I just finished Tunning the car, and it's still running hot. Today on the highway the CHT were getting past 375, up to 400. The only way to keep them below was to not drive, oast as much as possible, and not go faster than 55 for to long. And that's no fun at all.
What can I do?
Here is what I know. Timing good, cooling flaps open, valve clearance set, and it's not running lean.
What else is their?

in what gear are you trying to go 55?
with stock gearing and tire size, 55 is much too slow for 5th.

high CHT is a symptom of insufficient cooling air - which can be caused by lugging (fan speed too slow for the applied load).

it can also be a symptom of that shredded paper towel that got sucked into the fan and deposited onto the tops of the heads, or a garbage bag sucked into the fan...

5th is a track gear, or a fuel economy gear. if you're trying to cruise at 2000 rpm in top, you'll see high CHT...

I typically saw 350-375 with a stock cam and heads (on a 1.7), up to just touching 400 pulling up a long hill. This is "normal" for a stock engine. Headwork, particularly to the exhaust side, and a better cam will reduce head temps, according to Jake. The stock engine, however, will run about where you are. If you run well over 400 for any length of time, or run that kind of temp on a flat road, then you still have some problem.

I'd only see 310-325 at surface street speeds (up to 35-40mph), btw. On the highway, keeping it under 375 meant running in 4th until I was running at pretty illegal speeds.

Do you know what your oil temps look like?

Are you sure your CHT gauge is correct? Calibrated?

Have you searched for threads regarding the VDO CHT gauges and their fluctuation in readings dependent on the outside air temp?

If you know all of the above is good and the things you mentioned prior (timing, flaps opening correctly,etc.) leaves, debris, mouse nests on the cooling fins comes to mind.

It is a little time consuming, but better than dropping a valve, I would suggest pulling your tin off and visually inspecting your heads and cooling fins. Check your impeller too for missing fins or gunk buildup that may be preventing decent airflow. The answer is there somewhere.

You also might consider putting the gauge sender on another cylinder and seeing what type of reading you are getting. If your oil cooler is restricted, it may very well be restricting airflow to the cyl heads, but that would also cause high oil temps if you don't have an external cooler. Put the sender on the other bank and see what you get.

I had the opposite issue - very high oil temps, but good head temps. Everything was kosher, but the temps were still high - I installed an oil cooler, but that obviously won't solve your problem.

I was in 4th and 5th gear. Stock gearbox. I know about the lugging issue and 5th not providing the greatest cooling, but 4000rpms in 4th appeared to be making things worse.
Gauge is a Westtach, and calibrated to 75deg. which is very close to what it was out there today.
I think if I was not fethering the gas so much it would have settled in around 400deg in 4th.
About dirt and nests. The engine was just pulled in august(for headwork) and the passages, oil cooler, and fan are clean.

Is this a carbed engine? If so, do you know the size of your idle/main jets?

Inspect all your engine tin and make sure you're not missing any pieces.

Duck tape over any empty holes in the tin.

Are both of your air deflectors in place beneath the firewall?


..

any crud on the cylinders? you'd be surprised at how much crap one can find in the cooling fins ...

Andy

D-jet all tins are in place as well as deflectors. No crud between Cylinders. They are dished bus pistons, but I would think that to lower the heat.

are you *sure* the cooling flaps are working?
Andy

Yes
When I had it apart I read through the threds about how the flaps work, and am pretty sure I got them back together correctly. The spring is on the ,and if standing on the driver's side, I have to rotate the flap bar CW against the spring in order to close them.

There are 2 underside deflectors right.

you running a big sweeper front air dam?

Andy

Only if you consider a 75-76 rubber bumper a .

I see you are in Puerto Rico, I am east of Palm Springs and our air temps are in the 90's which makes mine run hot. (125 degrees makes it run even hotter) Did someone sudjest you change to a hotter plug when you did your tune-up or change to a electronic ignition/coil ?


Ok I see you did something to your car. What ever that thing was that you had hooked up to your car, did you notice this rise in temp after you did that? If so I would look into what ever changes you made to your car before you look for new gremlins

Andy,
How much does the LE style front air dam cut down on the fresh cooling for the engine?
Nate

So.Cal.914 that was accually just a wide abd O2 sensor. It's off now and really help a lot. Rightnow the car is in N Kentucky where the weather could not be more perfect for driving a teener.

Heh. It's somethign about KY I guess. Mine isn't working either. You still in KY?

b

Most importantly:
Where is the CHT sending unit attached to the head?

Other than running hot, how does it run?

Any other symptoms?.. misfiring, surging, etc?


(This topic has come up before, exactly the same problem you're having, and as I recall we were unable to determine a cause that time. I hope we find it this time.)

Exactly why do you believe it is not running on the lean side? Don't take much
My carbed engine ran MUCH cooler after reaming out the idle jet size from 50 to 53. 55 seemed too big as evidenced by A/F gauge.

WHat exactly is timing set correctly? what is your dwell and what metod are you using to set timing. is your advance and retard funtioning on the distributor?

To anwser the last couple of questions.
Brit, I'm now in PR again.
Jake, Westach CHT gauge, sender under #3 spark plug
Reverie, other than temps, it runs great, slight bog off the line, but smooth power straight to Redline. Very light popping on over-run, but you have to listen for it. When it starts to get around 375+ their is a small buck or hesitation on transitioning from decel to accelerating. And this doesn't happen when temps are around 350
Joe Ricard, I don't think it's running lean because I tunned it, and my AF gauge says it's not going above 13.8 anywhere from idle to redline. Dwell is set to spec 44°-50° and timing is 27° BTDC. I'm farlty sure the advance is working on my dizzy. The first times I tried to time the car I forgot to plug the dizzy advance and the car didn't sound right at all.

Have you checked to make sure all the fan blades are there?
Put a Fuel pressure gauge on the drivers side with a long hose that allows you to read it while driving. Than and only than will you know if it is lean. Or put it on a CO scanner. You can screw the flaps always open which is very common on Hot whether cars. are you running 30W? IMHO. Is the dist, advancing to much? Check for loss plate in Dist,. well thats where I would start.

What is the oil temp. doing. Maybe try a different cht gauge and sender.
Elliot

Fan is in great shape. Oil temps get pretty hot, but not into the red, but I think that's caused by running through the hot heads.
Gauge and sender is a Westach, which I'm fairly sure has Jakes seal of a approval as far as CHT gauges are concerned
Heeltoe914, I'm not real sure how a pressure gauge is going to help me, I was running it with a Wideband O2 sensor, and it was not leaning out.
As far as the dizzy, I would think if it's acting up, it would show up in the O2 gauge. Also I would be hearing Knocks and/or backfires. Would I have to pull the dizzy to run those checks?

Something's missing here. There's only a few things that should cause high head temps, and it looks to me like they've been covered. If the fan is good, the tin is good and guiding the air over the heads, the air passageways/fins are clean, the timing is good, the dwell is good, the head temp gauge and sender/placement is good, etc., etc.......

Well, what else is there? Does anything in that path need another re-evaluation?

Dude by me a ticket. I'll come out there and fix your car.

TIMING TIMING TIMNG. Even a little bit off will affect the temps.
Next pull a plug and take a picture post here.

If you think the engine is perfect then look somewhere else. ARE YOUR BRAKES DRAGGING?

How about the sound deadening material on the firewall? It looked a little loose on the tuning thread. Might be blocking the fan at speed. I had a karmann ghia that did that, the firewall material looked to be in place at idle and even revving with the trunk open but when the lid was closed it would pull it toward the fan opening. Simple fix but took a long time to find.

My motor is not stock so I'm not sure the following applies to your situation.

I found that my head temps were unacceptable at cruise at 13.8:1. I lowered my AFR to 13.2:1 and head temps now go to around 375 on #3. When I got the car it was running carbs tuned to 12:1 at cruise, head temps were really low but so was the MPG. My MPG is better but still poor, around 17.5 mpg but I think that is about as good as it gets with my engine combo. It is a 2056 with an aftermarket cam, 280 duration (FC-442).

I've been fighting high oil temps at idle that are probably caused by leaks in the tin around the ac compressor. I've sealed the hole a bit better and flipped the air filter housing so that the opening is toward the front of the car instead of the back. IAT's are better but the jury is still out on the oil temps. PO added an aux oil cooler but I'm thinking that is just making things worse as the hot air has no where to go. I added a fan but I need to duct the exit air out the back of the car before I throw in the towel.

Heeltoe914, I'm not real sure how a pressure gauge is going to help me, I was running it with a Wideband O2 sensor, and it was not leaning out.
As far as the dizzy, I would think if it's acting up, it would show up in the O2 gauge. Also I would be hearing Knocks and/or backfires. Would I have to pull the dizzy to run those checks?

In reply I can tell you from my own nightmares that just a little bit of advance changes makes a big dif, I have never used the 02 thing you mentioned but if you know it ok. but keep in mind you have a cat and muffler that cleans up what comes out, Kinda, I like the old fashion way run the hose. you will see it a short time of driving. Easy test. Also is your heater vents installed as it comes from the bottom of the fan. make sure you are not loosing air in that part of the system. Knocks and backfire Yes if the change was big enought. One other thing to check is the heat range on the plugs. and if you can tell me what the temp, reading off the exhust pipe are where it comes from the head. are all the temp close?? Use a Infa read temp gauge if you have one. Good luck