<html><body><div style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10pt; color: #000000"><div><br></div><div>Probably much more horsepower is lost by being too kind on a fresh engine than by running it at full throttle too soon;</div><div>Marcel</div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>Van: </b>"fot" <fot@autox.team.net><br><b>Aan: </b>paulricco@att.net, "fot" <fot@autox.team.net><br><b>Verzonden: </b>Zaterdag 25 augustus 2018 23:33:25<br><b>Onderwerp: </b>Re: [Fot] TR4 Race Engine Break-in Questions<br></div><br><div data-marker="__QUOTED_TEXT__"><span color="black" size="2" face="Arial, Helvetica, sans-serif" data-mce-style="color: black; font-family: Arial, Helvetica, sans-serif; font-size: small;" style="color: black; font-family: Arial, Helvetica, sans-serif; font-size: small;">
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<span size="2" face="Arial, Helvetica, sans-serif" color="black" data-mce-style="color: black; font-family: Arial, Helvetica, sans-serif; font-size: small;" style="color: black; font-family: Arial, Helvetica, sans-serif; font-size: small;">
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<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4168" dir="LTR">
<div style="margin-bottom: 0in"><a name="yui_3_16_0_ym19_1_1535222251184_2891"></a> Th<span size="2" data-mce-style="font-size: small;" style="font-size: small;">e s</span>hort version, rings flex.</div>
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<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4166" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4165"></a>
Piston pushes ring up, it's flat and against the lower face of the
groove. Gas pressure charge travels through the side gap on top past the upper face of the ring
and gets behind it right before TDC @ ignition point.</div>
<div style="margin-bottom: 0in"> At that point
the ring flexes and seals the top and lower faces of the ring
against the groove faces, and the charge is trapped behind the ring;
this is for pressure retention & max ring expansion. When the
piston starts to go down, the ring flexes back flat against the
upper groove face and loses the charge behind it and relaxes a bit.</div>
<div style="margin-bottom: 0in">Repeat this every combustion stroke.</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4559" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41651"></a>
The above is with power on.</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4300" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41652"></a>
On closed throttle (decell), there's a vacuum on top of the piston
so there is not a pressure charge to fully expand the ring, so it
doesn't flex the same.</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4400" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41653"></a>
This flexing of the ring will give it a very very slightly ) face as
a result, it's not perfectly flat.</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4560" dir="LTR">
<div style="margin-bottom: 0in">So ring seating isn't just to to get
the initial "burnishing" of ring/cylinder wall, it also
establishes the profile of the ring face for the best seal under
both full open and full closed throttle.</div>
<div style="margin-bottom: 0in">It's all in the ring FLEX!</div>
<div style="margin-bottom: 0in">This is also why ring side clearance
is so critical, I scrap more pistons for this being out of spec than
for any other reason, especially if the engine was running rich.<br>
<br>
</div>
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<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4699" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41656"></a>
My break-in routine is-</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4733" dir="LTR">
<div style="margin-bottom: 0in">Initial start, run to temp, 1 maybe 2
heat cycles, retorque & check all.</div>
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41658"></a>
(If new cam, 15-20 minute @ 2k rpm)</div>
<div style="margin-bottom: 0in">No excessive running beyond cam
break-in and basic tuning with no load!</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_4886" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_41659"></a>
On track, 2-3 warm-up laps @ part throttle, vary RPM 4-5k, use some
engine braking.</div>
</div>
<div id="yiv8453697846yui_3_16_0_ym19_1_1532862227910_5031" dir="LTR">
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_416510"></a>
2-3 more laps with more throttle and engine braking, same rpm.</div>
</div>
<div style="margin-bottom: 0in"><a name="yiv8453697846yui_3_16_0_ym19_1_1532862227910_416511"></a>
2-3 more laps using full throttle, maybe 85-90% revs, and intentional
repeated HEAVY engine braking from WOT in top gear.</div>
<div style="margin-bottom: 0in">After that I usually do a retorque and
follow-up; next time out should be good to go.
</div>
<div style="margin-bottom: 0in">This open/closed throttle running
subjects the rings to the loads that it will have under normal
operation.</div>
<div style="margin-bottom: 0in">HTH</div>
<div style="margin-bottom: 0in">Glen<br>
</div>
</div>
<div> <br>
</div>
<div> <br>
</div>
<div style="font-family:arial,helvetica;font-size:10pt;color:black">-----Original Message-----<br>
From: Paul Ricco via Fot <fot@autox.team.net><br>
To: Friends of Triumph <fot@autox.team.net><br>
Sent: Sat, Aug 25, 2018 1:30 pm<br>
Subject: [Fot] TR4 Race Engine Break-in Questions<br>
<br>
FOT,
Good afternoon and we hope everyone is having a great weekend.
We have a couple questions for those who have had experience and success building TR4 race engines. The information might be helpful others on the forum as well.
1. We have seen a few different recommendations for initial run-in. They seem to range from 5 minutes to 20 minutes at approximately 2000 RPM’s. How long and how many RPM’s are people running them for?
2. How long are people leaving the break-in oil in the motor?
a. Are people taking out the break in oil right after the run-in and replacing it with regular oil before leaving for the track?
b. Are people running a few sessions under load at the track with it in and then switching?
c. Something else? If so, what are you having success with?
Again, we are really gearing the questions towards race engines due to complication of breaking in the race motors at the track with limited time and the track session schedules.
We are trying to avoid re-starting the entire referendum up on oil brands again, so we apologize if we do. We are really trying to get to how people are breaking-in the TR4 motors successfully.
Thank you for considering my questions,
Paul Ricco
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