Engine mounting shim

Now that we have had the ultimate thread on isolastic rubbers and the Hemmings vernier adjusters, how about the "engine mounting shim" as it is called in my spares book. Part 06-0578 listed as polyurethane 1/16". I have seen several variations on this shim. Fair Spares calles it "HARD NYLON FRICTION WASHER (EACH) NOT PTFE", britishonly as "WASHER,THRUST,PTFE,BRONZE", and OldBrits as "Isolastic PTFE Washer". Walridge lists 2, "the genuine PTFE side play washers we also offer a nylon variety made for Norvil in the UK. These seem to withstand very cold temperatures experienced in Canada and the Northern USA better than the PTFE type." Fair Spares and Britishonly uses part 06-4748, OldBrits uses 06-0578, and Walridge uses 06-3556. Prices vary from US$7.50 to over $13 each, 4 required, front and rear same size. I have not seen any listed as a polyurethane washer.

Just for info, PTFE(polytetrafluoroethylene) is also known by the DuPont brand name of Teflon. My experience with this is it is a rather soft but very slippery, I think it would wear very fast. I know it is used for the pickoff guide next to the pickoff belts in the automated Siemens mail sorting machines by the USPS. We used to replace them probably once a week, having been through probably over a million pieces of mail. The nylon I have no experience with, and the Bronze one, is it coated or what, again no experience with it? I have had some experience with Delrin (another DuPont brand name for Polyoxymethylene), and as I remember it, it was as slippery as Teflon but much harder. Wikipedia list it as "an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability." I would think Delrin would be a good substance to use for this washer, but have not seen it for sale. Perhaps it is very expensive.

Can anyone share their experiences with any of these shims or washers whichever you like to call them? I, for one, am waiting to find out the advantages and disadvantages of them before buying.

I see that Acetal Delrin Sheet is available from eplastics.com for $11.70 for a 12"x12"x.060" sheet plus $8 shipping, that ends up being about $4.50/washer. That should more than enough to make 4 shims. I very well may try it. They list its properties as "APPLICATIONS & USES: Used as spacers & gears, washers, handles, wheels, bearings. Anything where high wear is needed!" But then I found this at k-mac-plastics.net "Acetal, has dimensional stability, lower moisture acetalorption, and easier machinability than nylon, but is not as good in slide wear." so maybe nylon is better. Nylon sheet at eplastics is $9.25 for a 12x12x.060 sheet, even better price. It shouldn't be hard to fabricate 4 washers from a sheet.

I hope I have not bored everyone to tears.

Dave
69 S project

The original shims were a polyurethane type, as you have noted from your parts book (however, the 060578 part number is now obsolete).

The polyurethane washers were superseded by 063556, now 064748 which is the recommended replacement part for all models, according to the Andover Norton website parts list?:

http://www.nortonmotors.de/ANIL/Norton% ... 09&Part=44
Item: ISO WASHER Part Number: 063556 (USE 064748)

DogT said:

Fair Spares and Britishonly uses part 06-4748, OldBrits uses 06-0578, and Walridge uses 06-3556. Prices vary from US$7.50 to over $13 each, 4 required, front and rear same size. I have not seen any listed as a polyurethane washer.

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No doubt there are still reasonable stocks of bronze PTFE washers available, but it looks as if the Nylon type will eventually replace them? And the old polyurethane washers would not have been generally available for quite some time, I think?

Great. Simple answer to a convoluted question. Thanks, I think Phil has the best deal at $7.50 ea for the norvil nylon ones.

Dave

DogT said:

I hope I have not bored everyone to tears.

Dave
69 S project

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Not at all boring. Anytime us Norton owners can see a comparison of parts and prices that we all need we all ears (or should I say "we are all eye balls" here on the net)!

I'm considering buying some sheets. I hate not having parts readily available and having to wait for delivery of parts coming 1/2 way around the world. I don't mind ordering a big bunch of parts but when you really are just stuck for these small items having to ship them in is a hassle.

Renniek,
Thanks
Dave

Dave,
I made a set of shims from Acetal w/Tefon and they work great. They are hard and seem to be indestructable. They were cut out from 1/8" sheet, thicker than the stock shims so you'd have to be using MkIII or Hemmings adjusters to get away with it, and I still had to turn the collars down some if I recall. Here's a pic, it doesn't photograph well. Got it from MSC, their new # is 63386213. If you'd like I can send you some. You too Renniek.

I see MSC has nylon sheets in 1/16" p/n 63396741 for $5.68 12"x12". I will either try that or get Phils nylon shims.

Thanks though,
Dave

The polyurethane washers were superseded by the bronze impregnated PTFE 063556 type, which have been superseded by the Norvil Nylon 064748 type washer which is now the recommended replacement part for all models, according to the Andover Norton website parts list?:

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Les, are you sure the Andover P/N 064748 is not just an updated number for the bronze impregnated PTFE? I have never seen a genuine Norton washer made from nylon.

I have pulled many of the early polyurethane (polypropylene?) washers out of isolastics in pieces or dust. The bronze impregnated PTFE's seem to last a long, long time. I would agree that without the bronze powder, PTFE would be pounded out of shape.

I'm sure the proper nylon or the Delrin would work if you wanted to make your own, but I have found the bronze/PTFE's easy to find and not that expensive.

Ron

Nylon or Delrin will not last.

Ron L said:

Les, are you sure the Andover P/N 064748 is not just an updated number for the bronze impregnated PTFE? I have never seen a genuine Norton washer made from nylon.

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Ron,

Logically, I don't see why Andover Norton would bother changing the washer's part number - unless a significant change had been made to the part, thus making it necessary to identify the new part from the earlier part?
I was also unaware that Andover Norton had changed the Isolastic washer part number - until this topic, so the change couldn't have happened all that long ago? As you say, the bronze PTFE washers normally last a long time?
However I do know that Norvil has been selling (and recommending) the nylon washers as: "064748, WASHER - NYLON - FITS FRONT OR REAR - REPLACES PTFE TYPE" which has been listed as such in their older parts catalogues alongside the bronze PTFE washers, right up to their latest version catalogue.

Flo said:

Nylon or Delrin will not last.

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Nylon, probably not.

Delrin? Really. Why not?

A decent headsteady will greatly reduce the wear of these washers .

Maybe it will, but I woudn't even bother trying it myself. Machined shims from PTFE & Nylon & both wore out quickly, Delrin doesn't inspire me, having machined that as well. Soft.

Flo,
So you are recommending the bronze impregnated PTFE? There are some new materials out there like Delrin (Acetal) with impregnated teflon also. I'm sure the plastic engineers would have many a field day with this subject.

Dave

Personally, maybe yes, the bronze impregnated ones. Sorry to be vague, but having experimented years ago on this, the straight plasticky materials did not last.

Hmmm... This 064748 part number gets curioser and curioser. It only appears in the '75 parts book. I have taken apart at least a half dozen Mk3's and always have found bronze/PTFE washers. In fact, I have an NOS Mk3 front mount assembly on the shelf that is complete with end caps and through bolt and it has bronze/PTFE washers. (Of course, this assembly may have been put together from dealer parts years ago).

The Andover site refers all pre-'75 models to use 064748, but when you look up the 1975 model part number 064748 it says "ISO. PTFE WASHER 06.3556"!! (That's why I asked the question, Les). But as you say why bother with a new part number?

Grand Paul, you seem to have done a considerable amount of work with Mk3's in the last couple years, did any of them have anything other than a bronze/PTFE washer? Has anyone found a non-bronze/PTFE washer in original Mk3 isos?

I suspect that as both Flo and Swooshdave point out, Nylon (both 4,6 and 6,6) are somewhat softer than the Bronze/PTFE, so why would Norton go backwards?

I wonder if Les Emery has not created the Nylon washers as a less expensive/more profitable version? I know that here in the States, DomiRacer has sold a version that I suspect is polypropylene (definitely not polyurethane or nylon) and are readily identifiable as a black pigmented disc. These last a short while before before self-destructing.

This is all just my curiosity as regardless I will continue to use the bronze/PTFE washers since I have no skills nor desire to make my own and I will purchase what I know will work.

Flo said:

Maybe it will, but I woudn't even bother trying it myself. Machined shims from PTFE & Nylon & both wore out quickly, Delrin doesn't inspire me, having machined that as well. Soft.

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UHMW

Used some machined blocks of this to lower the leaf spring on my car.

It wasn't Delrin I was thinking of before. I had some suspension bushings for my TR-4 way back when. They were white, rock hard and self-lubricating. I can't think of the name of the material now. I want to say it started with "C". DId I mention this was a LONG time ago, maybe 20 years?

Maybe one of the listers in the UK could give Norvil a call and ask Les about 064748?
Regarding PTFE/Bronze or Polyurethane washers, which is the one that you can fold like a soft taco, and probably leave teeth marks in if you were so inclined?

Bit late but got a bit of information from the nice people at Andover Norton

"06.4748 replaces all other part numbers of isolastic thrust washer. The
material is a resilient fibre encased in a thin cover of PTFE and contains
60% bronze. Various other materials have been used previously but 06.4748
has been the washer of choice since 1974 when it superseded 06.3556. The
material specification for 06.3556 is the same but the hole in the centre is
.030" smaller."

Think this pretty well clears things up.

Rich_j said:

Think this pretty well clears things up.

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Thanks Rich_j.

That sort-of clears things up a bit.

So presumably, Andover Norton have actually been supplying the 06-4748 washers in place of the 06-3556 type for years?

In that case, what Norvil lists as the "06-3556" washer could very well be the 06-4748 item, therefore their "06-4748 nylon washer" isn't an Andover Norton part at all! :?