Carrera Valve Guide Wear - Can it be detected by in-car inspection?

[CarreraS2]

Is it possible to detect the premature valve guide wear (or any excessive valve guide wear) in the 84-89 Carreras, with the engine in the car? I.e., by just taking off the valve covers and inspecting, wriggling, etc. the valves.

Or is oil consumption history the only way to tell?

[john walker's workshop]

the guides wear the most at the inner end, toward the valve head, so walking the spring end sideways only gives you part of the story. a quart in 300 miles and oil crust buildup on the plugs, sometimes totally closing the gap, is a good sign that the guides are gone.

[350HP930]

Noticeable and/or intermittent valve train noise with properly adjusted valves is also another indicator of valve guide wear.

[john walker's workshop]

yeah, 2.7s with copper guides were famous for that. noise comes and goes.

[Wayne 962]

It's tough. Compression tests won't really tell you and leak downs won't either, although if the guide is worn enough, then the valve may have difficulty properly seating, which will then show up in the tests. Worn guides also accelerate heat damage to the valve, since the exhaust valves can't cool as well with a larger gap. You can do some inspection of the exhaust valve using a borescope through the spark plug hole, or looking at the back of the vavle through the exhaust port, but both of these inspection methods won't tell you much.

-Wayne

[Eagledriver]

Sometimes the engine will smoke from worn guides. If you can have someone follow you when driving they can look for the smoke. I seem to recall that if you get the engine all warmed up and let it idle for 5 min. then rev it you might see the smoke. This is because the intake vacuum at idle will suck oil into the cylinder through the loose intake valve quides. This of course doesn't work for exhaust guides but if the intakes are worn the exhaust will be worse. If the exhaust guides are real bad there may be carbon present on the stems and valve springs inside the rocker covers.

-Andy

[Wayne 962]

Interesting thought I just had. The newer style oil restrictors that limit oil to the cam towers - they would probably help reduce oil consumption in that area. This may be good or bad, as oil consumption is an indicator of worn guides (sometimes). So, if you have the smaller restrictors, you may not be able to easily tell if the guides are worn?

Thoughts?

-Wayne

[Rot 911]

My '86 with very worn guides showed no oil burning, even on decelleration. No unusual valve noise either. Only evidence was that it used a quart of oil every 350 miles.