Date: Tue, 7 Oct 2003 15:04:31 -0700
Reply-To: Craig Oda <craigoda@COMMUNITYBUILDERS.INFO>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Craig Oda <craigoda@COMMUNITYBUILDERS.INFO>
Subject: burned valves or bad lifter? How to tell?
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi,
I ran an engine cleaner through my engine last night, changed the oil
and filter and I still have this loud ticking and pulsing exhaust. I'm
trying to figure out what I should do next to isolate the problem. I
now think that it is either a burned valve on one of the heads or one of
the lifters. Note that I have a spare head in my garage that was just
professionally rebuilt. So, if I isolate a bad valve or seat, I can
swap out the bad head with a good one with good valves and seats. I
need to figure out where the problem is. I only have one rebuilt head
and want to avoid the cost of buying another one. However, if it is the
lifters, I don't mind changing more than one. At $15/piece I can afford
a few. Also, I have a spare engine gasket set which I was saving for
another engine rebuild, but I am willing to use it.
Here's where I am now.
Problem: pulsing exhaust. HC levels measured as pulsing up abnormally
high. Tests done with professional emissions equipment. I passed SMOG
by putting a new cat on. the cat is masking the problem, not fixing
it. I want to get to the root of the problem. Engine vibrates.
Appears to be one of the four cylinders. Not sure which one. Loud
ticking sound appears to come from the center of the engine, near the
cam shaft. I have not been able to figure out if it is on the left of
the right.
Diagnostics and tests completed
- changed all four fuel injectors and rails
- changed all plug wires and plugs
- ran Marvel Mystery oil through the system for hundreds of miles
- flushed the engine
- adjusted valves and timing three times - last done by professional
- replaced rotor and distributor cap
- checked compression, balanced and good - last done by professional
- new fuel filter, O2 sensor, auxiliary air regulator
- have oil pressure gauge on engine and pressure is within specs
Have not done leak-down test (don't know how).
I have these tools in my garage:
- compression tester, digital multimeter with tach, full mechanics tool kit
Please advise on what I should look for. I don't mind taking the heads
off, but I am hesitant to do so since the gasket set is so darn
expensive. Also, when I get the heads off, do the lifters fall right
out? The last time I took the heads off, the engine was still in the
vehicle, so I didn't deal with the lifters. How can I tell if the
lifter is bad?
Thanks.
Regards,
Craig
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