legacycentral bbs

I am replacing the 2 intake valve's on the #4 cylinder in my 2001 Subaru outback 2.5l sohc engine. Due to the piston striking the valves and bending them. In my area the only valve's i could find are made by melling, or engine tech. Is one better then the other and is there anything to be looking for with doing any of this?. I checked the other cylinders and they have good compression the engine has less then 80,000 miles on it.

I used super tech valves on my last build. Not sure if they have options for NA sohc 2.5 heads, however.

That being said, you are running a pretty low stressed non-turbo engine, plus the valves you are replacing are the intake side. Those don't get nearly as hot as exhaust valves, so pretty much any halfway decent valves will last the life of the engine at this point.

I'd personally replace the valve seals, and make sure the valve Seats on those two are not damaged. Lastly since you're putting new valves in there, I'd use some valve polishing compound and clean up the seats.

I ll definitely take a look at doing that i picked up some clover leaf brand leaping compound and i order some melling valves. Any recommendations on how to remove the valves in the easiest way possible. I was told some times the tool the clamps and holds the spring is some times does not fit in the area it needs to get at the sorings. And I'd there any break in procedure that i should do at replacing it and putting the engine back to together. One oil that is better for breaking it in the another?

This is what I used for removing and reinstalling the valves: https://www.amazon.com/gp/aw/d/B000P0ZJ ... 0DER&psc=1

I don't think there's that much difference between break in oils, but I'm sure the main oil forum (Bob is the oil guy forum) has some internet petroleum "experts" that will have some opinions on that. I just used the cheapest break in oils on Amazon, that had zinc in it. Just for the first oil change, which I did in 50 or do miles. After that, normal oil changes

You want to be cautious about using oils with zinc in them as that will cause issues with the catalytic converters and O2 sensors.

Agreed, that's why I leave it in for 50 or so miles till the next oil change.

What does the zinc in the oil do for break in.

You know, I had it in my mind that you were replacing the bearings, rings etc. If you're just doing a valve job, I'd lightly coat the moving parts in assembly lube and do an early oil change (50 miles or less) to catch any loose metal.

How engine break-in oils work, is probably much better answered by a petrolium guru.

Legacy777 wrote:You want to be cautious about using oils with zinc in them as that will cause issues with the catalytic converters and O2 sensors.

Zinc in oils is only a "problem" for cats if you are DUMPING oil into the engine and leaving a trail of smoke wherever you drive. Older engines NEED zinc and other additives that are being removed from modern lubricants.