THermo-tec products as heat protection to avoid percolation under hood

[Jarvo2]

Have you ever considered getting a used head with the stock cam and having it rebuilt by a reputable local engine shop? I still think the root cause of this problem is the California Datsun / Datsun parts LLC engine and head combination that you're running. You're throwing good money at bandaids and not fixing the cause of the overheating.


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[Mark Maras]

 Did the ZX injector fan make any difference? 

The extra pump can't hurt. Nissan recommended it as PART of the solution. How much good it does remains to be seen and reported back by you.

 I've not dealt with the reflective heat barrier. Sounds like a good idea. I'm assuming that the reflective side faces the headers. As I recall your heat shield is two piece. Have you considered bridging that gap?

[jalexquijano]

The zx cooling fan  just arrived i need to wire it and install it. Ill let you know thw results.  I am also attaching the description of my engine. I dont think there is anything wrong with it. I replaced the far 311 race cam with a schneider 274f including new rocker arms and springs.

[Mark Maras]

 Be sure to let us know how the fan works.

[jalexquijano]

On ‎05‎/‎03‎/‎2017 at 6:51 PM, Mark Maras said:

 Curious if there was ANY improvement after bypassing the steel fuel rail? I'm of the opinion that wrapping fuel lines retains heat that comes from the fuel rail mounts, but that's just a theory and probably only part of the problem.

Mark,

Just got the Thermo-tec Heat barrier adhesive:

https://www.amazon.com/Thermo-Tec-13575-Adhesive-Backed-Barrier/dp/B00029KC2K

Do you recomend just pasting it on the side of the heat shield extensions that faces the manifold? or should i also paste it on the side that faces the SU CARB fuel bowls? Please advise! I am removing the heat shield extensions today to paste the heat barrier.

 

[Mark Maras]

 I don't know which side would be the most effective. Logically (this has failed me in the past) it seems to me that the reflective side would face the heat source but I would rely on the info and or instructions that came with the shielding product. Let us know which direction you install it and any change that you notice.

 I still have doubts about the two piece heat shield. It seems like it would be more effective if was one piece. You could bridge that gap with a third piece attached with speed nuts and screws.

[jalexquijano]

It didnt came with instructions. I guess the side facing the manifold is the one that should be covered. Please be advised that besides these 2 heat shields i have the original stock heat shield covering the center of the manifold.

THis guy manufactured my heat shield extensions!! He has great ideas:

 

[jalexquijano]

On 18/5/2017 at 8:16 PM, Mark Maras said:

 Did the ZX injector fan make any difference? 

The extra pump can't hurt. Nissan recommended it as PART of the solution. How much good it does remains to be seen and reported back by you.

 I've not dealt with the reflective heat barrier. Sounds like a good idea. I'm assuming that the reflective side faces the headers. As I recall your heat shield is two piece. Have you considered bridging that gap?

The thermotec product didnt help. Simply too much heat in that manifold. PO removed the mechanical pump and only left the electri airtex 8012s pump. Should i also install another mechanical pump and have 2 pumps pushing?

[Mark Maras]

 The original Z's only had a mechanical pump. Nissan added the elec. pump (among other things) to try to cure the heat soak problem. I can't say for sure if it will help but it can't hurt. 

[siteunseen]

35 minutes ago, Mark Maras said:

 The original Z's only had a mechanical pump. Nissan added the elec. pump (among other things) to try to cure the heat soak problem. I can't say for sure if it will help but it can't hurt. 

Correct me if I'm wrong but the electric pump was a '73 addition.  Would that have anything to do with the flat top carbs?

The only 240s I've heard of with the extra pump had triples or modified SUs.  Supposedly the cam nose pump couldn't keep up the fuel needed. One guy I bought a z from said his Dad only turned on the electric pump when he put his foot down. Said that was a fond memory when his Dad said "flip the pump on!" they were about to run it up.

 

[Mark Maras]

 I believe you're correct up to a point. I don't, however, believe that the reason for the added pump was flat top carbs. The engines used the same amount of fuel regardless of which carbs they used and the mech. pump alone supplied enough fuel to run the engine at any speed. The elec. pump by the tank added pressure in the lines prior to the mech. pump, possibly raising the boiling point of the fuel or just compressing the fuel to try to prevent the fuel from vaporizing in the lines. At least, that's my theory.

[siteunseen]

I don't get it.  It's hot as ever outside and I went for at least an hour this morning. My carbs are almost cool feeling. My efi 280 with the aluminum fuel rail feels sorta cool too, the fuel rail. I kind of think it has something to do with the fuel? When Alabama gas flows through aluminum it cools it down. My mercury outboard would have frost on it's carbs in the spring and fall. When I deleted the egr on my 280 an older mechanic said it needed the heat in the intake.  Also said when he was racing 240s they put Christmas tree light bulbs around the carbs for the heat they created. Crazy to me why some people fight it and I've never had a problem with the six Zs I've owned.