My cylinder head warped from an overheat, so I took it to a machine shop to be resurfaced, and the first thing that the man at the machine shop said when he saw the head is "there's a lot more wrong with that head than being warped". He grabbed one of the open valves and moved it back and forth and said "there's not supposed to be any play in the valves. Your valve guides are shot. That's causing the valves to not close right and is costing you power! It'll be $200 for new valve guides." So my question is are the open valves not supposed to move back and forth a tiny bit? I would think that a little play is normal and harmless, but I'm no expert. Is he trying to rip me off or do I actually need new valve guides? Thanks.

 

Pull up a factory service manual, take a gander. There is a tolerance of what it should be.


This is .005" of play.... how much more were your valves moving?


Usually if the valves are moving side to side, there is too much play and the guides need to be replaced.

 

Thank you very much. There was about that much, or maybe slightly more play than that. Is that bad? Will valve guides effect the way the engine runs, or just make it burn oil?

 

it's bad enough that it needs to be fixed. Don't skimp on it. Machinists aren't there to jerk you out of your money. If you question it, tell him to take measurements and get you the exact amount of play between teh valves and the guides, then compare that to tolerances listed in the FSM or if you can find it in some other manual like a Helms.

 

What would I notice driving the car with bad valve guides? The engine runs great, but uses a little oil, but it has a crack in the side of the oil pan, so I'm not sure how much of the oil that it uses is being burned. Thanks.

 

You'll start to notice more oil consumption.

Then you'll be low on power because the valve is not fully closing due to not seating properly


Then you'll have a dead cylinder.

Spend the $200 now to get it fixed and not have to worry about for the theoretical rest of the engine's life.

 

It's not a scam. They probably are worn over spec. By the time you need a head gasket from normal wear, your guides will be that worn. More often than not, people run them like that. To say they are shot is usually far fetched. Your spring slams the valve shut. Think about it. If it effects your compression that much, and they are "shot", you wouldn't have good compression, if that story time was true. I have completely dropped a valve guide, and spit the pieces out while riding a harley for a two hour ride, and it had good compression. Mind you, it wasnt pritty, and leaked lots of oil, but compression on both cylinders were the same. Valve guides are loose. If they were not, they would lock up, and sieze a valve. So its your call. Dont be suprised if you do it, and dont notice a power gain. You may, or may not.