'67 E-type, low oil pressure... meaning?
 

I just took my '67 E-type (90,000 miles on it) about 25 miles to be part of a class on "Sportscars as Art." As I got close to home, I noticed the oil pressure was 0 (no weird noises and temp was at 90 deg, as it usually is on hot days in Dallas). I pulled over and all looked fine. After a cool down, oil pressure back to 25ish and I limped the couple miles home. But now the pressure is at about 22-28 at start up and idle and only 44-48 lbs at 2,500 RPM (and 70 deg). No weird noises. Maybe (I'm looking for it) a little oil in the exhaust. I'm going to have it towed (flatbed) to my mechanic. I trust him, but any ideas what or how bad this may be?

I assume you're reading this from the dash gauge, in which case step 1 is to get a known-good mechanical gauge on it.

Yep. This is exactly what the mechanic has recommended and I'll be taking it in for that. He suggested I flatbed it in.

Thanks!

Ditto "69ots" recommendation. Could be a sender issue too.

My mechanic first said that had it been actual zero oil pressure, the engine would have failed pretty quickly. But now he says there is a chance (whatever that means) that it is more serious. I'd just like to have some idea of what he could find so that if he says I need a $10,000 rebuild, I'll have reason to question it. Not exactly easy to get a second opinion.

Since the pressure came back up I'd bet it is a lose wire or sensor, you are getting an intermittent problem. Oil pressure rarely goes to zero and comes back up. Normally it goes to zero you hear a load noise and your mechanic gets a nice new addition for his house. But better safe than sorry. My step mother had a '69 XKE and she thought the oil pressure gauge worked like the gas gauge worked. It didn't end well.

It was the oil pressure sending unit. $340 (+$170 for the flatbed ride) beats the alternative!

Thanks all!

Congrats!!

I am looking for a Jag mechanic in the Plano/DFW area. Can you give me the name of yours? Thanks.

British Auto Specialists in Ft Worth is who I use (britauto.com). Used to go to a guy in Carrollton, but he was almost twice the price.

great news that is was only the sender. I had issues with my water temp last summer, the gauge started bouncing then went to zero. I replaced the sender and then the gauge read 200 - 215 on warm days. I went through 2 new senders until the temp read properly. I added a stick on temp strip to the water jacket near the thermostat to always have a "real" reading.

I have what appears to be a more complicated problem and would appreciate any advice before I start pulling off sump etc. Oil pressure good at idle and at revs, but dropped suddenly after some hill country driving. Limped home, OK if I keep the revs above 2500. Checked oil level, changed oil filter, changed oil Penrite, checked pressure with external gauge and actually read higher than the dash gauge. Also changed the pressure sender and reading high when cold 50psi. The problem is it now drops to less than 20psi when hot at say 2500 rpm and has never done that before. Could this be a split oil pump housing?

i don’t think your Idle “ R”s are that low, if one subscribed to the rule that 10 lbs. per 1000 RPMs is a standard. Especially, when you state, your mechanical gauge read higher than your dashboard gauge. As far as a “split pump” “really”? How about a “weak” pressure spring?