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914World.com _ 914World Garage _ overheating

Posted by: tributary Mar 31 2005, 11:16 AM

914 bored to 2.1 seems to run at 220 to 260 up hills even in cool weather...
should I be concerned or not..
would an oil cooler do much to help the problem and if so any recommendations?

thanks

John

Posted by: Dave_Darling Mar 31 2005, 11:23 AM

Yes, you should be concerned. 260 is definitely hotter than you want your oil to be. And yes, an external oil cooler should help bring the temps down. How much it helps will depend a lot on the design of the cooler setup. (E.g., front-mounted coolers get the best clean cool air; ones under the rear trunk floor only see heated turbulent air but are easier to mount.)

The oil temps are only part of the story. How are your head temps?

--DD

Posted by: trekkor Mar 31 2005, 11:25 AM

I've heard the synthetic oils can handle that heat, no problem.

I'd rather not see anything above 220.
I'd suggest looking into a cooler or making sure your stock cooler is clean and clear of debris.

KT

Posted by: Joe Ricard Mar 31 2005, 11:26 AM

Oil temps seem hot but are your gauges calibrated and do you trust them?????
CHT gives you more info and quicker real temp of the motor. Again you get what you pay for in gauges.
In My humble Opinion If you don't have a CHT you are driving on borrowed time.

Posted by: SirAndy Mar 31 2005, 11:28 AM

QUOTE (Dave_Darling @ Mar 31 2005, 09:23 AM)
Yes, you should be concerned. 260 is definitely hotter than you want your oil to be.

around 200 is a gud temp, above 220 is hot, above 240 is TOO hot ...

couple of things to check:

- timing
- cooling flaps, make sure they're in the open position, which means the drivers side flap is up and the pass side flap is DOWN
- make sure the cooling fins on the cylinders are clean. if not sure, take off the tin and check
- make sure the oil cooler isn't plugged, on the outside with crud, or on the inside
- what year is the car? if pre '73, get the rubber flaps that go under the car. they help cooling (when moving)

if all that checks out OK, consider a front mounted oil cooler ...
Andy

Posted by: Bleyseng Mar 31 2005, 11:37 AM

What is your Air Fuel ratio??? Too lean will make the CHT temps and the oil temp rise up pretty damn high.
R U running Djet? Carbs??
If Djet and a 2.1L you should adjust the MPS on a dyno or a good shop A/F meter. Not one of those ones with led lites.
Same thing with carbs.....shop time will tune the A/F ratio with proper jetting.

A quick look at the plug color will help......White/tan is too lean dark tan is good

Geoff

Posted by: SGB Mar 31 2005, 12:08 PM

High compression will run cooler on high octane petrol....

Posted by: Jake Raby Mar 31 2005, 12:11 PM

The factory really screwed us when they didn't install a CYLINDER HEAD TEMPERATURE GAUGE!

Monitoring oil temperatures only is virtually only monitoring 1/2 of the engine! Head temps and oil temps are unrelated!

With that being said- Your oil is definately getting very hot. 260 oil temp is very high and it will thermally break oil down in a heartbeat. The next thing you know oil pressure drops and you spin a #2 rod bearing.

Oil temps are directly related to friction, typically from RPM increases. When you say that the oil gets hot when climbing a hill that seems odd because oil temps normally respond slower than one could notice from just climbing a hill.

Head temps are directly related to load. Climb a hill and you'll immediately see that.

For your oil temp to be rising so quickly you definately have an issue. It may be severely out of tune or the oil cooler could be obstructed by a varmit nest or other obstruction.

BTW- Buy a cylinder head temp gauge, monitoring oil only is virtually worthless. It is absolutely possible to have frying oil and cool heads or baking heads and cool oil- This is why BOTH must be monitored.

For a comparison.. The oil in my Type 4 3.0 liter 231 BHP test engine won't go over 225 and the heads run 275.......And it has 10:1 CR and only 4 cooling fins on the cylinder heads..... I dove it 105 miles this morning.

Posted by: Brett W Mar 31 2005, 01:44 PM

If you have anything other than stock rear gears and tires you can probably expect the car to run hot. My car would turn 4200 at 80mph and it would tend to get pretty warm on the highway. Most stock geared cars don't turn near that RPM.

Posted by: SirAndy Mar 31 2005, 01:59 PM

QUOTE (Brett W @ Mar 31 2005, 11:44 AM)
Most stock geared cars don't turn near that RPM.

3800 @ 80mph with close to stock tires ...

Andy

Posted by: Aaron Cox Mar 31 2005, 02:00 PM

QUOTE (SirAndy @ Mar 31 2005, 12:59 PM)

QUOTE (Brett W @ Mar 31 2005, 11:44 AM)
Most stock geared cars don't turn near that RPM.

3800 @ 80mph with close to stock tires ...

Andy

4k to do an ndicated 90....which is about 80mph with my tires

Posted by: Jake Raby Mar 31 2005, 02:13 PM

Not with the DTM....
23.5" tire and oil has never hit 215 yet! Head have been to 310 maybe 320 once..

It's bitchin

Posted by: mudfoot76 Mar 31 2005, 03:02 PM

So what types of CHT monitoring are people using? I've seen CB Performance and Westach have gauges available. I presume since Westach builds stuff for aircraft their quality might be superior? I didn't see prices during a quick survey of their website, though I'd guess it is more than CB?

Thanks!!

Posted by: Jake Raby Mar 31 2005, 03:21 PM

VDO is the standard gauges used by most.

I like the Westach gauges and have had many made up for my dyno and testing program over the years...

The quality of the Westach is much better than VDO. The instruments respond faster than the VDO by far.

Posted by: D-Jet Mar 31 2005, 03:28 PM

Sorry, I'm really a noob. I have a stock '75 and I don't know temp #s but when I'm on the highway or drive for a long period of time the stock temp gauge reads about 3/4 of the way up. It gradually gets there as I drive and once it gets to that 3/4 point it pretty much stays there till I slow down or stop driving. I plan on getting better monitoring for the temps, but in the mean time does this sound normal? It was recently tuned. I just want to make sure I’m not cooking my “new” car.

--G

Posted by: Rand Mar 31 2005, 06:56 PM

A guy brought a VW into my Dad's shop complaining of high oil temps. Looked underneath and saw a pretty nasty layer of gunk on the bottom of the engine... The guy drove on dusty roads quite a bit with a motor that was drooling oil. It built up a pretty thick layer of insulation.

After the steam cleaner, his temps dropped. "Hey, there's fins under there!?"

Posted by: Dave_Darling Mar 31 2005, 07:20 PM

QUOTE (D-Jet @ Mar 31 2005, 01:28 PM)
I have a stock '75 and I don't know temp #s but when I'm on the highway or drive for a long period of time the stock temp gauge reads about 3/4 of the way up.

That is the oil temp gauge. It is a poor indicator of how the engine is doing--there are no numbers, so you can only tell "cooler" or "hotter"--but cooler or hotter than what is the question!!

Either ignore the gage, or live with it for a while to see where it usually runs. If the behavior changes, you may have a problem.

Or ditch it and get a numbered oil temp gauge (with matching sender!!) and a head temp gauge.

--DD

Posted by: Jake Raby Mar 31 2005, 08:19 PM

Dirty cooling fans can also make for hotter temps. I have cleaned a fan and seen head temps drop 30 degrees.. Dirty impellers work poorly.

Posted by: D-Jet Mar 31 2005, 08:45 PM

Great advice. Thanks guys. Looks like some new gauges are in my future. How hard are they to hook up? Keep in my my experence and knowledge level at the moment is just above being able to locate the engine.