Hello all,
I've searched this topic already, so I'm pretty sure I know whats up. I ordered a set of VDOs, per your suggestions and started wiring them up. Right now, the CHT is in and working (haven't seen temps over 325 yet, which is very cool!) but the oil temp gauge is giving me problems. I am using a billet taco plate made by a gentleman in the UK with a VDO sender. Everything seems to be wired correctly, as the needle does move off its resting position after several minutes. However, I haven't seem oil temps over 130 degrees yet and this is after driving the car about 10 miles at a time. Is it possible I have the wrong sender for the gauge? I ordered them from egauges.com which I believe got the order correct. Unfortunately I'm not sure if I still have the box for the sender to verify the ohms. Would a mismatched sender yield lower temp readings? How about thread tape? Can't remember if I put any on the sender threads...

Maybe my engine just simply runs this cool, but 130 degrees sounds pretty darn low. Thanks gents!

If you put tape on the threads, that would insulate the sender & cause it to read wrong. That would be my first guess. Pull the tape off & I'd bet the gauge would read correctly. If you don't have tape on it, you may have the wrong sender.

The sender should be stamped with its value.

Thanks Mark. On second thought, I remember putting the sender in and only using the new copper washer I got from PP. I'll verify this tonight when I get home, but I'm pretty sure I didn't use tape, knowing I really wasn't supposed to. The pressure sender does have tape but I was able to ground the body to the engine with a bracket.

I should have mentioned two other things. The car still doesn't run quite right because I'm waiting on new linkage for the hex bar setup to be delivered. I think I've got the timing pretty close, but can't be sure till I can get the carbs straight. Also, this motor doesn't have the thermostat installed or the necessary components to do so. One of the DAPOS removed it. The flaps are still in place in their default position, which is max cooling. Still, I have a feeling that after being on the highway for 10 miles, I should see higher temps then that.

I might try testing the sender with the boiling water trick, but the question then is, how do I take the sender out without oil spilling all over the place? Not sure I have a plug for that hole.

Ah! I didn't think it would be. Okay, I'll put it on ramps tonight and check then. Again, not sure how to plug it while its out, but I'll think of something. Thanks again.

Not the sender we use, but it shows the stamped value.
Click to view attachment

It sounds like you did things correctly. Maybe 10 miles isn't enough to get it up to max temp. I had a carb'd engine once that took a long time to get up to temp. Especially if it's without the flappers.

Okay, I'm not feeling so bad about this then. I know that not having the thermostat hooked up is not good for longevity. That will be a project at some point (just finding the parts to get it working again is a project in itself). But I'm not planning to daily drive this car much over the next few months anyway. Some folks know that we're hoping to run Chumpcar with it in September. So if we happen to have a motor that runs a little cooler, I'll be thrilled. At least its not the opposite - those straightaways at Sebring are going to be killer.

Again, I'll report back on my findings when I can check the sender tonight.

The new style senders are shorter than OEM thus only the end of the sender is exposed so they take a bit longer to get up to temp. Couple that with the billet taco plate which probably has more mass = larger heat sink. More importantly, calibrate your instruments. I've had my experience with VDO senders. VDO CHT sender was off 45F+ and my current VDO oil temp sender is off 10F+. If you have an IR thermometer or a good digital style thermometer, you can take a reading from the dip stick or within. The dip stick cools very rapidly so be ready. My digital multimeter has a 3' wire lead so I can drop it down the dip stick hole which puts it next to the senders location.

Update: I got up underneath the car and verified its a 300/150 degree sender, so that clears that up. I am looking around for a cheap IR thermometer to bench test the gauge readings, and will get around to that eventually.

In the meantime, I did a little tinkering with the carbs and got it to run much better. To the point where it warranted a spirited drive Finally got the temps up to close to 180F! Guess I was just driving like a grandma

On another note, I'm going to start looking for a thermostat and bracket, since its been missing from the car since I got it. Thanks again all!

Read the instructions. IR thermometers % of accuracy varies for the size of any given area being measured and the distance that it is measured from. IIRC, you'll need to hold it close for such a small area.