thermal breakdown on the freeway

[64 200 ranchero]

what is the best oil to use against thermal breakdown, im running 10/30 royal purple synthetic, when im on the freeway my oil press drops, then it go's back up after driving on the street or should i just get an oil cooler

 

[BIGREDRASA]

How much does it drop? How many miles on the engine since last rebuild?

 

[64 200 ranchero]

the guy i bought it from told me it only had a couple miles on it then it was replaced with a v8, it drops to 20 psi, it runs good, i oppened up the engine before i put it in my car and everything was replaced with new parts

 

[BIGREDRASA]

I wouldn't worry too much. However, if it will ease your mind, switch to 15W-40 Diesel. It is better for the flat tappet cams, anyway, because it has ZDDP (a Zinc additive). See: http://fordsix.com/forum/viewtopic.php?f=5&t=58427&p=448311&hilit=zinc#p448311

 

[rbohm]

8) do any of the other gauges do anything strange? for instance when the oil pressure gauge shows a drop in pressure, does the temperature gauge show a rise in temperature? if so then it might not be the pressure that is a problem, it might be the instrument voltage regulator. i had a similar situation with my 66 mustang many years ago.

 

[64 200 ranchero]

my temp stays in the middle unless i am giving it full throttle for a long time, then it moves up a little, my oil press gage is mechanical, my warning light has never come on since i put the new engine in

 

[Lazy JW]

what is the best oil to use against thermal breakdown, im running 10/30 royal purple synthetic, when im on the freeway my oil press drops, then it go's back up after driving on the street or should i just get an oil cooler

That oil ain't having "thermal breakdown"; just put a piece of tape over the gauge and fuhgeddaboudit. This is a Ford Six, not a Ferrari.
Joe

 

[rbohm]

my temp stays in the middle unless i am giving it full throttle for a long time, then it moves up a little, my oil press gage is mechanical, my warning light has never come on since i put the new engine in

8) then i doubt you have an oil pressure problem.