EGR French Lock Washer. Is a replacement available?

[George H.]

[Jimmy P.]

Re: EGR French Lock Washer. Is a replacement available?

Hi George,
You are flirting with disaster there my friend with that French lock washer. Those aren’t readily available anywhere that I know of in that particular configuration with the little tab that fits down in the little hole on the retaining brackets. I always keep an eye out on eBay for them to show up once in a blue moon with the attaching bolt along with it. To be honest though, I’ve never bent a tab up over the bolt! I’ve had mine on and off numerous times and I’ve never had any issues with the bracket bolt backing out! No one but you will really notice that anyway, and you’ll still have your original washer. Here’s mine and a pic of my collection of big and small block EGR brackets. (Sorry none for sale at this time!)
Note: Red arrow pointing to an original unrestored 454 bracket. As I’m sure you know that these particular brackets were only used on 1973 & 74 GM cars. The brackets changed in 1975 to ones that had two bolts, one on each side to bolt it down to the intake manifold.

[George H.]

Re: EGR French Lock Washer. Is a replacement available?

Thanks Jimmy, great photos and feedback. I assume the 3 flanges (I refer to them as tabs) were bent up against the bolt when leaving the factory, yes? Jut my liuck one will break off!

[Russ S.]

Re: EGR French Lock Washer. Is a replacement available?

George, If the 1/4 inch holes you were referring to on a previous post don't have a corresponding hole in the manifold then I don't see a reason to change your wrong gasket.

[Jimmy P.]

Re: EGR French Lock Washer. Is a replacement available?

Thanks Jimmy, great photos and feedback. I assume the 3 flanges (I refer to them as tabs) were bent up against the bolt when leaving the factory, yes? Jut my liuck one will break off!

George,
Your assumption is correct in that at least one of the tabs would have been bent up against the bolt. Or even two or three, don’t think there was any consistency, really!
Again, FYI, I’ve attached a few photo examples from my 73-74 Revision Files. An original ‘73 L82 SB, an original ‘74 L48 SB and a nice original ‘73 LS4.
You can see the variations in the number of tabs bent against the bolts. Cool Stuff!

PS…Russ might recognize the first photo of the ‘73 L82!

[George H.]

Re: EGR French Lock Washer. Is a replacement available?

I'm not 100% sure, but I don't believe the intake manifold, casting # 353015, has the two 1/4" drilled holds. Only the EGR valve mounting base and the gasket I installed. Therefore, you are probaoiily correct in that I don't need to change it out. i'm going to see if I can find a picture of the manifold layout. That manifold casting was only used for one year on the LS4 engine.

[George H.]

Re: EGR French Lock Washer. Is a replacement available?

A follow up to my last post. I just found on line a picture of the manifold casting and there are no small 1/4" holes. Only the circular opening for the EGR valve plunger and a rectangular hole for the exhaust gas. I should be ok leaving the gaskte on. I wonder if the two small holes in the valve are to be used when cleaning the carbon out of the valve?

[Jimmy P.]

Re: EGR French Lock Washer. Is a replacement available?

A follow up to my last post. I just found on line a picture of the manifold casting and there are no small 1/4" holes. Only the circular opening for the EGR valve plunger and a rectangular hole for the exhaust gas. I should be ok leaving the gaskte on. I wonder if the two small holes in the valve are to be used when cleaning the carbon out of the valve?

Hi again George,
Not trying to beat a dead horse with all this. However, when I keep reading your posts about the two small holes (in the intake, and your EGR base,) I'm a little confused. (Not that hard to do!!) Without seeing photos of what you have I'm posting up two sample EGR valves. The first with the small holes in the base as you mention, and the other without. With the two mounting holes is for a 75 Corvette and later. Without the mounting holes is correct for all 73 and 74 Corvettes. Which do you have on your 73 454?
Thanks

[George H.]

Re: EGR French Lock Washer. Is a replacement available?

Jimmy,

I'm posting a pictures showing the mounting base on the EGR valve NR7047066 02231 taken off my 1973 LS4 454 with 4-speed. It's the original correct EGR valve. I'm also posting the picture of the gasket that came off the manifold.

The origianl gasket does not have the two small openings. The EGR valve does. When I reinstlled the valve, the gasket I receeived from ZIP Corvettes, marked EH-338 73-74 454 EGR Valve Gasket, was from NAPA ECHLIN, sku # 2-2519 GASKET / JOINT PLAT JUNTA. That gasket had the two small holes in it. After the EGR was back on teh manifold, I realized there was a difference in the gaskets. The original gasket does not have the two additional holes and the replacement does. The manifold does not have the two 1/4" hole openings. Therefore, I'm not going to change it out. Zip customer service, after I called, checked it's inventory and yes, I received an incorrect gasket. NAPA switched its gasket design for the 73-74 454 without letting them know. When they checked the boxes in inventory, 2 had the original style gasket (no holes) and dozens had the two additonal 1/4" holes. Zip is sending me one of the original style gaskets. Now do I put it on? Probabily not.

Corvette EGR gasket 1973 454.jpgCorvette EGR NR 7047066 1973 LS4 4-Speed.jpg

[Jimmy P.]

Re: EGR French Lock Washer. Is a replacement available?

Thanks for posting the photos George. It’s clear now which two little holes you were talking about. A picture is worth a thousand words. None of my original 73-74 gaskets have the small holes. The correct gasket is like Joe posted in the other thread and is like the one you show in your photo with your original EGR valve. Sorry, for keeping this going on longer than necessary. I’d reuse that one or the replacement you’re getting from zip without the little holes and move on!

[George H.]

Re: EGR French Lock Washer. Is a replacement available?

Good advise Jimmy. I'll do just that. I'm still not sure why there are the two 1/4" holes in thd valve itself, but, it is what it is.

[Joe L.]

Re: EGR French Lock Washer. Is a replacement available?

I’ve removed the EGR valve now 3 or 4 times on my ’73 LS4 454 engine and have reused the original French Lock washer with the original hex-head TR mounting bolt. Each time I have bent the tabs on the washer back to open, then bent the 3 tabs back to close after torquing the bolt. I’m in the process of replacing the gasket again. Stupid me installed an incorrect gasket. Assuming one or more of the tabs breaks off the washer this time, are the original type steel French Lock washers still available?

George Hunt
1973 Coupe, 454-4 Speed.
NCRS C3 Registered and Certifyed
1Z37Z3S432231
Body-build date, LO6 July 6, 1973
Last month of production.

George-----


The clamp bolt lock was never available from GM in SERVICE.