CHT Gauge, Suggestions? Options

[eyesright]

I went with a VDO CHT along with an oil pressure and temp gauge on my stock 2.0L rebuild a couple of years and 40K miles ago. Looked good under the dash. It was accurate in that my head temps were exactly what Len Hoffman and Jake said they would be with the 9550 cam kit and HAM rebuilt heads. I checked it with an IR temp gun from HF by pulling the plug wire and flashing it around the spark plug area. Hard to find an ideal spot to read from as you are shooting the gun pretty much blind and there are lots of angles to reflect off of, but all the readings were reasonable and none were higher than the VDO gauge.

[BeatNavy]

I just added the Dakota Digtial. I was wondering what would be normal ranges?

Running around see 350 to 375. Running hard it can hit 400. Comes down quickly on normal driving but I was wondering where the sweet spot should be and where the danger zone is?

Also it seems to respond quickly increasing with throttle. Was a bit surprised by the quick changes in temp.

Mike, I've been running the Dakota Digital for about 2 years now. Those temps you're reporting seem high - but what kind of driving are you talking about? Cruising around the parkways in my community I get over 300 only driving hard or up a hill, and then it will go back down quickly when I slow down for a light. On a long stretch of highway driving it will usually stay between 330 and 360, maybe slightly higher going up a hill.

Yes - the temps can change very quickly.

Here's the guide for reference: http://www.914world.com/specs/JakeRabyHeadTemps.php Stay away from 400+!

[McMark]

Researched this when I was looking to put one in my car. Most folks weren't too happy with the VDO CHT and many recommended Aircraft Spruce. I bought the following and have installed all but the sensor as I am still waiting on engine; I've included part numbers and what I paid back in November:

aircraftspruce.com

10-01425 2" CHT PYROMETER GAUGE 61.75
10-00823 CHT PROBE 14MM M-1000 23.95
10-01443 15 CHT EXTENSION LEAD 51.25

(IMG:style_emoticons/default/agree.gif) This is fine for most people, and is the bare minimum.

[Mblizzard]

I just added the Dakota Digtial. I was wondering what would be normal ranges?

Running around see 350 to 375. Running hard it can hit 400. Comes down quickly on normal driving but I was wondering where the sweet spot should be and where the danger zone is?

Also it seems to respond quickly increasing with throttle. Was a bit surprised by the quick changes in temp.

Mike, I've been running the Dakota Digital for about 2 years now. Those temps you're reporting seem high - but what kind of driving are you talking about? Cruising around the parkways in my community I get over 300 only driving hard or up a hill, and then it will go back down quickly when I slow down for a light. On a long stretch of highway driving it will usually stay between 330 and 360, maybe slightly higher going up a hill.

Yes - the temps can change very quickly.

Here's the guide for reference: http://www.914world.com/specs/JakeRabyHeadTemps.php Stay away from 400+!

Driving hard to me is WOT when ever possible! But based on the guidance it seems I am still too warm at the times I am not driving that hard!

In the process of refining the AF mixture as it goes a little lean at cruise (15 to 16) so I could richer that up a bit but the timing is 27 on the mark and I hane all electronic dizzy so dwell is not an issue. Verified flap over oil cooler is operating correctly. Valves recently set with head install.

So is the next step to retad the timing a bit? Any suggestions?

[Bulldog9]

I've been running the VDO gauge with the VDO sensor. It works. I'm sure there are more accurate and more expensive gauges and sensors, but I have a digital heat probe and the gauge is within 50 degrees of that. Is relatively cheap, and responds quickly to changes, but not perfectly precise I'm sure. Keeps me out of trouble.

[Bulldog9]

Thanks for the info - I knew y'all would be able to help. Naturally, I have follow up questions...

First - can I assume these CHT gauges utilize the OE sensor in the head (I have brand new HAM heads drilled/tapped for OE sensor at cyl. #3) and also assume they connect to the OE wiring (single lead from sensor)?

Thanks as always...

You can run the VDO sensor under a fine threaded bolt in the OE sensor's location, but the sensor is designed to go under the spark plug, so you will not get accurate CYL temp, only the head temp in the region of CYL 3. I tried it there, because of the location, is not as hot as on the plug, and the temp gauge is slower to report the cyl temps. So, you could spike temp in a cyl before you know it..... Important if you are racing or pushing the engine all the time.

[kgruen2]

I have searched - cannot find much on aftermarket CHT Gauges.

I am building a 2056 that will run dual Dells - would like to install a quality CHT gauge and wondering what others have used.

Try Summit Racing.

[Mark Henry]

I'm happy with my VDO gauge and sender. I'm not looking for 100% accurate numbers, but more over I'm looking for drastic changes while driving and for that I think the VDO is just fine. Plus the VDO matches the other gauges in my console (except for the wide-band o2 GAUGE)

(IMG:style_emoticons/default/agree.gif) While most definitely not the best gauge it is better than nothing.
My aftermarket EFI also has a head temp gauge and they seem to be in the same ballpark.

But I also agree the Aircraft Spruce Micro 1000 unit is a better choice.

[Elliot Cannon]

I have used a VDO gauge with the spark plug sender. I'm not looking for dead on accuracy. I have established a normal range of 325 to 375. High way cruising it's about right on 350. It could be 350 +or- a few degrees. I can tell with a quick glance at the gauge if things are OK. I saw temps over 400 one time. A long stretch up hill for a few miles west bound from Needles to Barstow into about a 40 mph head wind. The engine wouldn't answer the throttle. I had to pull over and stop to let things cool down. Luckily no damage. Without the CHT gauge, I might have over temped and damaged something. I highly recommend a CHT for every air cooled engine.

[kgruen2]

I just added the Dakota Digtial. I was wondering what would be normal ranges?

Running around see 350 to 375. Running hard it can hit 400. Comes down quickly on normal driving but I was wondering where the sweet spot should be and where the danger zone is?

Also it seems to respond quickly increasing with throttle. Was a bit surprised by the quick changes in temp.

I put a digital CHT Gauge in mine when I had my R.A.T. 2270SR engine installed. I, too was surprised at the rapid temp changes under all driving conditions. My understanding is normal range is the low 300's, ok up to the mid to high (375) 300's. hot approaching 400 and higher. Mine runs 300-320, gets up to 350 climbing hills (drops immediately when downshifting to 4th or even 3rd). Goes as low as 220-250 downhill with foot off accelerator.

Karl