What is the most common cause of puffs of smoke during upshift at higher RPM? They appear to be oil (blue) as I view them through the rear view mirror.

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nick

More than likely a bit of oil going down the valve guides. With an up-shift engine RPM drops between gears which creates high vacuum in the manifold. Worn intake guides or seals allow oil to be drawn into the combustion chamber and when you get back on the gas in the next gear it quickly gets burnt and you see the blue puff. Probably puffs some going down a long hill too.

+1, that sounds correct.

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Ron
1980 TR 8
1965 E-Type Jaguar
2016 Aston Martin Vantage GT
Oxnard, CA

Nick,

Usually a symptom of a higher mileage motor that's a little tired, unless you need max performance or have to deal with smog Nazis it's not much of a problem for a daily driver. I hope we're not talking about your cool sprint motor.

It is the Sprint motor. When I got the used head I had it tested but not rebuilt. I think the machinist may have changed one valve guide. I built up the block and have clocked about 1,000 miles on it and never noticed any smoking before. The car sat for awhile and it has turned quite cold here. I also changed oil recently and am running about 1/3 qt high on the oil level. I also dumped a pt of STP in just try something. So to be clear, the smoking seems to occur when shifting around 4k or above and no noticeable oil consumption or oily exhaust pipe.

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nick



Edited 1 time(s). Last edit at 2017-12-18 05:07 PM by nick.

I am not a mechanic, How sensitive is that engine to a high oil level? I know my TR 8 has warnings about over filling the oil in many p;aces on the car. I would think that could be your problem.
You could try draining some of the oil out of the oil pan, and see if it makes a difference.
Ron

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Ron
1980 TR 8
1965 E-Type Jaguar
2016 Aston Martin Vantage GT
Oxnard, CA

TR7 smoking at rest.

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1972 CC80594U Sapphire Blue

I didn't realize British Leyland offered a coal fired wedge.

It was offered as an aftermarket item by a steam generating specialist. I think it was H2O & electric, off the battery.
James Bond and 'M' were interested in the product.

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1972 CC80594U Sapphire Blue