I am just completing an project to return my 914 (73 2.0) back to fuel injection and may be having an issue with temperaturre. I replaced the webers that were on it when I got it with a custom setup. The set up consists of:

the original intakes for the webers, a custom intake manifold that uses modern injectors ( ford f150 high impeadance) and a pontiac throttlebody frrom a 3.4 liter, a trigger wheel from Original customs, together with a megasquirt2. New stainless steel fuel lines from Tnagerine racing and new fuel pump. New VDO oil temp guage and it's related sensor.

Several people sent me MS tunes to get me started with the tuning process., which I apprecieted. I now have it running and it seems to be settup well for throttle response and getneral drivability. Howerver I am conserned about temperature. The oil temps seem to be in the 210 to 230 range and the CHT seem to be in the 325 or 340 range. THis may be a bit warm but is it safe to the heads? (with the webers and old oil t guage I think i was about 180-190 but that was an estimate since the guage was not marked well.

The last thing I did was to put back the suplemental heater fan, original host to the drivers side duct and a new hose from AA to the pasenger side duct. I toke a 25 mile test drive and towards the later part of the drive I smelt warm plastic smelll but assumed that was due to the tubes joining the ducts for the heat exchanges. However a few mile from home the oil temp started going up and reached 280 when I got home. I really don't know what the CHT was but can assume 380-390. I discovered that the new hose going to the pasenger side was sucked into the impeller and was turned into a rats nest of wire and plastic. I was able to get that out and am hoping most of the plastic is accounted for.

Today I took a 2 hr drive around town and the oil temp slowly worked up to 220 where it stayed for a while but got to about 240. The CHT where at 355-360. The drive was primarily 25-30 mph and in 3rd and 4th gear. I was not trying to keep the rpm high to push air.

questions:
1. is my megaquirt tune off and causing the temps
2. do I need to drop the engine and take off ducting and clean out the cooling air passages

Thanks

Wait.
Sorry, I did not read fully.

Zach

Okay, lets try again.
oil temps 210 to 230 is a tad high at 230 but acceptable when it does not get higher.
Head temps at 345 are about perfect. Head temps to 375 are acceptable. 390 is hot, and you want to do what you can to keep them under 400 by all means.

You need to play with your tune. 240 oil is too hot. Oil at 280 is WAY too hot. If you have not done so, change it. A good oil can take it but it is warmer then it needs to be.

Make sure the cooling flaps are open on your engine. They direct cool air through the oil cooler. Many of us have also plumbed in and aux cooler.

If you are using MS, what are you doing for AFR? You may want to reduce timing a degree and test again.

the 280 was due to the impeller being full of the hose that it sucked in. Today the max temp was 240 but generally 230 during the 2 hr drive.

I have an O2 sensor in the manza muffler right next to where the 2 pipes join.

I'll back off on the timing and see what happens.

There are 2 holes in the ducting on the pasenger siide of the engine. on for the CHT access and one for the oil pressure sensor. What can you use to coverf them to reduce air loss to the cooling fins. Mine are both open.

What's your air fuel ratio? Air cooled engines use excess fuel to cool too. Most run richer than water cooled "accepted" ratios. Try to enrichen your fuel map by 1% at a time and see what the temps do.

For the two holes in your tin, you can use duck tape temporarily. Bus depot has the oil pressure boots for the pressure sender.
An electrical/electronics store has dust caps for electrical connectors that will fit in the hole for the CHT. You will have to cut a slit for the sensor wire if you are using it.
The black one in this pic is an example.
Tom

I have a narrow band O2 sensor so I assume it will alway try to move it towards 14.7. So do you suggest turning that off to do the test?

Narrow bands are a waste of time unless the tune is perfect. 14.7 is too lean for a T4 motor in most ranges. Get a wide band or pay for some dyno time to perfect the tune. Most dyno shops have a WB you can use.

backed down timing about 2 deg in most places in timing table. Added 1 to each entry in VE table. An hour drive found oil temp at 240 and CHT at 363. Pretty much no change.

I am looking for more suggestion:)

You are only speculating without a WB sensor. Increase fuel by 5% in the cruise range. See what happens...

ok will try that tomorrow...

With a wide band sensor.. What afr is appropriate for the 2.0 ?

You might want to be at 12.5 during cruise. If the performance is good, add fuel to cool it down. Too much fuel and you will lose power, but during cruise you need fuel to keep it cool more than you need power. It's a fine balance and best done on a chassis dyno and not on the freeway. I have used my wife to drive while I tune. Much safer than trying to do both.

12.5 is good for WOT, but rather rich for cruise. There was a thread recently where Racer Chris made specific recommendations for mixtures under different circumstances. He also (somehow!) was able to get useful information out of a narrow-band setup; I have no idea how.

--DD

Shoot for 13.5:1 at cruise,but narrow band is just an amusing light show... Lose that.

I run my engine at low 15s AFR in the cruise range. Keeps it very cool. You only want about 13 during idle otherwise you get a slow heat soak during stop and go runs that will drive your temps up slowly over time. My engine runs about 325 to 350 after about an hour of cruising and can go up to 360 during hot days but has no problems and that is normal. If you hit 375 then slow down and give the engine a break in 4th gear.

Invest in a wideband O2 and register your TunerStudio it will make a world of difference and you can autotune your VE table to match your AFR table. Even though you are running MS2 you can still use this page for FI troubleshooting
http://members.rennlist.com/pbanders/DJetParts.htm
It specifically states that a too rich idle will drive your temps up and almost stall the engine over time so be carefull and experiment with the settings.

914 CO specs for exhaust content

Engine Type RPM % Volume
1.7L MPC 850-900 1-3
1.8L AFC 800-900 2-3
2.0L MPC
Engine Code GA 850-950 Max. 1.5(max.3 from '74 mod.)

google the AFR to CO conversion and look up the chart. 3% is 13.4 and what I used as a start.

14.7 AFR will be optimal and the hottest for your engine so you should be above that for cruising and below that for idle. WOT is better set on a dyno but I have it set around high 13s to low 14s. If you feel the car surging when WOT then you need to richen the settings. It takes a while but good luck.

I would suggest that you also look at and external oil cooler but I don't run one. As long as your thermostat and impeller are functioning then everything should be fine.

Good luck