Is it time for a rebuild? I saw some gasket sets, piston rings, and bearings on ebay for dirt cheap - bad idea?. The engine really isnt burning any oil or at least nowhere near enough to be a problem.

 

The 100 is kinda weak, but if it starts OK and runs decent I'd leave it alone, unless you're lookin for somethin to do!

 

I do like to take things apart then leave them apart for months on end collecting rust while i take apart other things and start other car projects and have those sit.... wait. Thats probably bad. Is it possible to remove the oil pan and crank with the engine inside the car? I have a hoist, engine stand and a garage full of tools but id like to keep it quick and easy and just throw it all together in a weekend kind of thing.

 

Mine was 145 all the way, front to back. Im rebuilding it cause the bearings though. I wouldnt buy any rebuild parts until you tear down the motor and find out what needs to be replaced. For example you could buy regular rings, and the motor could already be bored 20 over, then you would have a set of useless rings. It might need bored too.

But, you might be able to take it out, tear it down, replace the parts, and put it back together in a few days. It took me and my dad about 10 hours to pull my 300 out, and strip it apart. Now its sitting at the machine shop. I wouldnt rush a rebuild though. I'd rather get it done right the first time, but who wouldnt!

 

Everything I've ever read about compression says that all readings should be within 10% of each other. There are a few things that pop to mind on the low cylinder: You could have a worn head gasket venting pressure (my particular problem), a valve that's not mating with it's seal all the way due to buildup of deposits, or worn rings.

 

squirt some oil in the low cyl and turn the engine over (no start) a few revolutions to spread the oil over the cyl walls and then test the cyl again and see if the pressure comes up--If YES-you have have bad rings. If NO--you have a burned valve or blown gasket.

stractor

 

Ford's take on compression is that they relate to each other, anotherwords you shouldn't have a very high number and a very low number.
According to their 83 Spec book, if your highest number is 134, your lowest number should be no lower than 101. In that regard, you sound OK, but unfortunately....134 is the lowest high number they list! You basically have a tired engine.

 

i would just leave that engine in there if i was u unless your looking for a performance rebuild but if your just going to drive it everyday to work i would leave it mine was 110 115 110 120 125 115 and it runs fine unless yours is burning alot of oil

 

What's your elevation?, don't forget that compression goes down as elevation goes up or at least that's what I was told.

 

I'm at 14 ft. above sea level, or at least that's what the city limit sign says. It doesn't burn oil, but my compression is at 120/125 all cylinders. When I put a new oil pan gasket on it, I found a broken off piston skirt in the bottom of the pan. The head change is just to get me through to the summer when I work mondo OT and can afford the 300 rebuild kit from Clifford Performance. I am going to go for higher torque and HP at that time as part of the rebuild/restoration of the truck. I like the old junkyard dog look but it pales after a while, and I just can't justify spending 40k on one of them thar fancy new trucks so I'll put 3 or 5k into this one instead and have a good looking classic workhorse instead.