I did a bunch of google'in and searching the forum but I'm not really finding the answers I want. What are optimal oil pressures and engine temperatures for a fairly mildly built engine? Right now, my 306 runs at about: oil: 55lbs cold, 20lbs idle, 45lbs cruising temp: 195 on the highway, 185 around town, gets near 200 at a light.
Your oil pressure looks pretty typical. Pretty much like mine. Old timers have told me a rule of thumb is you need a min of 10lbs for every 1000 RPM you run. According to this theory for 2000 RPM you need at least 20lbs. For 5000 RPM you need 50lbs and so on. Your temps are fine but would not hurt a little cooler. I have found with playing with cars the best temps are around 180-185 for engine wear and performace.
Bruce, I see nothing wrong with your numbers on oil pressure. I agree with lowering your temp. Of course the route to there is complicated according to your car. Airflow is critical at stop lights for engine temps. Do you have a shroud? I do not run a shroud but run a large fan and do not have any problems, even in hot weather. Make sure your rad is up to the task, if it has not been redone by a qualified rad shop, then do so. Thermosat is critical,,, use one, I have run both ways,, used one, not used one.. car runs cooler with one. Stupid little things like too much paint on a radiator can cause high temps at stop lights. Do you have a trans cooler? That will help on engine temps also. Dan
The temps are nothing out of the ordinary. Perfect. Only thing I question is the highway vs town, it's usually the other way around, cooler on the highway vs in town.
200 is a wee bit warm to my likeing, I perfer not to run over 190 on an older engine. I know some of the new cars run 200 all the time, but that's not much cushion before it overheats in my book.
I think the reason it's higher on the highway is that I'm actually running around 2700 rpm on the highway (for my 20 minute jaunt from college to my job).
i was thinking that a "roller motor" runs about 190-205 that's where i was going to run my "306". ......
10 psi per 1000 rpms typically my engine runs 30 psi at idle.. and up to 60 at speed engine temps.. that is about normal you could try a 180 stat.. it would open sooner.. but it sounds like you have a 195 stat in there
The optimum oil pressure May be higher than the minimal 10 psi per 1000 rpm but 50 psi running on the street is fine. The difference at idle is normal for a stock oil pump. You can get more idle pressure with the sam (or slightly higher) maximum oil pressure if you use a high volume pump but it doesn't seem necessary in your application. As far as temperature is concerned for best power and economy your cylinder head maximum temp should be 200 F. Unfortunately you have to put a cylinder head temperature gauge on it to know what the cylinder head temp is. On the average if your water temp is at 180 to 190 your cylinder head temps are good. The newer cars use higher temps (and coolant pressures) to lower emissions. You don't want to do that. Paul
