[TR] [6pack] Carbon/run-on/octane rating

Joe Burlein supertr6 at earthlink.net
Mon May 5 18:27:10 MDT 2008


If I remember correctly the early cars required 100 RON.  That equates 
to about 94ish (R+W)/2 here in the States.

Joe
72 TR-6

Bob wrote:
> I had a run-on problem and started using premium gas.
> Run-on went away. Car is a '71. I have not checked the compression and I
> don't know if there is any carbon buildup on the pistons.
> Regards,
> Bob
> ----- Original Message ----- 
> From: "Sally or Dick Taylor" <tr6taylor at webtv.net>
> To: <ggelhar at earthlink.net>
> Cc: "triumphs" <triumphs at autox.team.net>; <6pack at autox.team.net>
> Sent: Monday, May 05, 2008 4:24 PM
> Subject: Re: [6pack] Carbon on top of pistons - engine experts please help!
>
>
>   
>> Greg----I have also read at least one article about the results of
>> "steam cleaning" the combustion area. Since I already have a working
>> water injection system, I gave it a try. I was already going to do a
>> rebore, so any damage that might have resulted from breaking loose the
>> carbon could be later dealt with.
>> A mixture of soapy water and isopropyl alcohol was run thru the intake
>> manifold until the pump had emptied two quarts of water. (About 5
>> minutes with my injection nozzle) This with an engine speed of around
>> 2,000rpm.  Lots of dirty water came out the exhaust pipes, but when
>> later removing the head, found the piston tops to be firmly holding onto
>> elixar of carbon.
>>
>> The only way I would now believe this process to work would be to see a
>> "before and after" look at this area.
>>
>> I will admit that I never did have a run-on issue, so it could be that
>> this process could remove some sharp corners that were holding carbon.
>> So far as cleaning off the pistons tops...nope!
>>
>> Dick
>>
>> Greg wrote:
>> 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


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