'73 LS4 Metal Engine Tube?

[Peter G.]

At the last Judging Meet It was brought to my attention that I am missing the metal tubing that comes out of the bottom front of the carbureator and turns left 90 degrees and connects to a hose to the PCV Valve "T". The metal piece is about 8 inches long.

Can someone tell me where I can get this piece? Any repo companies, scrapeyards or fabrication. I did spend two hours fabricating a piece from some 5/8 inch brake line, but after the results the part was NOT up to my standards to be placed on the car.

This maybe a difficult piece to find as I think many LS4 owners do not even realize this piece is missing. Most like I did just have a piece of PCV hose running from the carb to the PCV T.

Thanks in advance.

[Harmon C.]

Re: '73 LS4 Metal Engine Tube?

Peter
I checked my pictures and found only one LS4 with the metal tube. I think it will be hard to find as I'm not sure that all LS4's had the pipe. Their would be no gain in horsepower by removing the tube so we will see how many others have the tube who read this.

[Joe L.]

Re: '73 LS4 Metal Engine Tube?

At the last Judging Meet It was brought to my attention that I am missing the metal tubing that comes out of the bottom front of the carbureator and turns left 90 degrees and connects to a hose to the PCV Valve "T". The metal piece is about 8 inches long.

Can someone tell me where I can get this piece? Any repo companies, scrapeyards or fabrication. I did spend two hours fabricating a piece from some 5/8 inch brake line, but after the results the part was NOT up to my standards to be placed on the car.

This maybe a difficult piece to find as I think many LS4 owners do not even realize this piece is missing. Most like I did just have a piece of PCV hose running from the carb to the PCV T.

Thanks in advance.

Peter------


I can't find any record of the piece you describe. What is the apparent function of it? Is it effectively just a metal section in the PCV line from the carburetor to the PCV valve which is normally all rubber tubing?

[Duke W.]

Re: '73 LS4 Metal Engine Tube?

I suggest you find the "missing piece" in the AIM and reference the page or scan and post it.

It's possible that you are chasing a judging error.

Duke

[Peter G.]

Re: '73 LS4 Metal Engine Tube?

Thanks everyone for all your interest.

I don't think it was a judging error as this pipe is listed and mentioned in the NCRS JG 73-74 Second Edition page 87.

I don't know the function of this part, but the way it is routed the metal tube is only under the EGR Valve that sits on the front of the engine directly in front of the carb. So maybe the EGR Valve warms up and the metal tube handles the heat better than a rubber hose?

Fellow NCRS TDB Member Bill Merhens (sorry Bill if I missed spelled your name) has it in a picture of his '73 LS4 Duntov car.

Just looked in my Mid America AIM Book and it does show the piece on page 250 under "Engine Ventillatioin System Pipe & Hose ASM

[Joe L.]

Re: '73 LS4 Metal Engine Tube?

Thanks everyone for all your interest.

I don't think it was a judging error as this pipe is listed and mentioned in the NCRS JG 73-74 Second Edition page 87.

I don't know the function of this part, but the way it is routed the metal tube is only under the EGR Valve that sits on the front of the engine directly in front of the carb. So maybe the EGR Valve warms up and the metal tube handles the heat better than a rubber hose?

Fellow NCRS TDB Member Bill Merhens (sorry Bill if I missed spelled your name) has it in a picture of his '73 LS4 Duntov car.

Just looked in my Mid America AIM Book and it does show the piece on page 250 under "Engine Ventillatioin System Pipe & Hose ASM

Peter-----



OK, now I see where I went wrong. I was somehow thinking that the car was a 1974. How did I think that considering the title of your post clearly said 1973? That's a good question for which I have no answer.

The tube's function, as you've surmised, was probably to protect the PCV line from the heat of the EGR valve. From what I can determine, the tube, GM #333890, was never available in SERVICE. Coupled with the fact that it was a one-year-only piece, used for LS-4 only, and apparently, not even used for many of those, this will be a hard piece to find. I really doubt that any reproduction source will "step up to the plate" on this one, but you never know.

The fact that it was not used for 1974 might imply that it was determined to be unnecessary and its use possibly discontinued sometime in the 1973 model year even though that is not shown in the AIM (we don't know that the copy of the AIM we have is necessarily the "final edition" with all pages updated).

[Bob J.]

Re: '73 LS4 Metal Engine Tube?

Here are a couple photos of my '73 LS4 engine showing the tube in question.


73 LS4 2.JPG73 LS4 3.jpg

[George W.]

Re: '73 LS4 Metal Engine Tube?

Peter

I have been searching for that tube for 15 years and so far have not found one for sale. There was a yellow 73 LS4 that was judged at Kissimmee FL in Jan, and it had the tube.

My AIM for 73 has two sheets, both labeled UPC 8D sheet 2, Title Canister Hose Routing. One shows the metal tube, the other shows a hose fastened to the air pump hose with a strap.

UPC 001.jpgUPC 002.jpg

[Russ S.]

Re: '73 LS4 Metal Engine Tube?

Peter

I have been searching for that tube for 15 years and so far have not found one for sale. There was a yellow 73 LS4 that was judged at Kissimmee FL in Jan, and it had the tube.

My AIM for 73 has two sheets, both labeled UPC 8D sheet 2, Title Canister Hose Routing. One shows the metal tube, the other shows a hose fastened to the air pump hose with a strap.

[ATTACH=CONFIG]42447[/ATTACH][ATTACH=CONFIG]42448[/ATTACH]

Do you know what the vin number is on this car? I am wondering if maybe early cars had the metal tube.

[Ken K.]

Re: '73 LS4 Metal Engine Tube?

My 73 LS4 has the tube. It is VIN 1Z37Z3S416327. It was built the first week of March 73. hope that helps.

[Peter G.]

Re: '73 LS4 Metal Engine Tube?

Bob, thanks for posting your pics. That is the piece.

My VIN # 2051 early car born Sept. 13, 1972.

[Peter G.]

Re: '73 LS4 Metal Engine Tube?

Thanks to everyone who responded...

I guess I will continue to look for a salvage part, but in the meantime would like to try and have a shop fabricate the part.

Can someone who has this part take a picture of the part OFF a car and also try and do a outline drawing of the part so I can get a "actual size" for the fabricator without my car being present during the Winter months?

[Peter G.]

Re: '73 LS4 Metal Engine Tube?

George..I was at Kissimmee last year too and I remember talking with the new owner of that yellow '73 LS4. I didn't notice the metal tubing because at that time did not realize that my car was missing that piece.


The new owner I remember him saying that he just had purchased the car a few months earlier and hadn't done anything to the car before having it judged at the NCRS Regional in Kissimmee.

PS: I am still looking for the piece as Winter time in Colorado is a perfect time to "tweek" on the Corvette or do needed repairs.