Steps To Increase Engine Operating Temperature..., Curse of the Temp Gage... Options

[Joseph Mills]

Before I had a temp gage, I worried about not knowing what temps my engine was running at. (IMG:style_emoticons/default/unsure.gif)

Now that I have a temp gage, I get to worry about the temps the engine is actually running at! (IMG:style_emoticons/default/biggrin.gif)

Since the ambient temps in my neck of the woods has dropped into the forties & fifties my engine temp gage reads between 120 - 180 running around town.

The flapper boxes and thermostat were removed by the PO. The vent door over the oil cooler is wired open.

At idle, the temp will not climb over 140.

I'm doing an AX tomorrow and these temps seem a little cold for running the engine at redline.

What have some of you in a similar situation done to increase temps?

I have removed the GT lid and installed the stock one with a raintray. I could cover the expanded wire mesh (including the little side openings next to the lid), with all mag vinyl.

Also considered blocking off 1/2 of the oil cooler.

The value I see in blocking the oil cooler is that it will increase oil temps, whereas blocking the engine air could possibly increase headtemps, but still not increase engine oil temps.

Any ideas, comments, advice?

[TheCabinetmaker]

Joseph, I can't answer your temp q's, but when and where is the AX? I'm ready for a short trip.

[Joseph Mills]

Curt,
The AX is a non-points fun event held at our smaller event site. It's at the OU Driving Range on the NE corner of Portland & Reno. You enter at the south entrance off Reno.

Registration is 8:30 with timed runs at 9:30am. We usually have four heats. I will be running in two of them and working corners in the others.

I'll be there at 8:00am to help setup the course. Supposed to have a high of 54 w/10% chance of rain.

Come on down! (IMG:style_emoticons/default/driving.gif)

[TheCabinetmaker]

Portand and Reno. I 40 west of I 44? 8:30? guess I better put the Fat Tire back in the fridge. (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/beer3.gif)

[Joseph Mills]

Portand and Reno. I 40 west of I 44? 8:30?

guess I better put the Fat Tire back in the fridge. (IMG:style_emoticons/default/laugh.gif)  :beer3:

South on I-35, exit west on I-40
Exit on May Ave. north one block & west on Reno
Go one mile west almost to Portland. Entrance is on Reno.

Step away from your fridge. (IMG:style_emoticons/default/biggrin.gif)

[Joseph Mills]

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(IMG:style_emoticons/default/confused24.gif)

[dmenche914]

Be sure to check your temp gage for calibration. Best test is to put the sender in boiling water, keeping it all hooked up, and read the temp. It should be pretty close to 212F depending on air pressure when you read it. Gages are off sometimes, maybe you really are running hot, which is a more likly problem than running too cold.

I would not think the lack of the flapper boxes are a issue, cold, nor hot, only down side is no heater.

If you can afford a new thermostat, get one, and hook up the system. When hooked up it will allow the engine to warm up faster, which is important to minimize wear. Adding it will cause faster warm up to correct temp. Unwire the "vent door" and get it operational again, the thermostat will open both side vent doors as engine heats up. Both sides must work in unision for even engine temps, as they are critical in directing air to the heads. When one side is up, the other side flap is down. (ie when hot, the one on the oil cooler side should be down, the one on the dirver side should be up, this is the maximum cooling position. If thermostat fails, both flaps go to this position as a fail safe, to assure enigne cooling. Never wire either or both in the opposite position, as over heating will result.

180F is not too bad a temp for your oil (i wish mine ran that cool sometines) sure it is a little on the cool side, for my car, but again, there could be gage reading errrors.
Too cool oil is usually only encountered when an over sized external cooler is added, if it has no oil thermostat.

I would be really supprised that there would be any engine problem nor stock cooling system issue that would cause too cool oil short of running very cold artic climate conditions. I really think your gage might be reading a bit off if anything is wrong.

Hence do not block off the oil cooler any, nor the engine lid mesh (you could starve the engine for air if blocked too much when running high rpms, this would cause a lean condition)


Hope this is helpfull. If you find the gage being off, let us know by how much.


dave

[dmenche914]

PS... Thinking about it more, if the oil cooler side flap door is wired into position, you either are missing the springs which fail safe it into the down postion (maximum cooling) and or it is wired against the spring (assuming spring is correctly installed) into the minimal cooling position. I believe that in this position, while very little air goes to the heads, some still gets to the oil cooler, hence you might be seeing cold oil, but have overheating head on that side.
Confirm you have the spring installed (spring in on the vane doors shaft, on the driver side), and that the spring forces both vane doors to max cooling (down on oil cooler side, up on driver side) The air must get to the heads. removal of the vane doors will cause incorrect air flow and result in short engine life. (and likely over cooled oil, and under cooled heads)

[SirAndy]

sounds like the PO wired the system for full cooling at all times (which is how mine is as well).
by removing the thermostat and locking the plate over the oli-cooler in place, you'll get full air flow to the oil cooler at all times.
on cold ambient days, that will result in a cold(ish) running engine which is *not* good.

assuming the gauge is working correctly, i would try to block off parts of the oil-cooler.
this is exactly what we do on the race cars if they run too cool.
block half of the cooler off and see where your temps are and adjust accordinly.

if you plan on driving the car more often during the colder parts of the year, i would highly recommend re-installing a fully functional thermostat and cooling flaps ...

(IMG:style_emoticons/default/wink.gif) Andy

[Brad Roberts]

Jo,

Do you have a front mounted cooler ? I dont know exactly how you plan to block off ANY of the stock cooler.

I personally would block off ONE of the air inlet area's like you where thinking.

Nice temps would be in the 200 range.


B

[SirAndy]

Confirm you have the spring installed

the common way to do this mod (un-install the thermostat) is by getting rid of the spring and all the linkage and either glue or otherwise fixate the "flaps" in the maimum cooling position.
on the oil cooler side, that position is "down" as that routes the most air to the oil-cooler.

in his post he mentioned that his "flap" over the oil-cooler is "is wired open" which i hope means it's *down*, otherwise the oil-cooler is not getting full air ...

in any case, this is the way this mod should be done, remove thermostat, rmove pulley wheel (don't forget to put the bolt back in! otherwise = major oil leak),
remove linkage including return springs. fixate "flaps" in maimum cooling position.

again, if it's running too cold for you, try blocking off some of the oil cooler and watch the temps.

all that, of course, only after you made sure your gauge is working right ...
(IMG:style_emoticons/default/wink.gif) Andy

[SirAndy]

I personally would block off ONE of the air inlet area's like you where thinking.

the outlet side of the oil cooler is accessible from under the car. it should be fairly easy to block off some of it from there ...

(IMG:style_emoticons/default/wink.gif) Andy

[Joseph Mills]

Thanks guys for all the good info. I knew this would not be simple. (IMG:style_emoticons/default/biggrin.gif)

For the sake of clarity, the flap for the oil cooler is wired for maximum air over the cooler. I don't have an external oil cooler.

The VDO gage & sender are brand new. I would assume they would be accurate to a degree or so. Is this not to be the case? Have you actually tested some and found them to be inaccurate? If so, how much were they off? I'm asking because I simply don't know.

I guess ultimately, I need to roundup the necessary flaps, thermo, etc. and install them. I haven't met anyone yet that still has them in their cars. Why the hell are they removed in the first place?

I have some magnetic vinyl material cut to cover the open mesh area of my engine lid. I just now completely covered the engline lid and went for a test drive. After about 4 miles of freeway the engine heated up to 180. I let it idle in the drive for almost 10 minutes and it stayed at 180. So that's a big help.

I know this isn't a cure-all, but it can raise the temps for my AX tomorrow. Before each run, I'll just slide the vinyl over to open up the mesh so the carbs can breath.

Mayabe I'll hold off blocking off some of the cooler's radiator.

Oh, does this sound like an okay idea? (IMG:style_emoticons/default/biggrin.gif)

[dmenche914]

The gage new could be wrong from the box, or maybe wrong from resistences in the wires, low voltage at the gage, state of battery charge, grounds. all these variables have an effect on what the gages reads.

There is no reason at all to remove the spring and linkage mechanisms. If you no longer have the bellows, the spring forces the flaps in the failsafe postion. I have not had one spring fail on my of any of my friends cars, and we have been in to 914's for a decade. Just make sure all is secured the screws on the metal tab that retains the spring should be lockwashered inplace. You can run with a leaky or missing bellows, just keep the rest of the parts on the engine, as the vanes are needed to control the air flow (if you run the car in cold weather, really consider the bellows, as a fast warm up is important. think about the expansion differences between the aluminum, and steel parts out to the valve train. A lot of stuff can move around until the temps are evenely stable. Engine clearances are designs for operating temps, dissimular metals can screw things up until they expand into place, and pistons for intance are looser in the cylinder bore when cold than hot. The engine is shorter in width when cold. Heads (aluminum) are on tighter to the cylinders when hot, cause the heads expand more than the iron cylinders and head studs, hence the head studs are "stretched" a bit when hot.
Fast warm up is important,

if you are really worried about somehow the spring failing to keep the vanes in the fail safe cool postion, and choose not too run the important warm up bellows, then a wire could be added to secure the vanes to full cool as a reduntancy.

Why do people remove the stock stuff? I do not know, perhaps not understanding the function of the parts. Some have removed the vanes altogether in the mistaken belief they block air flow. the vanes are required. The oil cooler side one is critical to bleeding the right amount of air to the cooler verses the head. The vanes should not be removed.

Spare parts are easy to find off Type IV Busses, the most common Type IV car made, so check out a wrecker for parts.

I would deffinatly NOT block off the engine grill, and go auto crossing. Your enigne should not need this, Too cool oil with an otherwise stock system at your air temps is not plausible, it has almost certainly got to be a gage error.

Put it this way. say it is a 90/10 chance the gage is right. a 10% chance it is wrong, and you are really running at say 220F or something. Until you check it, you do not know.

Now your two choices:

1. Now you block the deck lid, or cooler, the gage comes up to a higher temp that you like, and you run autocross, driving hard.

2. you go run the car hard at the autocross. you live with a "low" gage reading.



if you choose option 2 you ran your engine hard with slightly cool oil (180F is only a little on the cool side, not terribley cool) probably no real harm done.

If you choose option 1, well, the oil came up to the higher temp you wanted, and you have some funky thing on your deck lid, that no one else has ever done, cause the problem you have just dosen't normally ever happen.


Option 1, gives you the temp you want.
Option 2 gives you a slightly low temp, no harm really.

Now say the 10% chance of the gage being treeked out is true. You really are running a higher temp now, but it only shows up as a "low" 180F, so what do you do?

Option 1, You block off the stock cooling system, the oil temp (false temp) comes up to say 220F (more like 260F actual, but your gage is 40F off, so you do not know you are cooking you oil as you race with your modified cooler of deck lid) result after hard autocrossing is a RUINED ENGINE! Plus everyone at the Auto cross will remember you as the person that smoked his engine at the race cause he blocked his deck lid vents.

Option 2, the gage is really wrong, but you do nothing, and run the autocross with stock cooling intact, and your temps are JUST FINE!


You can see that unless you know what your oil temp really is with a calibrated gage, and you block the cooling air, the down side is a possible overheated RUINED ENGINE!

If you do not alter the cooling system, and run and the gage really is accurate, the worst thing that happens is you run with slightly cool oil, this is not problem worth risking over heating your oil without first calibrating the gage.

Maybe someone at the autocross can loan you a thermal couple wire to stick down the dip stick hole after a run, and compare to the gage reading, this is a good alternate method to having to boil water. Ask around some one should be able to help,

At anyrate, even if for some reason you have a super secret Porsche racing heavy duty atomic superduper oil cooler that is really causing your oil to run too cold, do not block the air flow to the eninge, as you will cook the heads in the process. Unless you have head temp gages running, you are treading on dangerous ground by blocking air flow. The VW engine is air cooled, not oil cooled! would you block the radiator on a water cooled car if you had low oil temp, but had no idea what the water temp was?
On these engines, you can at the same time have both normal oil temps, and dangerously high head temps. Block the air, and you are all but assurded high head temps.

Block too much air, and not only does the fan starve for air, but so does the engine intake, just the opposite of a turbo, you will loose power, with carbs you will run leaner, with FI it will adjust for the low pressure. That fan sucks a ton of air at speed, so it needs all the top side vents Porsche designed into it. You get less air to the heads, and you run lean with carbs, causing more heat. Any leaks in the engine sealing rubber will draw even more preheated hot air from the bottom of the car into the engine when the top is blocked.

DO Not block the top vents, even in artic conditions they need to be opened to supply air to the intake manifold, the fan competes with the intake for the air, faster you go, the more you need.

In my opinion you have a gage issue, and until you can prove otherwise, do not block the cooling air, not the oil cooler. You might be running blind, and really HARM YOUR MOTOR. 180F is not that cold anyway, and nothing makes sense that would cause it other than a bad gage, or wire, or battery voltage. The slight modification on you flapper vanes are not enough to cause a cool oil temp, although they should be brought back to stock for best engine life. it is unheard of to have overcooled oil in a stock Type IV engine, it is got to be a bad gage. Make a bad low reading gage read "correct' and you will really run hot, and running hot is MUCH worse than running COLD.


Whats you oil pressure, and type of oil? Pressure at start up idle, at speed 5 th gear 3000 rpm, after 30 minutes of highway driving? and at idle just after the 30 minutes of highway?

No oil pressure gage??? Then certainly do not block cooler or the engine lid, for if you are wrong, and oil temps gets TOO high, you will loose oil pressure. Of course by the time you see an oil pressure drop, your heads will have been already damaged from the lack of cooling air induced overheating, maybe a dropped seat. Heads can overheat in a quick minute, oil temps take much long to show up, and then it is too late.


Good Luck, don't panic over a new gage reading until calibrated. Ecspecaiily if it is low, as that is less a problem for the motor, and more likely the gage

[nebreitling]

damn, that was one hell of an essay!

(he's right, btw)

[redshift]

i am offended at this spouting of techincal stuff... i am speechless... except for the talking about being speechless part...


m