INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

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.

RE: Open Deck

Quote (enginesrus)

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.
< expand

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Open Deck

Not sure what is supposed to be special about 60 hp, but if a design functions well and is cheap then it meets two critical criteria for most product designs.

RE: Open Deck

An open-deck block is sure a whole lot easier to cast.

For most production automotive engines, "low budget" is really high up on the design priority list.

RE: Open Deck

Subaru may not have had the best success keeping headgaskets in several of their open deck engines, but some other manufacturers have given it a pretty successful go .


Mercedes 5.5 L V12

http://i.ebayimg.com/images/g/mAQAAOSwEjFXfnmO/s-l...

========
Does this qualify ?
http://speedhunters-wp-production.s3.amazonaws.com...

=============
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

(OP)
60HP I was thinking of a 55 HP Geo metro 3 cylinder engine. And how less HP is going to exert much less major thrust pressure on a cylinder wall, and cause less cylinder movement or in my terms cylinder flapping. That movement will tend to cause highs and lows in fire ring contact area. I see the design as for lack of better terms, BAD. And more like having a canary in the design and budget office, screaming "cheap, cheap, cheap". Its just not the case when engineering for cheap comes back and bites you. Cheap and saving money now doesn't always work in the manufacturing world, just think recalls.

RE: Open Deck

There's also an argument to be made for increased cooling capacity of an open deck engine.

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

The benefits of an open deck block are not only related to manufacturing cost.

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

(OP)
It is also to blame for head gasket failures. As long as the design is used for normal easy driving then maybe there are those listed advantages.

RE: Open Deck

There are literally millions of open deck engines operating as we type, and not all of them are being babied around parking lots.

A lot of high specific power engines- motorcycles, small displacement engines from companies like Honda, etc use open deck blocks.

RE: Open Deck

What about an open deck block causes head gasket failures?

RE: Open Deck

Quote (TugBoatEng)

What about an open deck block causes head gasket failures?

Nothing that can't also happen on a closed deck block if they aren't correctly engineered/manufactured/assembled.

RE: Open Deck

I hear about the top of the cylinder oscillating but I find that hard to believe considering many engines have replaceable cylinder liners that are a clearance fit in the block meaning they can actually move around and they still don't cause head gasket failures.

RE: Open Deck

Open deck liners are typically replaceable, but have to be pressed out. They are held in place by slight interference fits, thin-film adhesives (like retaining compound), mechanical trapping between the block vault and cylinder head, or some combination of all three.

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

I was referring to diesel engines with wet liners and one specific engine with clearance fit dry liners. All of them can move a bit yet head gasket problems are rare.

RE: Open Deck


The Jaguar V12 is a notable open deck engine.

RE: Open Deck

A couple of Toyota engines have been notorious for head gasket issues. Sometimes coolant to outside world. Sometimes combustion to the coolant jacket.
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.
===============
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

Engineering is a logical endeavor- but logic and intuition are not the same thing. Many core principles of engineering are logical, but counter-intuitive.

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

Quote (TugboatEng)

I was referring to diesel engines with wet liners and one specific engine with clearance fit dry liners. All of them can move a bit yet head gasket problems are rare.

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

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.

RE: Open Deck

I have some experience with the 3500- it's almost a hybrid of the two alternatives being discussed in this thread (wet sleeves but a closed deck).

RE: Open Deck

(OP)
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)

RE: Open Deck

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.

RE: Open Deck

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.

RE: Open Deck

(OP)
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.
https://www.youtube.com/watch?v=fs7WI2s-CVw

RE: Open Deck

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.

RE: Open Deck

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.

RE: Open Deck

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!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close