Case Perimeter Washers

[johnman001]

I have used aluminum washers under steel oblong hole lock nuts in the past. Each time, I end up crushing the aluminum washers that come as part of the "kit" from our host.

Later, I change these out for aluminum washers similar to those that come with valve cover gasket sets.

Has anyone else noticed that the WURTH aluminum washers are softer than those that come with the valve cover kits?

What do you use for the case perimeter washers?

[Flat6pac]

Use the gold steel washers that come in the gasket set along with nyloc nuts or prevailing torque nuts.
Bruce

[Henry Schmidt]

To answer your question: there are different "quality" washers that come from both hardware supplies and in gasket kits.
The Victor Reinz gaskets sets have horrible quality gaskets, seals and washers but they are not the only ones. That is why we only use Wrightwood Racing gasket kits.

I recently purchased 1000 washers from an outside source only to find the quality was unacceptable and filed them in the circular file under "never going to do that again".


BTW: I use wave washers under standard nuts (63-68 alum), aluminum washers under Nylock nuts (Mag case 69-77) and steel washers under prevailing torque nuts (78-98).

[930LDR]

I made the same mistake. Absolutely chewed up the aluminum washers once I torqued the nuts down. Ended up re-doing my seal job and when I did I followed Henry's advice and used steel washers under prevailing torque nuts. Once I had the case split I had to clean the shredded aluminum out of all the threads.

[johnman001]

Does corrosion pose any issues with having steel flat washers right next to the aluminum case? This is why I used the aluminum washers.

The case is sealed, and I will change out the soft aluminum washers one by one. I suppose that the through bolts use steel washers, and these don't seem to cause any problems. Yellow washers it will be.

[JFairman]

You could use stainless steel washers. They'll never rust or corrode against the aluminum case. Most good hardware stores have them.

Take a common 8x1.25mm bolt with you and try the 5/16" and 8mm washers if they have both and get the ones that are cheaper (probably the 5/16") or fit best if there's a difference.

5/16" and 8mm are r e a l close to the same diameter and I've found sometimes generic hardware store 5/16" washers have a little bit smaller hole and fit 8mm bolts nicer than the 8mm washers.

[tadd]

Does no one have any concern for galvanic corrosion with the mag parts?

Aluminum has the lowest potential with the 5xxx series the best with mag.

tadd

[D Miller]

I had the same problem with the soft aluminum washers deforming when assembling my mag case. However, no way was I going to use steel washers due to corrosion issues.

I found some hardened alloy washers at a local aviation supply - part number NAS1149D0563K. I think they may be an imperial size but are a very close or the same as the metric. If you search on-line there are lots of suppliers and they are not that expensive.

These washers do not deform under the specified torque for the perimeter nuts.

[johnman001]

Originally Posted by D Miller

I had the same problem with the soft aluminum washers deforming when assembling my mag case. However, no way was I going to use steel washers due to corrosion issues.

I found some hardened alloy washers at a local aviation supply - part number NAS1149D0563K. I think they may be an imperial size but are a very close or the same as the metric. If you search on-line there are lots of suppliers and they are not that expensive.

These washers do not deform under the specified torque for the perimeter nuts.

This is EXACTLY why I posted this question. I knew that I wasn't the only one.

However, now I am faced with the dilemma in my head. I am concerned with the long term effects of dissimilar material invoked corrosion with this engine. This is why I wanted to use the aluminum washers as the factory did.

I must be insane because I again tried the washers provided in the kit by our host instead of sourcing alternative aluminum washers. I may seek out these aviation aluminum washers.

[Henry Schmidt]

Originally Posted by johnman001

This is EXACTLY why I posted this question. I knew that I wasn't the only one.

However, now I am faced with the dilemma in my head. I am concerned with the long term effects of dissimilar material invoked corrosion with this engine. This is why I wanted to use the aluminum washers as the factory did.

I must be insane because I again tried the washers provided in the kit by our host instead of sourcing alternative aluminum washers. I may seek out these aviation aluminum washers.

Corrosion issues based on washer selection is something I have never seen.

BTW: All 3.2 engines were assemble at the factory with prevailing torque nuts and steel washers.

If you need a source for high quality aluminum washers we have them.

[johnman001]

Henry, are you certain of this? The washers removed from this one and the last one I did were not magnetic and they weren't stainless. They were steel top-lock (or if you prefer prevailing torque) nuts. I'm pretty confident that neither of these had been apart before. I could check a few of the other 3.2's/3.3's in my shop to compare.

Granted, I don't know if the galvanic corrosion gets blown out of proportion here in mid-America, but it can and does.

[Turbo_pro]

Porsche was a very small company back then and they could have done almost anything. That said: prevailing torque nuts should be installed with steel flat washers.
Good luck

[johnman001]

My 1984 3.2, and my 1983 3.3 both have the steel "prevailing torque" lock nuts and ALUMINUM washers. Neither of these engines have been disturbed (yet). The old washers that came off of this engine (1985 3.2) are all aluminum as well. (I haven't thrown them out yet)

[Walt Fricke]

Well, I've always used steel washers on my engine cases, which all have been aluminum, whether sand cast or pressure cast. I have seen zero evidence of galvanic corrosion. After all, no one worries about this with the case through bolts.

The torque you want on the case perimeter bolts is too much for many aluminum washers. They work fine where you are holding covers onto gasketed surfaces and the torque is not high (in my case, I just do valve and chain covers by hand with a short handled ratchet so I don't overtorque.

I've usually used plain nuts, and have never had one loosen. I've used Nylocks because they looked good, or were available. Worked fine also.

But good quality aluminum washers are strong enough for either job, and I am apt to reuse them (after all, these are just my motors, not a customer's). Squishy ones are nothing but a PITA when you want to take something apart. I haven't purchased a gasket set in a long time, as so much of this stuff can be reused without impairing function.

[Henry Schmidt]

Originally Posted by johnman001

My 1984 3.2, and my 1983 3.3 both have the steel "prevailing torque" lock nuts and ALUMINUM washers. Neither of these engines have been disturbed (yet). The old washers that came off of this engine (1985 3.2) are all aluminum as well. (I haven't thrown them out yet)

I guess that is the problem with saying all.
Whatever came with your engine, the best way to assemble a late aluminum case is with prevailing torque nuts and steel washers. This was the latest iteration of assembly technique used by the Porsche factory on air cooled engines.

Now that I've used the word "best" I guess we can debate that.

[Hebster52]

Ok. Old thread but I'll bump this. I have a 2,0L engine numbered 901/03 and case number 18296, sideflange number is *6190536*. Appearantly this is a magnesium case from -69?

So, from this thread I read between the lines that I'm recommended to use the aluminium washers? Do they work with Nylock nuts?

[KTL]

Get a box of 50 ultra coated high strength Grade 8 class 5/16" washers and you don't have to worry about potential crushing of the aluminum washer. Ultra coating is better than zinc

McMaster-Carr Ultra Coated 5/16 Washer

Or get some cad plated Mil Spec washers

McMaster-Carr Cad Plated 5/16 Washer


Or if you really gotta have aluminum alloy, get some fancy gold colored Mil Spec washers

McMaster-Carr Gold Aluminum 5/16 Washer

[Hebster52]

Thanks for that info but still didn't answer my question.

[KTL]

Your question was already answered by Henry. He uses aluminum washers and nylocks (yes this combo works) for mag cases to be "period-correct" so to speak

My point is, uses quality steel washers and they'll last longer since thet can be re-used. Aluminum washers sqish a bit and tend to get rough looking when used over & over again. That said, most don't intend to have the case perimeter washers changed but once.....

[Walt Fricke]

At one time I had it in my head that the proper washers were the thin, wavy steel ones. Then someone pointed me to a parts book for some model, and it showed aluminum washers for that one. So I guess Porsche didn't worry. I use the wavy ones, but have come to realize that the wavy part doesn't help (just doesn't hurt) anything. So any decent steel one should be fine.

I think that Nylocks may not have been the period correct nut for early cases. I don't think they are needed. I've not had a case perimeter nut come loose, and, unlike the valve cover studs, none of the case perimeter studs have an oil surface touching their bottoms so that oil could wick up the threads.

And I don't like the idea of aluminum washers for the reasons Kevin notes (reuse), and additionally I fret that perhaps they make achieving enough torque more chancy, or perhaps they may creep or relax over time.

With valve covers, the nylocks not only may reduce wicked oil, but they mean that a proper torque is less critical, and if you are a bit low the nut isn't going to vibrate off. And the valve covers don't require much torque to hold them on, as they are not mechanically stressed, whereas the case bolts have to deal with the boxer forces trying to push the halves apart (sort of - through bolts do most of that). I never bother with torque with the valve covers, just hand tightening.