In a message dated 11/29/06 12:04:20 PM Pacific Standard Time,
<< There are actually two valves in the TRactor motor (as in most engines).
The adjustable one dumps oil back into the pan to limit pressure rise; but
there is also a fixed one that will bypass the filter (feeding the galleries
with unfiltered oil) if the drop across the filter becomes too high. Jack's
"theory" is that perhaps this second valve opens even under normal
conditions ... which certainly seems possible to me. >>
You are right. The following is my second response to Jack:
Subj: Re: [FOT] BLOW-UPS
Date: 11/29/06 12:43:34 PM Pacific Standard Time
In a message dated 11/29/06 11:09:12 AM Pacific Standard Time,
<< I suspect it's the other valve, not the adjustable one, that I think is
designed to allow oil to go through the system in case the filter is
This is probably right. Ken Galanders wrote an article about this several
years ago. He recommended plugging off this passage for racing, and shimming
the spring for highway driving. I originally plugged off this passage by
tapping and installing a 1/8" pipe plug. Now, I am just shimming the spring
couple of small washers. Greg Solow is shimming this bypass in his car a
I am having an amazing amount of good luck with the last engine that I built,
after all of my recent blowups. The changes that I made were:
Drill and tap the center oil galley port to accept 3/8" pipe thread.
Connect the accusump at this location.
Went back to the stock oil filter.
Installed Greg Solow's sandwich plate with the oil cooler lines coming
off of the back of it.
Installed the oil cooler on its side directly in front of the radiator to
get the full blast of air.
Installed Greg's oil pump pickup, which draws oil from the bottom, near
the bottom of the pan.
Put baffles in the front of the oil pan.
Started using an 160F thermostat. I may go back to the restrictor washer.
You may have done a lot more exotic things than the above, but I have many
times outsmarted myself and ruined things.