How To Blow Up Your Saw With A Titanium Wrist Pin
Posted by Bill Lockwood at
The short answer: Install One!
However, with careful observation, and a pledge to yourself and your saw not to gamble, a Dominant Hollowpoint Wrist Pin will "wow" your friends and impress your neighbors.
Here's what we send out with our wrist pins:
These are racing parts with a shorter life than the OEM equivalent, and therefore sold with no warranty. Despite a very-noticeable performance increase, they will fail after 35 (or less) tanks of fuel in a ported 372xp running our piston. They are, however, very high quality and will stress your saw less due to lighter weight.
Reducing rotating weight is only one part of faster acceleration. Trimming down reciprocating weight is the other. An engine's reciprocating mass accelerates and comes to a stop twice per revolution. You don't want a saw spinning north of 13,500 RPM to do any extra work - that piston is coming to a halt 27,000 times a minute! Dropping few grams from equation adds up fast and has a direct impact on the performance of your saw.
The hard numbers: If you drop 8g by switching to Hollowpoint Ti Wrist Pin, your saw does almost 450 lbs less work per minute in the cut. Over the life of the wrist pin, your chainsaw's internals will be less stressed. Hollowpoint ti pins weigh about 9g, which is about half the weight of our Wiseco pins (about 17g). These run up to 0.0015" undersized for power gains, but we have found differences of a thousandth of an inch in all the manufacturers pins.
Failure. In our experience, the way these fail is the DLC coating on the pin wears, losing dimension inside the wrist pin bearing. This causes galling of the titanium, which eventually overheats and destroys the wrist pin, sending the roller bearings through the transfer ports, which, at 15,500rpm, will then “pin” the piston to the cylinder. It’s a very destructive failure. So, listen to your saw, set a limit to how much you run it before checking the internals, and change out the wrist pin early.
Fits 372 and some others with no modifications. Will fit all 12mm wrist pin saws, even those not listed. Pin is ~35.5mm long. Some shortening of the pin may be needed to equal the length of your OEM wrist pin and fit your saw. Grind from the outside edge in toward the center of the hollow, in a rotary motion, and sand/smooth in a similar way as not to have outward facing burrs.
Share this post with other cutters
- 1 comment
- Tags: chainsaw race parts, chainsaw race piston, chainsaw wrist pin, hot saw parts, hot saw piston, hotsaw parts, light chainsaw wrist pin, lightweight wrist pin chainsaw, ported chainsaw piston, ported husky piston, titanium chainsaw wrist pin, titanium chainsaw wristpin
Are the dominant pistons expected lifetime shorter than OEM as well? Or just the wrist pin? Looking to build a work saw so need long lasting parts,