Re: IML: gas types

[sosmi@xxxxxxxxxxx]

Joe, it's most interesting, and unfortunate that you've had such a bad time with #6. I can only say, we've rebuilt countless high mileage 361-383-413-426-440 engines, and never saw a pattern for detonation damage.Even our marine engines, that have consumed over 30K gallons of gas.If anything works hard it's a marine engine. What would you have to do to your Imperial, to empty the gas tank in one hour.I doubt driving up hill could do it. That manifold design was used on all the above engines, (marine included).I'm more inclined to believe it has to do with the vacuum port on the manifold, and the accessories. Since the manifold is a 180degree type,  the damage to pistons should be shared by more cylinders.I do know the right bank of cylinders, seems to loose the valve seals first, this would indicate the cooling of the head, is not as good as the left bank. The detonation issue, is a combination of problems. Engine heat,compression ratio, timing, carb jetting, ca rbon deposits and fuel quality.The tune-up specs for a 65 Imp don't work in 2007. The fuel is the biggest problem, along with that the timing needs to be backed up 4-6 degrees.Most important we re-jet carbs 2-4 steps richer, to start with.Along with that engine temp 180 degrees.I know that many may say: well I've been doing it by the book, and it works fine, well it may work for some, but we have to stand behind what we do, and our stuff runs better than the book. Just a little personal observation, and experience. Ya'll have a nice day, Dave.

 

-------------- Original message --------------
From: spicemanii@xxxxxxx
For Patricia and all with fuel issues. I use 89 in the Winter and only use 91 When I am driving up long grades like when I leave the desert. I also use it when towing, 91 that is. I also will adjust timing and you must listen for any pinging. Especially the closed chambered heads, 67 and older. I installed open chambered heads to help lower compression some and get rid of the two flame travel issues with the older heads. The weather, especially Summer, is where I have the most concerns. And using Air conditioning. The 61 Imperials for example, have a 22 inch radiator. That was not enough for the low desert. I installed a 28 inch radiator. No humidity does not help either. Their is another problem with the Imperial engines. Cast pistons instead of forged pistons. The cast ones will burn #6 real easy if the pinging con tinues, especially on an uphill, long climb. I have had it happen twice. Why I mentioned #6 is because it is the cylinder with the leanest mixture. The design of the early 413 manifold was the culprit. The wedge 426 suffered from the same fate. I have 2 of the 426's and the same #6 would burn a 2 inch hole thru the piston. This happened back in the 60's with a higher rated octane fuel. Joe Machado


-----Original Message-----
From: Patricia Pruitt
To: mailing-list@xxxxxxxxxxxxxxxx
Sent: Wed, 23 May 2007 12:19 pm
Subject: IML: gas types

We are in the throws of working on my â??62 Southhampton Crown. In the â??oldâ?? days when we had 50s-60s high compression engines (â??56 Plymouth Fury) that were supposed to use on high octane fuel, we always used â??regularâ??. We did adjust the timing for that.

 NOW, my query is; can we still use this method or must we buy â??premiumâ??? I am not familiar with the changes in the composition of todayâ??s fuels. Does anyone out there have the facts on this? We do not use ethanol and are not likely to do so in the future. Would like to hear from those in the know.

Â

Patricia  Pruitt

Bozeman, Montana 59718

pruittghl@xxxxxxx Â

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