[TR] [6pack] Carbon on top of pistons - engine experts please help!

[Greg Gelhar]

I was re-reading an article printed in a club newsletter from the distant
past about an old time mechanic who recommended water injection to
eliminate this problem. His technique was to remove the air cleaner
assembly and use a pump-up garden sprayer and spray water into the
carburetor while the engine was operating at 2000 RPM. The premise was the
steam generated by the water would clear the carbon from the piston tops.
The amount of water was regulated as to not stall the engine. He reported
that after this treatment the run-on problems were gone.

Does anyone have any thoughts to the validity of his actions?

Greg Gelhar
1973 TR6
1980 TR8
Osseo, MN     .


> Subject: [6pack] Carbon on top of pistons - engine experts please help!
>
> I had engine run-on issues prior to my restoration project, so while the
engine was on the stand, I pulled the head to look for carbon deposits on
top of the pistons.  I found significant deposits on five of the six.  I
used to run an external oil feed but stopped after going through oil at a
fast rate (ring problem?).  When I removed the oil feed, oil consumption
was greatly reduced but my run on problem was present.  What remedy do I
have available to a) clean the pistons and b) prevent the problem from
happening again.  I'm assuming that if my engine is put together and broken
in correctly, the external oil feed should not contribute to additional oil
consumption.  BTW, the engine was rebuilt in late 2005 with new pistons,
rings, bearings, etc for .030 over bore. 
> Thanks in advance for advice you can share.
> Andy