Another oil temp thread
 

After a 10 minute hard run my oil temp creeps up to 250. Goes right back down to 150 ish at idle.

My motor is a 509 recently rebuilt with 10 hrs on it. Motor runs great.

Water flow is good. Oil cooler is clean. Water temp is 125 with a 140 thermostat

oil psi is 75-80psi at higher rpms. 50-60 at idle. Oil temp is taken at the filter before the cooler. Running vr1 20/50 oil. Wix racing filter 51061 Gen 4 block oil by pass is plugged. 11 qt oil pan.

if anything the motor is running rich. (Soot on transom and plugs are dark black). Timing is 34 degrees all in.

im not a mechanic and going back to builder is not an option. Where should i start or should i do anything? Im gonna use my temp gun tomorrow to verify the actual readings. Other then oil temp the motor runs like a raped ape.

250 measured before the cooler is fine, unless you are going to run it harder and get more oil temp than that.

You know no 250 oil temp on a fresh motor is not out of line as a matter of fact all SAE oil testing for viscosity is performed at 260 degrees. If the temp stops climbing at that temp and maintains itself I wouldn't be concerned but if it climbs above that I would start looking closer. One suggestion is split the oil filter and look for debris if you don't find anything out of line install a new filter and keep an eye on it. We use the same VR1 conventional here exclusively to dyno and I control the oil temp to 220 degrees to make any power with consistency to be able to analyze and make comparisons between changes in mapping and tuning. CHeck that filter and if it's clean be at ease. Also if the engine is fresh don't wait 40 hours to change the oil change it maybe after 10 hours and check the filter again. Best of luck keep us posted. Laz

Thank you.

it does seem to stop at 250. Ill change oil and keep and eye on it.

Sorry, but that is incorrect.

Viscosity testing for the high end is done at 210F or 100C.

Ken

You may be right the guys I deal with at Valvoline have mentioned different numbers and 260 perhaps is what they may test their HP oils to . One thing I've seen in a situation similar to this was the person changed to a synthetic after the first 20 hours and the temp came down almost 50 degrees maybe from the use of a low quality oil for break in. Sorry if my info is not correct. One things for sure I wouldn't want to see it any higher because you'd be treading in dangerous water at that point. Good luck

So ive gone through everything double checking to make sure everything was good. Impeller, oil cooler, no kinks etc

was able to squeeze in another hour run time this weekend. Was 95 and sunny in iowa!

let her warm up and went for a run. DROPPED THE HAMMER..........look down and oil temp 275.....chit. So i come down to idle and gauage instantly drops to 225. Thats weird. As im thinking about what the phuck could be happening i open the hatch and hit the oil filter with my temp gun. 195. Gauge now says 250 again. About that time i see my volt gauage is barely on 12v. AHA! I tap the oil gauge it drops to 200. Tap the alternator gauage it goes to 13

so i believe i have an electrical issue.

Other then Running rich this motor hasnt skipped a beat since i had it tore down and rebuilt the 2nd time.

Didnt have my gps with me but she was still pulling like a freight train at 5000 rpms before i backed out.

if multiple gauges are affected it may be a grounding issue

Man that's not the greatest news but it's better than a damaged engine electrical is easy diagnostics and repair instead of removing engine and starting again. Best of luck also consider next time out a mechanical temp gauge they're inexpensive and will let you check between the two gauges as well. Best of luck . Laz
P.S. Check all the grounds as well while you're at it sometimes you'll have a bad ground where there's more than one together.

I have a feeling its a ground issue but ill be fixing it over winter for sure.