Question on oil temperature

[mattpatt]

Talking about pressure - when I'm around a temperature of ~90-95 C (standard Superformace sensor at remote filter) I have ~ 40-50 psi. At ~105 C it drops to ~20-25 psi. I'm using Joe Gibbs HR-2 (30 weight). Are these lower pressures OK or should I up the weight?

thx

[bobcowan]

Originally Posted by YerDugliness

I do have a Fox body oil pan on the Cobra right now, and there is a plugged port on the driver's side of the pan, directly to the side of the rear oil pan drain plug, that was probably for a factory "low oil" sensor, I'll try to use that location.

Mike Forte makes an adapter especially for this application.

I am guilty of thinking that I need heavy viscosity oil in my pan...think I will switch to 15W-30 or 15W-40. Right now there is a very slight leak at the rear corner of the passenger's side valve cover, so I check the oil level every time I get in my car. It must be a very slight leak, I guess, as the oil level never seems to drop on the dipstick. My oil pressure VERY seldom drops to 40PSI, and usually at any RPM level above idle is at 60PSI (VDO gauges, no idea how accurate they are).

Cheers, and thanks, again! An oil temp gauge is definitely in my Cobra's future.

Dugly

Good operating oil pressure should around 45psi or so. It will drop a bit at idle, but not too much. Too much oil pressure is not necessarily a good thing. The oil should be "thick" enough to maintain proper oil pressure. Whatever viscosity that might be. In the winter, you should run a fairly low winter weight. Since we rarely drive our cars in sub-zero temps, a 15W is probably fine.

I use 5W-30 true syntheitc year 'round. Maintaining proper oil pressure isn't a problem. When hot and on the track, it runs about 45-50psi. I tear the engine down every two years. The bearings look excellent after two years of abuse. I replace the bearings (just because) but I'v never had to cut the crank. Obviusly, crank and bearing wear is not an issue.

Originally Posted by mattpatt

Talking about pressure - when I'm around a temperature of ~90-95 C (standard Superformace sensor at remote filter) I have ~ 40-50 psi. At ~105 C it drops to ~20-25 psi. I'm using Joe Gibbs HR-2 (30 weight). Are these lower pressures OK or should I up the weight?

thx

20-25psi at hot idle is fine; while running down the highway it's probably a little bit low. I would investigate that a bit more closely.

[YerDugliness]

Thanks for the tip on the Mike Forte oil pan adaptor, Bob! I had figured I'd have to cobble up a bunch of brass adaptors, it's good to know that someone else has taken all the guess work out of it for me.

Originally Posted by bobcowan

Good operating oil pressure should around 45psi or so. It will drop a bit at idle, but not too much. Too much oil pressure is not necessarily a good thing. The oil should be "thick" enough to maintain proper oil pressure. Whatever viscosity that might be. In the winter, you should run a fairly low winter weight. Since we rarely drive our cars in sub-zero temps, a 15W is probably fine.

I use 5W-30 true syntheitc year 'round. Maintaining proper oil pressure isn't a problem. When hot and on the track, it runs about 45-50psi. I tear the engine down every two years. The bearings look excellent after two years of abuse. I replace the bearings (just because) but I'v never had to cut the crank. Obviusly, crank and bearing wear is not an issue.

I suspect my engine has a high-pressure oil pump and that it is already at the limits of the relief spring once I get the RPM's above an idle. I would rather use a high-volume pump, but for now it has what it has, so I'll deal with that until it is time to tear it down. At this point the only place where I have any oil leaks is the valve cover, so I know the pressure is not adequate to force oil past the front/rear seals, etc. It is totally street driven, and rather tamely for the most part as I know the local police would love to nail me for anything they can....I was on my way to a car show in Beaumont, TX and was stopped by a DPS officer for having an expired registration. It took 2 minutes to show him my receipt from the new registration the day before, but it took an hour to get away from him after that, he was a "car guy" too and wanted to talk cars.

As for the synthetic oil, I've been a bit reluctant to use it since I put it into a new Mitsubishi Eclipse I bought for my daughter (after 12,000 miles with normal petroleum based oil) and the car developed a severe oil consumption problem. I know it would be better from the standpoint of heat tolerance, and probably from the standpoint of wear protection, but that little experience I had with the synthetic oils has me afraid to try again.

Once I get the valve-cover gaskets and the thermostat replaced, I'll experiment around with oil viscosities to see which meets the guidelines you posted. I don't mind "only" 45 at full pressure, but would want at least 30 at an idle when at operating temperature.

I once had a '66 Cadillac with the 429CID V-8...the pressure required to illuminate the "idiot light" for low oil pressure was 8PSI, no kidding! I mention that b/c I guess it just illustrates how little oil pressure is required to maintain a decent film on the bearings and other operating parts, but I would still like for the low RPM oil pressure to be better than "minimum".

At some point I plan on installing an Oberg oil filter "downstream" from the canister filter...right now I use Purolator's "99%" efficiency oil filter (reportedly designed for the synthetic oils), but I like the idea of the Oberg as a "fail-safe" should the bypass function on the canister filter be triggered, and particularly if I were to install an oil cooler in the scoop below the fishmouth (radiator opening).

Cheers!

Dugly

[YerDugliness]

Originally Posted by bobcowan

Good operating oil pressure should around 45psi or so. It will drop a bit at idle, but not too much. Too much oil pressure is not necessarily a good thing. The oil should be "thick" enough to maintain proper oil pressure. Whatever viscosity that might be. In the winter, you should run a fairly low winter weight. Since we rarely drive our cars in sub-zero temps, a 15W is probably fine.

20-25psi at hot idle is fine...

I paid particular attention to the coolant temp and oil pressure gauges on a 100+ mile drive yesterday, ambient air temperature about 70*.

Once up to operating temperature (a stable 180* with occasional increases to 190* when I turned off the puller fan), the oil pressure at idle never fell below 30PSI. This drive was in a fairly high-traffic area (I-45 coming into Houston from the north), but it was at a fairly low use time and speeds seldom fell below 60 MPH, most of the time pushing 75-85 MPH. When traveling between 60 and 70 MPH the oil pressure was a steady 55-60 PSI (I think 60 PSI must be the bypass pressure for the oil pump) and the coolant temperature was consistently at 180*. When pushing 80-85 MPH, the pressure fell to about 45-50 PSI when the coolant temperature registered 190* (I had to keep the puller fan off to get it to that range, it never went higher).

Considering the recommendations you made, Bob, it looks like I'm right in the correct pressure range. I would probably run a higher viscosity oil during hotter weather to keep the oil pressure up with the increased coolant temperature that would naturally result from the higher ambient air temperature.

Feeling much better about things now......but, an oil temp gauge is still high on the "Must Have Items" list.

Thanks for the great info!!!

Cheers!

Dugly

[xb-60]

Originally Posted by bobcowan

Good operating oil pressure should around 45psi or so. It will drop a bit at idle, but not too much....... 20-25psi at hot idle is fine; while running down the highway it's probably a little bit low. I would investigate that a bit more closely.

I came in on this thread a little late.
I've got a low oil pressure story. Firstly, I agree with Bob, decent oil pressure is desirable, but sometimes you can get by on less if you have to.
A while back, I read an article in an Australian car magazine about a 2 litre Alfa twin cam that was driven from Sydney to Perth (4000km/2500miles) in 29 hours (average speed of around 85mph). Around 1000 km into the trip, the oil pressure dropped suddenly to 15psi at 170km/h and was zero at idle. An Alfa mechanic met them at the half way mark for a quick checkover, and told them not to worry about the low oil pressure. I had (and still have) a similar model Alfa, which has experienced the same dramatic oil pressure drop twice, the cause being an aluminium slug in one of the crankshaft cross-drillings coming out. On the first occasion, I had to continue driving the car for 2 weeks before I could take it off the road to fix it (wife and bub in hospital). At strip down, years later (with 220000 on the clock), no damage evident.
Cheers,
Glen

[Jerry Clayton]

Do you have the cooler hooked up or is it just a dummy with lines tucked up into fenders?

[mattpatt]

Originally Posted by Jerry Clayton

Do you have the cooler hooked up or is it just a dummy with lines tucked up into fenders?

It's the standard SPF MK3 cooler. The oil lines are connected into/out of it.

[bobcowan]

For the engine you have and the way you drive it, there's no need to use a full synthetic oil at $8-9 a qt. Stick with your favorite dino oil and change it once or twice a year. The engine will last a decade, easily.

The Purolater Pure-1 oil filter is one of the best on the market for the money. That's what I use in most everything, and have never had any problems. Adding an additional oil filter isn't necessary.

Of course, a lot of the stuff we do to our cars isn't exactly necessary. Sometimes you just have to do what makes you happy, and helps you sleep at night.

[Jerry Clayton]

I have serviced SPF where there were dummy lines hooked on the cooler and just tucked up into the fenderwell for looks--the cooler WAS NOT hooked up---sounds like yours might be the same

[bobcowan]

I spent the last couple of days in Estes Park, CO. Friday was a pretty nice day - sunshine, and in the mid 50's until the sun went ebhind the mountains. Then the temps dropped into the mid 40's. Yesterday was considerably colder up there. We went up Trial Ridge Road as far as we could, and then the road was closed due to snow - about 9,500' ASL. We were chased out of town by a snow storm. Once we got down out of the mountains, it was a very nice day again. Sunshine and low 60's.

Because of this conversation, I was wqatching oil and water temps closely, just to see what they would do.

My oil cooler is connected, but it has it's own electric pump, and cools oil in the pan. When the pump is off, there is no oil circulating through the cooler. Absolutly none; so it's like not having a cooler at all. I'm also using a 160* water thermostat. I like to keep the heads as cool as possibly, to limit detonation on hot days.

Water temp was a steady 160*. Driving through stop and go traffic in Denver and Boulder, it got as high as 185*. Oil temp was almost exactly the same. Because oil holds heat longer, it would take a few minutes longer to drop to 160* when we got going again. But then it stayed the same as water temp.

Last Aug, I was in Deadwood, SD, for Kool August Nights. We drove out to Wall one day, and it was about 100*. Driving down the highway at 80mph, water temp was right about 190*. Oil temp was a little higher; then I turned the oil cooler on, and it dropped to about 185*, and the water temp dropped to about 180*.

[madmaxx]

You also like to wear your cylinder walls out. Hot piston, cold cylinder equal wear.

I'm also using a 160* water thermostat. I like to keep the heads as cool as possibly, to limit detonation on hot days.

[DAVID GAGNARD]

Originally Posted by madmaxx

You also like to wear your cylinder walls out. Hot piston, cold cylinder equal wear.

I'm also using a 160* water thermostat. I like to keep the heads as cool as possibly, to limit detonation on hot days.

Yep, your not doing your engine any favors by running water temp of 160........minimum should be 180 on the water and oil temps..........

David

[bobcowan]

Multiple studies show excess cylinder wear occurs at temps under 160*. Engineers generally recommend 160* or more to prevent cylinder wear. There is virtually no differance between 160* and 180*.

And, really, I don't expect to get 120,000 miles out of this engine.

Oil temp is another issue, though. It's generally accepted that minimum operating temp is about 180*+. RP says there is no minimum on their oil m- although I'm not sure I believe that. I can get my temps up to 180-190* on a cold day, but I have to work at it. That's why I use a seperate electric oil pump for the cooler.

[boblyon1]

Matt - just an aside to this thread. I have a 351W stroker in my 633 SPF and learned the hard way that the distributor gear tends to wear if you have a high performance oil pump. I didn't catch it in time and ruined the crank and had to re-build the engine. Good idea to check the distributor gear wear every now and then. My mechanic says the 351W is famous for this problem.

[Mdman352]

I have a 427 (454) S.O. that runs 40-50+ psi oil pressure. I believe my thermostat is a 160. The 4500 CFM fan kicks on at 180F. My oil NEVER gets over 70C and often times barely moves the needle. I run 10-30W regular oil. My oil has never shown signs of milkyness rather just the normal color change as it gets used. I do drive my car "energetically." I have used a temp gun on the oil pan as well as the lines coming from and to the oil cooler and they are in the 130-45F range. My oil temp sensor is on the remote oil cooler adaptor on the block. From reading this thread I am guessing my gauge (Autometer) is not accurate and should be replaced. Any suggestions?
TIA
David A.

[bobcowan]

Originally Posted by boblyon1

Matt - just an aside to this thread. I have a 351W stroker in my 633 SPF and learned the hard way that the distributor gear tends to wear if you have a high performance oil pump. I didn't catch it in time and ruined the crank and had to re-build the engine. Good idea to check the distributor gear wear every now and then. My mechanic says the 351W is famous for this problem.

Unfortunatly, this is true. Same with the 302W.

There are a lot of reasons for this, too. In all the research I'v done, I have not been able to point to one thing and say that's what causes it most of the time. But, here's a list of things that seem to be common facters (in no particular order). And, I suspect that if you add 2-3 together, it's more likely to occur.

- Wrong gear. Especially with aftermarket distributers and comp cams gears. I'm a victim of that, but it was my own dumb fault.
-- steel on iron is a bad thing, and wears really fast
-- bronze gears wear fairly quickly (relativly speaking)

- Incorrect installation. Again, especially with aftermarket parts. Builder doesn't check depth and engagement during installation.

- Shear pin breaks/shears: this is pretty common, but usually causes the engine to die uimmediatly, since the distributer also stops turning.
-- shear pin too small
-- oil is too "thick"
-- high pressure oil pump
-- cheap/low quality oil pump, with too much drag
-- over revving the engine with cold oil and an open circuit cooler.

I don't think I'v ever heard of a sheared pin with a high quality (Ford or Melling) high volume pump. I'm sure it must happen somewhere, but it doesn't seem to be much of an issue.

I run a Ford HV/SP pump, ARP billit drive shaft, Mallory Unilite distributer. I get excellent oil pressure with Royal Purple 5W-30. 6 years of driving and racing, never a problem with those components.

[Jerry Clayton]

is your temp sensor reading the oil out of the engine or the oil return to the engine after cooling? if you want to check your guage, put it in boiling water---should read 212 *f

[JBCOBRA]

All distributors in Hi-Po Fords should have a larger pin (Chebbie) in the distibutors. I use a Melling pump and sheared that pin before putting a bigger one in. A common problem and happens all the time unless you just putt around in the car.
As far as temps, almost all you guys are running your engines too cool on both the coolant and oil sides of the equation. Oil Needs to be at least 212 on a long drive.
Now if you are just running to the store you may never get the car fully up to temp, but it is very important to get the car fully up to temp regularly. Even an occasional 250+f blast of oil temp is fine.
BMW's 335's run at 220-250 constantly. Harley's are about the same etc...etc..

[boblyon1]

Matt, Bob Cowan, JBCobra and anyone else interested -

Here is a partial quote from an FAQ written by Arron Johnson of BadAss Engines. This guy for years has built race engines for a living I'll also supply the link for the entire article. Hope you find it interesting.

What drives the oil pump? The distributor gear does. Chevy's use a much larger gear than a Ford does, in fact, it's about twice the size, which means it's about twice as strong. The distributor gear is what takes the load of spinning the oil pump. The more volume you pump through an engine, the more load gets put on that gear. Ford gears tend to get eaten-up because they just aren't big or strong enough to take the load that a high volume pump puts on it. Once you eat-up a distributor gear it is pretty much disaster for the cam gear as well. If you wipe either one out, count on having to replace the cam shaft! This doesn't even get into all of that metal going through the engine, which doesn't help things like bearings. We tend to use stock oil pumps on Ford's and high volume pumps on "performance" Chevy's.

Full Link: http://www.badasscars.com/index.cfm/page/ptype=product/product_id=91/category_id=13/home_id=3/mode=prod/prd91.htm

[JBCOBRA]

When I sheared the Ford pin it was when I let off the gas real fast at high rpm's.
My distributor gear has zero wear after 16,000 hard miles.
Now get out there and Beat on that Cobra!