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Approximate Progression Of Cylinder Liner Finish On Detroit Diesel Engines
The following is a very approximate progression of the various finishes that have been used on Detroit Diesel 2-cycle engines over the years by a variety of manufacturers, and our opinion of the results. There are other factors
and measurements other than RA finish; this is intended only as a comparison of the thinking through the years.
1940’s: Crosshatch was peaked honed to around 35RA.
- Many low HP applications.
- Crosshatch worked ok until 60’s when HP increased.
1970’s: Crosshatch was peaked honed to around 60-70RA.
- This was an attempt to seat the fire rings and reduce the ring scuffing and port clipping caused by the
- increased horsepower. Engines tended to slobber oil until the oil rings broke in if ever.
- Many combinations of oil rings and fire rings were used over the years to help the slobbering problem.
1980’s: Plateau honing came into the mix using a rougher RA but a deeper R3Z pattern.
- In many applications the fire and compression rings now would not seat, causing high base pressures, forcing oil out the air box drains.
1990’s: Brush honing was the next attempt.
- However the surface may still have been too aggressive for the sensitive oil ring scrappers and added to the problem of seating the fire and compression rings.
- This may have contributed to the excessive slobbering until the oil rings wore themselves in, if ever.
1999: IPD introduces an innovative “Two-Stage” Honing Pattern
This technique utilizes the best of the patterns used:
- Rougher finish above the ports to seat the compression and fire rings.
- Smoother R3Z finish below the ports to reduce damage to the oil ring edges.
- Standard OEM run-in procedures are required to experience Reliability and Durability with the innovative IPD liner.
Tech Tip courtesy of IPD.
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