Need serious help now, what's left, JW, Warren, Wayne?

UTKarmann_Ghia · 08-09-2003, 12:02 PM

Ok, you can check out my other heating threads and I've done everything that's been suggested including a mocal cooler up front with a fan. I just pulled the engine to check the condition of the engine oil cooler...absolutely perfect and clean as a whistle. Next I pulled the internal tstat. At 200 degrees, it's wide open on the bottom window. Probably at between a 1/4 & 1/2 inch open and the top one is completely closed. I beileve this is the correct operation.

I'm getting very desperate for resolving this overheating issue. I've been told that with everything I've done it should be running very cool now. Please, I'm starting to get very discouraged working on this for the past 3 months. Here are the links to my other heating threads:

Oil flow speed to cooler
250 degrees is just too much...
What else is left to do? Need help badly.

Is there anything else I can check whilst the engine is out? I'll probably put the engine back in next weekend and maybe there's something else I can check now

Early_S_Man · 09:01 AM

Matt,

Have you seen Mark Wilson's recent thread on a suspected overheating problem?

Overheating SC

Based on your earlier check at the mechanic with the Fluke meter and thermocouple probe ... I am not convinced that you have an oil temp of 250° F ... a Wal-Mart mechanical gauge doesn't give me confidence like a Fluke thermocouple reading!

When you have oil temp readings at what you suspect is 250° F ... does the engine compartment 'SMELL' FUNNY?? An engine that hot ALWAYS smells decidely different to my nose than one that is 200° F to 210° F, and though that may sound funny to you, I have never encountered an engine smelling that way at normal operating temps!

I suggest a test at your mechanic's shop with a saucepan of cooking oil, on a hotplate ... with your temp sender, Wal-Mart gauge, and the mechanic's Fluke gauge, from, say 140° F to 300° F, keeping notes along the way at 10° F intervals. Finally, do a calibration check with a pan of distilled water boiling ... I supect it will be closer to 205° F than 212° F ... but I don't know your altitude.

Finally ... do a series of checks with the Fluke meter around your car like Mark did, when your gauge is reading 250° F, just to give us an idea of the overall conditions temp-wise around your engine and oil system.

Good luck!

Pat S · 08-09-2003, 02:52 PM

Mark,
Sorry to hear your T-Stat workd

Look at this thread:
General theory question time, engine sheet metal?
Keep an eye on the talk of the engine seal and ignore the insanity.
Key point I saw was from GIBSON who said "The muffler seal is missing on many cars and it seems to me it would allow hot air to be sucked in quite easily."

Now to the experts here since I am a complete novice:

Mark's seal that connects from the engine bay to the engine sheet metal is dry and broken at the rear of the car (near the exhaust) is GIBSONs theory correct that the fan may be sucking in enough hot air from under the car and from near the exhaust to not cool the engine enough? Or would this just be a mild addition to the temps and not a reason to see 250?

Pat

Early_S_Man · 08-09-2003, 03:04 PM

Pat,

Gibson's observation is a FACT! One Pelican left the rear engine tin off while doing some testing and suffered instant overheating in mild LA weather!

A very good substitute for the factory seal, on a temporary, or semi-permanent basis, is the pink Owens-Corning fiberglass insulation in the 3" thickness ... with the backing paper peeled off. I have used it on multiple engines laying or compressed in direct contact with header tubing, and all it did was turn white-gray ... no charring or burning!

UTKarmann_Ghia · 06:45 PM

Warren, Pat S helped me drop the engine this morning--thanks Pat! He's right about the seal, it's fairly brittle and there's about 3" that is actually torn above the muffler. The engine tin is intact and complete, but the seal does kinda suck.

As for the gauge, I'm pretty sure it's right. I bought the calibrated gauge kit from Pelican and I actually hit 260 earlier this week. Now there's 3 temperature gauges I've used that say the exact same readings, so I'm pretty sure that it's hot.

As far as smell is concerned, it does have a bit of a strange smell. I cant really describe it, but once it hits those highs it's does smell kinda strange. Funny thing tho is that when I open the decklid, there's not alot of heat coming out like you would expect. Maybe it's underneath?

I also notice that my oil pressure goes from about +2bar to about 1bar or less than the rpms. I use 20w-50 Castrol syn blend.

Is it possible that even tho I'm getting hot feed and return lines from my cooler, that it's obstructed somehow? Am I barking up the wrong tree?

I will see if there's SOMEBODY I can borrow a pyrometer from and get those readings in the next couple of weeks.

Can someone point me to the engine seal on the pelican website?

Thanks for your suggestions Warren, you're giving me some hope...

Pat S · 08-09-2003, 06:54 PM

Matt,
Should be #39 on this page
http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_weathr_main.htm

Part# C-504-111-02

Interesting idea about the fiberglass too.

Pat

Wayne 962 · Wayne 962's Garage

Warren is right - make sure that your readings are 100% correct first...

-Wayne

UTKarmann_Ghia · 08-10-2003, 08:49 AM

I'll do my best to get a pyro meter in the next week or so. But I've got 3 gauges saying the same thing and I have a brand new numbered combo gauge from Pelican as one of them. Meausrements I take from the outside of the engine at places cant be as accurate as the temp of the oil inside the engine, can it?

Early_S_Man · 08-10-2003, 09:15 AM

Matt,

When you don't have more than a 20° F spread all over the oil system, including the dipstick location ... then it does give me confidence that you have a good picture of the oil system temps.

Even the VDO numerical gauge and sender has pretty wide tolerances ... compared to a thermocouple probe! Ever notice that you get a slightly different temp gauge reading when operating just from battery, compared to engine running at 2000 rpm??? It may only be one needle width ... but it does raise an eyebrow in my mind!

UTKarmann_Ghia · 08-10-2003, 05:33 PM

Ok, thanks Warren I'll beg, borrow, or steal a pyrometer here in Denver

Could you put my mind at ease for this one question I have. Is there anything in the engine that could be really wrong causing this incredible heat (assuming that there is a heat problem)? My engine runs great, and the mechanics at the local Porsche shop said it's running great. They didnt even want to do a leak-down for me once they heard it running and put it on an exhaust analyzer. I'm afraid that there's something terribly wrong and it's just a $5k ticking time bomb. What do you think?

Wayne 962 · Wayne 962's Garage

I would guess your internal t-stat is not opening all the way. Does it get hot if you just start it and let it idle? It also may be leaves or debris caught underneath the fan, in the cooling fins of the cylinders...

-Wayne

Steve@Rennsport · 08-10-2003, 05:50 PM

Is your ignition timing retarded?

Do you have 34-35 deg total advance @ 5500 RPM?

Are the rubber seals around the plug connectors nice and pliable to seal well?

Pat S · 08-10-2003, 05:55 PM

Steve,
I've read this plug connector thing before but I don't understand the reason. Can you explain why that is important?

UTKarmann_Ghia · 06:54 PM

Wayne, I mentioned a bunch of stuff in my previous posts and I also verified the internal tstat opens completely at 200 degrees. I didnt check the incremental temps for the internal tstat, but I figured that if it opens fully (really fully) at 200 degrees, that's probably pretty good (correct me if I'm wrong). Cylinder fins are clean as a whistle as is the engine oil cooler fins (why I pulled the engine). Ext tstat is brand new and working. Oil tubes are in perfect condition and I cleaned them really well too. Plug wires are brand new and have the rubber seals intact at the valve covers. My ignition is set correctly at idle, but I will check it with full advance also as you suggest. The Porsche shop actually verified the timing, but they checked it at idle.

Pat, the air flow through the cylinders is partially dependant upon the round, rubber seals at the top of the spark plug connectors at the spark plug end of the wires. If these seals are missing, air will escape through the valve cover holes and it can affect your cooling. That's one of the reasons I replaced mine because they were in bad shape. Course, that didnt help.

Guys, I just want to thank you in advance for all of your suggestions. I've examined the entire cooling chain, added the Mocal cooler up front, a fan for it, and everything else in the cooling system. I'm running out of options and you're helping me keep my sanity. Again, thank you.

Steve@Rennsport · 08-10-2003, 11:43 PM

Pat:

Each plug connector has a rubber seal around it to contain the cooling airflow being forced past the heads which are the hottest part of the engine. When these rubber seals get hard over time from the heat, they fail to seal all of the cooling air and the cylinder heads (thus the oil) run hotter than they should.

Matt:

Your shop MUST check total advance at 5500 to 6000 RPM for accurate timing. Late ignition timing will really make ANY engine run hot,...

Further, they should check the vacuum advance for proper operation as these cannisters do fail and can cause these very symptoms. Its easily done with a good timing light.

Roy M · 08-11-2003, 02:17 AM

Really an amateur here but have you considered your sender unit being faulty? - 3 gauges give same heat but all off same sender (or did I miss sonething?). As said earlier a hot engine smells HOT.

Good Luck

UTKarmann_Ghia · 06:07 AM

Good thought Roy, but I have a brand new numbered sending/gauge combo from Pelican. The other was a stock sending/gauge combo and the third was a water temp mechanical gauge which I fed through the oil filler cap.

Ok, my engine seems to smell hot, could I borrow Warren's nose please?

Steve - the advance seems to be working as the timing moves when the engine is revved, but I will certainly check the full advance once the engine is back in the car. I'm trying to ensure that I've checked everything else that I can before putting it back in.

Question - I did the static test on my internal tstat in boiling water and it's fully open at 200 degrees. Not sure at exactly what temp it finished opening, but it was somewhere around 190 I believe. This should be a good validation of my tstat, right?