Maybe your fuel priming circuit would help?

  On 10/28/2023 at 2:53 AM, Patcon said:

Maybe your fuel priming circuit would help?

Seems possible - I guess it depends where the vaporization is taking place - it would seem likely that it is more than just in the injector body, as it takes at least a minute (it feels like more) to level off & return to normal. Fiat added an injection cooling fan system to their 80's version of the Bosch L-jet - it had a shroud on the intake with a duct attached to a blower. There was a temp switch on the manifold to trigger the blower on shut down. 

I think I read some reference to something similar on here, however I've not seen any pics. I can't visualize what a mess that would like like on the L28 EFI.

  On 10/28/2023 at 12:27 PM, HusseinHolland said:

where the vaporization is taking place

It might be in this thread or one of the others but I had posted some links about Mopar's fix for a similar problem with their Jeep engines.  It was a foil heat shield for a certain injector.  Apparently keeping the injector body itself cooler helped solve the problem.  The L series engines are perfectly set up to overheat the injectors with their position right next to the bulky exhaust manifold.

They put them on some ZXs, not sure of the years. '81-'83?

  On 10/28/2023 at 4:35 PM, Zed Head said:

It might be in this thread or one of the others but I had posted some links about Mopar's fix for a similar problem with their Jeep engines.  It was a foil heat shield for a certain injector.  Apparently keeping the injector body itself cooler helped solve the problem.  The L series engines are perfectly set up to overheat the injectors with their position right next to the bulky exhaust manifold.

Interesting. Fiat has the same issue, since the 70's-80's EFI was also placed on a non-cross flow cylinder head. I added additional shields on mine to protect the injectors, which mounted in a similar fashion.  The X1/9 had massive vents in the engine cover though, so that made a significant difference over my 75 280Z. Presumably this was in part the reason for the hood vents on later Z's.

  On 10/28/2023 at 10:55 PM, siteunseen said:

They put them on some ZXs, not sure of the years. '81-'83?

Thank you for the pics - seems the center 4 are more prone, unless they just said **** it- blow some air in the general vicinity & hope for the best 🤪

Been out of town since Wednesday - before that, I had the heat soak issue even though the ambient temps were in the 40's-50's. I'm going to make a heat shield, however since I have to remove the rail again, I decided to get newer injectors & a billet rail, and just get rid of all those thin metal tube rails.

These came while I was away

ProtunerZ rail & injector seat adaptors, 19.4lb/hr Bosch injectors 0280155712 (GM, Saab application)

 

So buddy I recently went 4 row aluminium red and the fuel rail heat issues at idle or after a fuel stop have nearly all but gone.

Sure the temps dropped from high to low/mid 20°c when I was testing it but it made a difference like I couldn’t imagine. My carbs fuel bowls which used to get “warm” are also cool to the touch now also.

Even idling to warm up in the garage on a cooler day used to make the fuel rail too hot to touch comfortably (imagine what fuel would have been doing inside it)!

I used to think heat shielding was the main solution, but how much a decent rad can affect this has taken my by TOTAL surprise.

  On 11/13/2023 at 1:48 AM, AK260 said:

So buddy I recently went 4 row aluminium red and the fuel rail heat issues at idle or after a fuel stop have nearly all but gone.
Sure the temps dropped from high to low/mid 20°c when I was testing it but it made a difference like I couldn’t imagine. My carbs fuel bowls which used to get “warm” are also cool to the touch now also.
Even idling to warm up in the garage on a cooler day used to make the fuel rail too hot to touch comfortably (imagine what fuel would have been doing inside it)!
I used to think heat shielding was the main solution, but how much a decent rad can affect this has taken my by TOTAL surprise.

Not sure that a carb setup would be a direct comparison, however that is good to note. I'm not likely to be buying a new aluminum rad yet, as I will need to reverse the rad flow / hose locations when I do the VQ35DE conversion.

 

Edit - just noticed you are in Surrey. I was born & lived in Kingston-Upon-Thames until I was 10, after that we moved around various countries. Where are you?

Edited November 13, 20231 yr by HusseinHolland

  On 11/13/2023 at 12:41 AM, HusseinHolland said:

ProtunerZ rail & injector seat adaptors, 19.4lb/hr Bosch injectors 0280155712 (GM, Saab application)

How does the flowrate of those new injectors compare to the originals?

I did a very little looking around a while ago and it seems the originals are low flow compared to most of the newer stuff.

  On 11/13/2023 at 2:34 PM, Captain Obvious said:

How does the flowrate of those new injectors compare to the originals?

I did a very little looking around a while ago and it seems the originals are low flow compared to most of the newer stuff.

We had a conversation on this  - I had to look around to find it - it was in the FPR thread

Stock are 17.9lb/hr  - 188cc @2.5bar - which translates into around 19lb/hr @ 3bar  - so I bought 19.4lb/hr - 205cc. 

 

 

Edited November 14, 20231 yr by HusseinHolland

Test fitting the ProtunerZ rail & adaptors, made a new section of fuel feed using 6AN braided hose, and a 6AN U-bend to feed the CSV

Adaptors came with SS Allen head screws, I don't like them. So, I used coated Sems screws

Bosch 0280155712 205cc

Added a support off the stock forward head mount point

Back together & running. I'm working on a heat shield template. 

Edited November 14, 20231 yr by HusseinHolland

Here's a link to a table I had found a while ago.  The original web page seems down but the table exists in various forms.  028-150-105 seems to be the standard Bosch original form replacement for the Nissan analog.  In those early days they gave different part numbers based on hose length.  I think that up to -112 are the same basic injector.

It downloads a pdf file.  Those 712's are high impedance.  You'll want to remove the dropping resistors, I'd guess.  Although I ran high impedance on my engine and they worked fine either way.  Looks like you might be a hair rich with those.  Good luck.

https://alfaclubvic.org.au/forum/index.php?action=dlattach;topic=13145.0;attach=28987

and https://www.google.com/search?q=stanweiss+injector