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Functional Louvers

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I have a 68 Datsun Roadster with the 2L motor, and Mikuni Sidedrafts. I want to add louvers to the hood as I plan on vintage racing it, and was told by Peter Brock that the Roadsters have a problem with heat cooking the carbs under the hood. 

Heres a pic of where the carbs sit in the motor. Nothing new to you guys

25945572957_1253b0b3b6_b.jpg

 

 

Heres a straight on shot, thinking of that lower ridge area on the driverside as one possible location. The other is the center, behind the radiator exit to draw it out, but I dont think that will work with its location and the hood scoop. Maybe that has to stay as-is 

42942202422_88655ec7aa_b.jpg

 

This last pic is the bottom of the hood, just to give you an idea of what it looks like and potential locations of punching the louvers

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Basically, I have a few options Im considering and looking for input.

1: Behind the radiator exit, angled up/ out of engine bay

2: In front of the carb, angled down/ into the engine bay

3: Behind the carbs, angled up/ out of the engine bay

4: At the back strip of the hood to draw all the heat out

 

 
 

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A sheet metal heat shield between the exhaust and the intake/carbs would help block radiated heat.

 

Insulating the fuel line and even better, a fuel return line that circulates hot fuel away from the carb inlets and replaces it will cooler fuel from the tank.

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Campaigned a DP 2000 in the late 70s early 80s. Never had that problem. Maybe if your sitting in traffic, but then you aren't racing. Like Mike said, need a really good heat shield between the carbs & exhaust, bond some insulation to it, bring it over to the inner fender panel. Re-route your gas lines, right now you have them sitting over the header. Find away to bring fresh air in. If your insistence on fkng the hood up, just put the louvers over the carbs facing forward. At that point who cares about aesthetics. You'd probably be better off putting in a naca duct. Depending on what vintage racing association you plan on competing in, louvers could be a no no, not period correct after all.

Edited by docbainey
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Couldnt that big scoop on the hood be used?

Cut a hole and add some sheet metal as a duct or something.....

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Heat soak happens mostly when stopped or just after shut down or low speeds.  Unless you have a fetish for those slotted louvers DON'T cut the hood up. Vintage race it first as there may be no problem at all. I detest louvers.

 

Adjust the hood latch so it doesn't close all the way at the back and it there's a rubber seal peel it off. This will let the hot air out.

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After looking at your roadster thread and realizing your never going to cut the windshield off to make a proper race car, I take it you're not going track racing but going to run those rich people things on public roads , the Mille  things? Last run in 1957? In Italy? Wayne Carini comes to mind. Nothing wrong with that. Heat shielding under the carbs and maybe header wrap, get rid of the rubber fuel lines unless you want to see your car burn to the ground,  better yet relocate the fuel lines to the back of the engine compartment not routed on the engine, there's probably a fuel return line that's been butchered  out of site unless your car is pre smog, put in an electric rad fan, get your radiator boiled out and bypass your heater core, you're in  California after all, what do you need a heater for?  just one less thing to fail. Make sur the coolant overflow system is up to snuff. The hood does have a functional scoop, but the limited airflow goes to the top of the rad. Get a custom cross flow rad and then you can take advantage of the hood. But if you don't deal with the oiling issues and the other engine 'opportunities', it will all be for not, but California road crap, its probably all good. Doubt you'll be turning over 6K. U20s eat rod bearings with out proper mods when revd, and the over square short rod U20 with big valves begs to be revd. One good thing, doubt you'll ever break the crank!

 

Don't louvre the hood. You already fd it up drilling holes in it.

 

Just my 2cents.

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Leave the heater core installed and run with the heater "on", it's a free extra radiator capacity.

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I've done this in a pinch and it WORKS!!!

 

If heater core leaks, never join the hoses together in a closed loop. If you do make sure the pipe is plugged.

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