Snoopy

i've been doing research on lsvtec and b20vtec's and i've come across guys that put in a block girdle to help them rev higher. what is this girdle and what does it do?

qtiger

Just holds everything together, really.

inspyral

VTEC B series engines have a girdle on the bottom of the block to help brace the block so that the crank can rotate up to those higher RPM. When you build a xx/VTEC, you need to add one since the non-VTEC blocks don't come with one, and would not be stable if you ran them up to that high an RPM without a girdle. Stock VTEC B series block girdles don't fit non-VTEC blocks. Z10 makes block girdles for non-VTEC B18 and B20 blocks, but you can't just slap em on and expect them to work properly. They need to be installed with dowell pins to keep them in position.

Here is a detailed install complete with pictures:
http://honda-tech.com/zerothread?id=263598

Snoopy

thanks :thumbup:

MrFatbooty

Only the B18C block has a girdle. What it does is connect all of the main bearing caps together. The B16 and B17 blocks make do without it because they have a short enough stroke to not cause too much stress. The B18C however, is intended to rev just as high as the B16 and B17 and thus needs the reinforcement.

If you need an explanation of what the main caps are, etc I can probably copy something out of my Helms manual for you.

VtecApprentice

Sorry I'm confused so does all B series got the girdle or only the B18C has it ? ? ? ? If only the B18C have it . . if i want one on my B16A . . can i get one from Z10 or is there any other brands that produce them ? ? ? OEM Honda ? ? ?

ThankzZ

Snoopy

only the B18C has it. from what i understand the B16A has an almost perfect rod stroke ratio so it doesnt need a girdle.

MrFatbooty

All this talk of rod/stroke ratio is getting a tad annoying. It's not that simple. Basically you want to have straight up-and-down forces acting against the crankshaft (and thus the main bearings and bearing caps). The longer the rod in comparison to the stroke, the more the force of the rod moving is directed away from plain up-and-down. To get the B18C block to be reliable enough to rev to 8000 RPM and still meet OEM standards Honda installed a girdle which connects the main bearing caps together. Think of it as a strut bar for the main caps. With the caps tied together the force can be distributed over more mass, which lessens the effect of said force. It's an alternative to stepping up to stronger rod bolts and forged rods, which while semi-affordable to you the aftermarket engine builder, would present a good bit more expense to the OEM.

Now, if you're building up a B16 there's not much point in installing a girdle. All the stock B-series cranks are very beefy forged pieces. The rods are where you'll see a problem and since the B16 has such a short stroke there's a much more uniform up-down force exerted on the crank and rods. You really only need to replace the rod bolts with ARP pieces and install new bearings, plus make sure that the crank and rods are all within spec and you'll be fine out to 9000 RPM. No cams make power that high anyway, so the bottom end should be fine.

With an LS/VTEC you can either install a girdle with the stock rods, or step up to forged rods and ARP bolts. Either way the motor will take plenty of revs. The stock LS rods are no stronger than the GSR rods, yet there's no girdle and the stroke is longer. Needless to say they see more stress forces at the same RPM as compared to the GSR rods which is why you need to do some kind of upgrade.