valve guide specs and instillation

hoggyrubber

i have 3 exaust valves that wobble more than the other 3 and the intakes on my 52 308. i took #6 out and measured the valve guide id and it looks to be 0.350". the stock measurement is 0.3437" or something, best i remember, from the manual. so it looks to be .006" out and the manual says to replace anything over 0.003" looks like some mail order place has them for pretty cheap should i go to the trouble of replacing? or maybe just replace the valve? i have never done this before. can i start out with a slide hammer with rod and nut under guide and after it comes up a ways, finish with tap cut threads into the guide and a slide hammer up top?
i was wondering about making a instillation tool on the lathe. cut a rod down to 11/32nds or whatever id is and leave a shoulder to drive in. i also thought about using a plastic cone to keep centered in the seat- kind of like a cam bearing instilation tool. OR can you still buy the proper remover/installer? OR should i not atempt it? any thought, suggestions or advice is apriciated. thanks, hr

hoggyrubber

forgot to mention this is not a full rebuild or anything. i am going to try to fire up this 308. all i have invested is $40 oil pan gasket, $100 head gasket, $12 plugs so far. thought i might check the valves and such while the head is off, don't want to buy another $100 head gasket! the bottom end looked good best i could tell but who knows.

dougson

All I can say is that getting the guides out of my '56 308 was a b$%^&h :S . They came out in pieces, especially the exhaust. I finally had to beat down on them from above with a heavy drift and a 6 lb hammer. Heat (a lot of it) helped some. I don't envy you :blink: .

hoggyrubber

thanks (i think) for the info. i was afraid of that on these too. i measured the valve today and it is 0.006" wore at the bottom. i am kind of kicking around just replacing the valves that are loose, i would be half way to good just doing that! i will wait and see if anyone else has any words of wisdom. dougson, thank you for your input. may i ask if you installed the new guides yourself?

dougson

No, had it done professionally. He said the new ones went in "no problem".

Unknown

I have found that if you make a heavy driver on a lathe out of steel or brass it works pretty good to remove the old guides and install the new guides. The driver should be about a foot long and 3/4" in diameter. You want it nice and stout so you can really hold onto it while pounding. turn a pin on the end of the tool just a little less in od than the id of the guide. Make the pin about 3/4" long. Then above the pin cut another shoulder that is a little less than the id of the hole in the block that the valve guide fits into. This shoulder allows the driver to enter the hole in the block far enough to drive the guide all of the way out. If I remember right this shoulder should be about an inch long Use something like a 5 lb mall to drive the guides down from the top. You need to have the valve springs removed. When you have the guide driven down to where it is almost hitting the lifter then stick a stout punch up against the side of the guide and give it a hard smack and break it off. Now you can drive the rest of the guide down and out. Use the same driving tool to drive the new guide into the hole. Put the new guides in your freezer for overnight to shrink them a little. Wrap the cold guide into a rag, one at a time and run out to your shop, unwrap it from the rag, and drive it into the guide hole with your guide driver. Make sure to not drive it in too far. The book gives the specs on how far down the top of the guide should be from the deck of the block. If you do drive it down too far you can make a tool with a piece of all thread or a long bolt. Get a stiff bar about 8" long and drill a hole in the middle of it. Put your long bolt through the hole in the bar and lay the bar across the deck of the block. Now slide the long bolt down through the guide that you drove in too far. Put a washer and a nut on the bolt after it is passed through the guide. Now by tightening the nut on the bolt you can jack the valve guide up to the proper height in the block. This is what I have done and it works pretty good. I have to say that this is all easier to do if the engine is out of the car where you have more access.
I hope this helps. Good luck. Rob

hoggyrubber

thank you both and thank you rob for the good instructions. i may try one of them just to start. see how it goes, if it goes south i will take the engine to a machine shop and let the pros have a crack at it. the engine is out of the car on a very sturdy stand supporting all corners so pounding on it won't be a problem. thanks again, hr