2011 - October 22nd - Zenith Carby Upgrade - Stage 3 The Fiddly Bits

The last week and a bit has seen hours in the Chev shed like the days of old, 4 to 5 hours a night, but progress has been very good, and I am now on the home straight. After fitting the carby to the adaptor plate I then had to "tweak" with a capital T, most of the linkages.
There was a lot of cutting, bending, cutting threads, all of which soaked up an enormous amount of time, but never dampened the enthusiasm to get the result I was after.

This was never more adamant than the accelerator pedal linkage, which previously I had never been happy with. This was the time to get it right and that took me about 8 hours, including fitting an accelerator return spring with the right feel.

I took the Red Chev for the first test drive with the Zenith fitted last night (Friday 21st October), very encouraging. I was originally worried that the exhaust note was a lot louder, but that was only with no air intake hose and air filter. Once I temporarily fitted these, the exhaust note was more normal.

I found during the test drive that without being tuned yet, the Red Chev seemed to have more power in first and second, with quicker acceleration. I will update this area once the fiddly bits are completed and the carby is tuned at 1800 RPM.

This leads me to this afternoon (22nd October), and as per the picture below I have a carby fitted but no connection for the crankcase ventilation tube or the hot air intake hose.

You may be able to see from the next picture that the carby air intake is bigger than the air intake hose, 1 5/8" versus 1 1/2"

Earlier in the week I had the local exhaust shop expand a piece of 1 1/2" tube up to 1 5/8". The outside diameter was the correct fit for the carby intake, and the inside diameter was the correct fit for the air intake tube. I regard this as a stroke of good luck, perfect fit for both requirements first try.

You can see the tube insert fitted, but I still had a problem with the crankcase ventilation tube, no connection.  Now I am aware that some Chev 4 owners who have done a similar carby upgrade have fitted a small section of radiator hose into which they then inserted the crankcase ventilation tube. I chose to go metal all the way.

 I made a connection piece from a piece of 16mm solid bar, which I drilled out in stages to 12.5 mm, the biggest drill my pedestal drill press could handle. Out came the rat tail file to finish off the hole to the right size, somewhere around 12.75 mm.

Luckily I was able to bend, stretch and manipulate the existing crankcase ventilation tube to fit the changed connection points.

The picture below shows the connection piece in place but still needing to be welded.

 Being a polished metal junkie I then spent several hours polishing both parts before drilling a pilot hole and inserting a bolt to hold both parts in place for welding.

I will get the insert welded on Monday, but in the meantime, if the weather is good tomorrow, Sunday 23rd October I will do some more testing and tune the carby.

The Red Chev and the Zenith 14991 are nearly one unit at peace with the world.

Once all is well, in the next week or so I will do a shakedown run to Trafalgar to see Grant and his master Monty.

 http://montythe1928chevrolet.blogspot.com/2011/10/resto-monty-leaves-trafalgar-after.html

Monty left town today, the first time in 44 years to have his exhaust replaced.