Went for a nice ride today, put about 120 miles on with the top off, could see the ocean for a good bit, fantastic day. The last 15 KM or so I picked the speed up a bit as I was now on divided highway with very little traffic, when I got home the temp was up quite a bit but not near the red, and the engine sounded like the engine in a tired taxi, doesn't seem normal to me, what do the experts think??

Ian Stott
Moncton
Canada

You say your engine got warm? How did you measure it? Oil temp gauge or do you have a CHT?

I added a CHT last year because I thought my engine was getting warm, but I really didn't know. Come to find out at the higher speeds it got warm, but not over heated.

Eric

Glad to hear that Eric, I felt it was hot as the idle dropped a bit when I came to the stop sign at the bottom of the off ramp and then the engine made a clingeling sound like an old taxi when I pulled away from the stop sign. I live only 1/2 a KM from there so I drove straight into my garage and turned the engine off, checked my oil this morning and it hasn't used any. I think I have a totally untouched engine and it may have 242,000 rather 142,000, can't tell by just looking at it and the service records stopped having entries around 50,000 miles. The car runs smoothly and starts right away, has good power and doesn't seem to burn any oil. I was wondering how hot they must get in the summer in the southern USA, it's April in Canada and it just shouldn't be an issue, something must be out of whack if it is overheating. Your thoughts/suggestions appreciated.

Ian Stott
Moncton
Canada

It often happens that oil, dirt, leaves etc get pulled in the cooling system. The oil cooler in particular can get plugged up at the cooling fins. I have an old 1.8 and overheating was a big problem. I had the engine out for some reason so I removed the tins. I found lots of crud in the cylinder fins and the oil cooler was real bad. Temps are much better now. other than that, I would suspect engine timing first and go from there.

Sounds like you may need to adjust your valves?

I really strongly advise you install a CHT on cylinder 3 (considered the cylinder that runs hottest). The sendor fits around tyour spark plug and the gauge is easily installed in your existing center console, if you have one. I got the sender, extension cable and gauge for about US$100 last year. They are available through the usual outlets, AA, Pelican, etc. However I got mine from "Aircraft Spruce". That's a company dedicated to small airplane instrumentation adn all things avionic. As small plane engines are air cooled, you can see the relationship. And since the FAA requires fairly strict instrumentation parameters, it's very reliable.

The nice thing about the CHT is that it tells you your engine temp now, not 30 minutes later like the oil temp gauge. And it helps you tell if your timing's a bit off
as engine temp is a common sign of incorrect timing.

Eric

Long highway ride will heat up the motor....once you go above 70mph you will see the temps rise...
Airflow gets wierd at the back of the car and you are under a constant load at lower rpms...

Just a fact of these cars.

If you have never removed the engine tin and cleaned it....you should.
Its amazing how a little elbow grease will cool your car down.

Rich

first off there are at least two versions of the temp gage with differnt red zones, early cars had a bigger red zone that kicked in sooner, later cars had a smaller red zone. as far as i can tell the gages work the same, so the factory upped the red zone. (maybe cuase they heard complaints about being int he red zone from owners???)

at any rate on warm days (75F +) at high speeds 70+mph specailly going up hill my oil temps gets high, at some where around 230F you will note a drop in oil presure, leting off the gas and slowing down will restore the temp to lower.

the mid point of a couple stokc gages I tested with a thermocoule is close to 220F.

i would stoongly urge you to add a oil presure gage if you dont have one. if youget so hot oil pressre drops then fro sure you need to let it cool down
head temp is also nice to have as it resonds to temp s fast

even thouhg I have cleaned all junk off eh cooling fins ans sealed all engine seals well mine still gets hot when under load for long at 3500 rpm +
could be function of timing mixture compresion ratio ect... also

Since everybody here is a much better expert than I, I do not want to challenge other people's post, but I felt I should add my opinion.

As for the oil temperature, let's say that everything above is absolutely calibrated correctly. For me it represents a lagging indicator. It takes from 15 to 30 minutes for this sensor to give you information abnout what the engine is doing now.

The oil temp gauge is useful, but not to measure current driving conditions. The CHT on one or more spark plugs will give you the current temperature of your engine, which you need if you are concerned about your engine overheating. Waiting until your oil temperature peaks is way too late, the damage has already been done.

My other issue is with the oil pressure dummy light. If this light illumunates, you are screwed. Your oil pressure has dropped and your engine is in danger. I agree that an oil pressure gauge would provide a better measure of safety.

But for me, I rely on my tachometer, my CHT, my voltage gauge and my fuel gauge. The rest of teh stuff looks pretty, but I don't drive by them.

Eric

Thanks to all who chimed in, what a great resource this club is! Took the car out for a drive today, checked the oil level first and it is bang on the mark so I'm not burning any, car ran fine. I think a good cleaning of the fins and the oil cooler is the next item on the agenda and install a CHT. Love driving my 914, one of my buddies says it is the most fun you can have with your clothes on!!

Ian Stott
Moncton
Canada

Keep in mind that since the engine uses the oil for cooling, you should expect to burn some oil; I think it's something like a quart every few thousand miles. Maybe someody else can chime in with the expected oil loss (not including drips).
Eric

I change the oil every 3000 miles and it will be down 1/2 litre to a litre at the most, extended high speed driving uses a bit more but I only did that once. Can't wait to get the CHT installed, then I will have piece of mind. I keep thinking about what Jake Raby said a while ago, "most heads are probably heat cracked" or something like that, I guess it is only a matter of time before we need to upgrade to a better set of heads.

Ian Stott
Moncton
Canada

Canadian heads are often not cracked, FOD is the bigger killer and rusted out exhaust studs and all that fun.

You all are full of great info! If I may ask (being a newbie and all) Is installing a CHT an easy process? I would also like to install an oil pressure gauge. I love my 914 and want to keep it in tip top shape.

Thanks all

yes, but an head temp sendor will not tell you anything is wrong if you loos oil pressure until it is too late. an oil pressure gage is great to tell you if your oil is sloshing to one side and missing the pick up tube in hard corners, you will see a momnetary dip in pressure, you wont detect that with a temp gage oil or head temp.

all in all if there was one gage, oil pressure wouldbe my first choice, as it gives some idea of too high a temp (pressure drops when hot) and will also tell you if you have oil system problems like low oil level such that oil is not at pick up tube when corninging or stopping fast. sloshing oil is a big deal on a 914, even when topped off they can starve of oil in a corner, be a half quort low and the probelm gets much worse in a corner.

next gage in order of preference is head temp, then finally oil temp.
my oil temp gage will show high oil temps sooner than 15 minutes from start if driven hard.

remeber a blocked oil cooler will raise the oil temp too much yet you may not see that much of a probelm on teh head temp, meanwhile you oil is cooking.

best case is to get all three gage, but money some times reuires compromise, hence the ranking of importance. funny how factory offered the least practical of the three gages.

CHT sender is simply fitted on a spark plug and then put the plug back in. Use the number 3 cylinder spark plug. Due to how the cooling system works, the number 3 cylinder gets the hottest of all of them so its the one to watch.

The gauge...well you can make it simple or hard to install..take you pick where to put it.

Oil pressure is stock on some motors. You will be looking for used parts and a new sender, and a used gauge. the sender and gauge must match.

Call AA, George Hussey...he has all the parts used and new..he can set you up with what you need for the oil pressure gauge.

For the CHT system, contact Chris Foley at Tangerine racing...he is on this site also and he sells a CHT system that will work...again, sender and gauge must match.

Rich

Thanks Rich!

you might try rich at high Performance house in redwood city CA, he has an extensive 914 parts supply new and used, truely the largest 914 place in california very long time 914 supporter, sells them, fixes them and has huge parts inventory in a three story high ware house.

call him, he ships daily great 914 resource for parts and knowledge. 650 364-6234. he has saved the day many times with teh parts he stocks.