Valve cover?

[Tom L.]

A while ago I was able to get a set of original valve covers for m my LS5, a tough find. Anyway, I believe that the "Oil" plug is original since it's so hard and won't come out of the cover. Any ideas on getting t out and re-using it without destroying it??

[Loren L.]

Re: Valve cover?

Cut the hardened lower part off with a razor blade and glue it back in for judging.

[Joe L.]

Re: Valve cover?

A while ago I was able to get a set of original valve covers for m my LS5, a tough find. Anyway, I believe that the "Oil" plug is original since it's so hard and won't come out of the cover. Any ideas on getting t out and re-using it without destroying it??

Tom-----

I would not even consider re-using this oil fill plug. When these plugs get hard and brittle, that's the time to throw them away and get a new plug. Even if you succeed in getting it out unscathed, you're going to be fighting the same battle every time you try to install it or remove it. The reproductions I've seen look plenty good enough to me. Or, you could look for an NOS example.

I suppose what Loren suggests might be OK for judging, assuming that the judges don't remove it. It'll be virtually impossible to glue this back together in a way that will hold up when you pull it out.

[Russ S.]

Re: Valve cover?

Try heating it with a heat gun.

[Mike E.]

Re: Valve cover?

I bought a 71 Chevelle new. By 1973 that rubber cap was almost impossible to get off and back on. That was a 307, but same cap.

[Joe L.]

Re: Valve cover?

I bought a 71 Chevelle new. By 1973 that rubber cap was almost impossible to get off and back on. That was a 307, but same cap.

Mike------

GM backed off quickly on this incredibly dumb, foolish idea of rubber oil fill plugs. For small blocks, it started for the 1971 model year and ended sometime during the 1972 model year. For big blocks, it went from 1971 thru 1974, probably because GM did not want to revise the valve cover tooling for the relatively low big block production during this period.

Even 71-72 LT-1's got aluminum valve covers with the rubber plug. I bought these once-upon-a-time and actually used them on my 1969 small block until I could just not put up with the miserable rubber plug. Actually, for awhile and during the period I first purchased them, the left side aluminum valve cover with the rubber plug actually replaced the 1970 twist-in cap type for SERVICE. So, during this period, you could not even buy the twist-in style cover from GM. However, about late 1972 or 73 the rubber plug style aluminum cover was discontinued and the twist-in style brought back.

[Edward M.]

Re: Valve cover?

There are lots of these plugs around NOS. I also see repos that look pretty good, but I cannot comment on their accuracy.

GM Part # 3980273. I think (some correct me if I have this wrong) that the part number is molded into the inside of the plug

[Joe L.]

Re: Valve cover?

There are lots of these plugs around NOS. I also see repos that look pretty good, but I cannot comment on their accuracy.

GM Part # 3980273. I think (some correct me if I have this wrong) that the part number is molded into the inside of the plug

Ed------

GM #3980273 is the original part number. There have been supercessions which differ in configuration. As I recall, they do have the part number molded on the inside surface (I can't check my NOS examples right now).

The reproductions I have seen look perfect to me (but, I believe lack the part number). However, I have not examined them with a microscope to see if every nuance of detail is correct.

[Tom L.]

Re: Valve cover?

Thanks for the info. I'll look at it today and see if there's a number. If anyone knows that original did in fact have the part number I'd appreciate knowing. My concern about this part is not to have a plug that has a part number on it, just one that fits right. The repro I have is loose, will move in the hole when all the way in and also weeps a little especially after long runs. Not a huge issue but annoying and one I'd like to resolve. I'm mostly seeing this plug as a way to solve a small problem. Thanks again!!

[Edward M.]

Re: Valve cover?

I seem to recall (I owned a 71 base motor coupe, and a 74 454 coupe) that it looked like this.

I recommend not trying to save / salvage this oil plug. There are plenty of NOS ones out there.

However, if you really want to save it, try spraying some WD-40 around the plug and twist it back and forth while pulling up.

[Joe L.]

Re: Valve cover?

Thanks for the info. I'll look at it today and see if there's a number. If anyone knows that original did in fact have the part number I'd appreciate knowing. My concern about this part is not to have a plug that has a part number on it, just one that fits right. The repro I have is loose, will move in the hole when all the way in and also weeps a little especially after long runs. Not a huge issue but annoying and one I'd like to resolve. I'm mostly seeing this plug as a way to solve a small problem. Thanks again!!

Tom------


If you're more interested in functionality that originality, you could use the current GM replacement for the 3980273. It's GM #10110859. The outer-facing surface has completely different script but it's an OEM-quality part.

[Joe L.]

Re: Valve cover?

Tom------


Attached are photos of an NOS GM #3980273. Note that this one does not have an embossed part number. It does have an "NPC" and "24" embossed on the bottom. I have seen many original GM rubber parts that had "NPC" embossed on them. I suspect that "NPC" was a supplier to GM for rubber parts, especially engine parts. This cap is packaged in very old-style GMSPO packaging. I would say it dates back to the 70's.