The Stovebolt Site Forums The Shop Area Engine Shop 216 engine questions

Hello all.

I recently bought a 45 Chevy 1/2 ton PU. It is nearly bone stock, including its 216 engine. I have a couple questions. First some background. After reading through the tech tips looking for help with overheating issues, I decided to check the compression on the cylinders. All of them are 100lbs except number one. It is 80. Now, I have not noticed the motor missing (starts amazingly easy, and runs like a sewing machine), and I do not see bubbles in the radiator. It does not overheat driving around town, but when I get out on the country roads it starts to run up over 180 degrees. My question is this: What temp should I be concerned about? What is top speed driving for long distances?

In addition, I am curious about the first cylinder. Could it be a burnt exaust valve or seat due to no lead gas? It seems odd that a heat related problem would effect the front cylinder first. (closest to the cooling fan and getting more air flow than the rest) However, I do not think it is a prolbem with rings, because the truck doesn't smoke at all.

If I still have anyone's attention, where can I find a drive unit for the speedo? I checked the cable and it is good. I unhooked it from the gauge and drove the truck, and found that the cable doesn't turn. I assume the problem is with the drive on the tranny.

Any enlightenment with these questions would be greatly appreciated.

Thanks, Hal

What thermostat do you have in the eng ?
If the rad or block are gummed up a bit the truck will heat up when pushed , check if water flows from the drain bung on the lower left side of the block .
Standard gears ? then cruise at 45mph . Should last forever then
.
Low comp on one cyl could easily be a valve burnt . A squirt of oil down the bore , and another comp test will help eliminate the rings as the fault.

The question about the thermostat is a good one. I pulled it out and it seems to operate correctly, but I am not sure how to tell what temp it is rated for. Another thing I wondered about was the direction it should go in. When I took it out, the spring side was facing toward the engine. It seems backward to me. I would think the engine would build the heat and you would want the pressure to open it (sprung side facing the radiator). But, I know that it will open in boiling water, so maybe I am wrong about that.

I am guessing that the rad. cap is a 3 to 5lbs pressure cap.

I pulled the plug on the side of the engine and it was clogged. I flushed water through it (in a sorta haphazard way) until it flowed easily.

I had read that 45 MPH is top reliable speed, but wanted to double check. It is kinda a moot point right now since I do not know how fast the truck is moving (speedo not working).

Hal

The end with the spring goes toward the engine, like it was when you removed it.
About the speedometer, I would remove the cable and try to insert the end that goes toward the trans. in the trans. speedometer gear and then see if you can turn the cable. If you can't then the speedometer gear is good and the cable may not be long enough to reach from inside the speedometer gear to the speedometer. This is just a guess, but if the speedometer registers when you unhook the cable from the trans. and spin it with your fingers and the cable will not turn when it is inserted in the trans. then I believe it is not long enough.
Good luck!

racecarldad, that never occurred to me! I thought I had covered all the bases with the speedo, but you may be right, it's hard to tell what someone else did to the truck before I got it.

I'll give that a try and post what I find.

BTW- thanks for the help with the thermostat. I am a fairly good mechanic, but I spend most of my time on air cooled V-twins (motorcycles). The whole water in the engine thing (and 4 wheels) is something I normally do not mess with.

Hal

Thermostat might have the temp stamped on it. If not, rig up a pan of water to boil. Hang the stat in the water so it does not touch the pan. A piece of wire, string, twist tie or whatever tied to a spatula across the top of the pan. Get a thermometer that reads in the 140 to 200 degree range and slowly heat the water until the stat opens.

Check your radiator. Since the engine is hotter at speed, it is suspect. Can you see junk in the coils inside? Also check the fins on the outside. Any places where you can't see through front to back? You can hose the outside to clean, but be careful not to bend the fins. And you might open some leaks. If you have to take it to a radiator shop, be prepared to have to buy a new core. The old one is likely rotten.

Temp range should be under 210. these were designed as a zero pressure system, and the boiling point should be 212. I usually consider the top of the practical temp range to be 190. Y'all don't say where you're from, is it desert or ice and snow? Makes a difference.

FredT, Thanks for the information. I am not certain it is heating up because of a failure, or because I was simply running it too fast. I was attempting to drive it 60mph. I now know that is too fast for the gearing. To make it worse, I drove my new vehicle at 45mph to get a feel for how fast that is (again, no speedo in the old truck yet), and I know I have been running the old truck way too fast.

BTW-I live in Falls City, Nebraska. It is a pretty even climate.

The overheating won't be due directly to high speed, something else is wrong. I could explain the coolant temp if it was 110 outside, but it doesn't get that hot in SE Nebraska. Have you checked your coolant temp with a thermometer? This will verify your temp gauge, which could be wrong.

BTW - I've been through Falls City once or twice, dad was from Avoca.

Hal,
just a couple of thoughts:
I assume that your odometer is not working, right? If you did not check that,and it is, sometimes the bearings in these old speedometers will cause the speedometer head to hang up and not move properly.

When you spin it by hand, it should jump a liitle as long as you are spinning it counterclockwise.

Hal, depending on where you are I have an extra 216 head you can use for free to troubleshoot, although I don't want to ship it. You might want to just check your breaker point gap and timing (in that order) because if they are off far enough you will overheat.

FredT - It occured to me that I should check the engine temp to insure the gauge was accurate, but I haven't done it yet. I am still trying to decide which of my wife's thermometers would get me in less trouble, the one she uses on roasts or the one she uses for our girls when they are sick..... Seriously, is the gage reading head temp or cooling fluid? I just moved to Falls City in June. We love the town (and I found the cool truck here).

Truckernix - I think I have the speedo issue narrowed down to the drive unit. After the suggestion from racecarldad, I pulled out the cable from the housing and greased it. I then reinstalled it into the drive end, but left it disconnected from the gauge in the cab. I made certain it was seated and drove the truck around the block. It did not turn. Now, if I can find a drive unit, I will know for sure.

4onthefloor - Thanks for the generous offer. However, I am just not ready to pull the head yet. I still think the front cylinder has a leaking valve (most likely burned). It is the only one that doesn't pump up to 100lbs.

Well, I just read the thread entitled 235 loss of power and overheating . I printed most of it and think I will go through those steps with my 216. Thinking about the things I am seeing on my truck and comparing them to the checks listed in that thread, I can see where my problems may be very similar (but not to the same level of trouble).

Is this a great site, or what?

Good advice on that other thread. For a thermometer, I use the one I have for smoking meat. Cost less than $10, metal housing, and has a dial gauge which is easy to read.