Open Deck
Open Deck
(OP)
I can understand using them on a low budget project, but I can not understand them being used in production automotive engines, especially over 60 HP.
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RE: Open Deck
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
RE: Open Deck
RE: Open Deck
For most production automotive engines, "low budget" is really high up on the design priority list.
RE: Open Deck
Mercedes 5.5 L V12
http://i.ebayimg.com/images/g/mAQAAOSwEjFXfnmO/s-l...
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Does this qualify ?
http://speedhunters-wp-production.s3.amazonaws.com...
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The closed deck N55 is reportedly "better" but the N54 BMW does OK for itself.
http://f80.bimmerpost.com/forums/attachment.php?s=...
http://www.carbuzz.com/news/2016/5/2/Engines-Expos...
RE: Open Deck
RE: Open Deck
Seems to be reliable enough thus far. Heck, even Ford is using an open deck block in the V6 EcoBoost engines that's becoming the heart of a significant portion of their product line.
RE: Open Deck
1) Open deck blocks typically result in better control of the temperature of the cylinder wall in the combustion chamber. This is important.
2) Open deck blocks are easier to manufacture- sure this means lower cost, but it also means more consistent parts. More consistent parts make more reliable engines.
3)Open deck blocks (because of the cooling factor) result in less variation in bore shape over the stroke length. This leads to better ring sealing, which leads to better durability in the long term and (marginally) cleaner-running engines.
RE: Open Deck
RE: Open Deck
A lot of high specific power engines- motorcycles, small displacement engines from companies like Honda, etc use open deck blocks.
RE: Open Deck
RE: Open Deck
Nothing that can't also happen on a closed deck block if they aren't correctly engineered/manufactured/assembled.
RE: Open Deck
RE: Open Deck
Depending on design details, with some open-deck blocks it is possible to achieve higher bore/gasket sealing pressures at the inner edge of the bore, which results in better head gasket robustness.
I don't know where the OP is getting his information, but it's not very good.
RE: Open Deck
RE: Open Deck
The Jaguar V12 is a notable open deck engine.
RE: Open Deck
A bud had an SR5 whose inline 4, like many others, developed an external leak at around 100k miles. Not awful longevity, compared to cars of the 60s and 70s, but some makes then and now can be counted on to keep their inline 5 cylinder (!!) heads sealed up for FAR longer.
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Th Toyota 3vZ-E iengine is iron, with a closed deck. V6, so it is kind of like a pair of threes.
https://www.yotatech.com/forums/attachments/f2/192...
Here is one of the factory modification for improved gasket durability.
https://www.yotatech.com/forums/attachments/f116/1...
apparently Even that relatively short cylinder head suffers ( enjoys?) enough thermal expansion that lubing the gasket reduces chafing and wear over time.
RE: Open Deck
https://www.youtube.com/watch?v=3xd48wGEdg0
https://www.youtube.com/watch?v=ZbhOfXQWcuk
RE: Open Deck
People who modify engines (such as the people whose youtube channels you have linked) may be great at modifying engines- but that doesn't make them great engine designers. Again, not the same thing.
RE: Open Deck
I am familiar with at least one wet-liner diesel with clearance fit liners, but the liners are mechanically trapped in place when the heads are installed. Head bolt clamping forces pins the liner in place, between the vault and the block. When the engine is at operating temperature, the liners are no longer clearance fit; differential expansion wedges them in place.
If the liners are clearance fit and not trapped in any way, they absolutely will move- side force in any conventional internal combustion engine is significant- unless you're talking about a large marine diesel that is a crosshead design, with which I have no experience.
What specific engine are you talking about- not arguing with you, just curious if we have experience with the same series.
RE: Open Deck
RE: Open Deck
RE: Open Deck
And just like any mechanical engineering and product design, tests are done and problems arise, fixes are made.
Yes modifications, so I don't understand the lecture in core principles and all that.
<<<< quote>>>People who modify engines (such as the people whose youtube channels you have linked) may be great at modifying engines- but that doesn't make them great engine designers. Again, not the same thing.<<<qoute>>>>
It makes them a bit higher on the food chain in that they have to fix what should have been fixed in the first place. And if you went to some of the leading race engine builders with this statement, or for that matter anyone that moves in those circles I think you would change your mind real quick. And besides all the real engineers are gone now, all we have is computer aided designers using the information from old. (except for a handful)
RE: Open Deck
As for modifying engines, there are many hundreds of hack shops in the US alone claiming professional racing experience such as those on youtube but in reality nobody in professional motorsports has sent an engine to be modified via any sort of redneck guesstimation for many decades, they call in a design engineer such as myself to properly design a solution for their problem. Bandaids such as the common Subie two-piece block are easy compared to getting the last few points of efficiency or last few ounces of weight, and my rate and custom parts are cheap compared to the cost of a losing season. Not sure what you define as "information from old," but even 25 years ago we werent dealing with the chemical kinetics, close tolerances, or half the need for simulation as we do today, the engine world's been undergoing a bit of renaissance since ~Y2k. Insult whomever you want but reality is that my interns could build a better engine than those you believe experts.
RE: Open Deck
RE: Open Deck
https://www.youtube.com/watch?v=fs7WI2s-CVw
RE: Open Deck
The level of analysis and engineering that goes into a modern engine dwarfs what was done with the "old" engines. Lower emissions and higher CAFE numbers have forced this. When you look at specific output per liter it has increased dramatically over the past 15 years and this is not the result of redneck, backyard mechanics. Combustion dynamics and variable valve timing along with engine mapping have taken engine design well beyond that state. You are trying to make a case based on a lack of evidence.
Even engines as 'simple' as a outboard boat motor have progressed far beyond the output that they had in past years- the use of computer aided design has enabled this, not hindered it.
It is nice to look back and think that the 'good old days' were better than now, but I think back to the days of V-8, pushrod, carbureted engines and trying to start them in cold weather was always a exercise- everyone was different and you pretty much had a single shot or the engine flooded. Now, you step in, turn the key and let the ECM take care of things and you get a start every time. And don't even think about whet rebuild intervals used to be compared to modern engines; 100k is just getting broken in vs. ready for a valve and ring job in the old days.
RE: Open Deck
RE: Open Deck