Need pics of a stock 240Z downpipe

[Zedyone_kenobi]

That is an interesting Z on the down pipe Jim. I don't think I have seen that before.

-Mike

how do you know its not an 'N'

[Mike B]

how do you know its not an 'N'

I don't. Jim referred to it as a Z, so I did too. Either way, I haven't seen one on a downpipe before.

-Mike

[Arne]

Arne,

Take a look at Kats web sight, go to "Original Detail" and scroll down to a picture of the "cast junction" on his down pipe. It has always been my understanding that this style of downpipe is the early part number, while the down pipe with one pipe welded into another is the later redition.

Dan

Thanks, Dan. That is the type on my car, built in 7/71. So are we trying to decide that all the ones pictured in this thread (Mike and Jim's) are later replacements, not original to the car? Or that mine was replaced with an earlier type later in life?

Direct link to the pictures on Kats' webpage.

[a7dz]

I can tell you I have not replaced the down pipe on my car. I doubt my mother did she was not into that kind of stuff. Original to my 6/70 build. Whether it is a Z or an N the pipe is stock. I knew I would get a rise out of some one. I was hoping to get more of a definitive answer from one of the parts guys.

[26th-Z]

26th has the Arne / Kats type and 27th has headers. Also noted; Mike's new system is 20010-N3000. My NA parts book lists N3300 from 10/72 to 7/73... ah! Here it is ... Fairlady Z parts book 1972, 20010-N3000 from 10/72, models ZS and ZL, L20-L24.

There are separate listings in both parts books for the automatic transmission.

[geezer]

Whether it is a Z or an N the pipe is stock. I knew I would get a rise out of some one.

Well, it is deserving of some discussion and got a better reaction than my feeble joke. Jim, I am thinking it is entirely possible that your mother had a shop work on the exhaust at some point and the front section was replaced and it has long since been forgotten…or… another possibility that I wouldn’t discount for a second, is Nissan using an alternate supplier to keep up with the ever increasing production levels. Not an uncommon practice at all. Most manufacturers did have alternate suppliers for just this reason and also to offset parts shortages caused for any other reason such as natural disasters, labor disputes, a better negotiated price, etc. It will be interesting to see if more or other variations turn up.

The Mitchell’s illustration excerpt I posted is indicative of every illustration I have seen of this part being representative for 1970. They all depict the type that Arne has on his car. Here’s another one. We could probably find more illustration examples, but the actual parts are likely more difficult to come across.

Dan referred to the “cast junction”. Is the “Y” an actual cast piece or is it a heavy stamped metal part that has been welded together? I have never seen one. If it is indeed a cast piece, it could probably be reused in the reconstruction of a replacement pipe section. I know Summit has the heavy stamped metal type in stock also that would be somewhat keeping with the correct look and also being available in larger diameters, you could increase the flow.

[Arne]

OK, so Jim's car has the same type as Mike's new system, and Jim knows the history of that car from new, so we can assume that it is original to the car. The other used one that Mike has appears to be an original, but we probably can't confirm that.

I'm fairly comfortable in saying that mine is original too, considering the low miles, lack of under car rust, and all the rest. Mine also matches 26th's.

Conclusion? I'm thinking now that Nissan got downpipes from more than one supplier. It might be totally hit and miss as to which style a particular car (or batch of cars) got.

[Mike B]

Conclusion? I'm thinking now that Nissan got downpipes from more than one supplier. It might be totally hit and miss as to which style a particular car (or batch of cars) got.

My best guess is that Kats, Chris and Arne have the correct original downpipe for cars up to 8/71. It would appear that the examples I have are later OEM replacements. I would agree with Geezer that Jim's example is probably a later replacement too.

The Mitchell’s illustration excerpt I posted is indicative of every illustration I have seen of this part being representative for 1970. They all depict the type that Arne has on his car.

It looks like the same illustration (of the early part) is used in all USA and Canada parts catalogs for cars through 7/73. The illustration is changed for the 260Z (from 8/73). Nissan seems to only change the illustration when there was a model change (i.e., 240Z to 260Z).

-Mike

[Arne]

Well, at this point I'm going to work on the assumption that mine is (at least mostly) original. (I'll explain the 'mostly' part next.) But considering how many early cars we see here with the other style, the thought that Nissan may have had two suppliers is looking fairly good. As an example, while many of us know just how rusty Jim's car (a7dz) was, and that it seems likely that the exhaust could have been replaced due to rust at some point in the distant past, on the other hand, he doesn't remember it, and that unique 'Z' or 'N' badge on it gives pause. So either type might really be correct. We may never know the details for certain.

To Geezer - I don't know if it is cast or stamped. Kats' site refers to it as cast, but that may be an artifact of translation. I've always assumed mine is stamped in two halves and welded. I'll need to get under the car and check closely to determine which method was used.

As for my 'mostly' original comment - all this has me reconsidering just what I have under there. The original owner had the exhaust re-worked early in the car's life. He apparently didn't like the way the stock exhaust sounded. The exhaust is all welded into one piece, downpipe to glasspack in the tunnel to a long tailpipe out the back, all of it 1 3/4" pipe, as I recall. I've always assumed that the muffler shop cut the old off just behind the cast/stamped junction and welded new on from there.

Looking at Kats' pictures, now I'm not so sure. Now I wonder if the entire stock downpipe was retained and the glasspack was welded to the end where it would normally mate with the center resonator. If I can determine that to be the case, I may want to retain as much of the downpipe as I can, by removing the glasspack and building from there back, rather than building from the junction back as I thought had been done last time.

I guess I'll need to find time to crawl under the car this weekend....

[26th-Z]

Guys! Get out the spec books! Bless your mother's heart, a7dz, but your pipe is about as unstockafied as I have ever seen! Your great photo has me awash in "stump-the-guru" games and I love it! :kiss:

This diagram is from the service manual 11/1/69 clearly showing the Y-collector that is stamped metal with a seam welded tab. It is welded in place. Not a cast piece, geezer.

Mike's picture of 20010-N3000 with the pipe connection style is clearly the later / replacement version. And the Japanese version to boot!

[kats]

Hi,

Thaks for looking at my web's picture, I did say "cast" (casting?) but I did not know it is true or not.Could be metal press.

Could you see this picture, the junction is seen and looks what we are talking about.Even the shape looks slightly different from my 240Z's, but I may be not correct.If we go to the service manual, we can see more clearly pictures of the junction.

kats

[26th-Z]

26th has a glasspack too. The whole tube back from the downpipe was made for me in 1991.