"Steam" rising out of carburetor/intake?

[Jeepmb]

Mornin' everybody,

Need a little help from from those more experienced than I with carbureted engines. I am getting what appears to be a steam rising out of the intake manifold after the engine is shut off (full operating temp). It can be seen by removing the air cleaner and opening up the throttle on the carb.

In more detail:

Im working on a 1976 Scout II 345 4-speed with an edelbrock 4 barrel 1406. This truck has been a little abused in the past, and ive spent the better part of a year just working on getting everything working as it should. It runs great on the road, smooth with plenty of power. I was diagnosing a hot start issue when I discovered the steam.

In addition, about a week ago I did a coolant flush (non-pressurized water + flush solution) and changed the thermostat. The thermostat I found broken in 3 pieces and completely stuck closed . But from being broken, coolant flowed freely and the engine never got up to operating temperature. After replacing the thermostat, I finally now get the engine to warm up properly (It was bad enough I thought the temp gauge was broken before the change).

So is this light "steam" rising from the intake something to be concerned about?

As you can imagine, my worst fears are coolant leaking into intake, and fuel vaporization, but my exhaust is clean (for a 37 yr old truck) so I am hoping i'm just paranoid.

 

[blue smoke]

Since you are opening the throttle plates your pumping gas into the hot intake and it is vaporizing no need for concern. Unless of course it is a cloud.

 

[Eric VanBuren]

Considering that you are chasing a hot start problem, I'd say that your problem is the Edelboil carb. They like to after boil on a SV. A Holley carb with the proper heat dam gasket is your friend.

 

[blue smoke]

There is nothing wrong with an edelbrock card. As long as you put a heat shield gasket on the base. I used a 1 inch spacer on mine and never had a problem I could still get 15-16 MPG with the 345 on the highway.

The edelbrock has ability to flow more air than a holley but I think it is a matter of personal preference.

 

[Tucker H]

What Blue said above.

 

[Jeepmb]

Ya, I think I agree with you guys.

It certainly seems engine-temp related, and right now the carb sits directly on the intake manifold, barely a squished gasket between. Im trying to work with about a 1/2 inch or less of working room for a spacer. Ive got a triangle K&N roughly 3" high that I just can't bear to get rid of . I'll do with a small spacer, but i'll also look into getting a heat shield for the side/bowl area of the edelbrock. Ive got a nylon IH med-duty 10 blade fan that should help cool it off if i can get direct heat off of it.

Any thoughts on the spacers that are cut out squares vs. formed to the ports?

 

[Jeepmb]

Cut-out Squares
http://static.summitracing.com/global/images/prod/large/hly-108-70_w.jpg
Formed to the Ports
http://contentinfo.autozone.com/znetcs/product-info/en/US/edm/9267/image/3/

It seems like the difference between the two is that there is effectively a vent opened up between the right and left banks of the intake with the cut-out square. I would imagine it could help balance flows but i haven't found anything to support this.

 

[Eric VanBuren]

Without a 4 hole spacer the Edelboil will often make a whistling noise. In their owners manual they specifically note to only use 4 hole adapters and spacers.