NiftyFifty Posted August 28, 2015 Report Posted August 28, 2015 So as some of you know I was having some issues with a real lack of power in my 50, with the 251 in it, and I blamed a lot on the added weight of the box that I never had on the truck before, and the power steering pump I added, but I finally broke down and did a compression test last week, and I was not happy with the results. I have come to find out that brand new gauge I tested with was a pos, but the readings were still somewhat relative to what was going on. I had cold 30-30-40-45-54-60, and hot 7-7-35-55-60, but this engine was a complete rebuild only 3-4 years ago and maybe 1000 miles with shaved head, new pistons and rings and every wear piece, and a professional honing when it was in the shop for a dunk and new cam bearings etc so it wasn't making any sense to me. I know these engines are bad for stuck rings and valves and the engine did basically remain unstarted for about a year in my shop, but I really couldn't believe in that short time they would stick. I dropped about 1/3 cup of Marvel Mystery Lube down each cyl for a week, then blew it out by cranking it and filled them again for another day. I then blew it out again, and put the plugs back in and ran it outside while I sprayed carb and intake cleaner through it and man did a lot of black come out, eventually tho, you could spray all the cleaner you wanted and the exhaust remained clean. I got it to operating temp and checked with the same gauge again and got 58-60-55-60-55-55 which surprised me that #6 was worse, but regardless everything was close to the same numbers, but I was still upset at the low #'s from what it was after the build. This weekend I was cleaning out my one cabinet in the shop and found another brand new tester in the box, and the brand/type I've used before and been happy with until my previous one died a few years ago....and it gave me what I wanted to see hot 94-95-95-98-98-99 I finally got the time to take it into the city today which is about a 30 minute highway cruise at 70mph and where I was once having a real hard time to get to the limit, I was having no issues breaking it today when I wanted too. I'm sold...Marvel Mystery Lube worked fantastic and even in a short time these engines can have issues, which I attribute a lot to ethanol laced gas. So anyone else is dealing with lagging, try this method...all it will cost you is $10 for the bottle, and $10 for some spray cleaner. I did buy another bottle and 1/2 in gas and 1/2 in crank just for good measure. 2 Quote
55 Fargo Posted August 28, 2015 Report Posted August 28, 2015 Glad it worked out for you. I have similar numbers n my engine, they are good old beasts. I personally never thought that by you adding the box it would have taken away your power. You gotta drive her lots, to keep her happy.... Quote
Dodgeb4ya Posted August 28, 2015 Report Posted August 28, 2015 Glad you figured it out. Personally in all my dealings with any well maintained 218/230/251/265 or any other Mopar flatheads I have never had issues with stuck rings and valves unless the engine sat for years or was run with old gas that turned to varnish. Quote
NiftyFifty Posted August 28, 2015 Author Report Posted August 28, 2015 Ya, that was what baffled me, I forgot to mention I tried a bit of oil in the first two cylinders when it was hot before the soaking and it didn't change anything. My engine was all over 105-115 after the build and about 100 miles, so I still may make some gains with some more use and a bit more intake cleaner in the gas over time. Quote
Jeff Balazs Posted August 28, 2015 Report Posted August 28, 2015 I wonder if this is something caused by differences in weather conditions? I have never seen an engine here that did anything like this. But it is hot and dry here for the most part. Even my old truck had pretty good compression after it's long hibernation......20 plus years. I had a couple of sticky valves but they cleared up by themselves as the fresh detergent oil went to work. The only similar thing I have ever seen here is galling caused by poor lubrication and or running with diluted or dirty oil. I am sure that wasn't the case on your engine but it can happen here especially in hot weather. Jeff Quote
NiftyFifty Posted August 28, 2015 Author Report Posted August 28, 2015 Ya it's had very frequent oil changes, and was broke in with Joe Gibbs. Only other thing I can think of is a lot of freeze and thaw on it last winter, my shop is only hot when I start the stove and the reddy heater, and we do have a fair amount of humidity here..but wood burning typically dries the air quite well. No for sure reason, but I think it's fixed now, sure ran great yesterday and we're heading on a country cruise this Sunday, so I'll get another 100 miles on it. Quote
Jeff Balazs Posted August 28, 2015 Report Posted August 28, 2015 Hey well whatever the reason I am glad you found an easy solution. They are not always so simple you know. It is good to have a place like this to exchange ideas on stuff like this. Back in the old days ideas and sorces of solutions were much more localized. Jeff Quote
dmulhall Posted September 8, 2015 Report Posted September 8, 2015 I have been in the habbit of keeping a bottle of mmo under my seat and adding a few ounces every fill up...pulled the plugs the other day just for fun and they all look brand new... I'm a believer...especially for keeping the fuel pump from drying out Quote
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