Vapor lock questions for the hotter climate guys

[siteunseen]

1 hour ago, Patcon said:

This thread makes my tongue bleed...

My eyes. 8^(

I asked if he had plugged the coolant line through the carbs and he responded "yes" in those 7 pages.

I'm trying to participate whether they like it or not.  and doing the best I can.  We're all learning and contributing that will help us all, IMHO.

Participation a two way street Jalex.

 

 

[Stanley]

Maybe the carb tuning procedure in the Factory Service Manual would give better results than the procedure outlined in post #181.

 

[Mark Maras]

14 hours ago, Stanley said:

Maybe the carb tuning procedure in the Factory Service Manual would give better results than the procedure outlined in post #181.

 

 I agree. The pic of the plugs in post #181 were run three turns down. In my experience, three turns down should leave the plugs with a light to medium tan color. I'd check the float and the needle height first.

 Jalex. Back in post 181 when the car lacked power, did you try gradually adding more choke to see if performance improved? It's a great way to check for a lean mixture.

[rossiz]

i never liked the steel fuel rails or their routing around the front of the engine, so when i switched my from efi to carbs i started from scratch w/the fuel lines in the engine bay. i bent up the feed line that comes up under the battery 90 degrees and put a rubber line up the fire wall, mounted an old-school "filter king" glass bowl filter/pressure regulator with a bottom input/right side output and ran rubber fuel line across the firewall (up under the windshield washer hoses) over to the carbs, fed both and dead-end at the front carb. i rolled a strip of aluminum sheet into a tube and loosely wrapped the piece of rubber line in between the carbs to act as a radiant heat shield for it. the system is fed by a little electric pump mounted in place of the stock efi pump. my round-tops came with a steel heat shield which is installed.

never had a single problem. granted, i don't live in phoenix, but i've driven on some pretty hot days and never had an issue in traffic or at re-start.

[zKars]

The entire vapor lock issue, if it really exists at all, relies on high spot(s) in the fuel lines where the gaseous vapor can rise to, and block the liquid.  

I'd be interested to hear from those without issues if their line routing contains any of these theoretical high spots or not. The stock fuel rail certainly has one at the end, and from my experience the rear rubber hose to the rear carb is often routed up and over (ie creating a perfect vapor lock hump) over the linkage. 

Just postulating. Bit early for such things, but I'm stuck in a chair with a bad back today, so look out for more pearls of wisdom....

[jalexquijano]

well i will be taking the car out today. Have lowered the fuel mixture to 3 turns clockwise each carb to see if the spark plugs do not turn sooty black at idle avoiding smooth acceleration.

[jalexquijano]

On ‎10‎/‎30‎/‎2016 at 9:39 AM, siteunseen said:

You have 175F to 200F running through your carburateurs.  Fuel boils anywhere from 100F to 400F.

This is helpful for carburateurs in cold climates but if the thermostat doesn't close it could bring unnecessary heat into the carbs.  There's mention of it in the '72 FSM, according to this reply.  " The manual also states that if the thermostat fails to close in hot weather, carb percolation may occur."

 Z Therapy says plug it, I've plugged mine as well as Beer Man Pete (I followed his instructions).  I'm going to borrow Namerows disclaimer:

IMPORTANT:  If you are in any way concerned about your ability to do this type of work safely and successfully on your own, do not attempt it.  Instead, get a licensed mechanic to do it for you.

 

Which thermostat shall i plug? Can you point out?

[siteunseen]

3 hours ago, jalexquijano said:

Which thermostat shall i plug? Can you point out?

It's behind the rear carb, in the red circle. The line starts under the rear spark plugs and goes behind the motor into the rear intake through to the front intake. Then into the thermostat housing.  I posted a picture showing where I plugged mine. Not sure if its in this thread or one of your others. I plugged mine in four places but you could just do the two ends of the coolant flow for testing.

[jalexquijano]

Excuse me but how and with what do you plug it? this could clearly be the problem as the weather in Panama is 32 to 35° Celsius?

[siteunseen]

I would think for a temporary test run to see if it helps you could plug the outlet from the thermostat going to the front intake then plug the hardline behind the valve cover going to the rear intake.  Where the RED CIRCLES are on this diagram.

 

[jalexquijano]

is this safe? wont it affect the wáter circulation of the engine?  plugging those points will disable the thermostat or not. Panama weather is 29°C right now.

http://www.timeanddate.com/weather/panama/panama

Which page of the manual you read this??

 

 

 

[Jeff G 78]

It will be fine.  The later cars don't have that circuit and are basically blocked at the same points.  I have been running my race car that way for years just like Cliff showed.