[dracos2001]

I didn't see any posts on this so i thought i'd start a thread.. its interesting reading... Dart Machinery is producing finer grade B18 and B20 blocks. Anyway, just read on... i provided some more informational links toward the bottom. I think i just found a new project!!

• Dart B18 block has stock deck height, standard 81.5mm bore, optional 84.5mm bore.

• Dart B20+ block has extra-tall 8.900" (226mm) deck height, 84.5mm bore for increased displacement.

• Manufactured from aerospace quality C355-T6 virgin aluminum alloy for maximum strength and durability.

• Replaceable ductile iron dry sleeves are fully supported to reduce bore distortion andenhance ring seal.

• Closed deck design increases rigidity and improves head gasket
sealing.

• Steel main caps with high-strength bolts increase bottom end strength and minimize bearing bore distortion.

• Extra large water jackets increase coolant circulation around cylinders.

• Standard piston oil sprayers reduce piston temperatures to extend life and prevent detonation.

• Dart blocks use stock components, including oil pan, oil pump, water pump, alternator, and timing belt tensioner.


http://www.dartheads.com/hondab.aspx
http://www.dartheads.com/hondah.aspx
http://www.hondatuningmagazine.com/tech/0303ht_tenaciousb/
http://www.hondatuningmagazine.com/tech/0304ht_bastardb/

 

[jpnzbtl]

Yeah, I've heard about these. Seen them for a little under 2large. Out of my budget for a NA motor but if I was going turba I would considerit. From what I've seen, it costs about 2large for the machine work and parts to strengthen a stock block.

 

[ALL C5]

I have seen these as well and thought about getting one, until i found out it was closed deck. So i decided against it. I will get a new ITR short block for everyhting for around 2,300 and re-sleeve that.

But hey they are probally good blocks.

 

[FastNSX]

I have seen these as well and thought about getting one, until i found out it was closed deck.

Why would a stronger design turn you off?

 

[Rev ATARI]

Why would a stronger design turn you off?

Heat problems arise on closed deck high RPM performance engines

 

[ALL C5]

Why would a stronger design turn you off?

Yes what ATARI said. The closed deck, creates heat problems, escpecailly on honda motors, since they are an open deck design.

My project car i am going to have as a daily driver, when it is done, so having a closed will make the chances of the motor going bad sooner, then i really want to have happen. If i was going strickly trialer queen or even weekend warrior i would go closed deck, but since i am not going that route, i will use sleeves that keep my deck and allow better cooling in the motor, that way i will more then likely have a longer life out of the motor. One of the main reasons that honda motors go bad(in stock form) is due to cooling problems, and the open deck pro-longs that problem, so i say hey why not keep the open deck design.

But yes i do agree with you that closed deck sleeves are stronger!

 

[iV]

Closed deck doesn't cause overheating issues if the remainder of the block is designed around it. The Dart blocks use significantly larger water jackets than a stock (open deck) block. And just to mention it, Honda doesn't use an open deck design for enhanced cooling, these blocks are die cast and as such cannot be closed deck. This is one reason why some manufacturers have found alternative ways to move away from sand casting (not stable enough for really high tolerances); increased parts tolerance while retaining the closed deck goodness (lost foam casting is one example).

 

[Rev ATARI]

iV I do agree with you on most of that but would you like to explain the overheating problems found on engines with block guards and how the drilling of holes in the guard reduces this problem?

 

[iV]

I would try to explain that, if I knew any instances of it. #1- Overheating an engine is normally described by out of control coolant temps, which a blockguard won't cause (lack of coolant flow makes the engine hot, not the coolant). #2- Restricted coolant flow from an improperly designed blockguard would cause detonation and ensuing engine damage, not high coolant temps. And as you know, there are so many other things that cause detonation on highly modified motors that I'd be skeptical of anyone claiming detonation from inadeqaute cooling (without attendent proof).

Water flows from the block to the head through coolant passages, regardless of closed or open deck (all cylinder head surfaces are "closed"). It's these passages and their winding routes through the block and head that keep things cooled, not a 360 degree bubble around the bottom portion of the chamber. Block off a passage and you're in trouble, keep them open and flowing properly and there should be no problems until you run into the limits of the system design. There are myriad examples of closed deck blocks providing monster power output without cooling issues, in fact there are far more examples of cracked or broken cylinder sleeves from open decks not sufficiently supporting them than overheated closed decks (in my experience). So where's all this evidence I've been missing on block guards and closed decks being detrimental to engines?

 

[CRVTEC0WNZJ00]

Do the B20 and B18 DART Blocks have corrected R/S Ratio?

 

[iV]

Do the B20 and B18 DART Blocks have corrected R/S Ratio?

"• Dart B20+ block has extra-tall 8.900" (226mm) deck height"


A 226mm deck height allows for B16 r/s ratio using a B20 crank.

 

[ALL C5]

Closed deck doesn't cause overheating issues if the remainder of the block is designed around it. The Dart blocks use significantly larger water jackets than a stock (open deck) block. And just to mention it, Honda doesn't use an open deck design for enhanced cooling, these blocks are die cast and as such cannot be closed deck. This is one reason why some manufacturers have found alternative ways to move away from sand casting (not stable enough for really high tolerances); increased parts tolerance while retaining the closed deck goodness (lost foam casting is one example).

Then why do companies like golden eagle and some others make only open deck sleeves for motors? I am not starting a flame war but just curious.

 

[Rev ATARI]

I am not starting a flame war but just curious.

First of all let me say that I know iV and I know he knows his stuff so none of us are going to get into a flame war on this because I know iV will handle himself as long as the rest of you do…

I will however say that I do disagree and I think I remember reading a post where iV’s buddy “that will remain nameless” disagrees with iV as well….

I have personal experience with un-drilled block guards that caused overheating

 

[iV]

Then why do companies like golden eagle and some others make only open deck sleeves for motors?

I think we/ve got some problems with definitions. A closed deck block doesn't mean there are no oil and water passages, simply that the entire area around the cylinder bores is not open. Of course preventing coolant flow from the block to the head (particularly the area immediately around the bores) will cause engine problems, but this isn't what a closed deck is all about. There are many, many closed deck motors making tons of power with no cooling issues. Honda themselves have made many closed deck motors. So once again, there's nothing wrong with a closed deck (in fact I feel it's superior). The only point of contention here seems to be overheating because some products block off coolant packages, and I completely agree that this would be a major problem with anything other than a drag motor seeing just a few seconds of use.

Golden Eagle doesn't close the deck because they make cylinder liners, and the supports they've designed in (which partially close the deck) are adequate in providing the much needed support to the top of the bore. Leitner and Bush do close the decks completely, and they aren't the only ones. They simply drill the necessary coolant flow holes to keep water flowing and the engine cooled.


Ps- I got your PM Toda, but your mailbox is full. Delete some sent messages or something and get back to me.

 

[Rev ATARI]

That’s more of what these guys needed to know

I’m not sure but I think the last closed block Honda made was the H22, but somehow I feel that to be incorrect.

Oh and Toda please do clean out the PM box some its been full for a few days thanks for remonding my about that iV

 

[ALL C5]

Ok sorry guys, i only had like 8 messages in it, did not know it filled up that fast. So you guys can e-mail me now.

I think you are correct when you say there are some vauge thoughts about closed decks, and my bad i should have gone into more detail.

But in my opinon and my thoughts, i would rather go Golden Eagle over other companies sleeves, just because they leave more deck open.

So i guess it is all how you look at it. But i do agree with you, i just think that golden eagle has a little safer option for a daily driven car, IMHO.

It is good to have your input here, along with ATARI's input.
Thanks guys.

 

[FastNSX]

1) There is nothing about a closed-deck block that would cause cooling problems. Honda uses an open-deck design for production/casting reasons, not just engineering reasons. It saves time and money during manufacturing.

2) The Darton blocks are very nice. They also have better cooling passages and were designed from the start to be closed-deck. I can not imagine having a cooling problem with one due to the basic design.

3) Closed-deck blocks are also SIGNIFICANTLY more rigid than open-deck blocks.

4) If someone has had cooling problems with a block guard, I feel strongly that it was due to a poorly designed or poorly installed blcok guard, rather than any fundamental flaw in the closed-deck design.

Frankly, if they did not cost more, I think everyone who really new engine building would start with a Darton block. There is no real downside, except the cost.

 

[ALL C5]

1) There is nothing about a closed-deck block that would cause cooling problems. Honda uses an open-deck design for production/casting reasons, not just engineering reasons. It saves time and money during manufacturing.

2) The Darton blocks are very nice. They also have better cooling passages and were designed from the start to be closed-deck. I can not imagine having a cooling problem with one due to the basic design.

3) Closed-deck blocks are also SIGNIFICANTLY more rigid than open-deck blocks.

4) If someone has had cooling problems with a block guard, I feel strongly that it was due to a poorly designed or poorly installed blcok guard, rather than any fundamental flaw in the closed-deck design.

Frankly, if they did not cost more, I think everyone who really new engine building would start with a Darton block. There is no real downside, except the cost.

Cool, piont well taken.

 

[Rev ATARI]

Is it me or is something wrong here the stock B20 deck height is 270mm, but dart is claming there extra tall deck height is 226mm….

Sorry if I screwed up I got 2 sick kids to deal with and allergy problems so lack of sleep and my medicine is fucking with me

 

[ALL C5]

Is it me or is something wrong here the stock B20 deck height is 270mm, but dart is claming there extra tall deck height is 226mm….

Sorry if I screwed up I got 2 sick kids to deal with and allergy problems so lack of sleep and my medicine is fucking with me

I feel for you man....i hope everything goes better!