Subject: Re: [Fot] EGT's again

From: "Tim Murphy" <[email-masked]>
Date: Wed, 22 May 2013 18:19:48 -0500

We have a TR4 with about 11:1 CR.  Our EGT's are mounted on #1 and #4 header
pipes about 1-1/2 to 1-3/4 inches from the cylinder head.  They are not
exactly equal.  #1 and #4 header pipes were used because they were a lot
easier to get the probes on.  At 3000 RPM "idle" (no load) we get between
800 and 1000 degrees.  Down the straights we get between 1300 and 1400
degrees, WOT in 4th.

One note for what it's worth: the pistons are being cooled every cycle by
the incoming charge whereas the EGT probes do not get any appreciable
cooling.  Even the exhaust ports get some cooling from the water jacket.

Tim

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of [email-masked]
Sent: Wednesday, May 22, 2013 3:24 PM
To: fot
Subject: [Fot] EGT's again

Fot, 

I know this has been brought up before but I don't know if there is any
consensus. 

The question is two parts. 

EGT probe location and what are considered normal temps. Westach users guide
will say the probes should be located 

6" from the manifold but Sam H says you start getting flakey readings out
there so he suggests 6" from the valve. 

That's right about where I'm at but I am seeing 1250 F on the EGT's but yet
my plugs are telling a richer story. 

It's been suggested that any less than 3" from the manifold and the probe is
right in the flame coming out of the valve and thus 

reading artificially high. 

So, just curious as to where peo ple locate thier probes and what kind of
EGT's they see. 

When I read threads from other makes I hear about people considering 1400F
as normal. 

It seems that if that were a true reading there would be some piston melting
going on. 

Thanks again for the input, 

jim g 
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From: Tony Drews <[email-masked]> ryville.ca.mail.comcast.net>
Date: Wed, 22 May 2013 22:19:27 -0500

I run about 6" from the flange.  I run 1400 in the 2nd half of the 
straights and have never seen any evidence of melting on my forget 
pistons.  I suspect that thinner cast pistons may be more susceptible 
to melting.  I also run 110 octane leaded and about 32 degrees of advance.

Tony Drews

At 03:23 PM 5/22/2013, [email-masked] wrote:
>Fot,
>
>I know this has been brought up before but I don't know if there is 
>any consensus.
>
>EGT probe location and what are considered normal temps. Westach 
>users guide will say the probes should be located
>
>6" from the manifold but Sam H says you start getting flakey 
>readings out there so he suggests 6" from the valve.
>
>That's right about where I'm at but I am seeing 1250 F on the EGT's 
>but yet my plugs are telling a richer story.
>
>It's been suggested that any less than 3" from the manifold and the 
>probe is right in the flame coming out of the valve and thus
>
>So, just curious as to where peo ple locate thier probes and what 
>kind of EGT's they see.
>
>When I read threads from other makes I hear about people considering 
>1400F as normal.
>
>It seems that if that were a true reading there would be some piston 
>melting going on.
>
>
>
>Donate: http://www.team.net/donate.html
>Forums: http://www.team.net/forums
>Unsubscribe/Manage: 
>http://autox.team.net/mailman/options/fot/[email-masked]

---

From: Scott Janzen <[email-masked]>
Date: Thu, 23 May 2013 08:42:37 -0400

2" from the head.   1300 degrees on the GT6 at 7000 RPM, 32 degrees advance.
Tailpipe is tan/grey, leaded 110, forged Venolia pistons, 12:1 compression
I suspect I could lean it out a bit - need some dyne time with the webers to
determine.
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