Subject: [Fot] Oil Pressure Conundrum

From: marty <[email-masked]>
Date: Mon, 11 Jul 2016 14:09:23 -0400

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 =0A=
=0A=
I could use some opinions. Some history. Spitfire small=0A=
journal 1296 engine=2C rebuilt 6 race weekends ago included all new bearing=
s. I tore=0A=
it down this spring to check it over prior to last weekend PVGP event. Cam =
and crank=0A=
end floats were to spec. Rod and main bearings checked between .002 and .00=
3=0A=
clearance. I do not have the actual numbers in front of me at the present. =
Cam=0A=
bearings appeared to have some slight visual wear at the bottoms but I did =
not=0A=
actually measure them. I run Brad Pen 20W50. Oil temps run 210 and water te=
mps=0A=
run 190. EGT are 1200/1250 range on track. I was fighting low oil pressure =
at running temps all=0A=
weekend. Once my oil temps come up on track the pressure drops down to 35ps=
i.=0A=
If I add enough springs to the pressure relief valve I see over 125 psi col=
d so=0A=
I am thinking my pump is putting out enough pressure. I tried shimming to g=
et=0A=
50/60 cold at idle and it drops to 35 at operating temps at 7000 rpm. I tri=
ed a=0A=
new pressure gage over the weekend and the numbers did not change. I am=0A=
currently running an auxiliary oil line to the head=2C I removed it at one =
point=0A=
over the weekend and it had no effect. I tried a new pressure relief valve =
assy=0A=
and it had no effect.  I believe this=0A=
situation actually started a season ago because I added a washer to the=0A=
pressure relief valve last season.  I=92m=0A=
thinking it most likely is cam bearing wear even though all the bearings we=
re=0A=
fresh 6 events ago. Any guidance? One thing I did learn this weekend is my =
accusump=0A=
pressure gage is incorrect.  It was=0A=
reading about 30 psi higher that my dash gage. I was thinking it was probab=
ly=0A=
correct and my dash gage was wrong until I replaced my electric dash gage w=
ith a mechanical gage and its=0A=
reading matched the gage I just disconnected. Oil pressure readings are tak=
en=0A=
at the port below the distributer. =0A=
=0A=
 =0A=
=0A=
Side note. Car ran awesome. I ran a 2.22 at PittRace Sunday=0A=
and that was 6 seconds faster than my previous best lap there. =0A=
=0A=
 =0A=
=0A=
Thanks=2C=0A=
=0A=
Marty =0A=
=0A=
 		 	   		  =

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<body class=3D'hmmessage'><div dir=3D'ltr'>&nbsp=3B<font face=3D"Times New =
Roman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B">I could use =
some opinions. Some history. Spitfire small=0A=
journal 1296 engine=2C rebuilt 6 race weekends ago included all new bearing=
s. I tore=0A=
it down this spring to check it over prior to last weekend PVGP event. Cam =
and crank=0A=
end floats were to spec. Rod and main bearings checked between .002 and .00=
3=0A=
clearance. I do not have the actual numbers in front of me at the present. =
Cam=0A=
bearings appeared to have some slight visual wear at the bottoms but I did =
not=0A=
actually measure them. I run Brad Pen 20W50. Oil temps run 210 and water te=
mps=0A=
run 190. EGT are 1200/1250 range on track. I was fighting low oil pressure =
at running temps all=0A=
weekend. Once my oil temps come up on track the pressure drops down to 35ps=
i.=0A=
If I add enough springs to the pressure relief valve I see over 125 psi col=
d so=0A=
I am thinking my pump is putting out enough pressure. I tried shimming to g=
et=0A=
50/60 cold at idle and it drops to 35 at operating temps at 7000 rpm. I tri=
ed a=0A=
new pressure gage over the weekend and the numbers did not change. I am=0A=
currently running an auxiliary oil line to the head=2C I removed it at one =
point=0A=
over the weekend and it had no effect. I tried a new pressure relief valve =
assy=0A=
and it had no effect.<span style=3D"mso-spacerun: yes=3B">&nbsp=3B </span>I=
 believe this=0A=
situation actually started a season ago because I added a washer to the=0A=
pressure relief valve last season. <span style=3D"mso-spacerun: yes=3B">&nb=
sp=3B</span>I=92m=0A=
thinking it most likely is cam bearing wear even though all the bearings we=
re=0A=
fresh 6 events ago. Any guidance? One thing I did learn this weekend is my =
accusump=0A=
pressure gage is incorrect. <span style=3D"mso-spacerun: yes=3B">&nbsp=3B</=
span>It was=0A=
reading about 30 psi higher that my dash gage. I was thinking it was probab=
ly=0A=
correct and my dash gage was wrong until I replaced my electric dash gage w=
ith a mechanical gage&nbsp=3Band its=0A=
reading matched the gage I just disconnected. Oil pressure readings are tak=
en=0A=
at the port below the distributer. <o:p></o:p></p><font face=3D"Times New R=
oman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B"><o:p>&nbsp=
=3B</o:p></p><font face=3D"Times New Roman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B">Side note. C=
ar ran awesome. I ran a 2.22 at PittRace Sunday=0A=
and that was 6 seconds faster than my previous best lap there. <o:p></o:p><=
/p><font face=3D"Times New Roman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B"><o:p>&nbsp=
=3B</o:p></p><font face=3D"Times New Roman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B">Thanks=2C<o:=
p></o:p></p><font face=3D"Times New Roman">=0A=
=0A=
</font><p class=3D"MsoNormal" style=3D"margin: 0in 0in 8pt=3B">Marty <o:p><=
/o:p></p><font face=3D"Times New Roman">=0A=
=0A=
</font> 		 	   		  </div></body>
</html>=

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