DFI, Batch Fire, and other myths

[Greg Hermann]

>Geoff Richards wrote:
>>
>> ----------
>> <snip>
>> > According to a service bulletin, the 3.8l engine suffers from carbon
>> > accumulation on the back of the intake valve which significantly
>> > reduces performance.
>>
>> How to remove this carbon ?
>> Possible with the myriad of 'carbon blast' type of miracle cures,
>> you know the cans of cleaners etc,run 'em through the engine
>> while running or pull the heads?
>> Geoff
>Apparently, walnut shell blasting.  GM claims that no chemical works,
>but I would be interested in seeing the results from properly applied
>Top Engine Cleaner.  A mechanic I worked with left some in a cylinder
>on night while the head was out for reconditioning, and the piston
>wiped clean like new in the morning.
>
>Shannen

There's something that works, dunno what--years ago knew someone who had
what he called a cold tank in his shop. The stuff in it did NOT attack
aluminium, as the chemicals in a hot tank will, but it would (over a 24 to
48 hour soak) make an aluminium head look like new--chamber surfaces,
exhaust ports, inside of water jackets, everywhere!! And this was is the
days of leaded fuel, so the chamber surfaces and exhaust ports were pretty
nasty looking sometimes.

Wish I knew what the stuff in the tank was now!!!

Regards, Greg