A question about varnish (photos) 98 Civic 145K miles

[Rand]

I dont know that I would call the deposits sludge.. that seems to strong a word for the light -medium varnish.

 

[olympic]

In some engines, the valve cover is not bathed in a constant flow of oil like the rest of the valvetrain. So the moving parts are kept nice and clean by the detergents in the oil while any crud deposited on the valve cover by blow-by gasses stay there permanently. You'll see this in any part of the engine that has little to no oil flow over it. Perfectly normal.

 

[bruce381]

quote:

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Originally posted by olympic:
In some engines, the valve cover is not bathed in a constant flow of oil like the rest of the valvetrain. So the moving parts are kept nice and clean by the detergents in the oil while any crud deposited on the valve cover by blow-by gasses stay there permanently. You'll see this in any part of the engine that has little to no oil flow over it. Perfectly normal.

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Agree absolutly and this shows a good REASON that when comparing any oil/drian interval/oil quality issues THAT if you show pictures or have compression prssure reading that they must be about SIMILAR engines run in SIMILAR situations otherwise all data is OFF and not valid.

One engine here is clean and one with a SMALL AMOUNT OF VARNISH both are most likley normal but when compared side by side they differ and incorrect assumptions about oil type/brand versus protection may be made.

So always talk apples and apples or in my case bourbon and bourbon

bruce

 

[Bryanccfshr]

Both valvetrains look extremely good for the mileage. I have to agree with Bruce and those that he is agreeing with.

Great examples of appropriate maintenace for the vehicles and getting the value out of them.

 

[Thermactor]

quote:

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Originally posted by slalom44:
My '95 Corolla after 205,000 miles (picture is a few years old):

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Unbelievable. That engine is PRISTINE!!!

 

[MC5W20]

For that Toyota engine, are the cam lobes directly operating the valves?

 

[slalom44]

quote:

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Originally posted by MC5W20:
For that Toyota engine, are the cam lobes directly operating the valves?

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That question is a bit off topic, but yes, it is a DOHC engine, not a pushrod. If you're confused on how this works, I suggest you do a search or post elsewhere.

 

[javacontour]

Not directly, there is a "lifter" (perhaps it's a hydralic lash adjuster) and a shim that is activated by the cam, and this assembly presses down on the valve.

So it's not a flat tappet that is on the end of the valve, nor is the valve stem directly pressed by the cam.

 

[MC5W20]

quote:

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Originally posted by slalom44:

quote:

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Originally posted by MC5W20:
For that Toyota engine, are the cam lobes directly operating the valves?

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That question is a bit off topic, but yes, it is a DOHC engine, not a pushrod. If you're confused on how this works, I suggest you do a search or post elsewhere.

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I'm confused as to why you think this operates differently then the other poster. Maybe you are the one who needs to do a search.

 

[javacontour]

PS, my reference is the GM service manual for a 1994 Geo Prizm, which uses this very same engine.

GM Pub No: ST373-94-1 1994 Geo Prizm Service Manual Book 1 of 2.

Page 6A1-3 states the first paragraph of the page:

"Valve clearance adjustment is done through the use of shims inserted above the valve lifters. This outer shim type system permits replacement of the shims without removing the valve lifters."

The exploded diagram of the valve train indicates a valve in the valve guide bushing and an oil seal, typical valve spring seat, valve spring, spring retainer and valve keepers. On top of that is the Valve Lifter, and a shim that goes on top of the Valve Lifter. Finally the Camshaft lobe makes contact with this shim.