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|Glass beads are an abrasive
media used for fine blast cleaning of parts. If left in your engine they
will destroy it through abrasion. It is just like having sand in your eyes.
Besides it hurting, if you donít get it out it will eventually destroy
your eye. This too applies to your engine. However just by flushing your
engine out when it is together will not remove the glass bead.
Over a period of time there has been an increase in premature engine failures due to glass beads being present in the engine. Most of these failures have shown up in rapid wear in piston rings, pistons and cylinder bores, in some cases in less than 200 miles. We will limit the scope of this article to the engine but the same applies to the transmission and primary drive.
The photos of the failed parts (piston and rings) have been analyzed to determine what the cause of the failure was. It is easy enough for many people to guess why something failed but by digging deeper and doing analysis one turns up the real facts rather than just ideas or theories. Hastings Rings Company has been kind enough to conduct tests and supply the 2 highly magnified super duper photos of the glass bead and rings for us. The other photos are ones that we have taken of the same parts but not so magnified. During our discussions with Hastings they have mentioned that they are seeing an alarming rate of engine failures (auto engines) due to improper cleaning of glass beads.
For most people glass beading is a cheap and inexpensive way to clean internal parts like flywheels, conrods, cams, etc as well as crankcases and cam cover. The problem is in the lack of proper cleaning of parts after glass beading and prior to installation. Most people replace their old parts with new parts so glass beading of surfaces wonít apply however way too many times we see used parts glass beaded and then assembled into an engine. In some cases it is necessary to glass bead some internal parts however it is not necessary just for the sake to remove the oil discoloration and make them ďlookĒ pretty. For general cleaning of internal parts(on non glass beaded parts), solvent and good old fashioned hand scrubbing with a stiff brush is best and then a final high pressure clean water blast (garden hose is ok) to rinse away any contaminants left in the solvent.
In general it is recommended not to glass bead internal parts and here are a few reasons:
1/ On machined surfaces like, cam and pinion shaft gears, cam shafts, cam bushings, lower end shafts and housings, valve stems, etc, these parts are manufactured with a specific surface finish which is destroyed by glass beading. The worst of it is that the nice polished surface finish has now been destroyed and we have introduced a rough textured surface finish which now acts as an abrasive on each of its mating surfaces.
2/ When glass beading cases with cam bushings, drive and pinion housings, pushrod guides, rod races, etc still installed, the glass beads have plenty of places to lodge itself in and hide out and miss even thorough cleaning. Bushings have flanges on them that the bead can become lodged behind, likewise with the drive housing flange plus it also has an oil hole that glass beads can hide down in and pushrod guide underside area in the cam chest just to name a few spots. Valve ports with valve guides installed will allow glass beads to become lodged between the valve guide and port and enter the combustion chamber. Cylinder head combustion chambers can also hide glass bead in their pores due to their porous castings. If cases or cylinders need to be glass beading, make sure all parts like bushings, housings, cylinder base studs, pushrod guides, etc are removed first. So as you can see there are many places that glass bead can be hiding in.
At times it may become necessary to glass bead cases especially the exterior as we all want our cases to look like new. Here are a few ways to minimize the risk of glass bead to inside parts:
1/ Remove exterior parts like cylinder base studs from the cases
2/ Use ductape to mask all the inside areas.
After glass beading, give parts a blast off with air and then a blast off with water from the garden hose.
Tap out ALL threaded holes. Use dish washing detergent on the tap. This will aid as a lubricant and a cleaning agent. We donít need a cutting compound as all we are doing is cleaning out an existing thread. After the threading process, pressure blast the hole with the garden hose.
Thorough and final cleaning of your parts
from glass beads can only be achieved by using very hot soapy water (solvent
does absolutely nothing for glass bead cleaning). The most ideal way to
handle this is to use the kitchen sink. My wife Carolyn has come to accept
this however some of you may want to wait for your Mrs to be out shopping
or way out of town. This depends on the consequences if she unexpectedly
stops back home and catches you at it.
Close up of glass bead found in ring land. Note: The piston and ring photos are out of an engine with 200 miles on it.
Close up of abrasion on ring face.
Close up of oil ring face showing abrasive wear in 200 miles.
Ring pack showing abrasive wear in 200 miles.
Piston skirt showing abrasion in 200 miles of use.
Many places for glass beads to hide out:
Lift pin bushings
Push rod guides
Places for glass beads to hide out:
Cam shaft bushings
Lift pin bushing
Hiding places for glass beads:
Nut around outside dia,
slots and threads
Nut locking dimple
Drive housing photo to show that when glass beads enter the crankcase oil hole that they become lodged in the drive housing groove area. No amount of brushing can can get in here to remove it.
Hiding places for glass beads:
Lift pin bushings
Oil transfer holes