I'm most familiar with John Deere and the Cat 3500 series engines. In both cases the liner just drops in the hole so there is radial clearance. The head does pin everything in place but shouldn't the same be true for an open deck engine? The big difference is that with wet sleeved engine, the sleeve is pinned on top and axially free on the bottom. This means no distortion of the bore as the head is tightened. On a more conventional monoblock engine, the bore is supported from the bottom so there will be distortion. This may limit the clamp load and still allow some movement.
jgKRI, You missed the point. The one fellow explained the problems with open deck, and that does show the logic and the counter intuitive of thinking the open deck is a great idea.
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)
Given your stubborn belief that no OEM could overcome a pretty simple design problem despite modern production having done exactly that, I'm guessing you are not an engineer much less knowledgable about modern engine design.
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.
Every time I see someone complain about open deck it's always a specific Subaru engine they're referring to. Y'ever think that generation of engine may have had an improperly specified head gasket? Also, Subaru's higher performance engines also break ring lands and spin rod bearings as well as burning through head gaskets. All of these things can be detonation related and are not specifically an open deck problem.
So sorry to go a bit off topic, but necessary to show how someone forgot what the old guys (engineers) figured out years ago. I guess it was not in the computer simulation program they used for this design. Its just a sample of engineering disasters, wasn't there a tv show named that? I'm stopping here I'm done with this thread.
Too much reality for you in this thread?
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.
A few odd screw-ups (or more likely cost reductions) of economy car engines somehow prove there are few "real" engineers left? Get real, the old-timers did a good job with limited tools but they didn't get into half the design considerations we do today, hence why the number of patents and papers relevant to engine design is ever increasing. My family's been involved with factory motorsports on/off for ~70 years and I've worked on restorations as both tradesman and engineer for several hall of fames/museums, I know history better than most but reality is that today's engines are vastly better in every way than even those developed not long ago in the 90s. LS vs last/best 350 Chevy, the LS has roughly double the power capability before catastrophic failure, is ~50 lbs lighter, is more reliable, and will last almost twice the mileage. Today's Ecoboost is a 500-odd hp V6 from the factory with a full warranty and an open deck, not because CAD simplifies design (it doesn't) but because really bright engineers are continually finding new ways to improve both the tools and designs.
Alfa Romeo engines have been tooling around for over 55 years with open deck all-alloy engines. The same design grew from 1300cc to 2liters and makes over 100hp/liter in competition. Wet drop-in liners and std head gaskets seem to be entirely sufficient and historically reliable. The same engine turbocharged (1.8liters) easily puts out over 320hp in daily driver guise. In this form, the only change is a 2-piece steel O-ring head gasket. I believe this should be enough to clear any doubt about open deck reliability/potential!
