I have read some posts that refer to the problem of coolant leaks under the Weber adapter plate, especially when doing the conversion on an EA82 engine or adapting an EA82 intake to an EA81 engine. This is how I solved it.

 

I made another plate out of 16 guage aluminum which had "more meat". or was wider, over the area of the Hitachi Carburetor pre-heat pocket which is built into the manifold.(The open coolant hole)

 

I then cut an additional gasket, to match the "thin adapter plate" and placed the gasket on the intake flange using some "fuel resistant RTV sealant" on both sides. I then placed my "thin adapter plate/water port sealer" on next. I then stacked the adapter plate mounting gaskets in the appropriate order with the adapter plate for the Weber being last, of course. The addition of the "extra sealing surface" of the 16 guage "adapter plate" addition and a gasket to match that plate used under the Weber adapter and the Weber Carb has solved the problem.

 

I used the commercial 2 piece adapter plate set up because it gives a smoother fuel/air charge transition between the bottom of the carb butterflys and the bottom of the intake plenum, It also has the additon of more "shared fuel charge" which increases the bottom end torque.

 

I will try to post some pictures of this whole set up, or I may solicit the help of calbez to do this. Notice in the pictures how sanitary the intake is. I removed all of the vacuum ports that aren't being used and had them TIG welded shut. You can pull all of those brass tubes with a pair of side cutters, just clamp onto them at the base and using a little preasure to bite into the tubing you can "lever them out".

 

YEPABUS

I just put some Permatex 2 non-hardening sealer around the gasket (a thin coat of course) on both sides, and then installed the adaptor plate. No leaks so far...

I just put some Permatex 2 non-hardening sealer around the gasket (a thin coat of course) on both sides, and then installed the adaptor plate. No leaks so far...

What kind of jetting are you using in the primary and secondaries. What size imulsion tubes and air correction jets are you using in the primary and secondaries and what size idle fuel jets ate you using.

 

Do you have an O2 sensor welding into yuour exhaust and a "stoich meter" (rich/lean meter) of some sort in your system for tunning? When I was running performance Datsuns I just read the spark plugs, but that was befor all this new fangled technology came on the scene. haha

 

YEPABUS

Why not just clean the manifold up, and fill the hole with JB weld? Ought to do the trick. It's not like the hole goes anywhere special. It's there to heat the carb for emmissions.

 

GD

nice trick but since i do fuel injection... but it may come in handy on someone elses car

my question is since you had the vacum ports tig'd close why did you not make a plate that just fits inside said water pocket and have it tig'd in there as well

and then file down the welds till it was smooth...

couple less gaskets

I used the JB weld, but i seem to be getting some seepage, but i'm gonna recheck that some time this week. as far as jetting, for stock setups, and from what i hear, all setups.

 

Idle 60P 50S

Main 140

Correction 170P 160S

 

That should get you in the right dirction