[T3] Valve woes

[Jim Adney]

On 18 May 2014 at 11:56, Fiesta Cranberry wrote:

> Now, I'm having valve problems.  The # 1& 3 valves keep getting really
> loose.  The rocker arms have almost no resistance when when I move them,
> they're floppy.  It's like the pushrods are too short, even tho we measured
> them.  We replaced the pushrods with longer ones (yes, we measured) and now
> it's happened again.  They are not bent or damaged in any visible way.  My
> friend John thinks it needs a valve job, like maybe the valves are stuck.
>  But it gets such light use, that's hard to believe on a new engine.

There are no situations where longer pushrods would be a cure for a 
problem like this. You've gotten a few good suggestions for things to 
check, but my best guess would be that the new lifters you installed 
with the rebuild were too soft and are wearing down quickly. I hope 
your camshaft is still good, but that is also a suspect since 1 & 3 
use the same cam lobes.

It's vaguely possible that you have some valves that are sticking, 
but if you've watched them move up and down, and didn't see anything 
unusual, I think you can forget that possibility. If you want to 
really eliminate that possibility, check the cylinder compressions 
all around. Valves that are sticking or are bent will ruin the 
compression on that cylinder.

I suggest that you start by checking the nuts that hold the rocker 
arms in place. That's probably not the problem, since you've had them 
off already to replace pushrods.

Then using a real dial indicator, measure the lift on all 8 valves. 
Do this after readjusting the valves. Write down each one, then 
compare exhaust lifts and intake lifts. Exhausts will be smaller than 
intakes, but all the exhausts should be about the same and all the 
intakes should be about the same.

If you find that all your exhaust lifts are about the same and all 
your intake lifts are about the same, then your cam is still good and 
the lifters are the problem. If you find that the 1 & 3 lifts are a 
lot smaller than the 2 & 4 lifts, then your cam is also shot.

Either way, repair requires a complete engine teardown and 
replacement of the bad parts. If it's the lifters, that's the best 
news, but you MUST buy GOOD replacements. They are not easy to find 
and there's no sure way for people like us to know the difference. I 
buy from Berg just because I know he knows what to buy. It's best to 
replace the lifters ASAP, so they do minimal damage to the cam.

BTW, my very first engine rebuild ended up the same way: soft lifters 
that wore quickly. In my case, I saw rapid wear on all 8 valves, so 
this makes me think you may also have a cam problem. A call to Berg 
revealed that most lifters out there were too soft. Gene gave me the 
Rockwell hardness numbers and I was able to verify that my old ones 
were exactly as soft as he had predicted. I was lucky to have access 
to a hardness tester at that time.  

There's a lesson here: New parts are not always better. In fact, they 
are often inferior.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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