TR4/4A TR4a with CD175's Dieseling

[Geo Hahn]

Dang, mine hadn't dieseled in ages until today. I could blame this thread but perhaps I'll try the SeaFoam trick -- probably safer than dumping water in there (another old trick).

 

[JDstr4a]

Sorry guys, I got side tracked with the 59 Ford dumping coolant on the passenger floor. I turned the idle down a little on the TR and it seemed to help some, though it still occurs. Have a local scout putting together a car show for his Eagle project (10 can donation for entry fee) so I'm trying to get the radio back in the TR and get the Ford drivable to help him out. I'll get back to it eventually and let you know what's up!

JD

 

[CinneaghTR]

Dang, mine hadn't dieseled in ages until today. I could blame this thread but perhaps I'll try the SeaFoam trick -- probably safer than dumping water in there (another old trick).

Sorry to hear that, Geo. My car actually did not diesel today!! I think I am going to try the Seafoam, too.

 

[Member 10617]

The Seafoam treatment on BPNW's dieseling video is very impressive. But it raises a question in my mind: isn't this just one more example of "snake oil" that BCF contributors often warn against?

Or... is this the real thing?

Also, if this is the real thing, I wonder if putting Seafoam into the gas tank periodically will keep the carbon buildup at bay.

Any thoughts, advice?

In my other car and truck (there was a problem with the early 2000-2001 Chevy Silverados with carbonizing), I have always used BG44K. Auto mechanics I know recommend it highly for removing carbon buildup. One drawback: it is costly: about $26.00 @ can. Also, it is sometimes hard to find. It doesn't seem to be carried by many auto stores, so you may have to buy it from an auto shop.

 

[GerryL]

Actually tried seafoam and it did not stop my car from wanting to run with the ignition turned off. I obtained a great deal of snoke while pouring in the 1 third of a pint with the engine running. I shut the engine and waited five minutes before restarting the engine. After restarting, the engine the engine did not produce any smoke. I am disappointed. I have statically timed engine, retarded timing, set carbs using colortune, and reduced the idle speed to no avail. I will have to continue to pop clutch when shutting off then ignition.

 

[Member 10617]

Here are some instructions I found on the Internet...

"An engine diesels because it is running backwards which can lead to serious damage to the engine itself. This condition is caused by improper ignition timing. You can fix this problem by resetting the timing. This can be done with our without a timing light but the use of a light is more accurate. Simply loosen the bolt holding the distributor in place and turn it in small increments. Each time you turn the distributor, race the engine, you are looking for smooth operation. Then turn the car off to check for dieseling. If turning the distributor in one direction makes the problem worse then turn it in the opposite direction. Continue until the motor runs smooth through all RPM ranges and the dieseling stops."

Worth a try...

I would say, keep at it. There has to be a solution to this problem.

 

[TR3driver]

"An engine diesels because it is running backwards which can lead to serious damage to the engine itself.

That can happen, but most often it is still running forwards.

With the "diesel" cycle (the way a diesel engine runs normally), the fuel/air mixture is ignited by being compressed and heated to its self-ignition point. When you turn off the ignition key, all you remove is the spark, not the fuel/air mixture (unless you have a later TR with the anti-runon solenoid). So if conditions are right for the mixture to get compressed and heated enough, the engine keeps running as a diesel. That includes any kind of "hot spot" in the combustion chamber, like a sharp edge, or spot of glowing carbon, or even a plug tip that is too hot.

It's not especially good for the engine, but isn't going to destroy it in an instant either. After all, that is the way many engines run all the time, and they frequently run for hundreds of thousands of miles between overhauls.

There are some big truck engines that have a serious problem with running backwards, though. They can be quickly destroyed, because they are running on oil from the crankcase and will overspeed if the operator doesn't take instant measures to stop them.

However, I spent most of a summer once driving a gasoline tractor 6 days a week that would frequently run backwards briefly after being shut down with the throttle open. At the end of the summer, it was still running fine, no signs of damage. (Of course it was someone else's tractor. If I'd been caught doing that to my grandfather's tractor, he'd have nailed my skin to the barn!)

At any rate, I'm with Doug on this one. Tune it so it runs the best and idles as slow as possible, then make a habit of killing it with the clutch after turning off the key if necessary. "Lumpy below 750 rpm" implies to me that your motor isn't exactly stock, so there may be no complete solution unless you want to install the equivalent of the later anti-runon solenoid (which shuts off fuel as well as spark).

 

[Member 10617]

Randall,

I have to admit that it is hard for me to think of an engine running backward... but, as you say, it can happen.

 

[Member 10617]

GerryL,

Here are a couple of additional thoughts about your dieseling problem and what you've done to attempt to fix it.

1. You have set the initial timing using the static method, but now you might want to hook up an advance timing light and see what it tells you.

2. You used a Colortune to set the mixture. But when moving from yellow to blue, did you end up with blue showing? If so, you might want to have blue with occasional flashes of yellow. If it is just blue, it may be too lean for your car.

3. Try an idle setting of between 800 and 900 rpm. You can lower it a bit if the dieseling continues.

The more experienced folks on this forum may be absolutely right that you may have to settle for popping the clutch when you try to shut off the engine. I tried that and I didn't like it at all ... so I kept working on the problem until -- fortunately -- I finally fixed it. Of course, what worked for me may not work for you.... But it is worth a try.

 

[Geo Hahn]

Actually tried seafoam and it did not stop my car from wanting to run with the ignition turned off...

I tried it too - twice in fact - but it would be asking a lot to expect it to have noticeable improvement in just one or two treatments.

I haven't de-coked the tops of the pistons since the last time I had the head off, 5 or 6 years ago -- looking for results from a single Seafoam treatment is akin to trying to do a year's worth of flossing the night before you go to the dentist.

I plan to stay with it a few more times (using a squeeze bottle to squirt the stuff into the carbs) and see what (if any) benefits accrue. May at least keep the mosquitos at bay.

BTW - Seafoam is on sale thru Oct 9 at O'Reilly's (nee Checker/Schuck/Kragen) for $6.99 a can.

 

[Member 10617]

George:

I agree that it takes a while with Seafoam or any other treatment, for that matter.

Seafoam is good if carbon build-up is the cause; however, for this problem I think a more effective product is BG44K. Unfortunately, BG44K is about 5x the price of Seafoam (!)