Am I right in thinking that the only difference between any two B series blocks is the crank rod and piston? They all have 81mm bores (which is what makes it a b series). If thats the only difference than why wouldnt a B16 bored out to a 1.8 be the best drag engine?? You would maintain the 1.74 rod ratio instead of going to a 1.59 and you would move the walls away from the valves so you get a better tulip in the cylinder. Can someone please explain this to me?

 

ew! ew! me! me! [raises hand]

I have the numbers for you...
B16:
Stroke= 77mm
Bore= 81mm
Displacement= 1587.13cc

B18c:
Stroke= 87.2mm
Bore= 81mm
Displacement= 1797.32cc

B16 bored out:
Stroke= 77mm
Bore= 84mm
Displacement= 1706.87cc

B18c Bored out:
Stroke= 87.2mm
Bore= 84mm
Displacement= 1932.97cc

B16 stroked to 87.2mm and with 84mm bore (123.8mm Rod)
Stroke= 87.2mm
Bore= 84mm
Displacement= 1932.97cc
R/S Ratio= 1.42

Deck Heights:
B16= 203.39mm
B17a= 208.28mm
B18a/b & B20b/z= 211.84mm
B18c= 212.39mm

What is important to remember is that ONLY BORE AND STROKE determine Displacement. STROKE and ROD LENGTH Determine R/S ratio. DECK HEIGHT has nothing to do with Displacement but does help determine ROD LENGTH and COMPRESSION.

Hope this helps...
Charles

 

and as I read your post a second time Alan....You ask about B series STROKES but then go on to talk about BORE. Big Difference but I am sure you realize this...

If you just slapped a GS-R crank in a B16 you would match the Displacement of a GS-R but you would need a shorter rod (about 10.2mm shorter) and this would give you a R/S ratio of 1.42.

Can you tell Ive been doing my Homework?

Charles

 

Charles you are the king of nothing!!! I dont even want to know where you came up with some of the numbers I could only scrounge up half of those. Oh and about the title and then talking about bores I was originally going to just ask if you could switch the crank from a B18 into a B16 block and have a 1.8
Id like to add another element When dealing with a race motor and really high revs Wouldnt the B16 be better because the stroke is shorter which means the piston speed at 8500+ rpm is going to be much slower (and thus not want to self destruct). So is it worth giving up the extra 200cc in order to gain another 500rpm especially in FI??
What would you say is the best setup geared for each FI and All motor in the 1/4? For some reason I seem to think that a B16 bored out would work REALLY well with a low cr like 8.2:1 in the 1/4. But on the other hand for all motor youve got guys pushing 2400cc from a B18 and going fast. Real fast.

 

In the game of Speed...Torque is KING. To get torque in a Honda you need displacement. What John said about Theres no replacement for Displacement is absolutely true. Since I am no longer building my Big B motor (Cost$$) Ill tell you the design.

B18c1 Block
Crank: B20A (YES A...not B or Z)=95mm
Pistons: 86mm 11.5:1 C/R
Rods: Custom 166.20mm
Displacement= 2207.35cc
This setup would require a Special Deck plate to extend the hieght of the block. Golden Eagle can install the Sleeves to be Taller than the block for an additional $150. (releeving by them is about $750 with Godzilla sleeves). They can make a deck plate...but wont install it. We had come up with a Deck Plate design that might actually work well but its under development right now. You also need a longer timing belt (Already Located one! ) as well as longer head bolt studs (Modified ARPs). All in all you end up with a 1.75:1 R/S and a 12.1:1 C/R. Perfect for all motor. If you wanted to go FI then you would change the Piston from a Dome to a Dish...lower compression .

You must remember that its takes power to make power so reducing the friction in the bottom end is also a good idea. I would suggest Knife-edging the crank micropolishing the journals Moly coating the piston sides while ceramic coating the piston top and going to a light weight flywheel. This is just the bottom end. The head would need extensive work as well just to keep up with the additional flow. Another thing to remember is that if you increase the squish area of the head...you decrease your C/R (just something to keep in mind).

Now if you paid attention you will see that I said 86mm pistons. That WAS NOT a typo. Golden Eagle actually bores out the old sleeves past the actual casting. What does this mean to you? It means you could technically run a slightly larger bore. I wouldnt do this with short rods though as the Side Wall pressures may be to great but with a 1.75:1 or even better yet 2:1 R/S I dont expect there to be a problem.

As far as Piston Speed figured @ 9k RPM:
B16 maxes out at: 5070 M/M
B18C1 maxes out at: 5926 M/M
LS/B20 maxes out at: 6111 M/M
The motor listed above maxes at: 6245 M/M

With all that it is time for me to goto work.

Charles

 

Damn...finally some real Honda Tech.

 

Correction on some of the specs:
b16a stroke 77.4mm (1595 disp)
b16a and b17as have the SAME deck height. The block casting is identicle.
The deck height distance between b16a and b18c is about 7mm. Meaning an 87.2 mm crank will fit in a b16a block with the b18c rods if the ring package was moved up 7mm or so. This would keep the 1.58 rod ratio this is how the toda b16a stroker kit is set up also.

For an all motor street engine I wouldnt worry about changing the rod ratios too much as long as you dont overbore the cylinder too much. The low 1.52 rod ratios of ls/crv/vtecs gives it a nice low-end (for a Honda anyways) and broader powerband.

For an N/A race motor definitely the 86mm deck plated 1.75r/s 95+mm stroke motor. $$$$$. Ricerocket did you price out that motor setup? Im curious as to what kind of numbers you were looking at.


Just to think about:
The 1989 b20a5 motor ran a 95mm stroke 81 mm bore and 142.75mm rod. Now this motor has the largest stroke and rod length of any b-series motor so it would be reasonable to think it also has the largest deck height by far. Now if this motor was destroked to 89mm(ls crank) an even larger rod could be run giving a rod ratio somewhere around 1.64:1 or higher. Now if this motor was sleeved and bored to 86mm youd get a displacement of 2068ccs and a very good rod ratio for better volumetric efficiency at high rpms and decreased side loading on the cylinder walls. With an 84-85mm piston I think this could be a very good FI engine too. This is all assuming a vtec or even an ls head would bolt to the block. Any comments/ideas.

Kevin

 

I stand by my numbers. EVERYTHING I have ever read or researched CLEARLY states that a B16 is a 77mm stroke. The B16 and the B17 ARE NOT THE SAME CASTING. Go find a B17 and measure it but the DECK HEIGHT IS DIFFERENT. But lets forget the whole b17 scenario...I have seen 3 different Rod sizes and 2 different Deck heigts for an engine that was USA only and only for 1-2 model years...

The way I calculate it the deck height difference between the B16 and the B18C is actually 9mm.

Huh? Move the rings up to fit longer rods? Im lost. You would actually have to relocate the wrist pin and modify the top of the rod and even then I doubt you could get 9mms. I dont think this is what Toda does. It doesnt add up. Pistons would be popping out of the block with that set-up.

anybody else wish to chime in and give their thoughts???