I have a '91 F250 with a 460. It doesn't leak oil but smokes some under hard acceleration and consumes about a quart of oil per week. I'm assuming that the valve seals need to be replaced and I'd like to hear from whoever has done a valve seal replacement concerning how difficult it is and what to look out for.

Thanks in advance for your replies.

 

Very easy to do, I did them last summer. The only real important thing to look out for,, be aware of,, is dropping the valve stem into the head. Make sure you have it securely held up during the seal replacement. I used two sets of needlenose vise-grips with sponge coverings for the jaws. Hold it near the bottom, slip the seal on, then hold it at the top with the other, then release the bottom one. Just Make Sure you don't let it go. Other than that, piece of cake.

 

Thanks grapegravy. My Haynes manual says to get the cylinder you're working on to TDC. Do you think that is necessary or does it just create more work.

 

If you drop the valve with the piston at the top you don't have to pull the head. The valve will only be able to go into the cylinder a little bit. Cheap insurance, I would highly recommend it. Good luck.

 

you need an air compressor and a fitting for the spark plug hole.
Then go to AUto-Zone and rent thier tool for that purpose. It's a piece of cake.

Before you go to all that trouble, make sure you dont have a lot of blow by! You could have trouble with the RIngs, or an intake manifold gasket leak too.
Do a wet and dry compression test to make sure.

 

OR,

You can also feed some rope in through the sparkplug hole & bring the piston up to it holding thew valve in place.

The fastest way to do all of them is find the mention of 3 positions of the crank to be placed.Use the air pressure making sure the crank doesn't spin when applying air, turn the crank to its proper 3 positions and do 5 or 6 at a time.

We used to have a tech ariticle on FTE but it is now gone.

 

Ok, I just thought of something. Oil burning under acceleration is usually rings and under decceleration valves??? Or is my memory getting that bad?

 

That sounds correct. You will also notice smoke on start up if the valve seals were bad. Sounds like bad rings to me. IS there oil ending up in the air box?

 

I just had a thorough tune up along with a compression test that came out fine. The smoking is only noticeable under hard acceleration when the truck hasn't been running very long. How do you check for an intake manifold gasket leak?

By the way, there is no oil in the air box

 

Its pretty hard to check for a leak below the valley, It would probably idle erratic if there was. Is there oil in the lower intake? Your PCV Valve me not be working right. I would also pull the valve covers and check to make sure the drain holes are not plugged. In a lighter note, If you are going thru a quart a week you probably never have to change the oil just the filter once in a while. I guess I dont know anything else.

 

I have the similar problem with my 88 460, under hard acceneration when cold it burns oil, I'm guessing the best bet is to rebuild the engine and see what happens

Funky460, how many miles are on your engine?

 

Use some carb cleaner with the red plastic tube & squirt it along all the joints.
If the engine picks up speed while doing this ,that's you leaky area.

 

One other thing that might isolate the oil consumption.... It spits out the biggest cloud of smoke when it shifts under hard acceleration. It has an automatic tranny (C6). Thanks for all the responses - this site is kick a**!