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What happened to this 258?

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sweatlock View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2020 at 1:22pm
Sludge in the heads indicates waaaaay too long intervals between oil changes. It may have had new oil in it when you drained it, along with the new gaskets and other parts, but prior to that it was neglected badly and the damage was done. The burnt smell in the bottom end is another indicator. 

I knew someone with an ‘80 Concord back in the day that bragged about never changing the oil; it got an oil change every week he said from all the leaks, mainly from the valve cover. At 125K it gave up a con rod bearing and a post mortem performed mainly out of curiosity revealed a goopy syrupy black mess under the valve cover that in places was hard carbon. 
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232jav3sp View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2020 at 2:52pm
I don't care what brand or quality of oil you use, if you're not going to change the oil and filter religiously, it won't make a hill of beans difference.

As far as I'm concerned, you cannot change your oil too frequently. I change all of our vehicles at 3k and always will.
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vinny View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote vinny Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2020 at 4:03pm
My VW TDI is 15,000km (10,000mi) and wife's XC90 is 12,000km (7456). I follow recommended in a regularly used vehicle and usually change the vehicle before the engine is worn out. My toys get it once a year. I fired up the Rambler a couple of days ago, first time since probably September. With a good squirt down the carb she took right off. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: May/17/2020 at 10:52pm
Originally posted by 232jav3sp 232jav3sp wrote:

I don't care what brand or quality of oil you use, if you're not going to change the oil and filter religiously, it won't make a hill of beans difference.

As far as I'm concerned, you cannot change your oil too frequently. I change all of our vehicles at 3k and always will.

I completely agree with you now. I posted elsewhere about my current '68 American, 203K miles now, compression was 130-135 PSI all cyls, and leakdown was 6% max all cyls. Worn out timing chain, valve stem seals, leaky manifold gaskets. I had the privilege of asking the original owner, now 95, and owner for 47 contiguous years, how he changed the oil:

"every 1000 miles, but sometimes as much as 2000."

His goal was to make the car last as long as possible. Mine too.

Until this (May 2020) I was using highest-quality oil, and going for longest-recommended change interval.  I'm switching to high-quality oil every 2000. 10w-30. Certainly on the 68's 199ci. Done and done.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: May/18/2020 at 2:22am
Valve cover leaks are probably the number one thing that ruins an AMC six closely followed by poor crankcase breather maintenance. It's a long cover with few bolts, so it tends to warp or come loose and leak. Owners often don't realize how detrimental a valve cover leak actually is to the life of the engine, especially after the owner stops changing the oil because "it leaks so much".

1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
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Post Options Post Options   Thanks (0) Thanks(0)   Quote vinny Quote  Post ReplyReply Direct Link To This Post Posted: May/18/2020 at 9:10am
When these engines were driven every day with occasional trips of some miles they could get by with regular scheduled oil changes. When that oil is hot and flowing fast it does a pretty good job of keeping things clean inside. I've taken engines apart after a 100k miles that were still clean. It's the slow trips at near idling speed that gums them up. I bought a 650 Triumph motorcycle that had a blown rod after less than 10k miles and the guy had been scared to drive it. The sludge trap in the crank had totally plugged up. After overhaul I could get over 7k RPM out of that thing and there were no more problems with clogged oil passages. 


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