Quote:
Originally Posted by sasquatchgeoff
Assuming the following:
- rebuilt, calibrated original set of injectors
- rebuilt head, including prechambers, valve guides, seals
- non-contaminated fuel
With no apparent fuel leaks, can worn delivery vales/sealing washers & rings be the cause of nailing? If so, how?
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I wanted to update this thread:
Mind you this is an abridged version of a detailed story that relates a nailing problem that would surface slowly after purging air from my fuel system. I thought I had it fixed after I discovered that the injectors were not popping precisely within spec and made the shop reset them all three times. The shop was great, they were consistently nice to me, every time I went in there they gave me free goodies like return line hose, loan of special socket to remove delivery valves, and notepads/pens in addition to pop testing and calibrating my injectors for free three separate times. This shop was a great place to learn, I ran into some "old timers" (including a Stanadyne rep) and these guys felt pretty strongly that air infiltration was my problem.
After many trips to the injector shop, setting the pop pressure at 120, 138, and back to 125 in succession, 5 sets of injector heat shields, countless fuel hose clamp tightening operations, replaced primary filter, many sleepless nights visualizing my fuel delivery circuit, and expecting the inevitable horror of pulling my IP, I have solved this mystery wrapped in a riddle inside an enigma. When inspecting my secondary filter I discovered that as a result of over-torquing the hollow screw to hell and back, the center rubber seal in the canister was chewed up and distorted leaving the opportunity for the return fuel to mingle with the delivery fuel (see my latest thread). While I had the secondary fuel filter housing and canister off, I replaced the three connectors that link the housing/canister to the IP (milky white translucent plastic dealer items w/banjo and compression fittings). Put it all back together and presto, nailing problem solved.
Whether the problem was caused by the filter or by the IP/fuel filter connectors, I don't know but the car runs like a new one now. I wanted to let everyone know that all is well and I am ready to tackle the next problem. I have learned to slow my tortured brain down and expect the simplest solutions to be the secret to success.