Question: RUNNING TOO COOL

[minifridge1138]

If the engine coolant is too low, then the oil does not get hot enough to boil out the blow-by.
This causes the oil to degrade, which reduces lubrication.

As I mentioned earlier, I've tried 3 different 180 thermostats from Mr. Gasket and they all ran closer to 140 than 180.
I finally bought a "cheap" 180 thermostat and drilled two small holes in it. This is basically what the Mr. Gasket thermostat does (it allows a small amount of fluid to flow even when the thermostat is closed).

Running a colder thermostat does NOT increase power. Cooler AIR increases power, not cooler engine temp. Colder air is more dense then warm air. Dense air has more oxygen. This is why carburetors need to be adjusted for high altitudes (it is also why it is hard to breath at higher altitudes). Switching to a 160 thermostat does not decrease the temperature of the air, therefore it does not make more power.

 

[Bolisk]

100% Correct! It's amazing how many people think that a cooled engine will increase power. (including myself at one point) It's only the colder air that goes into the intake (hence cold air intake systems) that produce more power. Another thing that people get stuck on, is that they think that a 160 degree thermostat will lower the operating temp of their car. That is also incorrect. The 160 degree thermostat simply opens at 160 degresses. This means that the the car's "minimum" operating temp will be controled to 160 degrees. The thermostat does not control hight temps. If the car has an over heating problem. . .it will still over heat.

 

[Bolisk]

To answer BLK_VRT. . .

When I got my car, it had the incorrect temp sending unit, and an aligator clip sodered to the end of the temp send unit wire loom. This was common for our cars as the correct temp sending unit went out of production over the last 30 - 40 years. So people had to use whatever was available.

The problem is that the gague and the sending unit were calibrated at the factory, to work as a pair. When people replaced them with the wrong sending unit, they almost always got an incorrect readout on the gague. Many people had corrected this by placing a resitor on the back of the gague (you will have to check). If you replace your sending unit with the correct one (letric limited now makes the correct "calibrated" sending units & loom). Then you should remove the resitor from the back of the gague to start with. Before you do however, make sure that if there is a resitor there. . .that it's not supposed to be there. I have no idea what he back of a 1969 gague looks like. I can say that my 1970 doesn't have one.

At any rate, it's entirely possible that your car has the wrong sending unit, and loom (the wire attachment). . .so it is good to check. Here is the Lectric Limited link: http://www.lectriclimited.com/mainpage.htm Form there enter the online catalog at the top, then click "make/model . . .etc" button, then enter your make / model from the drop down list, then your year.

On the resulting page look for the following:

Look for part "06400759 - Temperature Sending Unit". there is a view button, that will show you what it looks like. I've attached a photo.

Also look for part "VRK6871TS - Temperature sending unit lead repair kit". I've also attached a photo. This connector just slides over the top of the pin (it's a male / female connector type).

There is also temp sending unit lead wire end jack. . .if you just want to fix the end of the wire. . .(note there should be an asphalt shield on the wire).

BTW, Since you asked about washer pump related stuff on my other post, take a look in this letric limited list to see all the Washer Pump adapeter leads for 1969. You may need some of those parts as well.

BTW: My temp sending unit and lead wire loom looks identical to the 1969. And no, this connector does not fit the thumb tac type sending unit. This one goes straight onto the sending unit, while the thumb tack style connects at a 90 degree angle to the sensor.

Hmm. . .this is a really long responce to a simple question. Sometimes I just like to wast time at work.

Lastly, make sure that no one used plumber tape to coat the sending unit threads. Lots of people have done that in the past, and it directly affects the accuracy of the sending unit. There is not supposed to be anything between the sending unit threads that the block. Don't worry. . .it wont leak. If it does. . .tighen it down some more.

Regards,
Bolisk

 

[Evolution1980]

Hmm. . .this is a really long responce to a simple question. Sometimes I just like to wast time at work.

No, long responses are good (as long as they are accurate) because later on down the road, someone else will likely be looking for this exact info and now they'll be able to find it (assuming they use the search function)! And as for 'wasting time at work', man, if I can't get on from work, I'd have to revoke my Moderator status, as I'd never have time to be here! :L
(I was away the past couple months due to all the CruiseFest planning. And also, occasionally they like to give our internet usage a smackdown here at work.)

 

[Bolisk]

I know the feeling. I just finished four fun filled days of Bloomington Gold here in Chi-town.

 

[Vettehead Mikey]

Cooler AIR increases power, not cooler engine temp. Colder air is more dense then warm air. Dense air has more oxygen. This is why carburetors need to be adjusted for high altitudes (it is also why it is hard to breath at higher altitudes).

Small point of correction, carbs need to be adjusted for altitude due to air pressure difference, not air temperature difference.

Atmospheric pressure does not necessarily change with temperature as it is not contained within a sealed vessel.

 

[BLK VERT]

Bolisk, Like you said about a simple question and long response and what Evolution 1980 said is right. It's not too long if it's correct. You don't know how long I've been waiting for someone to answer the question on the right thermostat and wire end. Sometimes when I ask a bunch of question, only certain one are answered. Then I have to think of another way of asking the question. People might get tired of me asking the same questions. But for me, it just brings me closer but just not there. I hope you guys understand that. For all of us working on our vette, it's cool when you can go to the forum and ask the members for help. But sometimes it just take time to get that right answer to help you move further ahead. Then when you get the answer you've been waiting for, it like yeh! On different venders catalogs, some show the thumb tack as the sender for the 69 and others show the rod like one as the sender. That's what make it too confusing. Believe me, your last information helps alot. Also, to the other members, great information. So I'm going to play around with the ohm meter, IR temp. gauge and see if I can nail it down to where I feel comfortible with the read that I don't have to worry when I'm out on a cruise with the wife. Thanks, Tony

 

[minifridge1138]

Small point of correction, carbs need to be adjusted for altitude due to air pressure difference, not air temperature difference.

Atmospheric pressure does not necessarily change with temperature as it is not contained within a sealed vessel.

Sorry, my post was a ambiguous. I was saying that colder air is more dense. Dense air has more oxygen. High altitudes have less dense air due to atmospheric pressure. That is why you have to adjust carburetors in high altitudes. I accidentally left out that part. Sorry about the confusion, and thanks for the clarification.

If the IR gun says your engine is around 180, but the gauge reads <150, then either the gauge or the sending unit is wrong. If the sending unit is the same as my 1982, it is a lot easier to get to than the gauge, so I would start there. It just threads into a hole in the block on the driver's side.

Good Luck!

 

[BLK VERT]

Thanks minifridge1138. The vettes been down for close to a year now. Blew the motor. Had it rebuilt which took a long time. So I just got it running. Putting it back together has been very frustrating to say the lease. Bolts that suppose to thread easy don't. Putting on motor mounts that just won't seat, new radiator support that just won't fit right and then find out that it's welded wrong, etc. I know your guys have your own stories. But one, I'm just glad that I got it running. Took alot of pictures because as you know, the memories just can remember what we did yesturday let alone months later. As the saying goes, if it not one thing it another. But let me tell you, driving it again is a great feeling . People checking you,look at the vette, the vette looking bad ass. You guys know the feeling. So thanks again for the help. Tony

 

[minifridge1138]

Congrats on getting it running again.
The longest mine has ever been undriveable was about 5 weeks.
I can't imagine what year would feel like.

Have FUN!

 

[Bolisk]

Good point, somtimes the parts vendors save time and money by putting a generic photo on the web page, or in their catalog. . .so it's usually a good rule of thumb to not 100% completely trust what you see. What I can say with certainty is that for electric parts (wire harness, sensors, electronic ignition conversion kits, coils, etc) Letric Limited is hands down the best place to get that stuff.

If you are still running points, and you want an electonic ignition that looks 100% stock, and doesn't require new wiring (i.e. it uses the existing wires) then get the Breakerless SE ingition conversion kit. I was blow away buy the difference in the way my engine ran.

 

[BLK VERT]

Another update: I went and ordered another sending unit from Willcox. I got the information from another forum. Willcox had three choices and recommended the inexpensive one, $18.00, but the shipping was $14.00 (expensive for such a small item) 7 days later,got it this monday and installed it. When I turned the ignition on, the needle went all the way to the left.That was a good sign. The other senders didn't do that. Started the car took it for a ride. The needle went to between the 100* and the first hash mark. Just like the first sender but the first one would also bounce around when I was driving. This sending unit though, the needle went up alittle bit when I accelerated. That was a good sign also. I parked the vette and watch the mechanical temp gauge sitting at around 160*-170* move to the 190* mark. The stock gauge moved to the first hash mark.So now I have a reference point for 190* Yeah! The first sender was from Ecklers. The second one is from Dr. Rebuild. ( went to just pass 210* ) And the third one is from Willcox. Three senders later!
Sometimes the simplest thing can be the hardest to solve. Thanks guy for your advices Tony

 

[Vette79]

Hey, I was right for once. I went through the same thing about two months ago. I am on my third sending unit as well. An 81 corvette temp sending unit worked for me. So much time and money for such a small simple part. Frustrating to say the least. Glad to hear it worked out for ya...