Contents
What causes too much compression in an engine?
High compression in a cylinder usually means there is liquid oil and/or high carbon deposit in the combustion chamber displacing room for air. The air gets more compressed (because the combustion chamber is essentially smaller) and the pressure reads high.
What does it mean when you have high compression?
A higher compression ratio (CR) is beneficial for engines. That’s because the higher ratio allows for an engine to extract more energy from the combustion process due to better thermal efficiency. Higher compression ratios allow the same combustion temperatures to be achieved with less fuel.
What does a high compression head do?
Higher compression also means better fuel efficiency. This is because this 2-stroke cylinder head offers improved thermal efficiency, which allows the engine to extract more energy during the combustion process.
How much engine compression is too much?
As a general rule a compression of 135 PSI or better is excellent. Similarly, a compression of 85 PSI or lower is extremely bad. The most desirable situation is that all cylinders, give the same or close to the same reading. Furthermore, that reading should be above 135 PSI.
What are the consequences of too low compression?
Low engine compression is detrimental to your engine and car. You’ll experience problems like misfires and reduced fuel economy that will only get worse with time. This is why we recommend fixing low engine compression as soon as possible to avoid costly repairs.
What is a bad compression reading?
An engine compression test will tell you if your cylinders have good compression. As a rule, most engines should have 140 to 160 lbs. Of cranking compression with no more than 10% difference between any of the cylinders. Low compression in one cylinder usually indicates a bad exhaust valve.
Can a propane engine increase the compression ratio?
In summary, the tolerance for increased compression ratio in a converted propane engine is relatively benign compared to the baseline gasoline engine. The exception is a system that injects propane as liquid in the intake; there you can easily increase the CR by 1 or 2 full points if everything else is equal.
Why does a valve in block engine have a higher compression ratio?
On a valve-in-block engine, one can tolerate higher compression ratio than a modern valve in head engine, due to a less efficient combustion process. In this case, its the engine, not the fuel that is dicatated by compression.
What kind of compression ratio does a CNG engine need?
As mentioned earlier, CNG, LNG and propane are high-octane fuels, so to optimize engine performance on these fuels the engine should be built as much static compression ratio that the fuel can handle.
Why do engine builders break in with gas instead of LNG?
When a newly built engine is first started, the rings go through an initial break-in process until they become fully seated. If the rings fail to seat, the engine will burn oil and leak compression. That’s why some engine builders do the initial engine break-in on gasoline rather than CNG, LNG or propane.