Bizarre engine problem...help
 

Hello guys,
I have a 2.4l engine with the upright fan shroud. I’ve owned the engine for 18years and never had an issue with it. Over the past year it has started having some issues maintaining the engine oil temp around 190-210F. That is were it normally would run.
The other day the temp reached 210 after about 20mins and the engine shut off and didn’t want to turn over. It turned over but very slowly like the battery was dying. After about 20min the engine oil temp cooled to 190 and the engine rotated, started and got me home.

Any ideas?

Thanks,
Russ

Several questions: do you have an external cooler, if so where, if not, why not? How often is the engine run? What oil is in it and how old is it? If there is the attached cooler are the cooling fines clear I.E. no mice nests? Was there any oil smoke when it got hot or any burnt oil smell? What is the oil pressure when cold, when warm and when hot?

210F is absolutely in the middle of the normal oil temperature range. Anything lower than 180F is not warm enough, in fact. Your temps should not have caused any problems at all.

Your description makes it sound like the cylinders were seizing in the bores. They shouldn't be, obviously. I wonder if you are running 105mm cast-iron cylinders? I have heard stories of the large cast-iron cylinders distorting given time and heat cycles, and that could possibly cause symptoms like this.

Any way you can talk to the builder of the engine?

--DD

Bizarre Engine Issue
 

John,
I do have an external oil cooler. It is located on the inside of the engine lid. The fan exhausts the air into the engine compartment. Which really isn't a great solution but it has worked for years.
The engine/ car is driven no less than three times a week.
The oil is Brad Penn 20-50 Syn.
The oil cooler appears to be fine with no debris.
Oil pressure cold is ~60psi at idel. At temp the pressure is less than 20 but greater than 10psi. The gauge does't give good detail between that range. The oil pressure light has never came on. It comes on around 8psi.
No smoke or burnt oil smell.

Thanks,
Russell

Dave,
I agree that the oil temps seem to just fine. It is just weird that around 210/220 the engine appears to seize???
I did check the cylinders and they are magnetic and they have a reddish oxide. So they could be cast-iron. I will call FAT today and see if they can remember what they might have used back in the day.

Thanks!

Yes, it is very very weird.

With a 2.4 liter engine and cast-iron cylinders, you very likely have 103s or 105s. They may be distorting when they warm up, causing your problem. That's the only thing I can think of right now.

--DD

Bizarre Engine Issue
 

Hello guys,
After some more investigating and driving the problem doesn't appear to be directly related to engine temp. I believe the problem is in the ignition system. I have a MSD box and a Mallory Unlite dizzy. I remember last year in July that the car would just shut sown without a symptom after about 15min of driving. The problem was the ignition module in the distributor.
After some research on the unlite system it appears that there are some issues with reliability.
Should I order another ignition module or change the system to a more robust system?

Thanks!

In a long trip I had a similar problem after about two hours of driving the engine would die. When the engine cooled, it started again. It happened several times. We found it was a kink in an old fuel hose from the fuel pump, which got softer when it got hot, it kinked more and closed the supply of fuel. A new piece of hose solved the problem.

There are two parts to the problem described in the OP. One is that the engine stopped running, the other is that it turned over very slowly.

A fuel delivery problem could easily cause the engine not to run. It would not cause the slow cranking.

A starter problem could cause the slow cranking, but would not cause the engine to stop running.

A problem with the engine itself could cause both. Also a problem with the ignition switch, or its wiring, could cause both.

A spark-control module problem is very unlikely to cause the engine to crank slowly. So if that is a problem, it is not the only problem with the car. I had not heard of reliability problems with the Unilite pickups, but I have not researched them. I do know that the most frequent trouble with electronic ignition triggers is that they stop working and never work again. It is unusual (but not unheard of!) for them to stop and then start again.

I would start out by simplifying the circuit--taking the MSD out of the equation all together. The engine may not run optimally, but it should still run, and if you do not experience the failure then you have a strong clue that it was causing trouble. I would also disconnect the tach, since it isn't needed to run the engine, and if it shorts its input to ground that might interfere with the spark. (Though come to think of it that would be plugged into the MSD now anyway.)

If you have anything else hooked up to the coil or ignition (sometimes people will power a fuel pump from the coil power wire!) then unhook it and find another way to supply power. Make the circuit as simple as you can, and see if the failures still occur. If not, then you start to suspect things that you have removed, and add them in one at a time until you start seeing failures again.

I'm still suspicious of the slow starter cranking.... Maybe the starter circuit has some connections that have high resistance when they get warm? Clean up all of the grounds.

--DD

:)

With a known history of normal operation and now showing higher temps I would look for a mouse nest in under the shroud possibly blocking the air to the oil cooler.

Been there with my old 911.

Len

:)

Bizarre engine problem
 

Len,
Yes. You are correct. I pulled the fan so I could see over the cylinders and sure enough there was a gathering of leaves, some paper towel mess, and general dirt. "Well your in there"...I adjusted the timing, valves, and pulled the spark plugs for some general maintenance. I think removing the leaves and paper towel mess helped the cooling. The main temp gauge on the dash reads ~190F and temps after the oil cooler is ~120.

The engine shutting down was a different issue. I believe that the unilite module is failing because I do not have the 1.5ohm ballast installed in the loop.

I've installed the resistor and ordered a new ignition module. Hopefully that will solve the shutting down issue.

Thanks,
Russell

MSD has a well known failure rate,go on ebay and check out the listing on units ...most of them aren't working and are cheap for that reason,researched all my options and MSD wasn't one of them,running later Permatune (blue module) and there correct coil with Pertronix Ignitor II very good setup for a carbed six IMO.

Engine issue
 

Hey guys,
Thanks for all the support with this odd problem. I did disconnect the MSD and removed the Unilite dizzy after replacing a few other parts. I decided that simplicity is the way to go. I installed the blue coil and an 009 with pertronix and the car is running well. At some point I’ll play around with different distributors ie...050 or a pertronix unit.

Thanks again and happy driving
Russell

I have had great luck with MSD's you have to run a 10 AWG supply wire and make sure the polarity is correct, often wrong and they seem to last very well. Just my opinion. William
Good job Len of finding the problem.