On 11/11/2021 at 4:27 PM, Zed Head said:

The aftermarket guys probably went cheap on their design and just grind the tip in to the bottom of the hole or let it sit above the bottom, not contacting.

Agreed. Maybe not quite as good as the OEM, but it's probably "good enough" either way.

Parts finally arrived from MSA,  so I now I have all the pasts I need to get this engine started.  Two questions. 
 

1.  The Z and Zx have different routing for the heater hoses.  The ZX has a pressure regulator on the hear hose near cylinder 5 and the Z doesn’t.   Anyone know about this?  I think have the ZX part in my box of parts they I pulled off the engine when I bought it from the salvage yard.  Is it a better way to go or just plumb it like.a Z. 

look at the images below.  

 

Very good question and just in time for me because i'm almst ready to put my 280zx N42/N42 engine back in my engineroom.

My car has a N42 head  (280zx) and is cooled as in the lower part of your picture.. i ask myself the same question..  Is that valve needed..  I know that in my first 280zx 1980 eu modell it leaked just a little bit.. (very few drops sometimes on the starter..) it was made of plastic i remember..

If i could leave it out, i would!  (Less parts less problems can occure) 

 

The only thing i can think of is when you don't use the heater there is a bit less water movement in the rear end of the head... as i see a N42 on the 280z (the same one as i got in my 280zx orig EU modell) i think it's not a problem to plumb it like a Z..

I don’t think this was plastic. Here a pick of a new OEM on for sale on Zcardepot. Also is a pic of the one that came off the engine I bought. Looks like the guy plugged up on port with a sensor. Not sure why unless he was just using it as a plug .





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Does the ZX still have a traditional water valve? If so I would guess the pressure reducer was installed to reduce the tendency for leaks in the passenger floor board from the heater valve

I have been running the F54 on my '80ZX without that valve for several years and have found no negative side effects.  I have no way of knowing if my heater core is original, but being as it's no longer available, I'd guess it's at least a decade old.  I inspected it last year when the dash was out while fixing floorboard rust holes and such. No apparent problems.  I run the heat pretty much constantly in the winter. 

I'm not sure if that would ave anything to do with coolant circulation to the rear of the head, but during the break in procedure of my engine, I checked temperatures from the front of the engine to the rear and did not notice any wild variations in temperature(with IR temp reader and spark plug observation). Roughly 3,000 miles since rebuild.

 

Edited November 14, 20213 yr by Reptoid Overlords

  On 11/14/2021 at 4:10 PM, Av8ferg said:

I don’t think this was plastic.

 

Yes... you are right.. but i now remember it correctly .. i hope.. 

It was like in the picture but the bottom (in pic on the 4 o'clock side)  it was sort of white plastic and sits inside the copper part..  And that was the place it was leaking a little. once in a while a drop..

If you had a pic from the underside it would show the plastic bit.. mind you it was 30 years ago i had that 1980 car.. (these last weeks i did'nt work on my '79. but i could look one time if the valve underside is plastic at the 280zx i have now..)

 

Looked on internet and...yep, here you can see the plastic part i was remembering... it was leaky right there!

  On 11/14/2021 at 5:08 PM, Reptoid Overlords said:

I run the heat pretty much constantly in the winter. 

I think i leave the valve out... also helps the heater to work even better i think..?  And no chance it's gonna leak!

Okay, final step before filling the cooling system today was to flush the heater core. Ran a garden hose in the inlet and a hose out the outlet to a bucket. Ran for fresh water for 5 mins, then filled the core with Distilled Vinegar and let set 30 mins, flushed again and ran vinegar again sitting 30 mins and ran fresh water and then blew out all remaining liquid. The water ran brown the first 15 secs on first flush. I got a fair bit of debris out of the core and that stuff that won’t be in my engine. Of note, when flushing the vinegar out after sitting 30 mins, the water came out green for the first 15-20 secs, I’m assuming glthat was build up on the copper coils. Here’s the particles in the bottom of the bucket. Now I have to flush the tankless water heater for the house, it’s time and I have all the gear out already.





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Finally finished all the hook ups, re-wiring, hoses and cooling system. It took way more time than I expected. She’s was done at 3pm today but kids got off school bus so I need to wait until tomorrow. Like I said I hope it doesn’t blow up [emoji1787]



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I looked over the pic as best I could and didn't find anything worth mentioning. Looks great!

So you're thinking tomorrow might be the first start try??

What did you decide to do with the EFI temperature sensor? You running the one out the side of the head?

  On 11/17/2021 at 3:13 AM, Captain Obvious said:

I looked over the pic as best I could and didn't find anything worth mentioning. Looks great!
So you're thinking tomorrow might be the first start try??
What did you decide to do with the EFI temperature sensor? You running the one out the side of the head?

Thanks CO. I did run that wire to the temp sensor in the head. No routing issues, clean install. I’ll take a closer pic to show you.
I’m going to follow your starting sequence advice verbatim. I don’t think I will start right away. Going to get some fresh gas this AM. Don’t know how off timing will be or even if the distributor I rebuilt will function properly.


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