That would explain the low numbers. The starter isn't going to spin it fast enough to build dynamic compression. You've got the static there, minus what the cam's overlap bleeds off.

 

so what do you suggest? fire it up, and let sit and idle for x minutes, and retest or what?

 

thats what I would do..

also pull all the plugs, wire the carb wide open and disconnect the coil. crank it over and let the compression hit the gauge at least 3 to 4 times.

 

thats basically what i did, and i spun each cylinder 8 times, but i for got to wire the choke open, also bat had 12.5.8V at start and 12.5.1v at finish

 

It doesn't really matter if the engine was cold or not in this case. The problem is that the compression is not even. Valve seals have no bearing on the compression. All they do is to keep excessive oil from going down between the guides and valve stems. You can't tell if the guides are bad by the readings you gave.

The readings are fairly close, so before i did anything else, I would squirt a little oil down in each cylinder and let it sit for a while. Then redo the compression test. If the engine has sit for some time, like you say, then there is a possibility that the rings are just seized a bit. By putting a small amount of oil, or ATF in the cylinders, you may loosen up the rings and get a better reading.

When you cranked the engine over, which way was it turning when looking at the engine from the front...the end away from the flywheel? Was it turning over in a clockwise or counter-clockwise direction? If it was clockwise, then you don't have to worry about it turning the wrong way. That is the correct direction for automotive use.

I am just a bit curious though, as to why you want to use an engine that was used in a boat. Can't you get one from a car or truck for about the same price? That way you can be sure it will work.

Dan Harriman 84 f150 lwb
Orange, Texas

 

Ill try the atf and re test, don't remember which way the engine spun, but is sapost? to be from a single engine boat, but was pressed for time at the moment-had to get back to the house, as far as the engine i hadn't checked the local yards, but i doubt i can get a running engine for <$300, maybe else were but i also have no .way of hauling it. the rear main is out on my bronco, which is why i want/need the engine plus the extra cubes is a bonus

 

Quote [When you cranked the engine over, which way was it turning when looking at the engine from the front...the end away from the flywheel? Was it turning over in a clockwise or counter-clockwise direction? If it was clockwise, then you don't have to worry about it turning the wrong way. That is the correct direction for automotive use]



just remembered, that its not the original starter, the one on there supposed to be from a ltd but doesn't look like a regular ford starter but like one from a 18 wheeler (no solenoid on top)

 

I'm not able to page up the posts after the one stating you made the test cold with jumpers. I never liked to take a compression test on a cold engine, especially one which has set for any period of time. The rings need the oil to seal so while they might be the same in all cylinders they may not. Also how do you know if a couple of the vales are not a little sluggish in going to the seats. My advice is have it run a bit and then check it. Kotzy

 

thought about that but, seeing as its in someone else garage and its labor day weekend, it might have to wait till next week