replacing valve stem seals?

[93fordturbo]

My head is back in the engine, And this may sound like a stupid question, but can the valve stem seals And the other things that came with a head gasket kit be replaced when head is in engine? Or do the heads need to come out? Also, is it pretty extensive? What special tools do I need

 

[Wyreth]

You can do them while the head is on, but it will be alot of effort. You will need to do it by pairs of cylinders. (not remembering the synched pairs off the top of my head) Basicly, get two cylinders to TDC, then clamp on a jaw type spring compressor, remove the retainer clips, and replace the stem seal. If you don't have the cylinder at TDC you will loose the valve into the cylinder, then the head will have to come off anyway. Replace the springs when done, rotate engine to the next pair, rinse and repeat 4 times.

Tools:
Jaw type valve spring compressor. (fair warning, these were designed by the devil to cause swearing)
Forceps
Long needle nose pliers
bandaids and neosporin
beers.

I've prolly overlooked something, but others will chime in.

 

[93fordturbo]

I don't have the spring tool, so should I really worry about this? Or is there a way to check if they are good

 

[Wyreth]

the spring tool you can get on loan from any Autozone or Oriley's.

if you're using alot of oil and getting gray smoke, that's a pretty good indication they're bad. Other than that, no, not without pulling manifolds.

 

[OLDBULL8]

The engine rotates in a clockwise direction as seen from the front of the truck, and for every 1/4 turn of the engine(crank) each next piston will arrive at TDC. So, When the line on the vibration damper is at the 2 oclock position, cylinders 2 and 5 will be at TDC. When the mark is at the 5 oclock position, cylinders 7 and 6 will be at TDC, 8 oclock has cylinders 3 and 8 at TDC, and back to 11oclock, 1 and 4 will be at TDC.

 

[jaluhn83]

The way I like to do it is to pressurize the cylinders with compressed air and then pull the springs. If you get an el-cheapo compression tester, or if you already have one just remove the valve core from the adapter, (same setup as a tire valve) then remove the gauge off the hose and thread an air tool fitting on. Then pull your glow plug(s) and put the adapter on the cylinder you want and hook the air up.

*Caution - the engine may turn 1/2 revolution of so when you put to the cylinder*

The air pressure in the cylinder will hold the valves shut. This also makes a good way of checking valve seat, as any kind of leak will show up air air flow into the intake or exhaust. Usually you can hear and feel it, just make sure you're not actually feeling air coming through the CDR valve into the intake, cause there will be some blowing out that way.

One trick that works well for putting the keeper back on it to stick a dap of grease on them and then use a screwdriver - the grease will stick the keeper onto the screwdriver so that you can use it as a handle to reach in there.

You can do everything but the head gasket and head/valve overhaul with the engine in, though the exhaust manifold are pretty nasty to get to the bolts on. No real reason too unless you know you've got a bad gasket though.

 

[Trying my best]

http://m.youtube.com/watch?v=ob_4-F-m1FI

Here is a video that describes the above technique, although on a gas motor.

 

[icanfixall]

Really not sure why your asking this question. Please tell me why the head was off the engine. Was any work done to the head while it was off. Now to answer your question. Yes. Ford did make a tool to remove the valve spring keepers. Once the spring is compressed you can remove the spring. The seal and the spring rotater. If no compressed air is used the piston must be at top dead center so the free valve wont fall into the cylinder. It will drop down about 50 thousands but thats all. There is no way to feel into the cylinder for tdc like on a gasser engine. But doing what oldbul8 describes is the best way to know where the piston is in the stroke...

 

[Kevin 007]

I like the 6.9 valve seals (even though) they allow more oil past. I like them because it keeps the valve guides and stems lubricated better then the 7.3 seals. Every notice how the 7.3's seem to have way more valve guide issues then the 6.9's....??

 

[Mulochico]

though the exhaust manifold are pretty nasty to get to the bolts on.

When I did my exhaust gaskets, I just removed the inner wheel wells (made of plastic, a few bolts and screws, then pull out thru the fender opening) and they were actually very easy to get to.

 

[93fordturbo]

Heads were off due to head gaskets, And I didn't think I was going to replace the valve stem seals so I just put the head in. Valve covers are still off, I just didn't know if I wanted to put the seals in or just run it

 

[Hydro-idi]

It would have been a good time to get those valve stem seals replaced when you were getting your heads rebuilt/inspected. When I do my head gaskets in the future, I plan on getting that done because my truck always has a puff of oil smoke at stop signs and when starting the engine when it is hot. I am sure they need to be replaced.

 

[RLDSL]

I really hate to say this . now that the head is back on, but it would have been a very good tome to check the guides. If you are trying to hold teh valves in with air, it's near impossible. If you run the piston up to tdc to where you wont drop a valve after you have the keeper off, you can check for stem wear, and you might want to consider that before you get it bottled up too much further. At this point it would only be an extra set of head gaskets to yank the heads back off and send them off for some guide replacements. Seals themselves on teh engine arent bad, but you will need 2 different type valve spring compressors, an overhead and a side clamp, ( you cant get to the ones at the rear of the engine with an overhead and there isn't room to swing the side clamp on a few of teh others ) Honestly, if you can pull the blamed things, it's easier.

 

[jaluhn83]

A bit late for this I know, but good practice is to *always* replace the stem seals and check valve guides and seats while the heads are off, along with head / block flatness. None of these are hard with the heads off and it saves you work down the road.

You can easily check guide with the air method - once you get the spring and such off put some electrical tape or a small hose clamp or something around the valve stem and then shut off the air. The valves are light enough it doesn't take much to keep them from falling. Just be careful doing it.

I forgot to add you can also use the air setup for a leakdown test, which is a good way to determine cylinder health - Just fit a valve and gauge on the air supply end of the compression tester hose you're using, pressurize the cylinder then close the valve and see how long it takes to bleed down to about 50 psi.

 

[93fordturbo]

I may try to replace the seals...