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joe kenna (aka My_33) [ View ] [ Email ] [ Car Ads ] [ Blogs ] Dayton, Texas

Small block chevy... Temp Sendor better in the head or better in the intake... Why???

Comments

Posted by dixie  -  02/01/2008 05:12 PM IN the intake ,get a truer reading, in the head to close to headers,hottest part of engine. your reading the water temp. jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by Starfire  -  02/01/2008 07:13 PM Ditto, the closer the sensor is to the thermostat the more accurate the reading. Starfire [ View ] [ Email ] [ Blogs ] [ Car Ads ] Weimar, Texas   Posted by Crazyhorse Rod Shop  -  02/01/2008 07:34 PM heat soak from the exhaust port. although gm has put them there for years. dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003   Posted by My_33  -  02/02/2008 10:58 AM Mine is in the head. Going to move it to the intake. While running down the highway even in the summer car runs 110, the minute you stop in traffic here comes the temp rise I believe from header and engine heat soak like Shine states. I agree starfire, should be looking at the thermostat outlet don't know why it was put in the head... Thanks for all comments! My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by Starfire  -  02/02/2008 11:32 AM Just don't relocate it between the thermostat and the radiator. If you do you will have no temperature reading unless the thermostat is open. As a side note: Having a sensor on each head with separate gauges is often used with racing and even marine engines in order to monitor head temperature verses common coolant temperature. Starfire [ View ] [ Email ] [ Blogs ] [ Car Ads ] Weimar, Texas   Posted by Crazyhorse Rod Shop  -  02/02/2008 11:51 AM i prefer mine in the head. not interested in temp in the aluminum intake. rather know what is going on in that head since the water is coming straight from the block. the only problem with the head location is most aftermarket headers are too close. i like the clipster headers best. dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003   Posted by 37tin  -  02/02/2008 12:14 PM .......clipster???? 37tin [ View ] [ Email ] [ Blogs ] [ Car Ads ] langley, Canada   Posted by Starfire  -  02/02/2008 12:49 PM Depends upon which engine as to the flow of coolant. In some engines coolant is pumped simultaneously into the heads and the block with the return from the block simply passing through a passage in the head directly into the intake manifold. It's a case by case basis base upon individual block and head design. In the case of a small block Chevy some variations such as the LT1 have coolant flow exactly reverse to previous designs. It is highly doubtful the temperature reading being taken from coolant in an aluminum intake would have significant variation verses a cast iron intake or any other point where there are no direct influences from exhaust temperature. Starfire [ View ] [ Email ] [ Blogs ] [ Car Ads ] Weimar, Texas   Posted by My_33  -  02/02/2008 03:13 PM I have a Holley aluminum intake. It has a small and large pipe plug at the thermostat ouitlet on top of the intake. I moved the sensor from the head to the small pipe plug in the intake. Cranked her up, temp slowly went to about 225, (180 thermostat) I put my shop blower fan in front of the radiator and the temp gage held at about 225 (only goes to 250). I never see the thermostat open by the temp gauge but it is open when I grab hold of the outlet hose. I'm no better off than before I started. I read a post where VDO gauges were not to hot. I got VDO gauges. I'm going to try a pyrometer next and maybe try to prove out the temp gauge, or run another temp gauge (outside the dash) to verify the VDO gauge. My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by Starfire  -  02/02/2008 05:59 PM My_33 - I'd be more inclined to believe you have gotten a bad thermostat rather than a bad gauge. I've gone through as many as three new thermostats before finally getting a good one. So many of the thermostats today are made overseas with apparently no quality control it's ridiculous. It's gotten to the point I even check the GM and Ford thermostats for point of manufacture before I take them. Starfire [ View ] [ Email ] [ Blogs ] [ Car Ads ] Weimar, Texas   Posted by My_33  -  02/02/2008 07:13 PM Good point Starfire... I'm using a sleeve type Mr. Gasket... Car had a poppet thermostat when I bought it, I recently changed to the sleeve type... I wish I could use the new radiator cap Mr. Gasket has out with a built in temp indicator, it will not fit my radiator, the temp probe bottoms out on the inside where the cap screws on... My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by lost34  -  02/02/2008 07:33 PM since you have VDO gauges, their sending unit gives false readings when teflon tape is used or teflon paste. use a touch of never -seize on the sending unit. lost34 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Reading, Pennsylvannia   Posted by My_33  -  02/02/2008 08:46 PM I have never heard that one, I do have teflon tape on the threads... My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by lost34  -  02/02/2008 08:58 PM I had the same problem a few years back. this is what the VDO reps told me at the NSRA East event. lost34 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Reading, Pennsylvannia   Posted by My_33  -  02/02/2008 09:16 PM Lost 34 where is your sending unit located intake or head? I will try removing the teflon tape... My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by JAWS  -  02/02/2008 09:30 PM Lost34 is correct, reason being is the gauge measures resistance to ground through the sender. If there is unnecessary or more resistance to ground than designed the gauge will show this. Never seize is conductor of electricity and will ensure that a sender grounding issue isn't the issue. By the way, true engine temp, not coolant temp is measured in the head as it is closest to the heat source, ie.. combustion chamber. Although as Shine said and others the headers, some, will actually cause a problem with heating the sender from the outside causing more resistance, not exactly the same as Teflon tape, but the principle is the same. This is due to the thinner metal in the header primary tubes, radiating more heat, as compared to cast manifolds or higher end after market headers that are coated. An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by My_33  -  02/02/2008 10:51 PM Good information Jaws... I bought a sender today and it actually had teflon tape on it out of the box. (never seen that).. It makes since what you and lost34 are saying... I will definitley remove it... I just dont think this motor is running as hot as the temp indicator shows but I cannot prove it yet... As the motor warms up I never see the thermostat open, in other words I never see a temp drop when the thermostat opens the temp just keeps slowy rising until 250 max on gauge... With a 16 psi cap I dont think the water will boil till about 260-265... With the sender in the head the temp only rises during idle in trafffic or just sittting still... Cruising speed temp will not run above 110 degrees... I do not like that at all... A temp indicator ought to run the thermostat setting on the gauge or at least close to it... Thanks My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by JAWS  -  02/02/2008 11:04 PM I think the problem or one of them is that the coolant doesn't have enough dwell time in the radiator to cool. It is constantly flowing due to too cold a T-stat, staying open and not cycling as it shoud. Also, air flow across the core is detrimental and that is another discussion. An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by 37tin  -  02/02/2008 11:45 PM OK..JAWS, good advice as always, I got a heat gun from a bud, checked it out, yep,,8 to 10 degree diff,. from the gauge, now I will drain fluid and clean threads..more work! don't like you right now! but, gotta make it right, thanks. I don't know how to do a little happy face so hows this,,,@ I say again, good advice 37tin [ View ] [ Email ] [ Blogs ] [ Car Ads ] langley, Canada   Posted by JAWS  -  02/03/2008 01:15 AM Don't be surprised if the gauge doesn't read that much more accurately. Most after market electronic gauges are just that far off. Remember they are only meant for an idea of how hot the engine is, in a set range. That's why they have a needle and a face with numbers and hash marks. The inferred gun is as close to exact as your gonna get. Ideally you should be looking for your motor to run in a desired range, verified by the heat gun, and then only be alarmed if it stops acting "normal"........ An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by Crazyhorse Rod Shop  -  02/03/2008 08:51 AM if it aint pukin it aint hot. if it runs warm put a higher thermostat in it. i never use less than a 180 and check it before using it. dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003   Posted by JAWS  -  02/03/2008 10:07 AM Shiner, that is the simplest way to tell for sure......molecules don't lie........ An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004   Posted by 46Chevy12ton  -  02/03/2008 11:18 AM Guys What should be a normal idling and running temperature with a 350, Alum rad and 180 thermostat. 46Chevy12ton [ View ] [ Email ] [ Blogs ] [ Car Ads ] Winnipeg, Canada   Posted by Crazyhorse Rod Shop  -  02/03/2008 11:24 AM the 56 big window i just did would come up to 215, then fan on for no more than 90 sec and it would drop to 190. dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003   Posted by ol bear  -  02/03/2008 01:20 PM I PREFER SENDER TO BE IN THE INTAKE ,WITHOUT ANY TEFLON TAPE,,, IF IT GETS TO HOT ,THE DAM THING WILL LET U KNOW WHEN IT STARTS TO PUKE ,,,,,,,,,,,,,, OL BEAR OL BEAR [ View ] [ Email ] [ Blogs ] [ Car Ads ] crown point, Indiana   Posted by 46Chevy12ton  -  02/03/2008 07:18 PM Thanks Shine 46Chevy12ton [ View ] [ Email ] [ Blogs ] [ Car Ads ] Winnipeg, Canada   Posted by 37tin  -  02/03/2008 07:59 PM Well!! I did the test, stove, pot, thermometer, Tstat, my 180 stat started opening at 163, it's stamped 180, I'll keep the pot on the stove and go get a couple more, testing goes on, I did clean the threads and never seized them, 37tin [ View ] [ Email ] [ Blogs ] [ Car Ads ] langley, Canada   Posted by My_33  -  02/04/2008 05:06 PM Thanks for the comments guys... Shine, I just can't make myself let it sit past the 250 degree mark with-out puckering me up... But your right if aint puking it aint HOT! I'm going to put the pyrometer on it and get a feel for what she is really running at idle I just don't believe it is running any where close to the VDO gauge... Thanks.. My_33 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Dayton, Texas   Posted by 41 Kustom  -  02/04/2008 05:26 PM I had to small of a radiater for years. Sender in the head. two strikes right there. I took to running straight antifreeze because that dose'nt boil. Strike three. I was young and dumb. You learn as you go. After I got every thing straight I still ran that moter anonther five years. Just shows GOD even wathes over idiots. 41 Kustom [ View ] [ Email ] [ Blogs ] [ Car Ads ] Essex, Vermont   Posted by Tweety37  -  02/04/2008 07:28 PM I'm a little confused by recommendations to put the sender in the manifold. Most all of the small block chevs I have owned had it in the head. My '37 Chevy with mild 350 has it in the head. It has a Walker radiator, hi flow Stewart pump, hi flow 180 thermostat and a 3000 cfm puller elec fan. I have the fan wired to a manual switch and when the gauge gets to about 195 in slow traffic or idling, I switch the fan on and within a couple of minutes the temp drops back to the 180 range. If the car is moving just enough to get some airflow it usually runs in the 180 - 190 range and always 180 on the highway. Tweety37 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Bismarck, North Dakota   Posted by hotrodgene  -  02/04/2008 07:43 PM Here is my two cents worth on this subject.As you all know GM put this sending unit where it is and if you are running a FI eng you best leave it there since the FI and most sensors are calibrated for temp.signal it is recieving from computor.I do know if example GM has all set for 200 deg.an you change another loation,diff.fan system,radiator etc.and you are giving computor diff. temp reading then you could be running way rich since computer thinks eng needs more fuel due to temp.None of this would apply to most hotrods since they ar using carbs.I am running FI eng out of corvette so it applies to me.Thanks Thanks,Gene [ View ] [ Email ] [ Blogs ] [ Car Ads ] Saint Petersburg, Florida   Posted by dixie  -  02/04/2008 07:45 PM Everyone knows do not use vdo u will get false readings most of the time . jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006

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