Help with spun rod bearings in my 496 bbc

OR it touched after the rod got super sloppy.

Dave Koehler
http://www.koehlerinjection.com

 

So it looks like four things to take care of;

Ensure adequate piston to head clearance

Run some good racing oil

Add an Accusump

Add a System 1 filter so you can inspect it after each pass if you like

 

Spun bearings

Here are another couple of suggestions-

Fat is better, unless your counting cholesterol! Run that puppy rich until you KNOW it needs to be leaned out. Read plugs after every run. They will tell you when you need to adjust fuel volumes. Limit what you do to the engine after the run is over and you're getting it off the track. This can screw up the plug readings and invalidate everything you do tuning-wise.

Use some grape ape odorizer in your methanol. If its getting into the engine pan (which it is, no matter what you might think) then you will smell it when you check your filter AFTER EACH RUN FOR METAL PARTS THAT INDICATE SOMETHING IS COMING APART! The methanol will evaporate quickly after a run through any engine vent, but will still dilute over the counter oil in short order during a run. Leak down tests will give you a good indication of how much methanol is getting into the pan, along with the grape kool-aid smell.

Use Brad Penn 50 wt. Just bite the bullet and spend the money! Compared to what you have had happen, it's cheap! You cannot dilute it with alcohol. I run a blown fuel altered with a 14-71 running 35% OD with nearly 40 lbs of boost and 20 methanol injection points. This oil will work for you! I use a 60 wt mix of 50wt and 70wt nitro oil mixed 50/50 to get it to 60 wt. I will never go to another oil after seeing what this stuff does under very bad circumstances! I can run it for 10-12 full passes between changes. Whenever I pull the pan to check bearings, I change it for new oil.

Drill and pin the rods. Go to the aluminum rods on alcohol, especially with the elevated compressions.