I got 93 300 SE W140 engine,I had Oil in
Coolant tried head Gasket replacement, meanwhiletook the Head to Machine shop & the head was .008 off. so we got it machined, check the Cams they were okay. they told me all my Exhoust valve Guides need replacement. also some valves leak. I am not original owner but car has only 70K on it. so they want $700 Labor, I am trying to see How I can get the guides off. I read somewhere I need to Heat them but not sure how , Any ideas welcome.

thank you[]

 

anyone? please

 

You have to heat the entire head evenly to about 300 degF in an oven. Then use a punch to push the guides out. A press is much better, but I have done it withcontrolled taps of a hammer.
If you try to beat the guides out when cold, you'll likely deform them so badly they will have to be machined out.
Then re-heat the head. press the new guides in. Make sure you bought the correct guides; they do not survive re-installation. After installed. check to make sure the valve fits. If you have dinged or dented the edge of the hole, use a hobby knife to clear the burr.

Blue

 

Thanks Blue, How long should it be heated in the oven?

thanks again!!

 

An hour should be fine. You want the head to be evenly heated. For example, you would not want to use a torch to heat the head because you might get it too hot in one place and warpor burn it. The heat causes the metal to expand and loosen its grip on the guides. There is also a special drift punch available for driving the guides out; local auto parts stores stock them. Most guides have a step cut on them, so they will only go in from one direction, and it is important when starting them in to make sure they go in straight and all the way in.

Of course a 300degF cylinder head is a dangerous thing to handle, so take every precaution. Wear long gloves, safety glasses, have a prepared work bench, and all manner of caution.

 

THANK YOU