The adapter will also be used to keep air in the jug when you take the keepers off the valve stems..that keeps the valves from dropping out of the head ...so the adapter serves both leak test and seal install purposes.

My compression tester came with the same male air fitting on the hose whip that I use in my shop. I use it, along with a regulator set at 30 psi, to hold valves closed for an in situ seal change or as a leak finder.

I am all ready to install the new valve guide that was supposed to arrive yesterday. My exhaust guide failed on a cylinder that fouled plugs. When I was replacing the seal the guide lifted right out. My repair guide says to heat the head up to 174-194 degrees and cool the new slightly oversize guide with liquid air or dry ice. I'll be heating mine in a little makeshift hot air oven and cooling it in a bag surrounded by salted ice. If I didn't already have the head off for another problem, I would be tempted to run the engine and have a cold oversize valve guide ready to put in. It's more time consuming than I expected removing the head, because you have so much stuff to clean and keep clean. That's assuming your valve is too loose like mine. If not, I know that some shops don't bother with heating and cooling but use a little air powered "rattling" device. It seems like in the long run that could do more harm than good, but you can think about it if you're doing a bunch of cleaning...
I have read some people think there should be no loosness between the guide and the valve stem but it would seize if there wasn't a tiny bit of room around those fat stems.

Hope you have an easy time of it and don't have to remove the head -it can become a can of worms!

Basil

Yup, and that will trash a head in short order.

I used a vacuum guage to help diagnose the problem, the guage needle fluttered violently, on the 190SL. It didn't smoke a bit, but it had a very odd misfire.

I watched a ham fisted mechanic ruin two VW air cooled heads using a "air chisel" valve guide installer. He cracked both heads, because he failed to heat the head and cool the guide. Then he blamed it on "mislabled" valve guides.

The machinst that I used to use years ago, specialized in Harley Davidson drag bikes. He would turn the oversized valve guide down on the lathe until he got it fit the way he liked it. It took him forever, but the racers could ill afford a blown motor at high speeds.

Hey, I wasn't suggesting actually using an air "chisel", but it is satisfying to learn the trivia. I ordered several valve guides in increments of .001, including standard just so I can get the fit I like.

Some useful (I think) advice on installing seals. The rubber ones are on the exhaust and just push on by hand and they're necked down before the keeper groove so you don't need to use an install shield. The teflon ones are tighter (because of suction?) and can be damaged by passing over the keeper groove. I hit the groove lightly with a stone to take the burr off, using a paper towel to catch any unseen bits of abrasive. Then I pulled the plastic sleeve "install" shield through the seal with a pair of needle nose until the end of the shield cleared the upper edge of the seal. Next I pushed the lower part of the shield over the stem just past the keeper groove, and carefully slid the seal past the groove, where the danger of damage is greatest, using the pliers to keep the shield from dragging down with it. Then I pulled out the shield. The seal takes quite a bit of pressure so I used the spring retainer turned upside down to give me more surface area. Just take care it doesn't "tilt" at the moment it pops on.
The valve "shims" have a different wear pattern if turned 180 degrees so mark them on one side( I like the "outside") with a sharpie pen so you don't get them turned around. Use a magnet to help with the keepers going out and use assembly grease on the keepers when you install them so they'll stay in place.

Easy as pi.

Basil

The guy a was watching really used a air chisel, with a special attachment made for driving a valve guide. It probably works pretty well, if you know what you are doing. This guy got fired a few weeks later, for doing something else, I think he forgot to roll the window up on a car he parked outside. That night, the rats got in the car through the open window, and ate half of the foam and leather on the drivers seat.

That's really good advice on the valve stems and shims. Thanks for sharing with us, for all the times I have had a shim out, I never thought about a wear pattern.

I suspect most of your original thoughs are correct. Stem seals do not disintegrate overnight usually. Even if one failed totally you still have too much oil flow since you see a lot of smoke coming out of the tailpipe. There was virtually none earlier I think you quoted. Keep a really close eye open for a loose intake guide when going for the valve stem seal. Now that might just do it. I really do not think it is a valve stem seal itself on the #1 cylinder.
My knowledge on how much smoke can be produced is small but probably unique. Once I purchased a car with a simular engine to yours that burnt oil. It was pretty bad but certainly not clouds of it. On investigation I found out the last time someone had done a valve job they did not even put the old seals back on mind new ones. On top of that the guides were worn. You are kind of quoting too much smoke for one bad stem seal in my opinion. Hope I am wrong. Any further conjecture of mine can wait until you have cleared the guides and stem seals on your #1.

Mr Basil, Sounds like you are moving right along. The tollerence fit between stem and guide is closer than american clearances in general. Look up the spec before you ream the guide. Things may have changed but I experienced some valve shops would just ream the guides to the standard say chev tollerence allowance. Thats the same as wearing them out quite a bit right after installation plus not getting as good a job as possible.
If you are going to run your engine on high speed trips. I might also consider adding a lead additive to your gas. The valve seats otherwise may not be too happy about the trips on unleaded gas. I think you do have a pre unleaded gas engine.

Barry- thanks for the info. I ordered the seals last night and they are going to be here by the weekend. I am going to keep a close eye for the loose guide.

Assuming that a guide has failed.
When trying to install a new one with the head installed - What do you think about a dry Ice bath and heating the head with a couple of halogen work lights. The other option is over the counter liquid nitrogen sold for wart removial used to cool the guide.

I am not getting the horse ahead of the cart, I just am thinking of options.

I've never done anything to the guide or head and have had no problems. The guides are not a very tight fit in the head, that's why they come loose.
I install guides using a mandrel and a hydraulic press. Driving the guide in by hammer or air powered "mad duck" will upset the end of the guide so that it must be reamed or otherwise opened so the valve will fit.

can't hurt having the guide cold and the head hot.

Basil

Won't hurt a bit. Getting the respective parts hot and cold enough to effect the job can be a chore.

you are going to try to replace a valve guide with the head on?

seems like a recipe for disaster.

tom w

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..I also have a 427 Cobra replica with an aluminum chassis.

I think you will get a much better temperature (and size) differential with dry ice. than with salt and ice.

I'm surprised that you can actually buy liquid nitrogen. A mistaken spill with it would be extremely, and permanently, bad.

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