Im doing some research on the ls vtec engine, and while im reading some things about it, b20 vtec keeps popping up in the same sentence. It makes it sound like they are the same engine.... well are they? perhaps this was a dumb question that i will regret later.

 

They are pretty much the same except the b20 (form a CRV usually) has a 84mm bore and the b18a/b (LS motor) has a 81mm bore.....the b20 is a 2 liter motor and the b18 1.8. The b20 has a considerably higher amount of torque.

 

Nope, they are not the same thing, but virtually the same.

B18B (Integra LS) with a VTEC head.

B20B or B20Z (CR-V) with a VTEC head.

the B20 is the newer version of the frankenstein motor and has alot more torque because of the longer stroke

 

Stroke ? As I understand it, the stroke is the same, but the bore on the B20 is larger... hence the thinner, weaker cyl. walls.

X2

 

ahh ****.

I stand corrected

i remember now how b20 walls blow

 

Wow!

 

same block, larger bore on the B20. 84mm compared to 81mm. yields more HP and torque, but definantly used for the increase in torque. the cylinder walls are different but i would not call the "weak" or prone to blowing out. they are strong and can take a beating.

later

 

It is the bore as mentioned above. 84mm for the B20 and 81mm for the B18.

The cylinder walls in the B20 are not weak. They do not have the same sleeves as the B18's. They are thicker and just as strong.

The biggest issue is oiling on these engines. What a huge pain in the ***. You will spend a hell of a lot of money to get these engines reliable.

I.E. HX_Guy had a built B20 VTEC (pushed over 210 to the wheels) and I remember him stating the total cost was around 7 grand.

 

If the sleeves are just as strong, why am I reading that many people are having issues with sleeve strength ? EG: That you MUST sleeve a b20 block for reliablility ?

BTW, wouldn't a thicker sleeve reduce water jacket volume and degrade cooling capabilities as compared to an LS block ?

X2

 

The resleeve is a hoax. Just compair and you will see.

And yup. Water jacket volume is reduced......Just means that the thermo is open more often than on the LS.

 

the sleeves are not the problem with the B18B/B20B, it's the lubrication as was mentioned before. the non-vtec blocks don't have the oil squirters that the vtec blocks do for high rpm lubrication, so they don't last as long in high rpm unless modified enough which is time consuming and can cost $$. not usually worth it in the end.

BTW i have nothing against the LSVTEC or CRVTEC, i just don't like the reliability factors for longevity involved with them.

later

 

Oil squirters aren't designed for lubrication... they're there for cooling the piston.

 

the point i was trying to make is that the B18B and B20B blocks aren't made to turn high rpm so there aren't extra steps taken from the factory to provide more cooling/less friction. whether the squirter is aimed at the piston or the cylinder wall, it's job is still to keep things operating properly during high rpm etc.
friction between the piston/rings/cylinder wall creates heat so the squiter can be used as an addition to provide extra lubrication and reduce heat that's caused by high rpm friction.

i believe the squirter is aimed underneath the piston so it can provide increased oil flow and increased cooling capacity for the piston.

later