
* Less noisy valve gear.

I think the Elephant foot tappet is an excellent invention (used by Porsche and VW, also by MB and Ferrari apparently, and pioneered by Dave Madigan on Triumph triples). Rejecting the idea because of convenience is a personal choice of course, but shouldn't clutter the discussion and prevent a serious test. The original German swivel foot tappets had M8x1 threads while Norton rockers have 9/32-26 TPI CEI threads, which means a custom EF tappet has to be fabricated. One has to set up the angle of these adjusters correctly, as the original swivel foot tappets have about 25 degrees of range. This may require an alteration to pushrod lengths.

I hope Jim's customer will add first hand experience.

- Knut

Image:

mdt-son said:

There are several advantages.
* No side thrust at valve guides. Particularly guides made of bronze wears due to side thrust. Valves will increasingly rattle in the guides, accelerating wear at both valve and valve guide further. If wear gets really bad, the valve's sealing will be affected.
* It's an incomprehension assuming hardened valve tips will prevent tappets digging in. Valves with hardened stem tips will still wear, though they should resist it significantly better than untreated tips.
* Friction between tappet and valve tip translates to resistance in the valve train, which means (additional) wear at the cam follower and camshaft lobe. The elephant foot tappet eliminates this factor.
* No need to maintain the valve to tappet clearance, contrary to the original design.
* Less noisy valve gear.

I think the Elephant foot tappet is an excellent invention (used by Porsche and VW, also by MB apparently, and pioneered by Dave Madigan on Triumph triples). Rejecting the idea because of convenience is a personal choice of course, but shouldn't clutter the discussion and prevent a serious test. The original German swivel foot tappets had M8x1 threads while Norton rockers have 9/32-26 TPI CEI threads, which means a custom EF tappet has to be fabricated. One has to set up the angle of these adjusters correctly, as the original swivel foot tappets have about 25 degrees of range. This may require an alteration to pushrod lengths.

I hope Jim's customer will add first hand experience.

- Knut

Image:

Einstellschraube Kipphebel für PORSCHE 911 SC 930 964 Einlass/Auslass Ventil 4251750544436 | eBay.de

Entdecke Einstellschraube Kipphebel für PORSCHE 911 SC 930 964 Einlass/Auslass Ventil in großer Auswahl ✓ Vergleichen Angebote und Preise ✓ Online kaufen bei eBay.de ✓ Kostenlose Lieferung für viele Artikel!

www.ebay.de

Click to expand...

Regarding their use in Triumph's, Dave Degens was playing with these long before Dave Madigan. So were Triumph as it happens, Tridents had a similar arrangement using a captured ball with a flat that sat on the valve stem. A problem with the Trident design (and some of the others IIRC) was that big, long duration race cams we used in the twins had a range of motion greater than they were designed for.

Degens final version was to use Rotax parts and machine off the threads so you were left with a small diameter shaft / pin, then make adjusters of the correct thread, bore them, and press in the modified Rotax elephants foot.

In fact, I just had a rummage and discovered I still have some !

Fast Eddie said:

Regarding their use in Triumph's, Dave Degens was playing with these long before Dave Madigan. So were Triumph as it happens, Tridents had a similar arrangement using a captured ball with a flat that sat on the valve stem. A problem with the Trident design (and some of the others IIRC) was that big, long duration race cams we used in the twins had a range of motion greater than they were designed for.

Degens final version was to use Rotax parts and machine off the threads so you were left with a small diameter shaft / pin, then make adjusters of the correct thread, bore them, and press in the modified Rotax elephants foot.

In fact, I just had a rummage and discovered I still have some !

View attachment 121131View attachment 121132

Click to expand...

I wonder if it's possible to use the T160 captive ball type on a Norton then?
In the triple world, owners are not 100% positive about them, there are reports of the ball moving when adjusting the tappets, so that the clearance ends up as far too much, and some report cracking on the cup.

SteveBorland said:

I wonder if it's possible to use the T160 captive ball type on a Norton then?
In the triple world, owners are not 100% positive about them, there are reports of the ball moving when adjusting the tappets, so that the clearance ends up as far too much, and some report cracking on the cup.

Click to expand...

Yes, just had a discussion with a renowned t160 owner (Tom Mellor...world record holder at Bonneville on his t160 powered streamliner). He was lamenting a loss of compression on one of his road going Tridents, stating he found some of the captive ball tappets had likely rotated out of position not letting the valve fully close. He planned to swap out for a valve stem cap arrangement.

Tornado said:

Yes, just had a discussion with a renowned t160 owner (Tom Mellor...world record holder at Bonneville on his t160 powered streamliner). He was lamenting a loss of compression on one of his road going Tridents, stating he found some of the captive ball tappets had likely rotated out of position not letting the valve fully close. He planned to swap out for a valve stem cap arrangement.

Click to expand...

Yes I think that’s pretty much the consensus, those capture ball tappets were / are the first things to go when tuning a tripe AFAIK.