Hay R3V, need your opinion on Valves

[StereoInstaller1]

OK, so Colby broke a rocker arm on his '89 325is.

We pulled the damn thing apart to find the tips of the valves really worn.

Does anyone think this is why it broke a rocker arm? Do you think it absolutely necessary to replace the valve?

The worn one is the one that broke the rocker. He SWEARS he was not bouncing off the R3Vlimiter...just cruising along when it broke.



A good one (all others are pretty much the same)



Thanks guys.

Luke (and Colby, sitting in my shop waiting on YOUR post)

[browntown]

Honestly I wouldn't even mess with a new rocker and valve. Find a used head at the junkyard. Don't you have like 3 engines sitting in your shop? (I believe I'm still owed some moolah btw). Can you pull off one of the heads lying around, new gasket, bolts, and timing belt. Send poor colby on his way.

[jlevie]

I think I'd replace the valve. The wear on the valve stem probably has nothing to do with the rocker arm failure. They just break on occasion.

[xLibelle]

more than likely, the pitting on the valve stem has to to with eccentric miss-adjustment for a great period of time.
replacement of the valves really depends on the required use of the car. if nothing more than DD, then replace that rocker and properly adjust the gap to best ability. ...i forget that the head has to come out for this anyway

[StereoInstaller1]

i forget that the head has to come out for this anyway

Well, we certainly did not pull the head. We did replace all of the rocker arms on the exhaust side, though...and anyone saying it is necessary to pull the head is wrong. Did not lift he motor, either.

Pulled the A/C condenser, radiator, distributor belts, hoses, etc.

I think I'd replace the valve. The wear on the valve stem probably has nothing to do with the rocker arm failure. They just break on occasion.

I am going to disagree. We had a HELL of a time getting the rocker shaft out. This is not my first time getting an M20 apart, so I was not guessing about getting that rocker shaft out...the only 2 rockers that were binding were the worn ones. I think the fact that they were binding made the rocker shaft break. I also think that is why the valve wore so badly...the valve tip had to work overtime to push the rocker down, so it wore badly.

Luke

[amdspitfire]

the timing belt didnt lose a few teeth?

[StereoInstaller1]

Nope. Belt has 10K miles on it. I really think it was the binding shafts killed the valve tip AND broke the rocker..it was hella sticky with varnish.

My motor was seriously abused by the PO. Has not stopped me from putting 25,000 miles on it (with 10K of it on the R3Vlimiter!) and I remember the insides being nasty varnish...I think I might take it apart before it takes a crap.

Luke

[bmwpower]

I can see an misadjusted valve clearance (too close) cause that to happen.

Replace the arm and get a bigger eccentric if that one won't adjust. It will get you by until the tip is completely gone.

I do see old headbolts, though.

[mode]

Every single one of those valves is toast. Replace all, get new valve guides, all new rockers. Get new eccentrics. (no oversize junk) Dont do a halfass job.



halfass job = replace rocker.

[bmwpower]

Every single one of those valves is toast. Replace all, get new valve guides, all new rockers. Get new eccentrics. (no oversize junk) Dont do a halfass job.



halfass job = replace rocker.

How do you know that ALL the valves are toast?

[NC325iC]

my opinion is that hay is what horses eat

[StereoInstaller1]

Hay is for da intarwebz....noob!

Haha! J/K.

SO the other valve stems look just fine and adjusted well. We yanked a rocker shaft out of a spare ETA, along with all of the adjusters. Once installed, you can hear the 2 valves rattle like hell

Personally, I cannot see the possibility of a bad adjustment causing this kind of damage...besides, Jordan was the last person to adjust. You guys might see him as a dick, but he does do fantastic work.

Luke

[LINUS]

Every single one of those valves is toast. Replace all, get new valve guides, all new rockers. Get new eccentrics. (no oversize junk) Dont do a halfass job.



halfass job = replace rocker.

Screw that. Fix it on the cheap, & save for a motor swap - unless you got a real good reason to keep on keeping on with that motor, and it doesn't sound like it if the PO thrashed on it.

[mode]

You can not check if the valve guides are worn out unless you pull the head. Did you do that? That causes some, if not all of the "m20 valve tick".

Slap a band-aid on it and save for a motor swap.

[mode]

How do you know that ALL the valves are toast?

How do you know they aren't?


If 2 of the valves heat-treat has failed, it only makes sense that the others are going.