c2 - 1967 327/300 oil pressure and coolant temp

[Brian Monticello]

I spent Saturday driving back my new '65 coupe from Michigan (400 miles). The car has what appears to be a stock '67 327/300 (haven't gone through the numbers yet) with a four speed manual transmission. According to the gauges the oil pressure was at about 15 lbs at cruising speeds with the temp between 200 and 210. The car ran perfectly and did not make any engine noise. What are considered "normal" operating ranges for these two parameters?

Besides the AIM and the manual for the car, what are some other spec. resources are that are good?

Thanks,
Brian

[Mike Yager]

Re: c2 - 1967 327/300 oil pressure and coolant tem

Those readings are not normal. I have a '64 with the 327/300 engine. It seems to me that oil pressure is generally 50 to 60 at cruising speeds. As far as the temp, I have never seen more than 180 at crusing speeds, even on the hottest 95+ degree day here in Virginia. In traffic, it will get a little higher on a very hot day but never above 190.

Since you said the car is running good, I would suspect the oil gauge could be a problem. You would definitely know there was a problem with the car if you truly had 15 PSI at crusing speed.

Although the temps you are running are high, they probably would not cause problems. However if you have temps that high crusing when the outside air temps are moderate, you may experience problems in traffic. You might want to look at the obvious stuff like the thermostat and hoses. If they check out, you probably have radiator problems.

[Joe L.]

Re: c2 - 1967 327/300 oil pressure and coolant tem

Mike and Brian-----

Actually, the engine oil pressure reading COULD be accurate without any outward sign of problems. Small blocks will run ok with 15 PSI of running oil pressure. However, it's not normal or acceptable and it should be checked out. Since Corvette oil pressure gauges can be quite inaccurate in an absolute sense, the first thing that you need to do is to hook up an accurate test gauge. You can remove the factory gauge line at the block and install the test gauge at this point or you can install a "T" so that you can have both gauges in operation at the same time. I recommend using as large of an ID flexible line between the block and the test gauge as possible for the test. This and an accurate test gauge will give you an accurate reading of oil pressure. If it turns out that the 15 PSI reading is accurate, then you need to go into the engine. A worn oil pump and/or worn bearings are the most likely culprits. If it's the bearings, then it's engine rebuild time since if they're bad, other components likely will be too.

Your temperature readings are a bit high, but not out of the "normal" range depending upon ambient temps. However, they likely indicate at least some level of deficiency in the cooling system. If someone has replaced the original GM #3155316 aluminum radiator with a copper-brass replacement, that's your problem. Otherwise, it may be just be that your radiator is old and scaled up or other cooling system components may be worn.

[Ryan Clark]

Re: c2 - 1967 327/300 oil pressure and coolant tem

Joe,

Could you suggest a good quality oil guage to use to accurately test the oil pressure.?

Thanks
Ryan

[Joe L.]

Re: c2 - 1967 327/300 oil pressure and coolant tem

Ryan-----

Go to a good hardware store or industrial supply house (like Grainger) and get a high quality test gauge in about a 0 to 100 psi range. It doesn't have to be an "oil pressure gauge", per se. Just a high quality test gauge. Ashcroft is the brand that I've used, but there are others.

You'll also need to get a flexible pressure line of adequate length and fittings to connect the block to the flexible pressure line. I believe that the block fitting for the pressure line is 1/8" NPT.

[Brian Monticello]

Thanks Joe - *NM* *NM*