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I have been mounting my intake/exhaust manifold. I have some of the brass lock nuts but need to find more of them or find the stainless steel ones that Wes said he uses.
I would assume that the brass ones don't need anti seize but should they have a brass flat washer under the nut.
If I can't find any of the brass lock nuts and use the stainless ones do they need a flat washer and should anti seize be used.
Thanks

If I remember SNL only lists the brass self locking nuts - I got mine from Brent Mullens. Check eBay he lists there from time to time...

MWM has them too. <Can't believe I beat John to that!>

Kind of pricey either way, especially because I've been told they can't (shouldn't) be used more than once. Haven't been able to find them anywhere else at any price.

No washers on the brass nuts except for the two special cone washers in the middle on the two bottom studs where the intake and exhaust manifolds mate, as I recall. Don't know about using washers under steel lock nuts. The cone washers are listed in the ORD9 page 48, ORD 7371389. I think MWM has them too.

I think I used a bit of anti-seize (can't hurt), but it alters the torque value.

By the way, I had a heck of a time with the #7 stud (closest one to the firewall). Too long and it'll interfere with the throttle linkage. At least it did on mine.

Don't forget to seal the studs as all 7 penetrate the water jacket.

One other thing I had to do with my manifolds, was to take them to a machine shop and have them milled while together to make them one face.

Bolt them together where they attache (heat Riser area) then as one unit have all the ports milled to make them mate with the block properly...

I had to mine this way as there was too much difference in mating surfaces.

Best money I spent, one gasket and NO vaccume leaks...

My Opinion...

Same here...

Hal and Ron
I knew Mullins had them but was trying to find a source a little cheaper than $3+ apiece. As it turns out Mullins was the cheapest among the other military suppliers especially since I live about 25 miles from him and can forgo shipping. I did some searching last night and found some on some aircraft hardware sites but the number and cost and shipping was prohibitive.

I also did some searching at some local places like Fastenal and others looking for 3/8 stainless locknuts that are not nylon. I couldn't find anyone that carried any and only Fastenal offered to order some. Fastenal did have a good selection of regular brass nuts.

I appreciate you all mentioning the spacers for the two center bottom studs. I had forgotten about them since they weren't there when taken apart. Mullins had them also.

I had already trued the engine block surface and the manifolds.

I appreciate your responses

The brass 3/8-24NF locknuts are pretty hard to take at $3.75 each for something that can only be used once, so I've been hunting.

I found a pretty good substitute. Same style as the brass, only mil-spec cad-plated steel. Hard to tell them apart without a magnet. The best part is they're only .15 cents each. Lifetime supply for $15 delivered. Get 'em while they're hot!

https://www.ebay.com/itm/100-Count-MS21 ... Sw4CFY7okC

The brass are used without (WITHOUT) antiseize because they are serving as self locking nuts. They are brass (a disimilar metal) they will not walk off the studs over time. The reason they are a one use nut is they leave some of their brass from their threads on the steel studs every time you remove them. Anything else you decide to substitute must have some type of locking capability. A plain steel nut will not stay on the stud for very long. What I suggested years ago as a substitute are stainless steel LOCK nuts. All metal stainless lock nuts. No fiber insert nuts!

AN363C ALL-METAL STOP NUTS - STAINLESS

The AN363 all-metal stop nuts are designed for use in high temp installations (up to 800°F). Stainless Steel, corrosion resistant and silver plated.

https://www.aircraftspruce.com/catalog/ ... inless.php

Mil-spec MS21045-6 cad-plated steel locknut (3/8-24NF):

$15 per 100, delivered.



MS21045-6 Specifications:

Bearing Surface Finish: 125.0 Microinches
Bearing Surface Type: Chamfered Or Washer Faced
Countersink Angle: 88.0 Degrees Nominal Nut
Material: Steel Overall
Nominal Thread Size: 0.375 Inches
Nut Height: 0.318 Inches Minimum And 0.469 Inches Maximum
Nut Style: Hexagon
Locking Feature: Prevailing Torque All Metal Design
Lubrication: Soluble Lubricant
Width Across Flats: 0.553 Inches Minimum And 0.564 Inches Maximum
Surface Treatment Document And Classification: Qq-p-416,ty 2,cl 3 Fed Spec Single Treatment Response Overall
Surface Treatment: Cadmium Overall
Temp Rating: 450.0 Deg Fahrenheit Nominal
Thread Class: 3b
Thread Direction: Right-hand
Thread Quantity Per Inch: 24
Thread Series: Unjf

The rest of the story:
My search for a source of these brass lock-nuts (that match the ORD9 nuts sold by several of our regular suppliers) led me to one and only one factory still making lock nuts in the USA. I cannot say that they're really the "one and only", but after a reasonable search they were all I could find that actually make a brass lock-nut that appears to be the same as the one commonly available from our suppliers for $3.75 each plus postage.

When I contacted them, they cordially told me they had stock on hand and the price was $8.50 each (yes, that's not a typo). After some conversation back and forth, they told me they had 100 in stock and hadn't sold one since 2015. They gave me a break after I pleaded my case as a geezer eating baloney sandwiches (true) while restoring a vintage Willys M38 (trying) and the rarity of finding any for less than a gold-plated price. They agreed to sell me the 30 I wanted at $3.00 each, which I promptly did, plus shipping.

Don't get me wrong here. I'm not trying to dig or ding or undercut our great parts suppliers in this hobby. I was just trying to understand ground truth about the $3.75 cost of one brass nut that can only be used once. Guess I'm anal that way. I also know that in today's money a dollar is really only worth a dime, but $3.75 for one brass nut that cost a nickel back in 1950? Really? Sometimes the truth hurts and I suck it up. I didn't get into this great hobby wondering what a nut will cost me. But sometimes curiosity isn't a bad thing.

The very nice lady I spoke with at the manufacturer took the time to explain the nature of manufacturing these particular style nuts and I understand the cost (labor and material) involved. The conversation quickly came to "crickets" when I asked for a quote for the quantity that would be necessary to buy in order to get the unit cost under $2 each. They declined to respond. I don't blame them (in a way) because how could a hobbyist like me make that kind of investment for a low-demand nut to justify even the effort required to work up a quote? Business must be good for them and I'm glad. They're very nice folks in Texas!

They still have 70 in stock if any body is interested (you'll have to sweet-talk your own deal):

https://www.lok-mor.com/products/prevai ... dura-flex/

I'm going to use the brass lock nuts on my manifold (9 of them). The pipe flanges down stream are getting the cad-plated steel lock nuts. I've got 100 so if anybody needs a few, send me a PM....