High oil temp readings

[hydraulic967]

I have an RV10 with a Vertical power VP200. My oil temps are fine on the ground but when I reach pattern altitude they will reach 350 degrees!!!
If I Turn The Field off it returns to normal! Any Ideas???

 

[Crash'nF16]

I have an RV10 with a Vertical power VP200. My oil temps are fine on the ground but when I reach pattern altitude they will reach 350 degrees!!!
If I Turn The Field off it returns to normal! Any Ideas???

Check your engine ground strap to the firewall. I just experienced nearly identical symptoms and found one of the terminals had broken in half. Now I have 2 engine ground straps.

 

[bjdecker]

Check your engine ground strap to the firewall. I just experienced nearly identical symptoms and found one of the terminals had broken in half. Now I have 2 engine ground straps.

I wonder if that's what contributed to your multiple alternator failures...

 

[Crash'nF16]

I wonder if that's what contributed to your multiple alternator failures...

I was wondering as well but it seems pretty clear in the engine data when the ground strap actually broke...I was flying cross country a couple weeks ago and had an EGT start fluctuating +/- 500. Oil temp shot up to 300+. Switched from the PlanePower to the Monkworkz (regulator grounded to the firewall) and everything smoothed out. I think the PlanePower return current was trying to get back any way it could and apparently those two engine sensors were the path of least resistance.

Of course I didn't figure out it was the ground strap until after I had the cowl off once I got home, so I'm sure the 2x starts I had after that were not great for my already buggy electrical system. Hence the desire for redundant ground straps.

The engine ground that broke was not a braided strap, but instead a 2 AWG cable which I have now read other folks on the forums warn about in this application due to the stiffness. I crimped a new terminal on to get flying again but am going to consider pulling the 2 AWG wire and replacing with a 2nd braided strap when I do the CI.

 

[rv8ch]

This is exactly why Bob Nuckolls of Aeroelectric fame recommends having two ground straps. If you lose your single ground strap, those electrons need to find another path back and it might be through some very small wires or even control cables, which could burn them up.

 

[Jonas1ne]

I have an RV10 with a Vertical power VP200. My oil temps are fine on the ground but when I reach pattern altitude they will reach 350 degrees!!!
If I Turn The Field off it returns to normal! Any Ideas???

The fact that the oil temp drops back to normal when you turn the field off points to an electrical issue. I’d check the alternator/regulator, VP200 wiring, and especially the oil temp sensor ground for interference or a bad connection.


First question: is the 350°F reading confirmed with another gauge, or is it only what the VP200 shows?