quench...

[malibu795]

whats stock?
with rough backward math stock is ~.025-.030 figure .010 protursion and a or b grade gasket with thats ~.035-.040 thick..

with the gaskets ranging from .0353(a) to .0433(C)

how tight can one go with stock cam?

 

[Fahlin Racing]

How much does the connecting rod stretch at higher rpms is what should be taken into thought as well.

 

[malibu795]

How much does the connecting rod stretch at higher rpms is what should be taken into thought as well.

true, along with wrist pin rod and main clearnces as well..
it seams common practice that a/b gaskets are pulled of and c are thrown back on when the protruistion is still the same ~.010

 

[duratothemax]

How much does the connecting rod stretch at higher rpms is what should be taken into thought as well.

yeah ok...is the rod really going to stretch any measurable amount at 3,000rpm? This isnt a race car engine.

 

[malibu795]

how many people stay below 3,000rpm in a race/sled application?

 

[Fingers]

The rods "grow" several thousands from being hotter than the block.

The clearances in the rod ends when you measure the protrusion are taken up worth another couple thousands. But only when spinning fast.

But, most of all, the Piston gets taller from getting hot. A conservative 0.005"-0.010"

All told. You need at least 0.020" to be sure not to smack anything.

 

[Stingpuller]

Pistons

You also need to factor in piston wall clearance. It will matter when the pistons rocks over TDC.

 

[Fingers]

Max "rocking" is approx equal to the cylinder to wall clearance. Still part of the 0.020" minimum.

Stock cam always clears the pistons IIRC. Even with shaved heads.

 

[Fahlin Racing]

How much does the heat absorption from operation effect our elasticity within the rod material? Yes Ben, low rpms wouldn't see much stretch but Adam's question, i thought would pertain to above stock operation.

 

[Fahlin Racing]

Anyone try this area for any alteration that may improve our combustion event?

 

[LWATSON]

How can a rod stretch even in high RPM applications? On the compression stroke there is allot of preasure pushing against the piston and on the exhaust stroke there is preasure also. Not nearly as much but I would think the fact the gas is in its expanded form after combustion and the piston is having to shove it through the much smaller exhaust port would keep things tight no matter the RPM? Just thinking out loud, I'm not an engine builder just a parts breaker

 

[juddski88]

http://www.enginebuildermag.com/Article/1443/performance_connecting_rods.aspxNot directly related to Diesels but this link gives a little insight towards the fact that compressive and tension forces are separate.

 

[Fahlin Racing]

Speed, weight, and direction change. We design an engine to breathe in and out. The fact that we have 1 or multiple exhaust valves open, we are relieving pressure by flowing the exhaust to turn our turbine. We try to drive the turbine wheel early from our blow-down phase, either way exhausting the cylinder is going to relieve the piston of the 'cushion' of spent gases in the cylinder which allows the rod to stretch. The sooner we exhaust our pressures, the more time we have to thoroughly clear a cylinder. Unfortunately if we do so and don't upgrade or inspect parts for damage from fatigue and replace, we break. Depending on how well the engine breathes at diff. rpms will dictate a few things. In a nutshell, there you go.

I remember Ben saying we have more probelems with cranks breakiing so, I guess until then rod stretch is far from a concern, for now.