Changing valve stem seals, head on car

[monomer]

Whats required/ anyone done this?
                     

Car runs great, good compression and all. Just starts bad with a LOT of smoke.


I may have miffed up by cleaning this old dirty head with kero, thus drying the seals out.

[8v-of-fury]

What color is the smoke? I would take some time to diagnose, it may not be the seals. Even if it were oil, being that it is a diesel engine it may not burn blue like a gas engine. It may just burn as fuel. If the smoke only happens on start-up why do you suspect seals? If it were seals, it would happen all the time.

I say it is the fact your ignition timing may be retarded.

[libbydiesel]

...or a glow plug out...or air in the fuel.

[bbob203]

I would like to know a good way to do this.

[ORCoaster]

Doing this job on the engine may not be a good idea.  Consider what will happen when you remove the keepers from the valve stem.  Down goes the valve to the top of the piston.  Unless you rotate the engine for each cylinder you stand to lose them deeper than you wanted.  Then you my have them under the head and no longer lined up with the hole they just dropped out of. 

I suppose if you were careful to do the check on TDC for each one you could get on each stem seal and pull it off.  But what a pain in the back this is going to be.  Ever rent one of those cheap valve spring compressors that go around the main bar that holds the springs.  They don't work very well and I have to use a C Clamp to keep it from kicking out and off all the time.  And those little bitty half round keepers.  Lose them and your toast.  They are nearly welded to the valves with compression, heat and old oil. 

This is a job for the workbench not the driveway.  You can clean the head all purty when you have it off.  Do the valves too and get the valve clearances in spec.  Sure it is going to cost you a new HG and maybe studs, but do it right and don't fight it.

DAS

[745 turbogreasel]

air in through a modded injector.

[burn_your_money]

With pair cylinders you only need to rotate the crank once. Set the engine at TDC, do cyl #1 and #4. Then rotate the crank 180 degrees and do #2 and #3. Using air, I would shoot it into one of the 2 cylinders that you aren't working on, as that will hold the 2 pistons you are working on right at TDC. Obviously the cam is out for this whole operation.

Compressing the valve springs is going to be a bugger though. I used a drill press and a 3 ton arbor press when I did this on the bench. (3 tons is way overkill btw)

[ORCoaster]

Novel solution.  I like the inventiveness but would still pull it and get it into a warm workbench where nimble fingers and super magnets will come in handy for the removal of those keepers. 

Then do all the other stuff needed as well.  DAS

[CarlosA]

There is a nice valve spring compressor available that i`ve used several times. When on the car you can use air to keep the valve up as mentioned earlier, and use the piston to hold the valve while compressing with this:


http://r.ebay.com/JR6aiv

[ORCoaster]

Well that is the Cat's meow for pressing down on the springs for sure.  And the additional injector adapter for air might work for compression testing as well. 
So you got the tools.

Now for those of us in the 60 years of bad back practices, sports injuries and abuse from all other recreational activities all we can do is dump pain meds and try to stay focused on those 8 valves long enough to get the job done.  Even on jack stands the engine is just a bit low at times.

[monomer]

air in through a modded injector.

They didn't leave the head.


It only smokes after sitting, leaning me towards some oil leak-down. I don't doubt it's also running retarded. I'm out of room for advancement, any further towards the head and the injector lines would rub. This is do to a sloppy keyway, which will be taken care of while the timing belts of.

 

[libbydiesel]

...or a glow plug out...or air in the fuel.

Any air in your clear return line right after starting when it has sat?  You're sure all glows are working?

[fatmobile]

 Yep, libby mentioned air in the fuel again.
I hope you caught it this time.

 Clear fuel lines to and from the pump. Even the little ones between the injectors.

[Syncroincity]

air in through a modded injector.

They didn't leave the head.

He's talking about using an old injector or an adapter to pump in air from a compressor; this will keep the valves from dropping into the cylinder. There's a youtube video of this, search valve seal...

[lloydbiker]

Here's an idea, I know it will work on gassers, probably TDI's (I've used it on Dodge/Ford V/8s and others w/ 'Cup' style seals), just not VW's. It won't work for 'O-ring' type (GM) seals, and may not work for IDI's. For TDI and gassers, with all cylinders at mid stroke, remove cam and plugs/injectors, take a ~3' (1m) piece of soft cotton rope, feed it in through the plug/injector hole, and roll engine over manually to jam rope against valves to hold up while removing keepers, springs, old seals, and replacing same. Reverse roll engine to loosen rope, and pull out. repeat for next cylinder until done. You should never roll the engine more than 1/4 turn in either direction, for fear of valve/piston contact on 'Interference' engines. I've used this method to do v/8 OHV engines complete in less than 3 hrs.