Dr. Evil

Never said it was a "Piston Temperature Guage" but pre turbo has got to be a LOT closer to the actual temperature.

Just my 2 cents

Big Blue24

I think anyone pulling a loaded trailer at 1100* post turbo egt reading is flirting with meltdown. I think anyone running a constant 1000* pre turbo with 30* timing is flirting with a meltdown.

If egt probe was 1/4"x1.5" and if exhaust manifold was 2" ID, the probe would decrease volume by 3%. My edge supplied egt probe is 3/16" wide by 1" protrusion so it takes up 1.5% of the volume. Steven buddy, I appreciate your counter points, but I think most people will benefit the most by having egt probe pre turbo. 90% of the members on here have theirs plumbed this way. This allows us to compare numbers and see how close we are to Bobcat and others who have had meltdowns with x degrees of timing and x degrees on the pyro etc. It's interesting to note that most of the melted pistons on here have been on tow rigs. Getting back to the HOHN idea of heat vs. temperature. It appears that advanced timing has eaten more engines than excessive temps. Lots of third gen guys losing pistons when they stack boxes that do pressure and timing.

HOHN

My bad-- i read more into your "actual temp" phrase than you intended. Actual EGT, of course!

JHew84

Exactly. I stressed out a TON before I did this because everyone was so worked up over it on the forums. I let the engine idle and what seemed like 10lbs of metal shavings flew right back out of the hole (thank you safety goggles!). Only took me a few minutes and nothing was abnormal during or afterwards.

Just be cautious, let the engine idle, and get the job done! No need to get all freaked out, it only perpetuates the problem!

PaulDaisy

I agree with Dr. Evil.
Also, just for the sake of argument, inserting a 1/4" probe into a gas stream is not "blocking" the equivalent area of the flow pipe. Not even close. The gas flows around, creating turbulence (not important in the exhaust gas stream) and flows back again through the full pipe diameter.

vrj

I'm about to install my EGT gauge (Autometer) and sender (1/8) and need to know the drill bit size and NPT tap size.

I've read numerious threads and I've got some conflicting information. Thx.

HOHN

I'm pretty sure it's 5/64ths drill size. Tap is 1/8" NPT.

Some pyros are 1/4"NPT, but most are 1/8".

meangreen96

Am I misreading your post?? But isn't....

Tap drill for 1/8" NPT is a letter R (.339"), 11/32 (.344) works too.

- Craig

vrj

Thanks for the advice. I purchased a 1/8 NPT tap from the local department store for my 1/8 EGT fittings.

I then went during the following week before work to a specialty nut & bolt company. This is where I validated and purchased the "R" (.3390) cobalt drill for the drilling. I also purchased a 1/8" drill for the pilot hole which will be drilled first and then following up with my final drill of .3390 hole to be taped.

I can't wait to be able to monitor my EGT. I'm surprised I made it without it this long.

HOHN

No, you're not misreading my post. Your just seeing me mistakenly pass bad info.

Thanks for correcting!

PaulDaisy

I tapped for the 1/8" NPT in a banjo bolt with a 21/64" bit. I think that is the second recommended diameter after size R.

smokinstrokes99

check online instructions from guage manufacturer and run a pen magnet in the hole with a well greesed bit and just keep running the magnet and cleaning the grease and adding greese thats what i did and it worked fine

vrj

I finally took the plunge and did the EGT install after doing my research and gathering up the needed items.

Like a prev. user, I drilled the manifod ("R" cobalt drill) while cold (not running) and stopped every few seconds and blew the particles away. When I was about to break-through, I stopped and had my a friend start the truck. I then put grease on the drill bit and broke through the manifold.

After it was shut down, I used a magnet to get whatever particles might have escaped me. I then lubed up the 1/8 NPT table and tapped it slowly.

I then inserted the EGT fitting approx. 1/2 way in (no threads in the exh. stream). I then completed the EGT sender install. I started it and let it idle for a few minutes without any boost.

Now my last gauge was installed. I now have gauges for: Fuel Pressure, Trans. Temp., Boost, & EGT.

It sure is a joy to know whats going on with important parts of the truck. I now know when to shut the truck down so as to save the turbo which is between 400 degrees 350 degrees.

Thanks to all for info. on the EGT install.