Single Plane

[Kent124]

What is this for and do I need it? I am installing the 1800 single plane and DFEV 32/36 on a 1979. One side looks like a hose goes on it; the other side has a screw in it.

[Kent124]

Also what height of spacer should I be using between the single plane and DFEV?

[manoa matt]

That is an EGR thermovalve. At a certain temp it opens or closes allowing the passage of gas from one tube to the other. Now its just serving as a manifold plug. Below it is the water jacket so if you remove it you must replace it so you don't have a massive coolant leak. Your local machine shop may have a suitable sized plug for the hole. You can just leave it if you don't mind it being there.

The 28/32ADHA has a thick throttle plate while the 32/36 has a thin one, the difference between the two is the thickness of the spacer needed for the carb hold down studs. If you buy shorter studs you can run the carb directly on the manifold, but the spacer should add a bit of torque so its a good thing to have and insulates the carb from the heat of the manifold.

[redek]

Also what height of spacer should I be using between the single plane and DFEV?

I used the 1" from millers mule. At $30 it is a bargain since it is machined aluminum. I would stay away from stacking molded plastic spacers, unless you get a great deal on them.

Derek

[So Cal Mark]

the thermoswitch doesn't flow gas, it's a vacuum switch. At temps below 100 it's shut to prevent the egr valve from operating. Having the egr operate on a cold engine will cause a stumble off idle

[manoa matt]

I should have used a better choice of words. In stating "gas" I was refering to a state of matter, ex: solid, liquid, gas. I was refrering to exhaust gases, vapors, vacuum, etc.

[Kent124]

Thanks for the explanations

Next question is the water outlet nipple on the 1800 intake manifold. Do I run a hose from this nipple to the metal heater pipe below the exhaust manifold? Looks like my heater pipe has a nipple near the firewall.

[124JOE]

yes they used that line for the wather heated choke
just make a loop from the heater tube port to the intake port
and tou will be fine

[Kent124]

Thanks Joe.

[Dougieb]

I am replacing my intake with one from a '74 Fiat. The sensor I believe is 16 x 1.5mm pitch. (I have checked the pitch but not the diameter. The only people I know that have any are McMaster Carr.

http://www.mcmaster.com/#metric-hex-hea ... ws/=gj3d5o

Does anyone have any other sources for this? NONE of the local parts stores have any.

Thanks

[131]

Is it a straight thread or tapered? You'll have to determine that before screwing a plug in.

[jsab]

You can use a 16x1.50 oil drain plug. I found them at most auto parts stores in the small engine section, same with Ace, Lowes and Home Depot. Just look in the section with the lawn mower parts.

[Dougieb]

I am so going to Home Depot tomorrow! ha ha

What about the sensor on the bottom of the intake?
I think it could be 12 x 1.5 mm. (same as a lot of lug bolts)
I put my pitch gauge on the sensor and it is 1.5mm pitch.
But I am not sure.

I would sure like to put a plug in that one also.

Does anyone know the correct bolt size?

[jsab]

I checked 2 Home Depots today, since I lead such an exciting life... one had them and one did not, so you may have to check around. I also stopped at O'Reilly and Napa, both of those places had them.
I don't remember what size I used on the bottom of the manifold, it may be 12, but I'm not sure.

-John

[Dougieb]

Ok, there are two sensors on the manifold. The thermal sensor is 18m x 1.5 pitch. This happens to be the same as an O2 sensor on most cars. Summit Racing has some nice plugs for about $9. Going there tomorrow for that.
The other sensor is 16m x 1.5 pitch. This is a fairly common oil drain plug and can be found at Napa auto parts. And probably elsewhere also.
Soooooooooo, with these two plugs and some teflon tape I will be able to make my new manifold look like it belongs on my car. I hope this helps other people also.
Thanks everyone for one great forum!