Diapering Head Washer Mystery?

[bobswei]

I'm rebuilding my 2.4 T engine and went to bolt on the heads today. I discovered, I'm missing one head bolt washer. I will do another search tomorrow but, if I don't find it. Can I use a standard washer? The head surface is flat and the barrel nut is flat so I can't see a logical reason why you need the thicker washer. But someone out there may know the answer?
Thanks.

[billybek]

I would use the proper thickness of washer designed for the job.

I would also stop putting diapers on my head stud washers....

[Walt Fricke]

I believe the Porsche washers are a harder steel than what you are apt to find in a hardware store. And thicker as well. I'm with Bill on this one.

On the other hand, since you are rebuilding the motor, I'd just use the best I could find for now, and replace with the right washer when I found the elusive one or got a replacement from some source. You can probably get one easily enough before you take the engine off the stand. Just don't use the valve cover gasket over this stud. You can replace the fake washer easily enough with the motor together.

[bobswei]

Thanks for the responses. First, I couldn't figure out what was meant by "diapering a washer". Then I realized, I can't spell disappearing and grabbed the first word spell checker came up with.
But, yea, I was going to get an original before I added more parts to the lump. Just not easy to find in a short amount of time. But it makes sense about the hardness since I'm torquing these at tedium. Thanks again......

[DRACO A5OG]

Well, if you can use one off of a 3.2 engine, PM and I will send you one of my old one, gratis. I am getting all new ARP sets for my rebuild.

Measure yours and I will check mine,

Jim

[Rawknees'Turbo]

Originally Posted by DRACO A5OG

Measure yours and I will check mine,

Jim

Freaky freakazoids in the Engine Building forum - nice!!!

[DRACO A5OG]

Originally Posted by Rawknees'Turbo

Freaky freakazoids in the Engine Building forum - nice!!!

You Crazy

[Flat6pac]

The 3.2 washers won't work.
Bruce

[prschmn]

If you can find a grade 8 washer with a small enough OD it will be strong enough not to distort
with the torque.

[Tippy]

Originally Posted by prschmn

If you can find a grade 8 washer with a small enough OD it will be strong enough not to distort
with the torque.

Ditto

[cgarr]

You sure you got them all out when pulled? I see a lot of heads come in with washers stuck down in the head that really need to be worked out:

Here are the different sizes. Just got one in today with a set of heads from one of our esteemed contributors.

If you need one I can toss it in the mail tomorrow.

[bobswei]

I like the idea of a grade 8 washer but looks like I may have a OE solution.
The heads were cleaned and bead blasted so no chance of a washer stuck down in there. I even checked all the nut heights, in case I put two on one stud. Nope. I arranged the nuts and washers in sets of four and did one head at a time.
PM on it's way....
Thanks for all the responses.

[chris_seven]

Are you guys sure that a 'punched' standard flat washer to DIN 125 (ISO 7089) or its equivalent is flat enough for this application?

Punched washers typically have a flatness specification (MS15795) of 0.005" for outside diameters up to 0.875" and 0.010" for outside diameters above this value which is not great but I could agree that most washers are better than this but in the limit they could be quite poor.

I think that factory washers are both thicker and made to a better flatness tolerance than punched washers.

I do realise that it is possible to buy Grade 8 washers as extra thick but are they flat enough?

The flatness of a washer does affect the frictional characteristics of the nut and this can lead to changes in preload which influence tightness and also increase the susceptibility to loosening due to vibration.

When the early small diameter washers became obsolete we started CNC machining and grinding our own washers from 17-4PH stainless steel, hardening them to 45HRC and then grinding flat on both sides.

We also make the larger sizes for the later engines and have been using them for seven years without any issues.

[bobswei]

OK, chris_seven sounds like a pretty logical answer. It does seem like washers have a top and bottom where the top has slightly rounded edges and bottom, more of a sharper edge. I guess from punching. So, would make sense it would flatten more under torque, (to put it in my simple terms). But, I do have the correct washer on the way, thanks to "cgarr" so I'm focusing on the opposite cylinder bank till it arrives.
Thanks for the responses.

[Fast Freddy 944]

Originally Posted by billybek

I would use the proper thickness of washer designed for the job.

I would also stop putting diapers on my head stud washers....

LOL! Yah I was wondering about putting diapers on my cyl head!