This is essentially a continuation of a thread I created a few weeks ago about my concern over a very low vacuum when cranking my engine. I will start over by summarizing my situation.
I bought a salvage year 68 E type which was in pretty good condition except a previous owner had removed key parts from the engine such as carbs and intake manifold, distributor and wires, alternator, etc. So i have never seen the engine run.
I have had the head rebuilt with new valves, I replaced the piston rings and bought and installed all the missing equipment. I get good and consistent results on compression tests. But the engine won’t start.
The ignition is good and set to fire at about 10 degrees BTDC, and it works.
I bought two Zenith Stromberg CD-2 175 carbs with both intake manifolds (as per the original 68 series 1.5 version) but have removed the internals in the weird intermediate manifold. The carbs were clean but I disassembled them for more cleaning, new gaskets and setting correct fuel levels, etc.
When I crank the engine, I get no firing at all except when I squirt some starter fluid in the carb. But this firing is much more sporatic than anything I have seen before.
After a lot of various tests and retests, I believe my problem may be very low cranking vacuum. I measure it as only about 2 inches mercury (or flucuating between 0 and 2 inches) while other sources suggest it should be around 3-5 inches. I have searched endlessly for leaks, including pressuring the intake system up to about 10 psi and checking where air comes out. Now the only leaks I can find are around the carb throttle shafts but it doesn’t seem large during the pressure test.
My conviction that these leaks are causing the low vacuum is reinforced because I observe that the pistons in the stromberg carbs do NOT rise off the bridge when I am cranking the engine. Thus I guess no air flow and no fuel.
After this long story, I have two questions for you:
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If others of you have watched the Stromberg carb piston during engine cranking (without ignition), does the piston rise up off the bridge?
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If the answer is yes, I conclude that the leak around the throttle shaft is the problem and I need to have the carbs professionally rebuilt. So my second question is who can I get to do this well and in a reasonable time.
I contacted Joe Curto but he reports a 10 to 12 week backlog.
Finally, if you think my basic diagnosis is wrong, please let me know.