DSS-DM200-3592 Dss Racing Pistons Instructions
- June 13, 2024
- DSS Racing
Table of Contents
Piston Ring Instructions
Rev 2024A
DSS-DM200-3592 Dss Racing Pistons
File Fitting Ring End Gaps: Both std gap and file fit ring sets require setting ring end gaps based on application. This is a critical step in engine building. Ring end gaps must be checked and set based on your application, End gaps should be checked at the tightest part of the bore that the ring will be traveling in while in use. We recommend carefully using an upside-down flat top or dished piston to square the rings in the bore. Then use a precision feeler gauge to check the gap. Rings should be carefully fit with a Ring Filing tool. Special care must be taken to break (chamfer) the edge with a fine file or stone after fitting. DO NOT PUT A LARGE CHAMFER ON THE RING EDGE OR COMPRESSION AND POWER LOSS WILL RESULT. Basic Ring End Gap Guide
Application| Gas/E85| Top Ring Minimum| Second Ring|
Oil Ring Rails
---|---|---|---|---
Naturally Aspirated| N/A| Bore X .005| Bore X .0055| Minimum .015”
Mild Power Adder| Up to 15lbs/150hp N2o| Bore X .006| Bore X .0065| Minimum
.015”
Medium Power Adder| 15-30lbs/150- 350hp N2o| Bore X .007| Bore X .0075|
Minimum .015”
High Power Adder| 30+lbs/350hp+ N2o| Bore X .008| Bore X .0085| Minimum .015”
NOTES: Every engine combination is different and may require different specs. It is ultimately the Engine Builders knowledge of a particular combination that should determine a perfectly optimized ring end gap. Crankcase ventilation systems or vacuum pumps may be necessary to help relieve the high crankcase pressures that can occur on power adder applications.
Piston with Oil Rail Support
Oil Rail Support Ring: On some piston applications the piston pin bore
intersects the oil ring groove. This design requires the use of an oil rail
support ring. This ring bridges the gap of the pin bore and supports the oil
rings. This style of piston is common on Stroker combinations that require a
shorter overall piston design. Some oil rail supports feature an anti-rotation
dimple that keeps the support ring from rotating on the piston (locate the
dimple in the pin bore area). Others rely on gripping the root diameter of the
ring land to restrict rotation. Never orient the gap of the support rail over
the piston pin bore. On either design make sure the support ring lays flat in
the bottom of the oil ring groove. Verify that your oil rings float freely
when installed.
Oil Ring Installation: Place the center oil ring expander in the groove.
Then spiral the first oil ring rail into the groove below the expander (Be
careful not to scratch the piston or bend the ring). Repeat the process for
the top oil ring rail. After completing the installation, inspect to verify
that the gaps on the expander are not overlapped and everything is in place.
Top & Second Ring Installation on Pistons: The top and second rings
are different and must be placed in the proper location. The top rings are
typically shiny silver in color and the second rings are darker. Locate the up
– orientation mark on the ring (DOT, Laser Top Mark or None). Rings that have
no up – orientation mark are bi directional and can be installed either way. (
See notes below). Using a proper ring installation tool, open the second ring
(orientation mark facing up) just enough to allow the ring to go over the top
diameter of the piston. Work the opened ring down from the top of the piston
to the second groove, place the ring squarely into the piston groove taking
care to keep it flat, release the tension of the ring installer tool (ring is
now installed). Repeat this same process for the top rings.
IMPORTANT! Compression rings must never be spiraled on to the piston.
IMPORTANT! Extreme care must be taken to assure that the rings are
installed and orientated correctly without bending or distorting.
NOTE: Some Top rings do not have up – orientation marks. Inspect the ID
of the ring for a bevel. If ring has both ID edges beveled, the ring can be
installed in either direction. Top rings that have one ID side beveled would
be installed with the bevel facing up. (NOTE) Only when no other up –
orientation markings are found on the rings would you follow these
instructions.
NOTE: Some second rings do not have up – orientation marks. Inspect the
ID of the ring for a bevel. If ring has both ID edges beveled, the ring can be
installed in either direction. Second rings that have one ID side beveled
would be installed with the bevel facing down. (NOTE) Only when no other up –
orientation markings are found on the rings would you follow these
instructions.
Piston Ring Back Clearance: Verify that your rings have back clearance.
With the piston held horizontally and the rings sitting in the bottom of the
grooves verify that the rings are below the outer ring land of the piston.
WARNING: Severe engine damage will occur if engine is assembled with rings
protruding.
Ring Back Clearance
Ring End Gap Positioning: To maximize ring performance rings should be
installed with the end gaps as shown in the diagram below. 
Break In: During ring break-in, use petroleum-based motor oils only
(synthetic oils may be used after break-in is complete). We recommend breaking
in rings at slightly elevated and varying RPM with a low to moderate load
applied. The first half hour of run time is most critical. Avoid high RPM and
high loads until rings are fully seated. Amount of time required to seat rings
will vary because of honing methods and type of cylinder finish achieved.
Seating times can be as quick as a few hrs. of run time to a few 1000 miles.
Do not be in a hurry to use synthetic oil. When you are satisfied with ring
seal and you want to use synthetic go right ahead.
Boring and Honing: Proper Cylinder finishing is critical for the
performance and longevity of rings. Below are some guidelines to help with the
job.
General Iron Cylinder Finishing Technique:
-
Hone to .003 off of the final bore size with 70 to 100 grit stones.
-
Hone to .001 to .0005 off of the final bore size with 220 grit stones.
-
Final finish to bore size with 280 to 320 grit stones.
NOTE: On this step, deglaze stones between each cylinder to prevent cylinder glazing. This can be done by rubbing the stones together. Cylinders must appear silvery in color, if they are dark in appearance the cylinders are most likely glazed. This condition needs to be corrected or ring performance will be negatively affected. -
Hone cross hatch angle should be 22 to 24 degrees off horizontal axis.
If using a profilometer the recommend values for generic performance applications is as follows:
- Reduced Peak Height (Rpk): 10 – 15 µ”
- Core Roughness Depth (Rk): 35 – 45 µ”
- Reduced Valley Depth (Rvk): 45 – 55 µ”
- Roughness Average (Ra): 15 – 20 µ”
For Competition, Racing, big boost applications:
- Reduced Peak Height (Rpk): 10 – 20 µ”
- Core Roughness Depth (Rk): 50 – 60 µ”
- Reduced Valley Depth (Rvk): 60 – 70 µ
TERMS OF SALE AND DISCLAMER: Due to the nature of their intended use
(i.e., high stress, high performance and racing), D.S.S. hereby expressly
disclaims all warrantees, either express or implied in law, including any
implied warranty of merchantability or implied warranty of fitness for a
particular purpose and neither assumes nor authorizes any other entity or
persons to assume any liability in connection with the sale of its parts and
/or products. D.S.S. INC. shall not, under any circumstances be liable for any
special, incidental or consequential damages of any kind arising from the
purchase, installation, or use of their products. D.S.S.’s liability shall be
capped at the purchase cost of the part purchased. Purchaser agrees to wave
potential recovery against D.S.S. Inc. to the extent that purchaser has
purchased insurance coverage for the loss at issue, In the event, purchaser
has purchased insurance coverage for the loss at issue, purchaser hereby
agrees to seek only those damages which are covered under this agreement and
are not covered by insurance. The user assumes all liability for the use of
these products. D.S.S. reserves the right to make product updates without
notice and without incurring liability with respect to products previously
manufactured. Check your state & local laws as these parts may not be legal
for use on pollution-controlled vehicles. Parts sold by D.S.S. Inc. but
manufactured by others are solely covered by that manufacturer’s warranty. The
parties to this contract agree that the contract and corresponding sale shall
be considered to have taken place in Kane County, Illinois and that the
agreement shall be interpreted in accordance with the laws and regulations of
the State of Illinois and that the corresponding sale shall be governed by the
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jurisdiction in the State of Illinois. In the event of legal action involving
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venue for such legal action shall be in the Circuit Court of Kane County,
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corresponding sale shall be considered to have taken place in Kane County,
Illinois and that the agreement shall be interpreted in accordance with the
laws and regulations of the State of Illinois and that the corresponding sale
shall be governed by the laws and regulations of State of Illinois.
Purchaser agrees to jurisdiction in the State of Illinois. In the event of
legal action involving this agreement and corresponding sale, purchaser agrees
that the exclusive venue for such legal action shall be in the Circuit Court
of Kane County, Illinois.
WARNING: Building performance vehicles and racing is dangerous and
involves considerable risk. Racing should never be done on public roads.
Racing should only be done at sanctioned race tracks and events with proper
safety equipment and personnel present. Damages / Shortages: Please inspect
your merchandise immediately upon delivery. If possible, inspect your order
completely while the driver is still present and note any damages on the
freight bill or bill of lading. If any damages are found after delivery,
please call the freight company immediately for an inspection. DO NOT RETURN
DAMAGED PARTS TO US. The carrier will take all necessary steps to settle the
claim. Damaged items returned to us without filing a claim will not be
covered. If any shortages are found contact us immediately. We do not allow
claims after 3 days have elapsed. Returns / Exchanges / Shipping Errors We
accept returns for un-installed items in their original packaging up to 15
days from date of purchase. You must call D.S.S. Inc. before returning any
item. You will receive an RGA (Return Goods Authorization) number that must be
clearly marked on the outside of the package to be returned. You must also
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product be returned. All returns are subject to a 20% restocking fee + credit
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Shipping charges are not refundable. Return freight must be prepaid. No
returns on special order items.
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