Results 1 to 12 of 12

Thread: 79 280 into 72 240

  1. #1
    Registered User Z dreams's Avatar
    Member ID
    CZCC-23169
    Join Date
    Dec 2010
    Location
    Lawton Mich.
    Posts
    82
    Blog Entries
    3

    Default 79 280 into 72 240

    Hi all,
    My 240 engine needs work, I found a low mileage 79, 280 engine with N-47 head and tranny. What am I looking at to do this transplant? I'll be using S.U.'s I want to be clear on what I may need for parts or change's I need to do.

    Thanks, John

  2. #2
    Low Budget/High Value
    Member ID
    CZCC-20342
    Join Date
    Oct 2009
    Location
    Washington County, OR
    Posts
    3,629

    Default

    In principle, theory, on paper, in your mind, it's a pretty easy bolt-in swap. You might just need to retune the SU's for the bigger engine (I don't know SU's). The dimensions of the parts are the same.

    In reality, you'll break a bunch of bolts and studs when removing various parts, like manifolds or exhaust pipes. So you just need to be prepared to fix some broken stuff. If you really want to be prepared you'll have some taps and tap drills waiting and just decide to replace parts that might or might not need it, like manifold bolts or studs.

    I'm not sure, but I think that the 240Z exhaust manifold and exhaust system might be a little restrictive for a bigger motor. I think that they're restrictive for the stock L24 even before you start. The pipes look small compared to 280Z pipes (you'll see if you compare).

    The 5 speed transmission will bolt right in. The shifter or shifter opening might need some work, or not, 1972 might be big enough. Early cars couldn't handle the throw of the 5th gear position.

    Overall, it's easy. But the broken bolts will be aggravating. And, of course, there's the "what should I do while I have it out" project bloat. Clutch, flywheel resurface, rear main seal, transmission front seal...etc.
    1976 280Z, with some minor modifications

  3. #3
    Registered User tlorber's Avatar
    Member ID
    CZCC-20299
    Join Date
    Oct 2009
    Location
    Los Angeles
    Age
    54
    Posts
    1,190

    Default

    This should be a pretty easy swap. Engine will go right in, as will the tranny (keep your old shifter though). As stated above you should plan on a header and new exhaust ( or use the one from the ZX if there is not too much smog crap on it). You will need the 240 intake manifold and the balance tube to drive the brake assist. You should also use the ZX alternator (get Dave Irwin's adaptor plug) and distributor. Keep in mind thought that your gear ratios may be a bit tall unless you swap out the diff for a shorter (numerically higher) one.
    Last edited by tlorber; 09-02-2014 at 09:03 PM.
    Tlorber
    '73 240 +/- done
    '73 240 survivor
    '69 SRL 311
    '54 GMC Going onto S10 frame w/LS motor
    '99 Lexus GS Driver

  4. #4
    Registered User EuroDat's Avatar
    Member ID
    CZCC-26512
    Join Date
    Feb 2012
    Location
    The Netherlands
    Posts
    1,420
    Blog Entries
    1

    Default

    Do you know when in 79? The transmission could be the same as the 280Z which had the same ratios as the 72 240Z , but with the 5th gear. They changed over around August 79 I think. Another point, if it came from a 280ZX 2+2 it will be the same as the 280Z, but with the heavy duty clutch.
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

  5. #5
    Rust Free'ish zKars's Avatar
    Member ID
    CZCC-12190
    Join Date
    Jul 2006
    Location
    Calgary, AB Canada
    Posts
    1,256

    Default

    The N47 head also has no provision to mount the mechanical fuel pump. Well you can, but it you have to machine out the port on the side of the head. The three bolt/stud holes are there but none of the N47 heads I've seen have the opening into the head. Perhaps this is the time to consider a low pressure electric pump.
    -----------------------------------------
    Jim
    73 240Z HLS30 149331
    69 510 PL510 77603

    www.zKars.com
    www.calgaryzclub.ca
    Reference materials
    www.xenonS30.com

  6. #6
    Registered User EuroDat's Avatar
    Member ID
    CZCC-26512
    Join Date
    Feb 2012
    Location
    The Netherlands
    Posts
    1,420
    Blog Entries
    1

    Default

    Quote Originally Posted by EuroDat View Post
    Do you know when in 79? The transmission could be the same as the 280Z which had thewhene ratios as the 72 240Z , but with the 5th gear. They changed over around August 79 I think. Another point, if it came from a 280ZX 2+2 it will be the same as the 280Z, but with the heavy duty clutch.
    A little clarity. Regarding the pre August 79 or 2+2 engine transmission combination. The ratios 1st through to 4th will be the same as what you now have, but then you will have an extra 5th gear for highway cruising.
    Its after 79 when they changed to the close ratio 71B transmissions. Those have a high 1st gear specially when used with the 240Z difff ratio.
    Chas
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

  7. #7
    Registered User Z dreams's Avatar
    Member ID
    CZCC-23169
    Join Date
    Dec 2010
    Location
    Lawton Mich.
    Posts
    82
    Blog Entries
    3

    Default

    Thank You, for sharing your knowledge guy's. Looks like a road trip tomorrow!

  8. #8
    Low Budget/High Value
    Member ID
    CZCC-20342
    Join Date
    Oct 2009
    Location
    Washington County, OR
    Posts
    3,629

    Default

    If the diff is available you might consider getting it also. The 79 ZX had a variety of diffs but at least it will match the transmission.

    Euro, I thought the same on the transmission but the FSM says that 72 still had the 3.592 first gear, not the later 3.321. It also says that it has a 3.9 diff ratio though, which would give a very low 14:1 overall first. I'm not sure the FSM numbers are right though, the 240Z guys would know for sure.

    Anyway, it's definitely doable. Good luck.
    1976 280Z, with some minor modifications

  9. #9
    Registered User EuroDat's Avatar
    Member ID
    CZCC-26512
    Join Date
    Feb 2012
    Location
    The Netherlands
    Posts
    1,420
    Blog Entries
    1

    Default

    I stand corrected. I didn't know the 3.9 came out in the US models. Thought it was only in the non US 5speeds. Learning something new all the time when it comes to these cars.
    But I did quote the early 71B 4speed as the same as the 280Z 4speed, which it is not. The 240Z used a similar ratio setup as the 720 trucks in the 80's had in the 5 speeds.

    Anyways if he has the other ratio (3.364) then he would end up with a 12.1 ratio compared to the 11.2 he would of had with the original 4speed.
    Chas
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

  10. #10
    Registered User Z dreams's Avatar
    Member ID
    CZCC-23169
    Join Date
    Dec 2010
    Location
    Lawton Mich.
    Posts
    82
    Blog Entries
    3

    Default

    Well I did the road trip and bought the 79,280 engine and tranny. Transmission appears to be early 79. O.K. for my stock 72, 180 rear end?

  11. #11
    Supporting Member Diseazd's Avatar
    Member ID
    CZCC-14126
    Join Date
    Mar 2007
    Location
    Richmond
    Posts
    1,852

    Default

    Z dreams.......I'd use your early 240Z intake and exhaust manifold (plug the air injection holes). Then.....all you need to do is figure out what goodies you want to add to the head if any. Either tranny will work fine, just make sure you match clutch parts to whichever pressure plate you decide on.
    http://www.flickr.com/photos/1404980...7600346077563/
    ______________________________________________
    http://www.flickr.com/photos/1404980...7603350695459/

    70, 71, 2 72's, and a 73 240z....
    90 300zx and a 1996 Acura NSX.....but who's counting?

  12. #12
    Registered User EuroDat's Avatar
    Member ID
    CZCC-26512
    Join Date
    Feb 2012
    Location
    The Netherlands
    Posts
    1,420
    Blog Entries
    1

    Default

    Hi Diseazd, Will the exhaust manifold line up ok one the N47 head? It has the round exhaust ports and the head he has now has square ports. On a stock engine it probably won't make a noticable difference in performance and he is going to L28 which will more than compensate.
    Chas
    Last edited by EuroDat; 09-07-2014 at 10:13 PM.
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •