b20/vtec reliability, part 436.
07-30-2002, 02:15 PM
#1
Honda-Tech Member
Thread Starter
b20/vtec reliability, part 436.
Ok. For those of you who dont know im debating between a b20/vtec and a b16. (both FULLY built and turboed 
)
anyway. Correct me if im wrong on this, but the only major problem with the b20 seeing 8000 rpm's reliably is the CRANK. its just not made for it, correct? so what about swapping it out with a b18c crank? the GSR crank is already balanced for reliable use up to 8000 and it will only sacrifice 150cc's of displacment.
any input is welcome.
[Modified by KAMiN, 3:33 PM 7/30/2002]
)anyway. Correct me if im wrong on this, but the only major problem with the b20 seeing 8000 rpm's reliably is the CRANK. its just not made for it, correct? so what about swapping it out with a b18c crank? the GSR crank is already balanced for reliable use up to 8000 and it will only sacrifice 150cc's of displacment.
any input is welcome.
[Modified by KAMiN, 3:33 PM 7/30/2002]
07-30-2002, 02:31 PM
#2
Member
Join Date: Nov 2000
Location: www.boomslang.us
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (KAMiN)
If you swap a b18c crank into a b20 block, it wouldn't make any sense. Just build a b18c if you are going to do that.
b18b and b20 cranks are the same.
The thing going for the b20/b18b crank is the longer stroke. Have the whole assembly balanced before the rebuild.
I wouldn't touch a b16 with a 15 foot pole if I had the choice to build a crvtec.
b18b and b20 cranks are the same.
The thing going for the b20/b18b crank is the longer stroke. Have the whole assembly balanced before the rebuild.
I wouldn't touch a b16 with a 15 foot pole if I had the choice to build a crvtec.
07-30-2002, 03:17 PM
#3
Honda-Tech Member
Join Date: Dec 2001
Location: connecticut
Posts: 2,202
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Inlinefour)
I wouldn't touch a b16 with a 15 foot pole if I had the choice to build a crvtec.
you can balance the thing out and slap a gridle on it (assuming it's built) no problem to 9k rpm......although the gsr crank in the b20 is still "better" (ie more displacement) and a lot cheaper than buying a gsr block and sleeving it. oh btw i have a 95 gsr crank for sale make an offer 
07-30-2002, 03:26 PM
#4
Honda-Tech Member
Join Date: Apr 2002
Location: Atlanta
Posts: 1,020
Likes: 0
Received 0 Likes
on
0 Posts
07-30-2002, 07:00 PM
#6
Honda-Tech Member
Re: b20/vtec reliability, part 436. (KAMiN)
The crank is not the problem. There are three problems. One is rod ratio. With its shorter stroke, the GSR can accommodate a longer rod for a better rod ratio (1.57:1 vs 1.54:1). This may not be much. But everything counts. The second problem is the strength of the internals. GSR internals are more stout and, therefore, more rev-worthy. I should note that these two factors can be dealt with by using aftermarket parts. If you add a main bearing girdle, aftermarket rods, and aftermarket pistons, you make the engine quite a bit more stout. Also, the lighter pistons and rods will help reduce the stresses associated with the poorer rod ratio. You could actually improve the rod ratio with little loss of displacement by just using the GSR crank. But the GSR crank is actually no stronger. The final problem with using the B20 at high RPMs is oiling. There are really two problems here. One is lack of oil pump capacity. The other is the lack of piston squireters. But as with the other problems, they can be dealt with. It IS possible to build a reliable CR-VTEC. It just takes some work.
07-30-2002, 07:10 PM
#7
Member
Join Date: Nov 2000
Location: www.boomslang.us
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (StorminMatt)
[QUOTE]There are really two problems here. One is lack of oil pump capacity. [QUOTE]
B20/ITR/GSR oil pumps are the SAME.
B20/ITR/GSR oil pumps are the SAME.
Trending Topics
07-30-2002, 08:24 PM
#8
Honda-Tech Member
Join Date: Nov 2001
Location: georgia
Posts: 2,484
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Inlinefour)
ive heared that the long stroke= high piston speeds which causes ring flutter and also creats lots of vibrational stresses throughout the entire motor
07-30-2002, 09:11 PM
#9
Honda-Tech Member
Join Date: Jan 2002
Location: Sydney, Australia
Posts: 2,267
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (johnzm)
ive heared that the long stroke= high piston speeds which causes ring flutter and also creats lots of vibrational stresses throughout the entire motor
it is all relative.
its all about trade-offs...
torque VS revs!
that is all.
t..
07-30-2002, 09:27 PM
#10
Join Date: Mar 2002
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (tinkerbell)
IF the B20b/z crank is fully counterweighted and balanced with its rods/pistons/pins/rings/rod bolts, you shouldn't have any vibration problems.
Using the B18C crank with the 87.2mm stroke you only lose 40cc to the 89mm crank. ~4hp on an 100hp/liter engine.
Is the B20B/Z crank fully counterweighted from the factory?
[Modified by Rembrant Q. Einstein, 1:28 AM 7/31/2002]
Using the B18C crank with the 87.2mm stroke you only lose 40cc to the 89mm crank. ~4hp on an 100hp/liter engine.
Is the B20B/Z crank fully counterweighted from the factory?
[Modified by Rembrant Q. Einstein, 1:28 AM 7/31/2002]
07-30-2002, 11:04 PM
#11
Honda-Tech Member
Join Date: Jan 2002
Location: Sydney, Australia
Posts: 2,267
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Rembrant Q. Einstein)
Is the B20B/Z crank fully counterweighted from the factory?
(it would be too expensive to balance a completed rotational assembly at factory i would think though...anyone)
it is now a question of tolerances - is it balanced to 0.01% of a gram or what?
(good question for all Honda engines eh?)
t..
07-30-2002, 11:09 PM
#12
Join Date: Mar 2002
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (tinkerbell)
I mean as in: opposite of one rod journal there are two weights. I know they drill holes in them, and they are balanced pretty close just becuse of the quality of the forging (but there is room for improvement).
I can't find any good pictures to explain it better.
I can't find any good pictures to explain it better.
07-30-2002, 11:12 PM
#13
Honda-Tech Member
Thread Starter
Re: b20/vtec reliability, part 436. (KAMiN)
Thanks everybody.
ok so.
1) this block will be FULLY built from crank to valves. top to bottom. sleeved, pistons, rods, etc etc.
2) block girdle. the z10 was reccomended to me. ill probably use that one.
i came across that during my research. sound about right?
ok so.
1) this block will be FULLY built from crank to valves. top to bottom. sleeved, pistons, rods, etc etc.
2) block girdle. the z10 was reccomended to me. ill probably use that one.
As far as reliability of the B20 VTEC, it all depends on the quality of the parts you use, the measures taken in the buildup, and the competence of the builder. If you just slap a VTEC head on a B20 bottom end, don't be surprised if the engine does not last. In order to have a reliable B20 VTEC, there are a few things that need to be done:
1. Upgrade pistons and rods. Stronger and lighter units are needed to withstand higher RPMs. Also, the pistons need larger valve cutouts to accommodate 33mm VTEC intake valves (non-VTEC intake valves are 31mm).
2. Add oil squirters. These are present on VTEC engines but not non-VTEC engines. They help cool pistons and improve cylinder lubrication. These are important when it comes to improving engine longevity at high revs.
3. Upgrade to a GSR oil pump. Because you now have oil squirters, the VTEC mechanism, and better cam oiling, you need to be able to feed it. Upgrade your pump, as non-VTEC pumps are not up to the job.
As for rod ratio, consider that the B18C5 that you think is so great really does not have a great rod ratio. Like the GSR, it is only 1.58:1. A stock LS or B20 bottom end has a rod ratio that is 1.54:1. This can be improved to 1.58:1 by using a B18C crank. This destrokes the engine by about 50cc. But you will still have over 1900cc displacement - quite a bit more than a B18C5. A B17A crank will give you a 1.74:1 rod ratio. This would be very reliable and GREAT for turbo use. But it will lower displacement to only 1.8 liters. A B16A crank will give you an even better 1.85:1 rod ratio but will lower displacement to 1.7 liters. For allmotor use, I would stick with either the stock B20 crank or go with a B18C crank. If the engine is built competently with good quality internals and the required upgrades, there is no reason why it shouldn't be reliable. B16 and B17 cranks destroke the engine to the point that alot of the advantages of going B20 are negated. I would use oneof these combinations for forced induction only. Not that they couldn;t be used allmotor. There would just be little point.
1. Upgrade pistons and rods. Stronger and lighter units are needed to withstand higher RPMs. Also, the pistons need larger valve cutouts to accommodate 33mm VTEC intake valves (non-VTEC intake valves are 31mm).
2. Add oil squirters. These are present on VTEC engines but not non-VTEC engines. They help cool pistons and improve cylinder lubrication. These are important when it comes to improving engine longevity at high revs.
3. Upgrade to a GSR oil pump. Because you now have oil squirters, the VTEC mechanism, and better cam oiling, you need to be able to feed it. Upgrade your pump, as non-VTEC pumps are not up to the job.
As for rod ratio, consider that the B18C5 that you think is so great really does not have a great rod ratio. Like the GSR, it is only 1.58:1. A stock LS or B20 bottom end has a rod ratio that is 1.54:1. This can be improved to 1.58:1 by using a B18C crank. This destrokes the engine by about 50cc. But you will still have over 1900cc displacement - quite a bit more than a B18C5. A B17A crank will give you a 1.74:1 rod ratio. This would be very reliable and GREAT for turbo use. But it will lower displacement to only 1.8 liters. A B16A crank will give you an even better 1.85:1 rod ratio but will lower displacement to 1.7 liters. For allmotor use, I would stick with either the stock B20 crank or go with a B18C crank. If the engine is built competently with good quality internals and the required upgrades, there is no reason why it shouldn't be reliable. B16 and B17 cranks destroke the engine to the point that alot of the advantages of going B20 are negated. I would use oneof these combinations for forced induction only. Not that they couldn;t be used allmotor. There would just be little point.
07-30-2002, 11:38 PM
#14
Join Date: Mar 2002
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (KAMiN)
That's a really good peice of info. Save it somewhere that way next time has a B20 reliability question, you can just post that. Will you be building it for boost/nitrous or just natural aspirated?
07-30-2002, 11:43 PM
#15
Honda-Tech Member
Thread Starter
Re: b20/vtec reliability, part 436. (Rembrant Q. Einstein)
That's a really good peice of info. Save it somewhere that way next time has a B20 reliability question, you can just post that. Will you be building it for boost/nitrous or just natural aspirated?
and its saved on my hard drive. i have no idea where i found it. its just in this txt doc that says b20vtec.
[Modified by KAMiN, 12:44 AM 7/31/2002]
07-31-2002, 12:04 AM
#17
Honda-Tech Member
Thread Starter
Re: b20/vtec reliability, part 436. (Rembrant Q. Einstein)
Fast.
hehe
bla bla JE 9:1 pistons, bla bla crower rods, golden eagle resleeve, portflow head work,
the only things i havent decided on are WHAT MOTOR and what cam setup
hehe
bla bla JE 9:1 pistons, bla bla crower rods, golden eagle resleeve, portflow head work,
the only things i havent decided on are WHAT MOTOR and what cam setup
07-31-2002, 12:30 AM
#18
Join Date: Mar 2002
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (KAMiN)
I would have said "in about a month."
I like Ross pistons better. They usually come up lighter than comparable spec JE or Wiseco pistons, and use their own special alloys that shed heat better and resist burning.
Crower rods
Portflow
It just depends where you want to start. A B18C from a GSR already has the VTEC head and lubrication system, good gearing, and fully counterweighted crank, etc. A B20 longblock ($800), GSR or B16 drivetrain ($1000), VTEC head ($500-700), Hondata (not sure), VTEC ecu ($300), axles (not sure).
I am not sure which would have a lower base investment. Since you are re-sleeving it doesn't really matter what block to use as long as it isn't the B16 (displacement and deck height).
Cams depend on how big of a turbo you want to run. Stock VTEC cams are good enough, you might want to dial out a little of the overlap. I haven't heard anything bad about Crower or Skunk turbo-oriented cams.
I like Ross pistons better. They usually come up lighter than comparable spec JE or Wiseco pistons, and use their own special alloys that shed heat better and resist burning.
Crower rods
Portflow
It just depends where you want to start. A B18C from a GSR already has the VTEC head and lubrication system, good gearing, and fully counterweighted crank, etc. A B20 longblock ($800), GSR or B16 drivetrain ($1000), VTEC head ($500-700), Hondata (not sure), VTEC ecu ($300), axles (not sure).
I am not sure which would have a lower base investment. Since you are re-sleeving it doesn't really matter what block to use as long as it isn't the B16 (displacement and deck height).
Cams depend on how big of a turbo you want to run. Stock VTEC cams are good enough, you might want to dial out a little of the overlap. I haven't heard anything bad about Crower or Skunk turbo-oriented cams.
07-31-2002, 12:49 AM
#19
Honda-Tech Member
Join Date: Jan 2002
Location: Sydney, Australia
Posts: 2,267
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Rembrant Q. Einstein)
um, anyone actually done the oil squirters?
what size thread are tehy? (seems really fine)
will the oil gallery that feeds them in hte B16 block be in the B20 block?
hasnt it been said that the GSR oil pump is the same as the B20 pump?
t..
what size thread are tehy? (seems really fine)
will the oil gallery that feeds them in hte B16 block be in the B20 block?
hasnt it been said that the GSR oil pump is the same as the B20 pump?
t..
07-31-2002, 01:35 AM
#20
Join Date: Mar 2002
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (tinkerbell)
Not sure. You might have to tap holes, but there should be an oil gallery. I am pretty sure that the pumps from VTEC engines are different, having to supply higher oil pressure to engage the VTEC. Different part numbers, the ITR is a P72, don't know the B20's.
07-31-2002, 02:02 AM
#21
Honda-Tech Member
Join Date: Jan 2002
Location: Sydney, Australia
Posts: 2,267
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Rembrant Q. Einstein)
yep, there arent any pre-taped holes for oil squirters on B20 blocks...
be interesting to confirm the B20 oil pump part number...
ill call my dealer tomorrow...
t..
be interesting to confirm the B20 oil pump part number...
ill call my dealer tomorrow...
t..
07-31-2002, 05:10 AM
#23
Member
Join Date: Nov 2000
Location: www.boomslang.us
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (Ruby Civic)
Oil squirters are there to cool stock cast pistons. Aftermarket forged pistons can take heat much, much beter.
Use a stock gsr girdle. It costs $60 instead of $300 for the Z10. You will have to machine your main caps to get it to fit. The gsr girdle also has 2 extra dowel pins in it, which helps against shifting. If you want a stock girdle, you'd better order it a month or two before you need it. I've been waiting for mine for about a month, and it's on critical backorder.
Use a stock gsr girdle. It costs $60 instead of $300 for the Z10. You will have to machine your main caps to get it to fit. The gsr girdle also has 2 extra dowel pins in it, which helps against shifting. If you want a stock girdle, you'd better order it a month or two before you need it. I've been waiting for mine for about a month, and it's on critical backorder.
07-31-2002, 11:13 AM
#24
Honda-Tech Member
Thread Starter
Re: b20/vtec reliability, part 436. (Ruby Civic)
gsr girdle. got it
can a machine shop balance it? or an engine shop?
balance the bottom end , complete with crank pulley, clutch, pistons, rods, etc. - it will be worth it
07-31-2002, 11:31 AM
#25
Member
Join Date: Nov 2000
Location: www.boomslang.us
Posts: 1,829
Likes: 0
Received 0 Likes
on
0 Posts
Re: b20/vtec reliability, part 436. (KAMiN)
can a machine shop balance it? or an engine shop?
Aftermarket pistons and rods are balanced well from the factory.