Lateral Crankshaft Creep

[brnwaxa52]

FTF. Thank you for sharing. You cause us to think it out. You knowledge and openions are respected. I will have more questions to share.

 

[david5244]

Hi All,

I first posted my question in this thread on 11/2 and I deeply appreciate all the varied information that you have been willing to provide me. So, if I run NHRA E/EA, the engine of choice would be the Ford 240 inline six. If I am not correct, you are treating this engine as you would a reduced stroke Ford Boss 300 with the stroke down in the 2.7 inch lenght. These are absolute high RPM screamers producing startling horsepower at the upper end. As to harmonic dampers, I may have provided some misinformation. If you are interested please PM me. I will start a new thread to try to focus on some other matters of interest regarding this engine. Thanks again.

David

 

[brnwaxa52]

Thanks David. I am traveling right now. I actually have a 300. But I am using the 240 rods because they are 5/8" longer. The 300 was marginal on the rod angle ratio and this should cure that and make other improvements. Much the same as the long rod 383 Chevys. I had JE make me a set of pistons @ 8.8:1. I had them use Chevy wrist pins. I have put bushings in the rods to make them full floating. The wrist pin cuts into the oil ring land so that is less also. I'm using a support rail under the oil ring. I'm using Total Seal rings also.

 

[CNC-Dude]

Actually, the stroke does affect the harmonics a great deal because the journal overlap in the crank changes with the stroke. The shorter stroke cranks are often more desirable because they are usually lighter, but also more rigid because they have more journal overlap and resist harmonics are specific frequencies more than longer stroke cranks with less journal overlap. Also, an ultralight rotating assembly(lightened and knife-edged crank, aluminum rods and hollow domed pistons) can move the harmonic frequencies higher up in the RPM because there is less mass pushing back on the throws to flex it. Our 292 Comp Eliminator cranks were lightened by almost 12 lbs and the harmonic frequency that originally was around 6200 RPM moved to over 7000 RPM. So it can be a benefit to trim weight off of the crank where you can.

Very interesting CNC DUDE and Frenchtown Flyer. Share your thoughts if you would. I am turbocharging a 300. I plan to run a conservative boost of 15 lbs but limit the RPM to around 5k . The pistons are lite. a lot lighter than stock. The rods are from a 240. Taking a shot at helping the rod angle ratio. The crank is a steel F600. It is all balanced and the crank has been cryo treated. One thought is do harmonic balancers get old? Does the rubber deteriorate? Do you see a weak spot or problem brewing? Thanks in advance.

Sorry I missed part of your request for input.
In forced induction applications, its essential to realize that you have to build the engine in an opposite fashion as you would just a bracket engine or average N/A engine. Light weight components are not always the best choice because the higher loads imposed on them due to the forced power adder of choice increases the stresses on those parts more intensely. When using longer rods for instance, as you can see, you quickly run out of room to get a good ring stack and can even end up with a less desirable top ring location as a result. In my experience building many blown and nitrous 5.0 engines during the heyday of the Outlaw 10.5 series, if the top ring is less than .300"-.350" from the top of the ring land, the rings will be lifted at even relatively low boost pressures and low nitrous levels. The crown thickness needs to also be a minimum of .350"-.400" thick as well or you can blow through the top of the pistons. The best course of action is to design the piston first to accommodate these needed minimum parameters, then have the rod length made to fit the pistons. You'll end up with a much better rod and piston combo and have a more bulletproof assembly.

 

[compsix]

David. I might have some parts that could help you out with your build.

Let me know what your looking for.

Pat nahan.

 

[brnwaxa52]

Maybe for the next round. I will be welding the header this next week. Im using one of the Borg Warner EFR series 7163 ina twin scroll housing.

 

[pmuller9]

Maybe for the next round. I will be welding the header this next week. Im using one of the Borg Warner EFR series 7163 ina twin scroll housing.

Excellent turbocharger choice.
Please take the time to post your progress on the Turbo, Supercharger and Nitrous forum.
Pictures of custom headers are a wonderful thing to share especially when they are part of a turbo project.
Thanks