Chris sez:
The harder question: I've been hearing a sharp tapping from the valve
train, so I set about to check the gaps. (This is a longish story...) I
pull the plugs, and get my first surprise: 3 and 4 are very lean, 1 is
fine, 2 is rich (almost fouled). OK, I'll enrich the rear carb later.
I sez:
If #2 is wet fouled, I would suspect an oil burning situation, rather
than an over-rich carb. If it was dry-fouled, something is probably
screwed up in the ignition, unless compressin is so low, the plug isn't
firing. Don't forget, it shares #1's carb, and #1 is ok.
Then he sez:
I can't quite isolate which rocker is making the
noise, but it's certainly here (any hints on this?) I notice that rockers 3&4
have much less oil on them -- they're wet, but nothing is coming out the
holes on top. What does this mean? Could this be related to the fouling?
And I sez:
With the engine just ticking over, carefully, and I sez CAREFULLY, push
down with a finger on the pushrod side side of each rocker in turn to
isolate the noise. You might also try the old garden hose in the ear trick.
And then he sez:
Also, one of the pushrods is visibly bent -- when I rotate it, I see the
clearance to the sealing tube change. Should I worry? Replace it?
Replace all of them? There's also oil leakage around the sealing tubes
-- can I seal these? How?
And my final sezing is:
This bent pushrod, along with the funny oiling on pushrods 3/4 which
go to cylinder #2, indicate some bad news in the camshaft dept. The
cam lobes can be fairly worn or damaged, and you can still get the
correct clearance. Time for a compression check.
I hate to be the bearer of bad news, but these symptoms aren't very
encouraging. I would pull the head to check for valve damage on cylinder
#2 and whichever cylinder had the bent pushrod. I would then pull the
timing cover to look at the condition of the chain and sprockets, and
then I would pull the cam to check for wear on the lobes and journals.
This is a lot of work, and probably a lot of money.
Sorry, maybe some SOL'er can come up with a brilliant suggestion along
the lines of "They all do that, just replace the bent pushrod, and don't
worry about it"; after all I am not all that familiar with the TR4A
engine.
Aran
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