[s-cars] //S4cylinder, almost again!

[audijim at comcast.net]

Taka, yes I have. What are you trying to say? The original Lehmann engine that this car came with was a problem from the time I drove it home. It was F'd up and I knew it. I bought it cheap and it had everything I wanted it to have. My rebuild engine spun a #5 rod bearing. I'm still scratching my head on that one. I can only try to say that I had a bad bearing to start with. I used BG assembly lube and triple checked everything from the crank bearing on up. My newest AAN is still going strong, less the bullet I recently dodged. My current set-up is KS main bearings with the Lehmann crank, ARP main studs, Pauter machine rods with Clevit 77 bearings, ARP rod bolts, ARP head studs on ported head, RS2 EM/Turbo/Ex Cam/MAF/Injectors/Cam gear/Water pump/T-belt and Uncle Bob's current software w/ V-map. As Tim eluded to my driving technique of running my foot to the floor while under 2000 rpm and "teaching" a customer of his how to drive his S-car, I think he is way off in my situation.

I talked to Uncle Bob over the weekend and he stated that this has happend to him a few times. He also said that he sent the plug back to Bosch for an explanation. They told him is was do to thermal shock. Should I read that as detonation? Why would that happen at easy throttle highway speeds (65 mph) and then slowing for a toll and downshifting?

What if this plug was dropped prior to me recieving it and installing it? In aviation, if I dropped a reciprocating aircraft engine spark plug, it is considerd "junk" at that point and should never be installed onto an engine. The same applies to turbine engine ignitor plugs, I was at a Champoin Aviation seminar years ago and they showed us examples of what happends when you drop a spark plug. The "shock" of being dropped caused fine cracking of the ceramic material around the electrode. The electrode started to arc to the body of the plug before it reached the tip. This caused excessive heat and blew the plug apart and the aircarft lost a cylinder in flight. Could this be what happend to my #1 cylinder on Friday?

How does an electrode get from one cylinder to another on your A4?
 -------------- Original message ----------------------
From: "Taka Mizutani" <t44tqtro at gmail.com>
> Jim-
> Sorry if I'm somehow stating the obvious, but you've gone through a couple
> engines now, right?
> 
> Is there something fundamentally wrong with your car? I just wonder if your
> software, or something else
> is causing all of these issues. Electrical system issue somewhere?
> 
> You definitely dodged a bullet- I lost the electrode in our old A4, it went
> pinging away into 3 of 4 cylinders,
> did quite a bit of damage (one valve seat had to be repaired) and caused the
> car to be out of commission for
> two weeks to the tune of over $2500.
> 
> Refresh my memory- what is your setup? I never lost a plug in my '91 200q,
> maybe I'm just lucky, but it was
> merely a chipped K24 car, nothing too exotic.
> 
> Taka
> 
> 
> On 11/17/06, audijim at comcast.net <audijim at comcast.net> wrote:
> >
> > I almost turned my name back to "Angry Jim" today. On the way home, as
> > soon as I started to slow down and down shift for the toll booth heading
> > west on the Atlantic City Expressway, I lost a cylinder and it sounded like
> > I had a lifter collapse. So I babied it to the rest stop and checked it out.
> > It wasn't a fuel injector and I always keep spare POS's in the glove box. I
> > swapped them out and it made no joy. So I jumped in the car and drove it
> > slow. I made it home and immediately pulled the coil pack cover and started
> > pulling plugs. Of course you find the culprit in the last thing you do. I
> > started at #5 and made it all the way to #2 with the plugs looking perfect.
> > #1 was missing the entire center electrode and the body was very loose from
> > the rest of the plug. I fished around the top of the piston for any magnetic
> > bits and installed another plug. Now this is the exact same thing that
> > happened to the previous owner of my S4 when it was the complete Lehmann
> > engine. Except that time it
> > was #4 cylinder. Is there another alternative to the Bosch F5DPOR plug? I
> > think these plugs work great, but at the price for these things, who needs
> > to replace them every few thousand miles? These plugs were brand new and I
> > have about 5000 miles on this engine build. I dodged a bullet this time. The
> > center electrode disintegrated and after I installed the new plug, a test
> > drive confirmed that everything was back to normal.
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