Too Hot?, 914/6 engine temp & RPM Options

[boxerboy]

I just drove my 914-6 from California to Colorado and for the whole trip it seemed to run at a very high indicated temperature. I have stock instrumentation and the temp gauge was almost always in the first shaded red zone (not the solid red zone but beyond the white zone).

It didn't seem to matter if I was in the heat of the desert or in the relatively cooler mountain air. The temperature always seemed too hot. At one point, after unpacking our luggage, this luggage was still hot to the touch in our hotel room one hour after arriving.

Also, at an indicated highway speed of 80 MPH (and this seemed to be higher than actual speed) the engine was turning 4200 RPM. This felt too high. I had a 74 914 2.0 and the engine never felt like it was spinning this fast at highway speeds.

Can anyone tell me what is normal engine RPM at 80 MPH for the 914-6? And what is a normal temp guage reading at a sustained (2 hours or more) 80 MPH?

[ArtechnikA]

...seemed to run at a very high indicated temperature.

...at an indicated highway speed of 80 MPH (and this seemed to be higher than actual speed) the engine was turning 4200 RPM.

first, welcome ! tell us about the car ! is this a factory /6 with the stock 2,0 engine ?

i don't have my owner's manual with me but i can tell you that 4000 rpm ~= 90 mph. are you sure you were in 5th gear ? (sorry - hadda ask...) 914.6 do have a -slightly- shorter than 914/4's and will run a few more revs in top.

so - time to cross-check a few gauges... check the tach against a calibrated reference, check the speedo with a GPS... if you are running nonstandard tire sizes it'll have a big effect on indicated mph... you can calibrate the temp gauge with an IR thermometer or boiling water...

you shouldn't have had too many heating issues at 4200 rpm - they like to cruise there. could be a lot of things, but we need to know more about the car and its equipment first. i've had temperature indications similar to yours on cross-country trips but i was probably going too slow in top for really good cooling airflow...

could have been running lean, could be off its tune, could be 'stuff' plugging airflow over the heads and cylinders and oil cooler.

[Root_Werks]

Yeah, that makes a difference if this is a stock 914-6 or a converted one. The stockers have a lower final drive and turn higher RPM's, so this is probably a stock 914-6 by the sounds of it? (IMG:style_emoticons/default/wink.gif)

[Ferg]

Welcome to Colorado (IMG:style_emoticons/default/beer.gif) I don't have much to add that has not been already said, but we do have a strong gourp of teener owners here, so whatever problem you have if any, we'll get if figured out.

I just did that drive for the WCC, 80% of the drive my temp was between 190-205, with a few spikes to 220 when it was above 95degrees.

since your at 5k feet elevation now, a re-tune is in order for sure.
Ferg

ps, our local 914 group is on yahoo groups, do a search for colorado 914 and sign up!

pss, this thread is wothless without pics. (IMG:style_emoticons/default/wink.gif)

[boxerboy]

Great responses... thanks.

This is a 914-6 and yes, I'm sure I as in 5th (and its ok to ask because I have made my share of 4th to 3rd shifts - not intending to downshift - over the years) Wheels and tires are stock 185 x 14 as well.

The engine has been recently upped to 2.3 liters with bigger valves installed, and new tensioners. I can provide a complete list of what was done, but the one change that springs to mind was that I had a new alternator installed to replace the old one that failed and the new one has an increased output to compensate for an electrical ignition system I had installed. Sorry, I do not have the brand at hand. I am out of the country at the moment and my files are back at home in Colorado.

I seem to recall some modification to the pully on the alternator and I'm not sure if this had an effect on the speed at which the cooling fan runs but I will have this checked out.

The car ran hot (I think) the whole trip though and it didn't seem to matter if I was in the desert or at altitude where the air was cooler. The needle lived in that red zone. I did not notice the small numbers mentioned but I will look for them the next time I am in Colorado.

This is a 914-6 though, not a conversion from a 4. The VIN number supports this as do the standard engine compartment features of a 6 vs a 4.

I appreciate all of your help. Trying to diagnosis this from so far away is problematic I know. I do know that I need to have the carbs adjusted for altitude and if anyone can recommend someone in the Denver area I would appreciate that too. As I drove the car into higher altitudes, it ran fine at speed but as soon as I got into traffic it was difficult to maintain idle. I found I had to use the throttle and bring it up to somewhere around 1,500 rpm to keep the engine alive. I could "nurse" it to idle at just below 1,000 rpm, but then as soon as I hit the throttle it would seem to load up on fuel and stall again, so I simply held it at 1,500 rpm as I went through those few mountain towns with stop and go traffic. Once I got out on the open road again it ran fine... just a little too hot for me to be completely comfortable with it.

What a joy to run through those mountain roads with the power of the flat six though. It made me remember what I loved about my '73 2.0

I just need to work through this temperature issue and make sure that either everything is normal or make the needed adjustments. Thanks again for your help.

[ArtechnikA]

The engine has been recently upped to 2.3 liters

I seem to recall some modification to the pully on the alternator and I'm not sure if this had an effect on the speed at which the cooling fan runs but I will have this checked out.

The car ran hot (I think) the whole trip though and it didn't seem to matter if I was in the desert or at altitude where the air was cooler.

... VIN number supports this

...as soon as I got into traffic it was difficult to maintain idle.

more displacement will definitely increase the heat output...

when the /6's were new, Porsche noticed that due to the less-effective engine air intake that the engines ran about 10F hotter than they did in the 911. so they just moved over the red zone on the /6 temp gauge! (might it be possible someone has replaced the oil temp gage with one from a 911?)

pulley ratios will affect things too, it's possible to play mix-n-match to a certain degree between crank (drive) and alternator pulleys to a certain extent.

the air at altitude may be cooler, but there's less of it, so the net effect on cooling might actually be worse than somewhat warmer but denser air lower down ...

you'll definitely need smaller idle jets at altitude; there are a few CO /6 owners who will be able to give you more specific sizi information.

love to know your VIN & engine # ...

[brant]

boxerboy...

welcome and that sounds like a great car.

If your looking for a local (colorado) -6 expert and a good carb guy.. I'd call pay moyle at motorsports inc. in denver

he has an original -6 probably since new, and an awful lot of experience and expertise.

definitely get on the colorado yahoo group and come along for a drive or something... I personally would love to see the car.
brant

[propricer]

According to the original 914/6 owner's manual, the engine should be turning about 3,750 at 80mph.

Good luck ...

[smg914]

On the stock 914-6 combination instrument, the first red shaded zone starts at 260 degrees. The second red zone starts at 300 degrees. In the 26 years I've owned my 914-6, I've never seen my engine temp get anywhere close to 260.

[ArtechnikA]

On the stock 914-6 combination instrument, the first red shaded zone starts at 260 degrees....In the 26 years I've owned my 914-6, I've never seen my engine temp get anywhere close to 260.

i no longer have the original guage to check for numbering, but i recall a long flat stretch of hot New Mexico highway where i was kinda drafting behind an 18-wheeler (less airflow) at 70 and i watched the needle climb. got real darn close to the red. once i got into clear air, and started going a little faster, the temp came right back down.

[joea9146]

Pull the plugs what do they look like if Milky white looking that is bad you are running to lean.
If you are running lean this will cause you to run hot.

[Gint]

Welcome to the board! And you sure want to sign up to our Colorado-914 list.

Rich is dead nutz on everything he said. Tire size, pulley size, altitude will all affect running temps. BTDT. I've driven many carb'd classic cars from California to Colorado.

Call Pat Moyle at Motorsports Inc. as Brant suggested. He on the local list, Rocky Mountain PCA, and has the experience to assist you. Great guy too.

[SirAndy]

the first red shaded zone starts at 260 degrees.

if that is true then it's definately *too* hot ...

260 over a longer period of time will kill your engine, optimal operating temp is right around 200, you should never see more than 240 ...

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

[boxerboy]

Thanks for all the good info. I'm not sure yet how to solve this problem but I know where to look. I will definitely be looking up the recommended carb guy in Denver and that should be a good start.

I don't really plan to use this car as a daily driver and I don't expect to do another cross country trip again. Most likely I will use the car as a weekend fun ride and get to know some of those other Colorado 914-ers.

The VIN number is 9141430441. I don't have the engine number at the moment so this will have to do, but I am told it was the original engine and transaxle. I am the 4th owner with pretty good records from the past owner. Overall the car is very nice. No body rust and just some surface rust on the battery tray that I have treated. Certainly not a concours example but a very usable car that is in very original condition.

Thanks again for all of your help.

[Root_Werks]

The change in the alternator should probably be looked at. I know there are different sizes for the pullies in the engine, but cannot recall for the Alt/fan? (IMG:style_emoticons/default/confused24.gif)

[boxerboy]

Can anyone help me with an email address or phone number for Pat Moyle and/or Motorsports Inc in Denver? Don't post it, rather send it to my email address: bclark@attglobal.net

Thanks