Motor lost compression: What do I do?
 

My 1999 Ranger has the original engine with 218K miles and started running rough. The mechanic told me that cylinder 3 has no compression, which in a search of this forum means that it could be an exhaust valve or broken ring, both seemingly the kiss of death for an engine this old. I want to keep the truck, as I just put a new transmission in it and owe quite a bit on it. On top of that, it is in really nice shape.

I can't afford a re-built(1800.00 with warranty) and a re-build of this motor doesn't seem to make sense. A local salvage yard has my exact motor with 106K on it for $700.00, but the mechanic wants $1,500 to install it.

My question is how hard is it to swap engines, and could I leave the transmission in?

Re: Motor lost compression: What do I do?
 

That's really cheap for an engine. But I would pull the head off and see what you have. You should be able to hear it if you have an exhaust valve stuck open.

Re: Motor lost compression: What do I do?
 

If it's the ring your plug will be all oily

Re: Motor lost compression: What do I do?
 

x2

If you can get compressed air into the cylinder, get it on TDC, put some pressure in it, and listen in the oil fill, exhaust, intake, and look in the radiator/coolant for bubbles and the problem should become quite apparent.

Not so bad if it's just the heads, but that is still a pretty decent amount of work. If you do pull the heads, but sure new head bolts are on the bill. Also keep track of which push rod went to which cylinder and lifter.

Re: Motor lost compression: What do I do?
 

Whenever I take a head off I always replace the bolts with studs.

Re: Motor lost compression: What do I do?
 

Why?

Re: Motor lost compression: What do I do?
 

They are better for preventing head lift and gasket damage. The clamping force is better.

Re: Motor lost compression: What do I do?
 

the clamping force should be the same if you torque them correctly. they do prevent head lift, but it doesn't matter on a stock motor.

Re: Motor lost compression: What do I do?
 

During engine assembly or maintenance, a bolt must be installed by torqueing it into place. Due to the head bolt’s design, it has to be rotated into its slot in order to engage the threads and secure it into place. This process creates both twisting force and a vertical clamping force, which means that when the cylinders within the engine’s combustion chamber begin accumulating load, the bolt will both stretch and twist. Because the bolt has to react to two different forces simultaneously, its capacity to secure the head is slightly reduced and it forms a less reliable seal in high-powered engines.

By contrast, a head stud can be tightened into place without any direct clamping force applied through the tightening. A stud can be threaded into a slot up to “finger tightness,” or the degree to which it would be tightened by hand. Afterward, the cylinder head is installed and a nut is torqued into place against the stud. The nut torque provides the clamping force, rather than the torque of the fastener itself, and the rotational force is avoided entirely. Because the stud is torqued from a relaxed state, the pressure from the nut will make it stretch only along the vertical axis without a concurrent twisting load. The result is a more evenly distributed and accurate torque load compared to that of the head bolt. This ultimately translates into higher reliability and a lower chance of head gasket failure.