Engine needs a valve job what should I do?
 

Hello I am still a newbie and not that automotive inclined. I have some mechanical skills. My 1995 F250 with 460 was looked at by a mechanic he says it needs a valve job. The truck has 126,000 miles. Two cylinder's have low pressure. Actually number two had zero pressure. The mechanic said he would do the valve job including labor and replace some more parts such as water pump and freeze plugs for $1200. I can get a used engine with 68000 miles for $800 dollars and 800 labor to install. What would you suggest?

Should I try and tear down the engine myself and have the valves done?

Should I pay a mechanic to do the valve job?

Should I have the engine replaced by a mechanic?

Should I get a used engine and try to replace it myself?

If I work on the engine and tear it down would a mechanic be willing to help me put it together?

I am just throwing out questions hoping for some advice guidance. I don't have a lot of money to work on the truck.

Thanks David

Pay for the valve job - at least get a few other estimates. That sounds a bit high, even with the water pump.

You'll have essentially rebuilt heads on a bullet-proof engine. Miles aren't that bad. With a used engine - even a known "good" one, you never know what might happen tomorrow. You already know your block is good - don't mess with it.

The 460 isn't too difficult to work on. If you're capable with tools, you can pull the heads yourself, have them "done" and reinstall. You'll save a ton of labor $.

X 2 if you have the time & the tools you can do it yourself ?? , i wound check the slack in the timing chain to , its not that much more work to do when the motors apart if it needs one....Lew

Theres no high tech voodoo going on inside a 460, tear it down yourself, take the heads in to the machine shop...........put it back together. 126,000 miles is nothing for a 460, last time I checked around here, a 3 angle valve job was $89.00.....add any new valves required if burnt.......I would say you are back on the road for less than $300 and your sweat and time.

All that and you will know what you have.....

Tough call, do you have the time/tools to do it yourself? It sounds like you may have a neglected/abused motor, 126k needs valve job. I'm just wondering about the integrity of the rotating assembly, and cylinder wear, due to neglect and possibly over heating damage. If it was my choice to choose, I would drop in another long block motor, and be done with it. With the aid of a good manual, I'm sure that you could do it yourself. You can get one in the $2000. range and below, I have seen them go for $1500. with a 5 year war. Really not that far from the quotes you got...best luck to you

I am still a newbie and not that automotive inclined. I have some mechanical skills.

Sounds like the perfect time to add to both.

Two cylinder's have low pressure. Actually number two had zero pressure.

But first how so sure its a valve at this point? Exactly what was done to determine that?

Which two cylinders, both adjacent to each other?

Be a pretty bad valve to have zero pressure, about sucked into the cylinder type bad or bent/burnt right off.

Hear a "Pop...pop....pop....pop" from either the intake or exhaust side while at an idle, "Pops" faster as rpms are increased? "Pop" speed matches RPMs?

Or it suffers from blow by or severe blow by? at an idle oil spewing from dip stick tube and out filler cap, oil found in breather box etc etc?

Suffers both conditions to varying degrees?

Was a vacuum gauge used on it?

Was a small amount of clean motor oil put down the spark plug holes and a retest of the compression taken? Did it increase the compression readings in the low cylinders? remained the same?

Hope its mechanic/shop you know and is trusted? really need more to go on then posted in the first post.

I can get a used engine with 68000 miles for $800 dollars dollars and 800 labor to install.

68000 mile engine for 800 and installing it yourself would probably be the better option, faster too if many things on the other one are a unknown at this point, unless that price is dependent on your paying them to install it?

Thanks Guys for all the replys. The "mechanic" warmed up the engine and checked the compression on the first four cylinders 4# was 150lbs, 3# was 150 lbs, 2# was zero compression it tried to build up and instantly leaked down to zero, 1#was 150 lbs. The engine does not make any funky sounds except for the misfiring on two cylinders number 2 and 7 when he pulled the wires from the distributor they sparked at the distributor but the engine did not run any smoother just not firing on two cylinders. He only tested the cylinders on one side but said no need to test any farther the engine needed a valve job. I paid him $35. dollars he said he would deduct it from the valve job. Again what do you guys think? Is his diagnosis accurate? :-X20

Little quick to call it a valve job based on that little bit of testing/information, unless he seen/heard/noticed something you're not aware of.

Might have a couple busted rocker arms or just fell off, push rods bent or just fell out of place. Wouldn't be the first time for either one of those.

Could be cracked/broken rings or pistons.

Valves generally don't leak to the point of 100% compression loss and yet remain in place. loss of the keepers yea, valve sucked into the cylinder for example but you'd tend to notice that when it happen. It makes a little noise when that happens.

Valves bent or burnt to the point of total loss of seal yet remain in place you'd hear it.

thanks for the advice
 

danr1 thanks for the reply and advice. I will try and remove enough components to take the valve covers off and have a look. David

Pull the heads yourself and look it over, any damage should be fairly apparent. If you have questions just ask, many here can guide you through the process start to finish regardless of what you find and do to correct the problem. Repair that motor or replace it.

Taking it apart, keep track of all parts and their exact location.

Like the valve train, all parts removed should be kept in order and returned to the same location during reassembly. Each rocker arm and push rod goes back where it was when you removed it even though they are the same. Includes the lifters if you end up having to remove them, doubt it but same applies to them.

Make up a simple tray, small sheet of ply, egg carton what have ya remove each bank moving the parts to the tray in the order front to back as removed so you know where they where. Mark the tray "Front" so if you move it from place to place during the engine work, always do, you do not loose its orientation to the block.

You might not reuse the parts, but then again you might so don't just throw them all in a bucket.

Not all parts matter in that regard but if in doubt, you're just not sure and no one handy to ask, keep track of em.

As a general rule parts that ride/wear on one another need to go back where they where originally for best results. Saves em seating into each other again, previous wear patterns made by previous parts create excessive wear doing so.

Shouldn't take you much more then couple hours to pull the heads, little more for time for the learning curve if you never done so before.

Gotta digital camera, take pictures right from the start, linkages wire harness connections, bracket locations etc etc as you work.

I have seen several bad valves with a reading of 0 compression , usally burt exhaust valves , sounds like he might have hooked a air hose to it , if the air comes out the exhaust you know....Lew