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Re: [Fot] Race Engine Refreshing Frequency - compression results

To: "fot@autox.team.net" <fot@autox.team.net>, James Trudeau <jgtrudeau@comcast.net>
Subject: Re: [Fot] Race Engine Refreshing Frequency - compression results
From: fubog1 via Fot <fot@autox.team.net>
Date: Sun, 29 Oct 2023 14:32:49 +0000 (UTC)
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <143ACDB5-F1BA-4401-B5B7-47DB9F62DDA5@comcast.net>
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 Every engine will have a different service life, depending on state of dev=
elopment, tune, rpm range, general maintenance, etc.A competitive full-tilt=
 National spec engine will likely get a freshen-up every weekend, a mild-tu=
ne/low rev Vintage engine can last seasons w/regular maintenance.Leakdown, =
oil filter inspection, valve lash check, oil pressure & temp readings, & pl=
ug check will give an idea of the engines health.Next step is a bearing che=
ck; anything beyond that involves full teardown & hands-on inspection.Also =
set valve lash prior to compression test, & realize that the compression te=
st is of limited value; a leaking cylinder can still pump up pretty good...=
HTH
Glen Efinger
.

    On Saturday, October 28, 2023 at 05:02:44 PM EDT, James Trudeau via Fot=
 <fot@autox.team.net> wrote: =20
=20
 I finished a 9 weekend race/school/track day season that started in April =
and finished at Thompson in October with no obvious performance problems. T=
otal of 38 engine hours including warmup, grid, race, cool down.=C2=A0
Did a dry compression test today:  =20
   - 210
   - 225
   - 195
   - 200

I get some oil blow by at the valve cover cap and maybe some drips from low=
er end seals (not sure if oil starts at valve cover).=C2=A0
I=E2=80=99m sure I=E2=80=99ll hear a suggestion to do a leak down test and =
/ or wet compression.=C2=A0
Oil filter forensics?
In the absence of obvious issues, how much of a tear down is warranted?=C2=
=A0
Jim

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m


 =20
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<html><head></head><body><div class=3D"ydp38579740yahoo-style-wrap" style=
=3D"font-family:Arial, Helvetica, sans-serif;font-size:16px;"><div></div>
        <div dir=3D"ltr" data-setdir=3D"false">Every engine will have a dif=
ferent service life, depending on state of development, tune, rpm range, ge=
neral maintenance, etc.</div><div dir=3D"ltr" data-setdir=3D"false">A compe=
titive full-tilt National spec engine will likely get a freshen-up every we=
ekend, a mild-tune/low rev Vintage engine can last seasons w/regular mainte=
nance.</div><div dir=3D"ltr" data-setdir=3D"false">Leakdown, oil filter ins=
pection, valve lash check, oil pressure &amp; temp readings, &amp; plug che=
ck will give an idea of the engines health.</div><div dir=3D"ltr" data-setd=
ir=3D"false">Next step is a bearing check; anything beyond that involves fu=
ll teardown &amp; hands-on inspection.</div><div dir=3D"ltr" data-setdir=3D=
"false">Also set valve lash prior to compression test, &amp; realize that t=
he compression test is of limited value; a leaking cylinder can still pump =
up pretty good...</div><div dir=3D"ltr" data-setdir=3D"false">HTH</div><div=
 dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=
=3D"false">Glen Efinger<br></div><div dir=3D"ltr" data-setdir=3D"false">.<b=
r></div><div><br></div>
       =20
        </div><div id=3D"ydp1782500ayahoo_quoted_8817326337" class=3D"ydp17=
82500ayahoo_quoted">
            <div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
               =20
                <div>
                    On Saturday, October 28, 2023 at 05:02:44 PM EDT, James=
 Trudeau via Fot &lt;fot@autox.team.net&gt; wrote:
                </div>
                <div><br></div>
                <div><br></div>
                <div><div id=3D"ydp1782500ayiv2186919804"><div>I finished a=
 9 weekend race/school/track day season that started in April and finished =
at Thompson in October with no obvious performance problems. Total of 38 en=
gine hours including warmup, grid, race, cool down.&nbsp;<div><br></div><di=
v>Did a dry compression test today:</div><div><ol class=3D"ydp1782500ayiv21=
86919804ol1"><li style=3D"margin:0px;font-stretch:normal;line-height:normal=
;" class=3D"ydp1782500ayiv2186919804li1"><span class=3D"ydp1782500ayiv21869=
19804s1">210</span></li><li style=3D"margin:0px;font-stretch:normal;line-he=
ight:normal;" class=3D"ydp1782500ayiv2186919804li1"><span class=3D"ydp17825=
00ayiv2186919804s1">225</span></li><li style=3D"margin:0px;font-stretch:nor=
mal;line-height:normal;" class=3D"ydp1782500ayiv2186919804li1"><span class=
=3D"ydp1782500ayiv2186919804s1">195</span></li><li style=3D"margin:0px;font=
-stretch:normal;line-height:normal;" class=3D"ydp1782500ayiv2186919804li1">=
<span class=3D"ydp1782500ayiv2186919804s1">200</span></li></ol><div><br></d=
iv><div>I get some oil blow by at the valve cover cap and maybe some drips =
from lower end seals (not sure if oil starts at valve cover).&nbsp;</div><d=
iv><br></div><div>I=E2=80=99m sure I=E2=80=99ll hear a suggestion to do a l=
eak down test and / or wet compression.&nbsp;</div><div><br></div><div>Oil =
filter forensics?</div><div><br></div><div>In the absence of obvious issues=
, how much of a tear down is warranted?&nbsp;</div><div><br></div><div>Jim<=
br><br><div dir=3D"ltr">Sent from my iPhone</div></div></div></div></div>__=
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