Joe Mondello Feb. 2001 by Evey Roth
Most engine builders and home enthusiasts take a new engine out of the box, hone the
cylinders, install new rings, some use a torque plate and some don't and they wonder why
the engines do not seal the rings and use a lot of oil. I am going to share with you
my 40 plus years of engine building technologies I have applied to this unique 1 cylinder
aluminum Briggs engine. A seasoned block is always better to start with after about
75 to 125 laps in your chassis karting or 15 to 25 laps in a junior dragster.
We are using alternative and more successful ways to stabilize engine blocks and
components before machining and finals engine assembly. We are using cryogenics
freezing and heating of the blocks and components, high frequency stress relief shaking to
internally stress relief and align all molecules and porosity's in the material.
This also relieves all stress areas where welding has been done. Also heating and
cooling in an oven, hot water pressure washing systems will also work if cycled at hot to
cold -- hot to cold at least 6 to 8 times. All block procedures, high frequency
shaking, freezing, heating and cooling need to be done with a torque plate, side cover and
bottom motor plate torqued with the same fasteners you are going to use for final assembly
including the head gasket. The torque plate, motor plate and side cover need to be
torqued 10 to 12 hours prior to any boring and honing operations. If you do not let
the block normalize and stop moving for at least 10 to 12 hours before final sizing and
honing of the cylinder bore is done it will change over .001 in diameter and will be out
of round causing inadequate ring seal. Nearly every one including some engine
builders install a torque plate, used head bolts and a used head gasket, torque the torque
plate and hone the block. They remove the torque plate, clean and assemble and
believe me this is when the problems start. If you then use a different set of head
bolts and do not cycle them properly or use a different assembly lube on the bolts or use
a different head gasket the cylinder bore will change size. The size of the bore can
change up to .0003 to .0005 just by using a different head gasket or head bolt.
difference in bore size between just bolting on a torque plate or leaving the torque plate
on for 10 to 12 hours is usually about .0009 to .0013. When cryogenically
freeze the engine parts we see no change in size like we do when we shake them. We
do find 1 to 3 points of a harder cylinder bore surface on the "C" scale on our
Rockwell hardness tester but the lubricity factor is much better allowing rings and all
bearing surfaces to have less friction and more longevity. We have increased piston
and ring life over 400% by just freezing the piston and rings. When we shake the
parts we do notice a size decrease especially in cylinder bore dimensions both height and
width and side to side plus overall block height up to as much as .0035.
The cylinder bores will usually reduce their diameter up to .0006 to .0008. The
largest decrease is the top and middle of the bore after high frequency stress relief
shaking. I think by now a lot of you are wondering what does all this mean to me and
the way my kart runs and performs.
Well it is hard for me to honestly tell you but I can tell you one thing for sure and
that is that 75% or more of you out there do not have good sealing rings. I am going
to try and advise you in the right direction to obtain and keep a good ring seal and of
coarse good rings, pistons, piston ring grooves, cylinder bore finish plus piston, ring
and cylinder block preparation is real critical. The last word on all this engine
preparation is real simple: machine it round and straight, keep it round and
straight. I realize a lot of you think cryo processes and high frequency stress
relief shaking is smoke and mirror black magic voodoo, think again. I have been
using cryo for over 15 years and stress relief shaking for over 10 years on every thing
from chain saw and kart chains, transmissions, sprocket, gun barrels, cranks, valve
springs, valves, heads, blocks, rods, even carbide cutters for porting heads and blocks
and believe me this stuff all works.
Once you are comfortable with your seasoned, cryoed or stress relieved block then
choose your head gasket, fasteners, (if they need to be cycled, do this before final
torquing of Torque plate is done) always use the same assembly lube start to finish of
your engine. Always have your cylinder bored within .002 to .003 of finished bore
size using a Torque plate, side cover and engine mounting plate. Install Torque
plate, new gasket, fasteners, side cover and gaskets plus engine mounting plate toque all
fasteners to recommended torque and let stand for 10 to 12 hours, for roughing then go to
a 300 to 320 grit stone for a semi-final and final honing procedure for the last .0003 to
.0004 tenths removal is a 400 grit with about a 45 degree cross hatch.
When this final plateau honing is completed you should still be able to see the 320
grit below it. During all this honing operation do not ever allow your cylinder bore
to ever get overheated especially on your final honing procedure.
I will guarantee you that your cylinder bore is round and will stay round. Always
use a .0001 reading dial bore gauge while honing your cylinder bore for ultimate roundness
and accuracy. The use of aluminum cylinder bores stock or coated or steel sleeves,
all respond to these procedures. The rings we use and have tested Briggs and
Stratton, Burris, Speed pro and Wisco, these are all good rings if they are prepared
properly. They must be end gapped correctly 90 degrees square to the bore. Always
deburr sharp edges of the rings before installing in your freshly honed cylinder
bores. I make an RS-100 1/2 round ring deburring stone and an RST-125 ring squaring
and ring lapping combination tool, these are a must to do rings correctly. After you
have end gapped your rings to your preferred specs I like .001 to .002 for Top .0015 to
.002 for 2nd and .018 to .20 for oil rings.
Deburr all rings except sealing surface before engine assembly. Hand lap
both sides of rings lightly with 600 wet and dry sandpaper and solvent on a flat plate or
piece of heavy glass using RST-125 lapping tool.
For your piston installation we make an adjustable tapered piston-ring installation
tool for all Briggs and other engines. Our Briggs part number for the 5 H.P. Briggs
which covers 2.5625 bores to 2.625 is ARI-262. This tool elimainates ring
breakage and scuffing. I recommend Marvel Mystery oil for ring land lubrication, use
automatic transmission oil on the cylinder bore (any type is fine) and on the piston
skirts, wrist pin and the rest of the engine use our 2115 engine assembly lube, do not use
on piston rings. These are many engine secrets shared by no one, so take advantage
of them; of coarse we teach you these and many more things at our Tech School.
We do cryogenic freezing, high frequency stress relief shaking, boring, honing and
complete block preparation as mentioned in this article, we also sell complete prepared
blocks with pistons and rings sryoed, fitted and rings deburred.
Do not be fooled by a lot of false advertising, all cryogenic freezers are basically
the same but the way it is done is totally different. Find a person with a lot of
experience that knows his metals for proper soak and cycle times. I have already
figured this all out. If you would like me to put your parts through either the
Cryogenic or Stress Relief Shake Processes please feel free to contact me.
I hope you have enjoyed this article which is one of many I will be doing on Briggs and
Stratton motor parts, engines, oils, cams, complete assemblies, etc. We will be
testing Cast-iron and Stainless Steel nickel coated cylinder liners from England in the
NOTE: If you are going to re-ring your engine on a engine freshen up rebuild a
fine 400 grit or finer ball hone is OK to use, WD40 works well as a lubricant when ball
honing. Always use your Torque plate. Remember one of the biggest problems of
ring seal is your engine oils and additives. More horsepower, sometimes means less
ring seal, be careful. My next story Oils, Lubricants and Oil additives.
Always remember we make Horsepower, not promises! by Joe Mondello