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Ratbuell
| | Posted on Saturday, July 20, 2019 - 01:20 pm: | 
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Valves and pistons occupy common space on all overhead valve engines.
I came to this late, but...that statement is wrong, which may have been cleared up in posts since.
I have multiple 2.2 / 2.5 liter Mopar (Dodge) turbo engines from the 1980s and 90s, and these are NON-interference engines. I have broken any number of timing belts over the years, and the engine simply...stops. Nothing hits anything, nothing bends anything. Time the gears (turn the crank and the cam till the marks line up), install a new belt, and go. The lowest point of the valve is never lower than the highest point of the piston.
I have had a version of the 2.2 turbo, with the Lotus 16v cylinder head, that WAS an interference motor due to the head design and its clearances - THOSE valves would, when fully open, extend below the highest point of the piston, and if you break a belt on THAT engine, you can bend a valve or put a hole in a piston because they smack into each other.
Both these engines are "overhead valve engines".
Both these engines, actually, use the same engine block, crankshaft, rods, and pistons. They are called, respectively, a "turbo I", "turbo "II", or "turbo IV" for the 8v non-interference versions (for non-intercooled, intercooled, and VNT intercooled versions), and "turbo III" for the 16v interference version.
The "Diamond-star" cars from the 90s - Mitsubishi Eclipse, Eagle Talon, etc - were also turbocharged 4 cylinder interference engines. Break a belt, and pistons hit valves.
Sorry Steve...but "interference" and "non-interference" ARE legitimate terms to describe these engine designs. "Overhead valve" describes anything that is NOT a flathead V8 or I4 from the early 20s.
Anything that has valves in the heads, as opposed to valves in the block...is "overhead valve".
Just because the valves are in the heads, does NOT mean they will hit a piston if a timing mechanism breaks.
Interference engine
An interference engine is a type of 4-stroke internal combustion piston engine in which one or more valves in the fully open position extends into any area that the piston may travel into. By contrast, in a non-interference engine the piston does not travel into any area into which the valves open.Wikipedia
What Is a Non-Interference Engine?
A non-interference engine is one that has enough camshaft lift to open the valve and allow the charge of air and fuel into the combustion chamber but does not open so far into the chamber that a broken timing chain or belt would cause the valve and moving piston to collide when the camshaft stops. |
Stevel
| | Posted on Saturday, July 20, 2019 - 01:57 pm: |
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Joe,
Your definitive test is that in your experience with a valve train drive failure has not caused a piston valve collision? That's your argument? Please take any one of your examples set the cam to max lift (both valves) and rotate the motor. Then come back here and tell us what happened. |
Ratbuell
| | Posted on Saturday, July 20, 2019 - 02:05 pm: |
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I have.
The engine is DOCUMENTED and ADVERTISED as a non-interference engine.
Come on by sometime. I have one on a bench. We can hand-turn the cam, and the crank, through multiple rotations and I'll prove it to you.
"Non-interference engine" is a thing. Period. |
Ratbuell
| | Posted on Saturday, July 20, 2019 - 02:06 pm: |
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They call it "free-running"...but here's a picture for the big words.
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Ratbuell
| | Posted on Saturday, July 20, 2019 - 02:11 pm: |
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Ratbuell
| | Posted on Saturday, July 20, 2019 - 02:16 pm: |
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https://impremedia.net/non-interference-motors-lis t/
http://www.agcoauto.com/content/List_Of_Interferen ce_Engines |
Willmrx
| | Posted on Saturday, July 20, 2019 - 05:28 pm: |
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Remember, you are arguing with a man that states" You can't rebuild a 1125r motor". So my complete disassembly, inspection and replacing all worn parts on the 1125r engine, is NOT a rebuild, in his world. |
Shoggin
| | Posted on Saturday, July 20, 2019 - 06:01 pm: |
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There is stubborn... and there is obtuse. I think we made the point, no need to hammer it home
I have a good friend who just discovered thread chasers (not taps). He SWEARS they were just invented and he discovered the first kit! So I took a pic of my Matco kit from the 90's. His honest response was that I made it dirty to "look old". LOL sometimes theres no winning... |
34nineteen
| | Posted on Thursday, July 25, 2019 - 03:18 pm: |
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Who are you calling obtuse?!
In solitary for a month DuFresne! |
Shoggin
| | Posted on Thursday, July 25, 2019 - 11:31 pm: |
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Oh wow. Good call 34:19 |
Natexlh1000
| | Posted on Monday, July 29, 2019 - 04:12 pm: |
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