60 Desoto engine- Adatives

[Lou Earle]

Ok Looks like the 60 382 engine has no hardened seats.

Now anyone have suggestions as to what addatives to use in the gas to forestall a valve job?

Lou

[greg g]

For normal operation additives are probably not necessary.

From another forum:

With an unhardened (pre-1972) exhaust valve and seat, the valve and seat can micro-weld to each other if they get hot enough. Lead acts as a buffer to prevent this happening. The important thing is that exhaust valve and seat recession ONLY takes place when the valve gets hot enough to undergo localised welding. Then, when the valve opens next, the metal pulls apart like taffy. This roughens the meeting surfaces, and they become quite abrasive. The pounding/turning of a valve with such "pulled" metal on it creates a nice grinding wheel effect on the seat. In addition, the roughened surfaces no longer seal against each other properly, which eventually allows still-burning combustion gases to flow through the "closed" valve, causing a blowtorch effect on the poor valve and depriving it of any prayer of a chance to cool while it's on the seat.

The blowtorch effect rapidly deteriorates the seal further, snowballing the seat recession.

The main thing to remember is that this bad stuff *cannot* happen If the valve never reaches the crucial temperature. Whether the valve reaches the crucial temperature depends mainly on how the car is driven and used (Towing, drag racing or pedal-on-the-floor hauling WILL heat the valves--driving down the highway at a constant 70 won't, and neither will hopping from traffic light to traffic light in the city or running down to the local grocery for a carton of ice cream.) Other factors in the margin of safety include the size of the exhaust valve, its material, and the efficiency of valve seat cooling in that particular engine design.

Send a PM to Desoto Frank and see what he is doing with the 60 Chyrsler he put back in service a year or two ago.

[Captain Neon]

This is what I use. Nothing better than using the real deal.

http://www.batterystuff.com/fuel-treatments/OS6q.html

To prevent getting too high octane as I don't usually run the tank empty (and lead is expensive), I often alternate with the following.

http://www.amazon.com/CD-2-Lead-Substitute-oz-4295-6/dp/B000E7HBTW

If I could mix larger quantities of fuel and then fill-up as needed from that source, I would use the lead additive all the time. Ever since my father burnt up a couple of valves on a '62 Falcon despite daily, light use, and factory hardened valves and seats, he's been mixing his own leaded gasolene at home from a large gasolene barrell. I even use the lead substitute in my wife's '92 Acclaim 3.0L V6 as the valves are a weak link on that engine and it also has fuel system cleaning properties.

[Lou Earle]

Quote:

From another forum:

"The main thing to remember is that this bad stuff *cannot* happen If the valve never reaches the crucial temperature. Whether the valve reaches the crucial temperature depends mainly on how the car is driven and used (Towing, drag racing or pedal-on-the-floor hauling WILL heat the valves--driving down the highway at a constant 70 won't, and neither will hopping from traffic light to traffic light in the city or running down to the local grocery for a carton of ice cream.) Other factors in the margin of safety include the size of the exhaust valve, its material, and the efficiency of valve seat cooling in that particular engine design."

I am sorry but my practical experience sayys othewise. My 49 caddy engine was drven normally - never over 65 and sure enough after abvout 5,000 miles of driving the valve seats were seriously receeded- I personally saw the effects on that engine and on a anotyher engine- the caddy was mine I can speak with experience from that- the other heads I do not know only told it was buick engine of the 50's that had same mess.

I wish the above were true but my experience says othewise. Cost me 1500 ten years ago to get that mess resolved. I wish the quote were true

Lou

[greg g]

True enough but metalurgy had progressed a bunch fro 49 to the 60's. But your experience is real, CD 2 makes one as do others in the aftermarket additives sector.

[Plymouthy Adams]

according to Mopar the use of unleaded gas with non hardened seat has a average on the road use of 25000 miles...by that time the valve is cupped and recessed quite a bit...

Lou..be on the lookout for a set of 400 heads as these babies are direct replacment with factory hardened seats or invest in a set of 8 and have them installed...

[james curl]

I have driven my 55 Chevy pick up with 235 I/6 over 100,000 miles on unleaded gas without any problems and I run it hard, cruse at 70 mph on the highway. Maybe next week all 6 exhaust valves will burn, who knows?