>Hopefully, you will soon be able to confirm airflow thru the REAR (main) cooler. Unless you've already confirmed - have a friend hold a 2500 rpm speed and sneak your hand up to feel lots of air coming thru.

You know, I have not done that ! Underneatht he car you mean, where the cooler is partially visible ?


>MO you are ducking the most obvious culprit...air baffles and air flow

Sure, it's just that everything done so far was feasible by a guy with 2 left hands. Pulling all the shrouding to look for the baffles is not a trivial project for me ;-) But I'll try this w/e ! I promise !

>take an actual temp reading of the oil with a laser thermometer to make sure you're not chasing a ghost reading.

Done. I carried the thermometer with me for days ;-) The temps are real, thought there is not ONE single point in the engine compartment or lines that match exactly the gauge readings - it's always a bit hotter or cooler depending on location. But it's in the neighborhood, and once at home I cannot touch my rear bumper without pain! It's HOT. I've calibrated the gauge with boiling water as well, and double checked oil temps in the tank by dipping a thermometer in there! Also thereabouts, cooler, but that's not a correct location anyway !

I owned a 1983 911 SC for 11 years and fought high temps similar but not as high as yours for years. I had a turbatrol cooler installed and I gutted the cat. These helped slightly but what really helped was having the engine pressure washed when I had a new clutch installed and my trans rebuildt. Accumulated grime on the engine cooling fins over the years, that I could not see, added about 20 - 30 degrees when the engine was under load! Try it if nothing else works.

Either your mixture is too lean somewhere, or your vacuum advance mechanism is not working. My bet is on the latter. You've indicated previously, with advanced ignition timing, while driving under a moderated load, the car does not ping, but does so under hard acceleration. Under light loads, such as during cruise situation, the intake manifold vacuum is high, and the cylinders do not fill up with as much air and fuel. The air/fuel molecules are much farther spread apart than at full load, which would burn slower, and thus need more ignition advance (through the vacuum advance mechanism) to fire the mixture and provide peak combustion pressure at the optimum point after TDC. Typical low load ignition advance should be around 15 degrees more advanced than full loads. Therefore if full load advance at 5000 to 6000 (measuring with vacuum line disconnected is 30 degrees btdc, with the vacuum line connected, the advance mechanism should advance it a further 15 degrees for best part throttle cruise efficiency. I really do not know the actual tuning specs of a SC motor so don't take my words as gospel, but 20 to 22 degrees at 5000 with the vacuum lines disconnected seem way too low to me.

To test the funtion of a vacuum advance I'd use a Mitivac vacuum pump. However Steve Weiner said it best, if you're not sure what you're doing, get your distributor tested.

Yeah baby ! ....although I'm making it sound like a piece of cake - it may not be. With so much air swirling under there and limited access for your hand - it may be easier to hold up a scrap of cloth with skinny extended pliers to 'see' the evidence of flow. Or..., a 3/4" rubber hose held up flush to the cooler and hand at the bottom of it to feel for air pressure.

________________

'82 Targa - sold
'80 928

Thanks, that was a good explanation ! Actually, 20-22 degrees with the vacuum lines disconnected IS the porsche specs for an 83 motor ! Surprisingly low, huh ? A 78-79 motor would be 26 !
I really need to measure what that translates to with the lines ON, I was too embarassed to do so last night (halloween - me revving the crap of the motor and scaring the kids)

I've had issues last night on my way home with the very advanced timing, so I eyeballed it back by the side of the road, and then when I got home it turned out I did it perfectly. A little bit more advanced that stock (2 deg), but not quite as much as yesterday. No pinging, no problems.

The temps decrease I saw yesterday morning was not all that significant after all (realize this is a bit empirical), it was very close today, and it'll be back to normal (hot) this evening I am sure. I plan to get the distributor cleaned, tested if I can find a local guy ( I need my car - unless the Don MArks of this world provide exchange units, I cannot lose my dizzy for a month), and I'd love to have the motor cleaned but that is a big engine out job. I'll price it, see what happens, that'll make checking the baffles super easy ;-)

You do not need to pull all the shrouding. The left side access cover (Behind Distributor) is the harder one to remove, I suggest you start by removing the right side cover it has 3 or 4 10mm screws and it's out. It really is easy to remove and once removed you will see the Air Baffles between the cylinders (cyl 4,5,6) they should be inserted between the cylinders from the bottom of the engine (they go in from the exhaust side) just like in the picture below with the tin strips holding them in place at the top of the cylinders. Here are the pics once more.

http://forums.pelicanparts.com/uploa...1162388302.gif

http://forums.pelicanparts.com/uploa...1162388332.gif

Thanks ! Somehow this explnation makes it sound easier than the first ! I will do that tonight, and also measure advance with the lines on ! For grins ! I'm gonna win this fight ! I'm stubborn enough !

This may seem very basic, but no one asked: What oil filter are you using?

standard german fare... I forgot but mahle maybe ? It's the one you get from most players, this one from pelican...

Sonds fine, just thought I'd ask.

Greg,
Glad to hear the temps went down with timing adjustments. Regarding your front oil cooler additions. Are your using two oil thermostats? One back by the right rear wheel well and up front? If so, why?
Secondly, are you using the stock oil lines at the rear wheel thermostat or have you added braided oil llines to your car?

Well, the temps went down but the car also pinged and ran like crap later on, so I would not call that a success necessarily. Also, since the car does not have a knock sensor and not all pinging is audible, I hesitate to play God with my timing anymore... I am currently on the upper side of the range supplied by the factory... Good'nuf, I will have the dizzy and vacuum checked anyway !

2 oil thermostats ? No, one for the oil cooler, the second is for the fan that I installed on the oil cooler and determines when it triggers. ;-) Sorry about the confusion !

Stock lines, yes.

I think we've gone around the problem now - once the dizzy is checked as well as the vacuum advance, the air diverters and the cleanliness of the motor, we should have an answer. If all is well and it still runs hot after all this, I swear I will put black tape over the temps gauge and rive the car to the ground ;-) It worked on my ex- 356s ! (ignoring the temps, I mean)

Can you borrow a distributor from another SC? What does the parts dismantler in your area get for one of these? You seemed to have discovered a path to the correction, now the proper correction is in order.

Also, you seem to have not accomplished to full inspection to the top of the engine. A lot of these engines just get plugged up with oil and fuzz from who knows what. You can take an air nozzle and from the bottom between the baffles, blow air upwards. If you see debris coming out of the fan, you know what you have to do next, get that fan out of there and get some access to really see all 6 cylinders. And, if you have "fuzz" on your cylinder fins, you also have it on your engine mounted oil cooler. I've seen VW engines blocked nearly solid with caked and baked oil mixed with "fuzz."

Most of the cooling comes form the main On-engine oil cooler (Not to mention cylinder head cooling). I still say that you don't know anything until you pull the fan and take a look....

This may have been covered on page 1 already.

What is the heat range of the spark plugs? You don't want hotter plugs installed.

Sherwood

Update
 

Tonight's update to this unending saga !

http://members.rennlist.com/greg/911SC_fins1.jpg

http://members.rennlist.com/greg/911SC_fins2.jpg

If you ask me, it looks pretty damn clean for 170000 miles !

There is a piece of a leaf in the back, very small, and a tiny feather in front - sorry about the picture quality but it's hard to focus in there...

The diverters don't look upside down though !

Bam, just like that, I am left with the distributor, possibly, and that's pretty much it. Ok I will pull the fan and look at the other side as well ;-)

PS: sherwood, no idea about the plugs, I guess I'll pull one, but I am pretty sure they are correct...

I mentioned this about 40 pages ago...and no one commented on it, so I'll try again.
As we all know the external thermostat housing has a thermostat that controls flow to the external cooler but there is also a pressure piston on the bottom of the housing. I'm not sure of the function of the lower piston but I would imagine that if it hung up it would restrict the return flow of oil. Any thoughts on this??

http://forums.pelicanparts.com/uploa...1162429088.jpg

Also, wasn't there an issue with external coolers. Something about an internal baffle missing??

Good thread

The cylinders looks good. Were you able to get a mirror back near the internal cooler to look for nests or dirt collecting on an old oil leak? If you didn't see anything, then you are probably OK there. DAMN!!! I was hoping it would be that simple for you. Sorry.

Just out of curiosity does your vehicle have the sump plate at the bottom of the engine case?

If so, is the oil drain plug on the left side?

If you have a sump plate and the oil drain plug is not on the left side the drain plug will interfere with the oil pump...reducing oil flow creating heat.

Just a thought.

(If you have a later production year the case drain plug is on the left and there is no sump plate thus a non-issue)

I second check the plugs for correct type. Replace them regardless.

Yes to the sump plate... Yes, the plug is on the left (driver) side of the plate.

>Replace them regardless.

With what ? Any specific brand/type you can think of that promotes running cooler? Thanks !

Use copper plugs, nothing fancy. Bosch W5DC or W7DC. $2 each.

Avoid todays new fangled 2-4 electrode, platinum, gold plated pimp my ride gimmick plugs. Keep it simple.

Check AFR's. Borrow LM1 from someone and do a run. If AFR's are >13.50 @ WOT then you need to richen it.

If they are OK, blow compressed air trough main engine oilcooler. You can also try to clean in underneath with pressurized water hose.

If that doesn't help, fiddle with ignition.

Re: Update
 

OK, that right side looks GREAT! Extremely clean for 170Kmiles! You can look at the left side by just removing the other cover, it wil be easier than removing the fan. At least now you know what you have in there.

Nice pictures.

Here is what you do NOT want it to look like. This is my 2.4 several years ago. Drove it for 6 months and no one could figure it out, so I finally stuck a 2.2 loaner in it and pulled it apart.

Found that the critters had been busy over the winter...

http://forums.pelicanparts.com/uploa...1162484949.jpg

Ok, for the record, the other side is just as clean !

But wow, what a pain in the butt to pull all tht heater crap just to take a look. Considering the need for heating I have in FL, maybe 2 days per year, I am very very tempted to pull all that stuff for good... Another thread I guess ! ;-)

i have skipped a few pages because this is so long.
retarded timing wont make it run hot, it is the other way around. when the timing is advanced, the combustion temp goes up causing preignition. that is why u have to richen the mixture when u advance timing.
with the mileage on the car, u could have oil and other debris blocking the ais flow over the cooler. u might want to remove the engine oil cooler and have it cleaned

77911S - http://www.pelicanparts.com/support/smileys/clap.gif I believe you're 100% correct....however, there are quite few guys here who believe that in the 4 stages of the piston travel, the hot gases will not be able to escape easily if the timing is retarded....So those hot gases are believed to be a factor in the overheating issue.

You seldom (never) hear of anyone removing the main cooler for inspection or cleaning. At least - not as a routine type of maintenance. Deschodt may be inclined to give it a try...we'll see.

_____________

'82 Targa - sold
'80 928

I think you may have your vacuum lines reversed because as soon as you connect the lines, the timing should be retarded to about 5 degrees atdc...not advancing to 12 degrees btdc.



That could explain all your problems including pinging at 4k.


Cheers,

Joe

Huh, now that is a thought ! Results in 10 minutes ;-)

I've asked for the numbers with the lines connected and nobody answered that. What shoudl I see with the lines on ? 5 ATDB (aka -5 BTDC for me) and what at 5000 ? Thanks Joe, good idea !

I believe the 964 fan delivers less CFM. It's curved blades are quieter though.
-Chris

Joe, Outstanding thought. I hope that's it!

Greg, Been meaning to tell you; I can't believe how focused you've remained on this problem.

I probably would have lost it at page 3! :eek: http://www.pelicanparts.com/support/smileys/wat5.gif

Your an inspiration to us all !!!

Cheers! http://www.pelicanparts.com/support/...s/beerchug.gif

thanks duckworth,
i felt like i was sticking my neck out on that on.
i did a lot of research on the net under spark plugs and timing because my car was running hot and it was detonating under load. in the end it was the CAM timing and a bad thermostat that was the problem.
cams are the main thing that have to do with when and how much hot gas escapes. the ign timimg just determines WHEN they start to burn. google "reading sparkplugs" the drag racers have it down to a science, also search cam timing. i have learned how air/fuel mixture,timing,plug gap and heat range affect each other, now if i can just figure out what to do with it!

Guys, I'd love to kill this thread but I'm not out of the woods yet...

I could not test Joe's theory right away because one of the 2 hoses was much shorter and would not reach the other side of the distributor vacuum "biscuit".. So, on an unrelated fit of "why the frack not?", I decided to pull the heater blower motor and all the $%$#%$ hoses that take precious space in the engine compartment. It was a long time coming, and I live in Florida, no worries !

I've plugged the open ports for now, I have heater backdate parts coming soon ! No 911 parts were hurt in the process..

Anyhow, long story short... A while back I was asked to check vacuum and there was some. I say "some" because unless you stuck your cheek next to a vacuum cleaner hose, you (and I) will have no idea what "proper" vacuum should feel like. So anyway, thanks to the newfound access to the rear of the motor, I pulled both vacuum lines and replaced them with fresh rubber ! Results ? Now, the bugger will suck the skin off my finger (poetic license) - it's 10x better than before. I did not swap the lines and I don't think they need to be, because the other line produces little if any vacuum at idle, so I think I've got the right ones in place - photos to follow to determine this!

I think the other one only works at higher RPMs. So, it is entirely possible that my distributor was not getting enough (vacuum) and now will... So Thanks Joe for getting me to do that ! Of course, I don't know which port is which so maybe this will turn out to be one of the 25 things I have fixed since page one that does not do squat for my temps problem ;-)

On a related matter, please riddle me this, gentle reader. The left side fan shroud blocking piece that flows air to the heater... you know, the one behind the distributor ? Now that I had to block it, I can tell it pushes a lot of air thru ! Does't this thing rob a lot of cooling air from the left cylinder bank ? Seemed like a lot of flow to me, and the right side does not have this handicap. Opinions ? I mean I blocked it with a poster tube plastic tap, and the car promptly spat the thing out 3 feet when I revved it !!! ;-)

I cut up a heavy Betty Crocker pie tin, molded it over the hose outlet tube, and put a hose clamp on it. Worked just fine. You can maybe make it out in the photo.

http://forums.pelicanparts.com/uploa...1162696186.jpg

Here we go
 

Pictures:

Hose A, can you see ?? (sorry, it's late, it's probably not funny)

http://members.rennlist.com/greg/911SC_distro.jpg

So, if I pull the freshly installed hose A at idle, the idle jumps 600 rpm at least. It sucks hard now !

Hose B is also fresh but not so sucky (vacuum wise). Is that the high speed vacuum hose ? Anyhow, I can't prove what hose B is doing but if A was barely holding a vaccum, B was probably just as bad. I need to go test the car again at higher speeds now!

Now... before and after - way more room after !

http://members.rennlist.com/greg/911Sc_engineBA.jpg

The vent I am talking about, that does not exist on the right side of the fan, does not this rob some Fan air for the heater and make the left side hotter ? Fret not, I am getting correct heater backdate parts on wednesday and will restore a modicum of heat and proper engine compartment look ! The blue tape and collars hold the poster tap ;-)

Thanks guys !

PS: Pat, nice McGuyver fix ! Pelican sells a cheap bloxk off plate for this that you might prefer, in therms of looks, but I am getting a proper heater backdate one so I retain some heater)

Greg, I've been watching your progress, along with about a thousand other guys I'm sure. Why did the vacuum hose replacement increase the vacuum? Was it the connection at the "front" end or a leak in the middle somewhere?

It's a braided line, it's hard to tell, kinda like a brake line.... The front end was split but that coul dbe after all the removal/reinstall I did. But even after I cut the split end and retested it it was not as "sucky" as it should have been. I guess there are small cracks throughout under clotch cover. The line was harder and brittle !

What gets me (assuming this helps any), is that I could have solved that on day one if I could find the timing numbers with the hoses connected. Those numbers appear not to exist !!!

Measure hoses disconnected -measure hoses connected: if the #s are off you know you have a lazy dizzy or a vacuum leak - simple ! Yet nobody's come up with those #s so I guess they're not public knowledge!

I have a full set of NIB factory manuals that I haven't even opened yet.... I'm sure the #'s are in there..when I get a chance I'll dig them out and have a look-see.

Re: Here we go
 

Our host sells a left Block-Off cap for this left side vent search for part # PEL-PP910181 it's $84.95.

If you live in Florida I would most block this left side off. BUT! do not give up the Blower Motor and the ducts to the heat exchangers as these will help keep the exchangers cool and overall help with your temp troubles. This also means you MUST have a Blower Motor that is working! The Blower Motor will just draw it's air intake from the engine bay and not from the Left Side of the air shroud.

I had a 75 911S and caped off my left side with Metal Flashing much like the pie tin idea already mentioned, this works just fine.

The experiments continue
 

The 911 lab experiments continue unabated...

The removal of the heater blower and subsequent blocking off the left side vent that stole air from the left cylinder bank (in my opinion - see the pictures 2 posts above) did ...absolutely nothing for my temps ! There is a trend here - nothing I do does anything !! ;-) If anything, it might be a bit worse than before, leading credence to the idea that air going over the heat exchangers helps lower overall temps a bit ! Not much, but maybe... Anyway, I have backdate parts coming soon !

So step 2: I made this (note my metal fabrication talents), good thing I am in software !!

http://members.rennlist.com/greg/911sc_diverter1.jpg

And shoved it in there. The plate should prevent air from going anywhere other than the cooler and the angle in the back of the plate should deflect the air upwards, where the cooler main body is...

http://members.rennlist.com/greg/911sc_diverter2.jpg

The zip ties are temporary obviously, if this works I'll drill nice holes, if not, my front end has enough scars as it is !!

PS: kinda bummed that replacing both vacuum hoses and getting much better vacuum did nothing for me ! But like I said, that's the story so far.. I've fixed a ton of little things that made zero difference !