MEL Engine Series Combustion Chamber & Piston Design

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Theo
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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by Theo » Mon 2. Aug 2010, 10:55

Here's a link to an interesting post that Rick "Shelby#18" has posted just recently. It's interesting informationon on how much factory stated HP rating can differ from real world dyno results.
viewtopic.php?f=2&t=611&p=2470#p2470
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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by 430 6V » Mon 7. Feb 2011, 16:57

The step pistons are indeed the best. No matter what the compression ratio I recommend the quench pad or "step" be at zero deck with a .040" head gasket. .020" in the hole if you use a .020" steel shim gasket.

In theory it not only helps with squish and turbulance but allows you to run higher compression with out detonation due to improved piston cooling.

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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by mugundhan » Wed 4. May 2011, 22:38

I'm new here.
I'm looking forward for the wonderful topic and new learnings. :roll:

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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by Chris Craft crazy » Thu 8. Mar 2012, 18:07

I have been doing some research on Chevrolet 409 engines lately, and came across the following quote from wiki, which I post here. As some of you may know, the 409 also had a triangular combustion chamber, and it was in the cylinder, like the MEL series of engines. In 1963, you could order a Impala SS with a dual quad 409 which produced 425 horsepower. The 409 had a brief but storied life, but it was this information that interested me.

Unlike many of its contemporaries, the "W" combustion chamber was in the upper part of the cylinder, not the head, the latter having only tiny recesses for the valves. This arrangement was achieved by combining the use of a cylinder head deck that was not perpendicular to the bore with a crowned piston, a novel concept in American production engines of the day. As the piston approached top dead center, the angle of the crown combined with that of the head deck to form a wedge shaped combustion chamber with a pronounced quench area. The spark plug protruded vertically into this chamber, which tended to cause a rapidly moving flame front during combustion.

The theory behind this sort of arrangement is that maximum brake mean effective pressure is developed at relatively low engine speeds, resulting in an engine with a broad torque curve. With its relatively flat torque characteristics,
MEL Marine division... and if you thought MEL car parts were scarce....

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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by Theo » Fri 9. Mar 2012, 01:38

Here's an other important note 'bout the 409 ;)
viewtopic.php?f=41&t=1302
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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by Chris Craft crazy » Fri 9. Mar 2012, 15:39

I love Junior Brown... a wicked guitar player.
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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by 430 6V » Thu 15. Mar 2012, 19:54

I've thought it curious that the 409 and MEL chambers have been described as having a fast flame front or fast burn.

It makes cense yet on the dyno mine made it's 420hp peak with 43 degrees total.

Due to the lack of shrouding that would indicate a slow burn. And I would think that same slow burn contributed to the 430's smooth power.

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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by mrbthebarber » Thu 2. Apr 2015, 23:25

An interesting and frustrating topic - I bought a rebuild kit for my 58 back in 03 and in total naivety fitted the flat top pistons and whilst the engine runs well I could never understand the lack of power. The car used to lay down rubber in a straight line, no chance now. What to do? Are the stepped pistons available anywhere now?

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Re: MEL Engine Series Combustion Chamber & Piston Design

Post by Shelby#18 » Tue 14. Apr 2015, 03:26

mrbthebarber wrote:Are the stepped pistons available anywhere now?
Please see the second page of this thread, third post down. That is the order form for the step down pistons.

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