SC running "too damn hot": Mechanics stumped, So am I !

[Mookster]

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.

[beepbeep]

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.

[scarceller]

Originally posted by Deschodt
Tonight's update to this unending saga !





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...

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.

[Joeaksa]

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...

[Deschodt]

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 ! ;-)

[T77911S]

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

[Duckworth]

77911S - 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

[stlrj]

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

[Deschodt]

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 !

[ChrisBennet]

Originally posted by Duckworth


Curious also if a 964 curved blade fan would do you some good in sunny Florida...more CFM thru the fins would likely have an effect at the temp gauge.. I'm not sure if it's easy swap.

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

[Goth]

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!

Your an inspiration to us all !!!

Cheers!

[T77911S]

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!

[Deschodt]

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 !!! ;-)

[patkeefe]

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.

[Deschodt]

Pictures:

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



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 !



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)

[Howard M]

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?

[Deschodt]

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!

[audi2.7t]

Originally posted by Deschodt
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.

[scarceller]

Originally posted by Deschodt
Pictures:

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

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 !

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)

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.

[Deschodt]

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 !!



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...



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 !