Sunday, September 6, 2020

Good News and Bad News 2020

 I have good news and bad news.

That's not true.  I have great news and okally-dokally news.

Before I could get it to run on it's own, I had to drop the 18 PSI fuel pressure down to 8.  I installed a fuel pressure regulator for that, and then it only took an hour to get it "running".  The Corvette has now been started on it's own (no more pouring fuel down the carburetor throat).  The timing was 4 degrees after top-dead center.  It makes a difference when you advance it enough.  Right now it's at 8 degrees before top dead center - I need an additional 4 degrees advance, but it still runs.

Now for the okay-dokally news.  There are a number of issues I need to work through before I run it again.

First, the radiator hose is 1.510" on the inside diameter.  The radiator is 1.131" on the outside diameter.  Yes, it didn't just "leak", it flooded my garage.  That's okay.  I just need a Gates 26390 hose reducer.  It should go from a 1.5" size to a 1.25" size.  That problem is "solved", but is waiting on parts.

Next, I need to work on the fuel delivery.  The engine runs best with the idle mixture screws in all the way (barely seated).  That's not right (hear me out - it's really not).  It means I have fuel coming from somewhere.  The main jets don't engage until you have a little more pressure (your power circuit for fuel).  So, it's not my jet sizes.  The throttle plates are probably going to need adjusting,  to get the transfer slot mostly covered.  I know the secondary throttle plates are good.  The primaries I cannot see, so I'm going to have to take off my carburetor again.  If I am going in there, I probably need to do some work on my metering panels.

I want to (while I have it off) check that I have the power valve blowout protection, and get some new power valves in there to make sure that isn't my problem.  The symptoms align with the power valve being blown.

I need a ported vacuum for the distributor vacuum advance.  I need to install that to my fuel metering panel.  It looks like it has everything there (channels, etc).  I think it will be just drilling the fuel metering panel out and installing a hose flange for the distributor.

A little more information.  The intake manifold, 14057053 GM CFM 43, is for some 350 CUI blocks.  It's a spread bore intake.  I have a spread bore adapter for a square-bore carburetor.  Note, I still have my "Holley Contender" intake manifold from my old 350 CUI engine.  It is a dual-plane 300-38 (701R-38) "dominator" intake manifold.  If I remove my carburetor to handle the power value blowout protection, I'll probably swap that in.  Here's the "Contender" information :

The carburetor is a LIST-7010 carburetor (4160-style).  It has a secondary metering panel installed to it, center-hung floats (fully adjusted now), and should flow 780 CFM on it.

This thing should be able to idle smoothly.  Let's get started tuning it!

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