1973 Oil Pressure Question

HarryD · 07-21-2003, 05:54 PM

I have 500 miles on my new top end rebuild (the jugs were not pulled nor the case split).

Yesterday, I took a long drive and noticed that, when I had the car at 210-220 F, the oil pressure was 20 psi. In the past, it would be 30-40 psi. On cold startup I see about 60-80 psi.

Some more facts. My wrench refilled the car with 15W-40 oil while I have used 20W-50 in the past. Also, I had him install Carrera Tensioners. In my 1973, the pressure sender is on the same line as the right hand cam tower line/tensioner supply line.

Do I have a problem? Should I be concerned?

TIA

Hockey fan · 07-21-2003, 06:21 PM

Hi Harry,

My 73.5 T with about 18,000 miles on a rebuild runs about 35 psi at operating temperature and around 60 psi at startup. Don't think this helps you at all but gives you another "like" car to compare with.

Jeff

HarryD · 07-21-2003, 06:38 PM

Jeff,

What weight oil are you running? Is your pressure at 180 or 210?

Hockey fan · 07-21-2003, 06:50 PM

Harry,

I've been running 10W-40 based on the previous owner's advice. The last couple of days I've had that pressure at around 210 degrees. My engine was actually rebuilt 10 years ago but sat for quite awhile neglected. I've got numerous oil leaks (but still good pressure).

HarryD · 07-21-2003, 07:01 PM

Hockey Fan,

Thanks.

FWIW, I have had several discussions on 10W-40 oils with folks I trust and they all say to stay away from that particular weight range. TThe reason has to to do with the additives they use to get the 10W-40 viscocity range and the fact that heat breaks down these additives. In a P-car engine, there is more heat so viscosity breakdown is expected to happen faster. Most suggest 15W-40 or 20W-50 as the effective range of viscocity is not as high so less additives are used.

Are you driving ? Have you joined PCA? Have I seen you at some events? We are going to Mt St Helens on 8/2.

Hockey fan · 07-21-2003, 07:08 PM

Harry,

I've joined PCA. I've just worked out some ignition problems and have started driving the car again. It's in dire need of a cosmetic restoration. I've seen a few of your "barnstorming" (pre rebuild!) runs at past autocrosses. Also saw you and your car on the Friday of the historic races. Haven't been to any PCA social type events yet.

Jeff

HarryD · 07-21-2003, 07:16 PM

If it's drivable, don't obsess, just drive. You can finish the cosmeics later. Running my car regularly really does seem to keep her healthier.

Are you on the ORPCA e-mail reminder list? If not, send me an e-mail and I'll tell you how to get on the list.

HarryD · 07-26-2003, 01:06 PM

Saw my wrench yesyerday. He listened tothe engine and inspected his work. Had a second fellow review the same. conclusion? Most likely a a combination of my reused transmitter, the transmitter location, lighter oil, and the new pressure fed tensioners all make it appear like my pressure is low. Not to worry

.