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Pistons-- what should I conclude from this pic?

 
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journeyman
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PostPosted: Fri May 30, 2014 10:18 am    Post subject: Pistons-- what should I conclude from this pic? Reply with quote

OK guys,

When I pulled this motor apart after 500 miles, I found the pistons looked like this:
https://drive.google.com/file/d/0B8kKPJNjpNkYSjhDV18yelp6eTA/edit?usp=sharing

The totally black ones were perfectly dry on the top surface and are from the UPPER plane of the TBI manifold (two from each side of the motor). The ones that still show some silver were a little oily on top and were from the lower manifold plane (again, 2 from each side of the engine).

What would you conclude from this?

Thanks!!!
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af2
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1933 Willys Coupe

PostPosted: Fri May 30, 2014 5:29 pm    Post subject: Re: Pistons-- what should I conclude from this pic? Reply with quote

journeyman wrote:
OK guys,

What would you conclude from this?

Thanks!!!


Very typical with a throttle body.
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SMOKEmUP
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PostPosted: Sat May 31, 2014 7:53 pm    Post subject: Reply with quote

I think what Adam is saying that the fuel distribution looks very uneven, which is typical of throttle bodies.
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af2
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1933 Willys Coupe

PostPosted: Sat May 31, 2014 8:16 pm    Post subject: Reply with quote

SMOKEmUP wrote:
I think what Adam is saying that the fuel distribution looks very uneven, which is typical of throttle bodies.


Yes, thanks Smoke, that is what I was saying. I should write more so people can be totally confused with what I am trying to say LOL Embarassed
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af2
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1933 Willys Coupe

PostPosted: Wed Jun 04, 2014 4:37 pm    Post subject: Reply with quote

I want to add that the injector that supplies the washed pistons should be looked at.
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Big Dave
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PostPosted: Thu Jun 05, 2014 12:49 pm    Post subject: Reply with quote

SMOKEmUP wrote:
I think what Adam is saying that the fuel distribution looks very uneven, which is typical of throttle bodies.


Big Blocks have a real problem with fuel distribution. This due to the good port bad port that Edelbrock tried to address with the angled Trantula single plane intake manifold (and Crower addressed with different length and angled velocity stacks on their mechanical fuel injection), in addition to the normal distance issues of the end cylinders running leaner than the inner cylinders in a single four barrel carburetor.

Big Dave
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motorman
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PostPosted: Sun Jun 15, 2014 4:42 pm    Post subject: Reply with quote

Big Dave wrote:
SMOKEmUP wrote:
I think what Adam is saying that the fuel distribution looks very uneven, which is typical of throttle bodies.


Big Blocks have a real problem with fuel distribution. This due to the good port bad port that Edelbrock tried to address with the angled Trantula single plane intake manifold (and Crower addressed with different length and angled velocity stacks on their mechanical fuel injection), in addition to the normal distance issues of the end cylinders running leaner than the inner cylinders in a single four barrel carburetor.

Big Dave
some chevy engines use 2 different flow rate injectors to solve this problem
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Big Dave
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PostPosted: Mon Jun 16, 2014 9:29 am    Post subject: Reply with quote

motorman wrote:
Big Dave wrote:
SMOKEmUP wrote:
I think what Adam is saying that the fuel distribution looks very uneven, which is typical of throttle bodies.


Big Blocks have a real problem with fuel distribution. This due to the good port bad port that Edelbrock tried to address with the angled Trantula single plane intake manifold (and Crower addressed with different length and angled velocity stacks on their mechanical fuel injection), in addition to the normal distance issues of the end cylinders running leaner than the inner cylinders in a single four barrel carburetor.

Big Dave
some chevy engines use 2 different flow rate injectors to solve this problem


Not with a TBI they don't

Big Dave
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Paul P
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PostPosted: Mon Jun 16, 2014 1:15 pm    Post subject: Reply with quote

Since they only have 2 injectors on the Big Block TBI I don't different size injectors would be an option. Kind of a problem.
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