Okay short version I built a '70 2.2L up with 86mm JE pistons, about 9.2:1,
mod-solex cams, so 2.3L. And just cruising on the highway eventually oil
temp gets to ~225F if outside temp is in the 80's.

I was expecting to get by with just the engine oil cooler. Anybody else doing
something similar? Farther down I will list all the things I did to prove that yes,
the reading is correct, and I tried everything I can think of to get cooling to work
the best.

Maybe the last thing to do is add the undercar flaps. Is that going to make a
significant difference? Any other options before adding coolers?

Thanks.


List of things I did:
Gauge and sender proven good calibration. I put the sensor in water at a boil
and with another thermocouple+meter (not touching bottom of pan). Needle is
where gauge thinks it should be at 210F.

Checked that thermostat is fully opened when engine warm.

Running 160 idle jets and 135 main jets. My innovate was showing good
numbers, but in case it was wrong I put in 140 main jets. No difference.

Distributor was rebuilt when I got it 5 years ago, it is supposed to have the 2.2L
E/S curve in it. Normally I have it at 30 degrees at 6000. I retarded timing about
5 degrees just to make sure at highway RPM ~3400 it was not somehow too
advanced. No difference in this test either.

Got new Stoddard oil cooler. Dropped temp by maybe 5 degrees or a bit more.
Will send mine old one out for cleaning and probably sell it.

I have headers so no heat is happening. But the 2 heater holes were always
open. I made up plugs for these. No difference. Oh, the heater outputs on the
fan shroud were already capped.

Removed both pressure relief valve and safety relief valves, made sure the
pistons were not stuck and also that I have the right length springs and right
pistons for this case. Everything checked out fine. Although I did find a piece
of paper towel just big enough to be captured by the spring under the pressure
relief valve.

I have the aftermarket aluminum sump cover by Mainely. It was put on with
the drain plug facing the driver's side, which is wrong because that's where the
tube is. Apparently on the stock plate that would partially block the oil pickup.
On this plate I think it has clearance. Anyway I turned it around, but it made
no difference. Also, nothing of interest on the sump screen.

Sounds like you performed a thorough check. Usually, the engine size threshold for an external cooler is 2.7 liters. Was the car parked over the winter or for a period of time? If so, it's been known that rodents can nest in the engine. If under the engine shroud, you might have nuked the family, but their household furnishings (shop cloth not unheard of) may be blocking needed airflow to the engine-mount cooler. Remove one or both hot air ducts on either side of the fan and take a look.

Other possibilities:
- Loose fan belt
- 75-76 fan with low ratio crank/fan pulleys.
- Driving style - lugging engine verboten

225 would be on the borderline. However, it may increase with higher ambient temperatures.

Sherwood

225 'way too hot imho

-(caveat) depending on what oil you are running

multi-grade oils maximize viscosity at 210 - then break down beyond that - and below 210 they don't fulfill the advertised viscosity either - walking a tightrope

- see KEW link below

if you are running straight SAE 40 or maybe even SAE 30 then you are fine -but if 20w-50 10w-40 et al you got a problem

might want to defer to the late guru Bruce Anderson on this: - ""240° F is hot, 250° F is too damn hot.". (google it)

or see oil temps

or just see this for more confusion KEW - viscosity explained


your OP suggests you are chasing goblins based on sketchy internet "old mechanic's tales" opinions

- clearly, you have plenty of cash to spend chasing such solutions since you detail them

the basic rule is "do and change only ONE THING at a time"

at the end of the day - you take your chances based on which internet thread you choose to believe

it will take a LONG time to kill your engine if the oil temp is the issue - and it may never happen in your lifetime unless you flog it really hard on the track every weekend

Well I only got the engine together in april so I think if there was any chance
of blockage in there the mice would neeed to be staking out waiting. It's hard
to test this because it's not 80+ degrees all the time here . It should not be
about my driving, I'm just testing this cruising at ~3400 which should not even
be generating the max heat.

So, if other people can get by with stock cooler but this engine isn't doing as
well, then I'm running out of things to try. 914-6 doesn't have a pressure gauge
but I think I should check pressure at this point. I have been running Brad Penn
either 20W-50 or 15W-40 and/or Rotella-T 15W-40 for the last few years when the
motor was similar but still a 2.2L.

Is it even possible to have a long-term slipping 911 fan belt without hearing
anything or having the G light come on? My fan and pulleys are correct ones.

It will be easy to pull the right side heater plate to get a good look under the
shroud again.

Very interesting as I am about to install the same motor and was hoping to stay extra cooler free

How many miles on rebuild??

What shroud are you using??

Why aren't you running the flaps? I think they're needed to funnel the air up to the fan. Do a search. Seems there were a couple discussions years ago.

I'm with Larry. 210 is the number you want to shoot for when hot.

Shroud is normal early one from my original motor. Has gray piece going to
cooler. Bottom end wasn't opened for this upgrade. AA new cylinders, JE Pistons,
some opening up of intake ports as the heads I have are the smallest ported
type.

Early cars did not have the flaps, I think it started in 73? I don't have direct
experience how much those really help. Willing to add, but may need a test.

The -6s never had the undercar flaps, but they certainly won't hurt anything and may help bring the temp down a bit.

In the long run, going to a front oil cooler may be the best route to take as it sounds like you've done due diligence in chasing down the elevated oil temp causes.

Is this a street or track car?

Street and autocross car

How does the oil flow?
So, when cold, it should not be going through the oil cooler, at least until the motor hits an operating temp.

Of, it goes through all the time and air is blocked off to the cooler (all type 4) until it hits a specific operating temp.

So, what stops the oil from getting to the cooler...I would investigate that to see if it is ever getting to the cooler.

Also, from my experience, cruising on the highway is when you get the motor the hottest....so you can do the same test in most temps to push it.....just keep it in fifth and it will get hot.

Rich

This is true, I've just found when the outside temp is lower the 'final' oil temp is
lower too.

Oil 911 oil flow diagram
Click to view attachment

Thermostat is in the top of the case like 1" from the oil cooler. If it is opening,
oil is going to the cooler.

My 2 cents.

First, this is a relatively fresh motor(less than 90 days old and low mileage), you may still be breaking it in. Suggest lots of short trips using the gears and not a long freeway trip at a constant speed. Depending on how much you drive, it may take several more months to get it broken in.

Change the oil during the breakin process too

As for jetting, check the plugs for color, tan or light brown desirable.

GT engine lids work to let more air in, less desirable in the rain, but if this is a fair weather car, I would recommend

Just remove your engine lid and go for a drive to see if a gt lid will make a difference.
Add in the lower engine bay flaps.
Make sure the vanes on the alternator cone are there.
Make sure air is flowing through the oil cooler.

I'm not 100% sure, but does that early a case have oil squirters installed ?
Also, don't most builders suggest replacing the early oil pumps with a later style
larger pump to increase the flow of oil through the cooler when going for more HP ?

I had a 2.5 built on an aluminum case without squirters and with the original
oil pump. 2.7 RS pistons and cylinders and the original solex cams.
It always ran hot... I was told the only way to get it cooled down was to do the
case mods for the squirters and put the big pump in it.

Sold it first..

I have no direct experience (yet) with this set up, but I do have a bunch with air cooled flat four aircraft engines with vey similar set ups. The biggest issue in getting efficient cooling in those applications is management of the airflow. Small leaks can have a significant effect. Seal your shroud so that the only way for air to get out is through the cylinder fins or through the cooler. Sounds obvious but even small leaks can matter.

I wonder what kind of CHT's you are having?? They are directly related to oil temps. If they are running cool, you could divert some of the cylinder cooling air to the cooler

Fish a light bulb into the shroud turn out the garage lights and you may be surprised at what you find. Worth a try

Just to clarify, only things breaking in would be rings, and I'm sure that
happened quick. I changed the oil after that, too.

It would be pretty hard to determine how much air is making it through
the cooler.

I checked under the shroud, it still looks good in there. I'm sure the deflectors
are pointing at cyl 1/2.

I can make a note to run without the deck lid, that should be easy.

The duct to the oil cooler is basically a formed metal piece that is riveted to the
fiberglass part of the shroud. I'm sure there's a gap in places as the rivets don't
seem tight at this point. I'll have to check for leaking air while revving up.

Are you certain the oil is going through the oil cooler?

All this over 225F? I don't think that's a problem, myself... Worry when you get to 250F.

--DD

My 2.2s runs 180 all day, but I have a front mount and 17 quarts of oil running through the system.

To a point I agree. But maybe all the people who used to claim they did it long
ago are all talk or they tool around in the suburbs of Anchorage.

Also, this is just cruising, if I was on the track it would be trouble. At autocross
a few days ago, I did 6 runs shutting down for about 5min after each, and it got
to 225 at the end of that.

did you cut the cooling fins between the cyclinders? that tip is in Bruce Andersons books.

my 2.4 runs cool in the PNW but I also have piston squirter
MikeC

Mark, its a PITA but you have done due dilligence. Put an external cooler on it and dont worry about driving it hard.

I have a new Tstat if you want to swap out and see if it makes a difference. Glad to lend it to you.

Mark,

good to see you are still autocrossing your car. Maybe one of these days I'll dust off the autocross wheels.

My engine is only 2.0L E, so I'm not sure how relevant it is. I am running the flaps, I have piston squirters, and I updated the between cylinder tins. Otherwise we are similar, headers, 40IDA3C carbs, stock shroud, stock early fan.

Running 225-50-15 rear tire I run on the highway at 3400RPM a lot. I only see 225-230 on the gauge on the highway when it is 90+ outside. Normally I'm 180-200. Not sure how helpful that is since there are a number of differences.

I would definitely try the flaps. They are easy to install. When we have had -4 cars missing one or both it has been good for 10F putting them back on. Though usually a bunch of work tightening shrouding up etc happens at the same time, so it is hard to tell how much they really help.

I have also run a GT lid in the past. It makes the car really loud, so I prefer not to run it unless I am going to autocross. I didn't take numbers, but I did notice it runs hotter with the stock lid. Maybe 10F

Good luck

Kelly

Thanks all. Rain and cold is here for at least a while, so I have time to do
a bunch of 'easy' stuff that can't hurt.

I do have the recommended mod to the cylinder tin. But, as my case is from
'70 it does not have oil squirters.

Did you solve this Mark?

No, nothing new to report yet. Outside temps have not been co-operating
and I've been too busy to do much on it.

nearly all engine oil viscosity charts end at 210*F or 100*C

- because that is the SAE test standard - "automotive designers usually call for their engines to run at 212°F oil and water temperature" - presumably there is some good technical reason for that?

the factory 911 Tech Spec book for the 2.0-2.2 says "Max oil temp 130*C, SAE 30 oil, oil psi 5.5-7 kp/cm2 at 80*C" ; the 2.4-2.7 book says same; the '74-up 2.7-3.0 book says 10W/50 or 20/W50 or SAE 30 oils

that tells us something about the Porsche engineers' view: it apparently takes a "50" multi-grade to match the protection of 30 single grade, measured at 100C - (apparently the relative operating temp viscosity value of straight vs multi-grade oil is notable)

Porsche put the oil psi spec of 5.5-7 bar (55-80 psi) at a conservative 80*C

so - above 80C, we are on your own in achieving spec oil psi since the oil is thinner & we'll have less psi unless we "use heavier oil" or boost the pump output and boost the relief valve settings - (the latter 2 strategies routinely used in MG/Austin engines with which i have some experience) - - didn't Bruce A recommend those bigger pumps & late galley mods for our 911 builds ????

(10psi/1000rpm is the generally accepted psi bottom line) - (so 55 psi is just good enuf if we are running at 210F near redline, and quite nice enuf tooling down colorado boulevard on a cool eve)

at Max=130C - we are in uncharted territory

if we are using multi-grade, we need to consider the VII factor
why viscosity drops
"exposure to high heat is the biggest factor in causing the sheer of the viscosity-index improver."

do we really want to cruise all day at 225 on multi-grade ?

- if so, we just change our multi-grade oil OFTEN (before it breaks down) and select a bit higher advertised viscosity number than we need at the Porsche "50" design spec - your engine will not die under those considerations (oil changes 'way cheaper than bearings)

just for the heck of it - check out these charts

oil viscosity vs temperature , "... A change in temperature always affects the viscosity .".

(mult-grade) VI additives prevent thinning as the oil is heated so that it can pass the SAE viscosity rating at 210. viscosity explained

viscosity - measured at 210 F see table 1

here is a VI chart that goes up to 160*C VI vs Temperature pdf - (VI is not the can V number)
,

comparo - - my 3.2 with an oem six engine cooler and a thermostatically controlled external Behr GT cooler and a GT engine lid runs at 185-190*F under a variety of conditions, and has hit 200 at AX (and has a lot of air leakage around the engine seals) - and, sometimes i worry i'm not quite hot enuf to reach full viscosity of my multi-grade - but my oil psi is golden, so why worry???????? (yet)

there is no solution - seek it diligently
.

All scientists/engineers use 100 degrees as a standard because it is so easy to verify and a universal standard temperature. It is why Celsius chose it for 100. Word is that Fahrenheit used his cat as a standard for 100 degrees .

So the fact alone does not indicate that the engineers considered that temperature optimal for the oil. Rather optimal for the test. Which is how I design an assay.

Difference of running lid vs. no lid. It's somewhere between 5 and 10 degrees F.
I ran this test today about an hour apart no other variables.

With lid:
Click to view attachment

Without lid:
Click to view attachment

I'll look into a GT-style one. Also I have yet to get and add flaps.

maybe they just can't design (or see no market for) a VII for a multi-grade oil that performs above the target 100C design spec? - and why should they when auto engines are designed to that spec?

the CHEAP and simple solution is to just toss in a can of STP - it's a VI improver - but has a very short life STP etc

it won't lower our oil temp, but it will temporarily protect an engine if we insist on running at higher temps 'cuz we don't want the expenses of an external cooler and frequent oil changes

.

that is a really valuable report - somebody should sticky it - lot's of folks want to know this

Unfortunately I'm sure the magnitude of the result is going to be different based
on engine type and if you have flaps or not.

I have also seen around 10F regular lid vs GT lid. My specs are above.

kelly

Installed flaps. This is the result still using the normal deck lid. It was
84F outside, same driving loop.

It looks very much like the run with no deck lid and no flaps. I wonder if the
effects willl add together if I try it
Click to view attachment

Several people said their 3.0L had good temps without an external oil cooler but mine was hitting 250 (I didn't push it any further) in good weather. Perhaps each engine has a mind of its own. So I had to install an external cooler which I put under the trunk and it peaks at 210 now.