Swapping 1996 JDM b20b in to my 1991 DB1...

ASSISTANCE Hybrids & Advanced Aftermarket Engine Performance
1

I’m just wanting to go over every “must-have/must-do” before I begin the work. Looking to get this swap done in a few hours, so I don’t want to run in to any “crap, I forgot to get that” moments. The less down time I suffer on my daily driver, the better.

So far I have…

  • A 1991 Acura Integra GS Sedan 5speed w/ ABS, my mostly-stock daily driver.
  • A 1996 low-compression JDM b20b with short LS intake manifold and LS head, the most common 96-98 b20b(head recently rebuilt with fel-pro top-end gasket kit)
  • An Exedy OEM-replacement clutch kit(clutch, pressure plate, two bearings, grease packet, alignment tool).
  • Prothane motor-mount inserts(90-93 Integra).
  • Prothane shifter bushings(90-93 Integra, already installed on the linkage set below).
  • OEM GSR shift linkage bar, stabilizer bar and shifter + knob.
  • Four quarts of Royal Purple 10w30.
  • Two bottles of Pennzoil Synchromesh + fluid transfer tube.
  • Magnetic oil drain plug.
  • STP oil filter.
  • Two jugs of coolant.
  • Two bottles of power steering fluid.
  • Oil pan gasket.

To the best of my knowledge, I have to retain the following from my b18a1 gear…

  • Throttle Body
  • Fuel Injectors
  • Fuel Rail
  • Distributor
  • Engine harness
  • Any sensors that aren’t already on the b20b
  • ECU
  • Spark plug cables
  • Header + downpipe
  • Intake
  • Engine mounts
  • Crank pulley
  • Transmission/axles

I still need to buy…

  • Idler pulley kit
  • Trans seals
  • New gasket that goes between header and downpipe(stainless 4-2-1 style, I think the current gasket is fubar)

I may delete the power steering and the a/c. Undecided at this time, may just delete a/c so I don’t have to mess with those lines and possible leaks afterwards.

Does everything above seem correct so far? Is there anything I need to change, or other stuff I need to buy? Anything else I need to retain from my b18a1? Anything in the above b18a1 parts list that I shouldn’t retain? The parts I’ve been buying for the b20b are from AutoZone, purchasing for a 1997 Honda CRV and that has worked fine for me so far. The clutch kit was purchased for a 90-91 Integra.

Should I invest in main seal / main bearings / piston rings for the b20b, or should it be fine as-is? The motor turned over fine with and without the head installed, with head installed I can feel the compression, cylinder walls / pistons / valves looked fine, valve train was nice and clean…so there’s no immediate signs that any problems will occur, crossing my fingers that this car runs and drives like a champ after the swap. :rockon:

2

Looks like your looking good. I swapped a b20z into my auto ls. Went in no problem. Got the motor for free with only 100k it had sunken exhaust valves so I swapped my b18a head and intake on. Using b18 distributor and alt etc. Went straight in no problem fired right up. Love the torque even with the auto. Not sure about the b20b but on the b20z I had to swap my sensors on the back of the block to the b18a ones.

3

I don’t think I’ll have to swap sensors, unless I’m missing any on the b20b or they’re broken. It’s an obd-1 b20b, 1996(96-98), I believe yours started life as an obd-2 motor…98-01 or something like that.

4

Your 96 swap is also OBD2 as well. But that makes no difference as the sensors are the same, and the your old engine harness will plug right in. Like I said in the other thread, the only difference is that ECT switch is on the thermostat housing on the B20b vs on the back of the block on the 90-91 (92-93 is thermostat housing as well) B18A1s. Colin posted an article in the Articles/teg tips (not the one at the top) regarding the differences

5

Forgot I did swap thermostat housings but thats easy to do.

6

Would anyone happen to know the Honda part number for the idler pulley kit I need for the b20b? I got a timing belt and some other stuff this week, so all that’s left is that pulley kit and I’m ready to do this swap!

7

ttt

8

Still needing to know some info, I have the following questions…

  1. Need to know what the new vacuum line routing will be…

Example…on my integra there are two vacuum cylinders on the firewall, right next to the MAP sensor. They each have two vacuum lines. Cylinder 1 has the first line running to the fuel rail and the other to the back of the intake manifold. Cylinder 2 has the first line running to the vacuum canister and the other to the back of the intake manifold. The intake manifold obviously has two vacuum line entries on the back of it…the b20b intake manifold only has one. The b20b intake manifold has a vacuum line entry on the front, whereas the b18a1 intake manifold doesn’t but instead has that weird looking mechanism that has “UP” stamped on the top of it and has lines running to the intake pipe. This is pretty much all that has me confused at the moment, all the other hoses/plugs/lines/etc seem pretty self-explanatory.

  1. Need to know what the part number is for the idler pulley kit I’ll need for the b20b.

  2. Will I need the b18a1 throttle body, or can I keep the b20b throttle body? I’m keeping the b20b intake manifold if that matters.

  3. Should I stick with obd-0, re-using my b18a1 distributor / harness / ecu…or should I upgrade to obd-1 with a socketed p28 and just throw in a b20b basemap? I have a socketed p28, just no b series chips.

  4. In the first post I listed what I’ll be using from my b18a1 for the b20b…is that list correct? Is there anything I don’t need, or other stuff I need that’s not in the list?

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  1. Which manifold do you have? If it is the low compression b20b manifold, that is the extremely tall one that won’t fit under your hood. If it looks just like a LS one, do you have a P8R head? If you have the high compression one with the box on top, I can give you specific instructions on how to use it. If you are using a b20 intake manifold of any kind, it should have a MAP sensor on top of the throttle body. If you extend the wires from the one on the firewall to it, you will eliminate the two vacuum lines that run to the one on the firewall and that should solve your vacuum line issue.

  2. By idler pulley are you referring to the one on the timing belt? B20B/Z or B18A/B shouldn’t make any difference - they are all the same.

  3. Depends on which intake manifold you use. See answer to #1.

  4. That’s mostly up to you and how well you want it to run. If I was recommending anything, it would be to go OBD1 and actually tune it on a dyno (I don’t see a lot of advantage in switching if you aren’t going to tune).

  5. See next post.

10

It’s a low-compression 1996 jdm b20b, with the short LS intake manifold and LS head…the most common early model b20b. I plan on retaining that intake manifold, and that throttle body…unless switching to the LS stuff has any benefits. I’m putting my LS injectors and fuel rail on this b20b, as well as the distributor / alternator / power steering pump / ac compressor.

By idler pulley, I mean the one for the timing belt. I’m told it’s a good idea to replace those on imported motors.

I’ll just stick with obd-0, my harness / ecu / distributor / etc. I won’t ever dyno this thing which would defeat the purpose of going obd-1 with this p28.

Pretty much all the b20 swap threads I’ve found on here or HT, are for the late model b20 in to a late model 2nd gen. Too many differences for me to use those guides for what I’m trying to do.

11

I commented in red on anything I saw.

[QUOTE=DOHCIntegraLS;2095478]I’m just wanting to go over every “must-have/must-do” before I begin the work. Looking to get this swap done in a few hours, so I don’t want to run in to any “crap, I forgot to get that” moments. The less down time I suffer on my daily driver, the better.

So far I have…

  • A 1991 Acura Integra GS Sedan 5speed, my mostly-stock daily driver.
  • A 1996 low-compression JDM b20b with short intake manifold(head recently rebuilt with fel-pro top-end gasket kit + that new Fel-Pro MLS head gasket) - how many miles are on the engine that it was needing the headgasket redone? probably should have stuck with an OEM headgasket.
  • An Exedy OEM-replacement clutch kit(clutch, pressure plate, two bearings, grease packet, alignment tool).
  • Prothane motor-mount inserts(90-93 Integra).
  • Prothane shifter bushings(90-93 Integra, already installed on the linkage set below).
  • OEM GSR shift linkage bar, stabilizer bar and shifter + knob.
  • Four quarts of Royal Purple 10w30. - 5w30 is what I would recommend.
  • Two bottles of Pennzoil Synchromesh + fluid transfer tube.
  • Magnetic oil drain plug.
  • STP oil filter.
  • Two jugs of coolant.
  • Two bottles of power steering fluid.
  • Oil pan gasket.

To the best of my knowledge, I have to retain the following from my b18a1 gear…

  • Throttle Body - only if using the B18A intake manifold
  • Fuel Injectors - only if using the B18A intake manifold and staying OBD0 - if you convert to OBD1, you can spice in the OBDII injectors - on my B20Z manifold, the OBD1 B18A fuel rail and injectors wouldn’t fit
  • Fuel Rail - see above
  • Distributor
  • Engine harness
  • Any sensors that aren’t already on the b20b - all the sensors you need should be on the B20B - you will not use the crank sensor that is on the B20B and will have a green plug left over in the back that is for an oil sensor that is not on the B20 - Injectors and MAP sensor if using a B20 intake manifold are the only wiring other than extending the wire for the temp sensor
  • ECU
  • Spark plug cables
  • Header + downpipe
  • Intake
  • Engine mounts
  • Crank pulley
  • Transmission/axles

I still need to buy…

  • Idler pulley kit
  • Trans seals
  • New gasket that goes between header and downpipe(stainless 4-2-1 style, I think the current gasket is fubar)

I may delete the power steering and the a/c. Undecided at this time, may just delete a/c so I don’t have to mess with those lines and possible leaks afterwards.

Does everything above seem correct so far? Is there anything I need to change, or other stuff I need to buy? Anything else I need to retain from my b18a1? Anything in the above b18a1 parts list that I shouldn’t retain? The parts I’ve been buying for the b20b are from AutoZone, purchasing for a 1997 Honda CRV and that has worked fine for me so far. The clutch kit was purchased for a 90-91 Integra.

Should I invest in main seal / main bearings / piston rings for the b20b, or should it be fine as-is? The motor turned over fine with and without the head installed, with head installed I can feel the compression, cylinder walls / pistons / valves looked fine, valve train was nice and clean…so there’s no immediate signs that any problems will occur, crossing my fingers that this car runs and drives like a champ after the swap. What kind of mileage are on the engine? If it’s a good engine, you shouldn’t need to rebuild it. Normally people swap B20’s so that they can get a low mileage engine that they don’t have to rebuild.:rockon:[/QUOTE]

12

  1. It was an imported motor, and I thought “well…better safe than sorry” and decided to buy the fel-pro top-end gasket set. No idea on miles, got it from TigerJapanese…another reason why I wanted to get in this motor, with those dicks you never know what you’re going to get. I had actually ordered the high-comp b20b and they sent me this one, after several months of fighting and filing reports with different bureaus, I gave up and kept this one.

  2. Is it important enough to take this jug of 10w30 back? I’ve used nothing but 10w30, so I just went with it again.

3, 4 and 5. I’m keeping the b20b intake manifold AND staying obd-0. Which throttle body, injectors and fuel rail do I use for this particular setup? I heard that the b18a1 intake manifold will cause power loss due to not being port-matched to the b20b head.

  1. I know I need to extend the MAP wiring, still not sure what all this temp wiring is about, not sure what I have to do about the injector wiring. I also didn’t know there’s a crank sensor on the b20b I won’t be using, and that there’s a lack of an oil sensor on the b20b…how will my ECU be able to throw an oil light without that? And will that cause a CEL?

  2. No idea on mileage.

13

http://ef-honda.com/ben/EFB20swap.php
Same principles

14

Got my motor pulled. Removed the injectors, fuel rail, harness, distributor, alternator, power steering pump and a/c compressor. It all transferred over to the b20b without a hitch. I didn’t even need to do anything special for the injectors/fuel rail like what was in Ben Ogle’s walk-through. Thinking about switching the upper radiator hose housing since the b18a1 one has a bleed screw and the b20b one does not.

On the b20b throttle body there is a spot for the red hose from the vacuum can, so I won’t be deleting the can or the purge solenoids. I just don’t like deleting stuff that may be somewhat important to the function and reliability of my daily driver.

I noticed that on my b18a1 there’s 3 sensors to the left of the oil filter. A 2-pin sensor, a 1-pin sensor and a plug sensor. On the b20b I only see the 1-pin sensor, so now I have two spare connectors just hanging back there. What are those three sensors, and why is the b20b missing two of them? If I’m correct, isn’t one the ECT switch which will be on the theromstat housing of the b20b meaning I have to extend the plug?

15

One of them should be the ECT and the other should be a green connector that you don’t use.

16

The other switch that isn’t there is the Oil Temp Switch.
Engine Coolant & Oil Temp & Pressure Swiches, Sensors, & Sending Units Explained

17

Going by that thread, specifically the picture…

ECT = 2pin sensor
Oil Temp = green plug sensor
Oil Pressure = 1pin sensor

Those are all present on the b18a1. On the b20b, only the oil pressure switch is present.

The ECT switch is apparently relocated to the thermo-housing on the b20b, but that brings up a new issue. In that thread it says and shows the ECT having a 2pin connection, and the engine harness has the two single-pin female connectors wrapped in a big rubber boot. That adds up fine, except the sensor on the b20b thermo housing looks more like the Oil Temp switch…it’s a plug-style connector. There are no 2pin sensors that look like that ECT anywhere on my b20b. What’s the deal?

18

Yes the connector is different…

19

See post below.

20

It finally warmed up a little so I was able to get back out to my shop and get some work done. Snapped a few pics of the thermo housing, ECT switch, ECT switch plug, the connectors for ECT and Oil Temp on my b18a1 harness, and the back of the b20b.

Here’s the b20b thermostat housing with that ECT switch you all told me about, note the plug type.

Here’s the connection-end of that plug.

Here’s the wire-end of that plug.

Here’s the ECT switch connectors on my b18a1 harness.

Here’s the ECT switch connectors and oil temp sensor plug on my b18a1 harness.

Here’s the back of the b20b.

So the oil temp sensor plug is not used at all, but what do I do with those ECT switch connectors? Do they hard-wire up to that plug on the b20b ECT switch? If so, what colors go to what colors? And will I get a CEL due to the missing Oil Temp sensor?

This swap was VERY similar to putting in a b18b1. P75 head, P75 intake manifold…the only thing b20b about this motor is the block stamp and valve cover, but now that I think about it that valve cover looks awfully similar to a b18b1 as well. What’s the deal with that?

Once I get past this speedbump, there’s not much left to do. I still need to install the resurfaced flywheel, install the exedy clutch kit, install the trans, swap the engine mounts over, put one or two more coolant lines on, swap oil filter, new oil pan gasket…then it’s ready to drop in. At that point I’ll run all my tests and do my inspections, check the valve-lash, install new valve cover gasket, hook everything back up, fill everything back up, turn the key and see what she does. Can’t wait!