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160 head on B21FT

V

VolvoPrince

New member
Joined
Feb 10, 2016
Location
Phoenix
Alright, I have another form going on converting the KJet system on my B21FT. Currently my car has B23F in it running LH 2.1. I want to take my 160 head and put it on the B21Ft (also from an 84 but with KJet 398 head) since the 398 head needs a rebuild and has holes from the KJet injectors. So basically, will my 160 head work on my b21ft, and will. I need anything else to get rid of the KJet? My plan was to take my LH 2.1 manifold and fuel rail with injectors, along with the AMM and idle control valve, and the distributor. I will leave my current Lh 2.1 wiring in the car. Am I missing anything?
 
Yes. You are missing something. A 1984 245DL or GL has LH 2.0, not 2.1. LH 2.1 is turbo compatible, since it came only in turbo cars, namely the 1984 760 Turbo.

It'll be easier to update to LH 2.2 and use the 700 Turbo EZK system with a B230 LH 2.2 distributor. Head-wise, I'd stick with the turbo head, but have it rebuilt and the injector holes plugged. Either that, or take both heads to a machine shop and have them swap the guts of the 398 head into the 160 head. Turbo heads have sodium filled valves, which are nice to have (albeit not really necessary if you're running stock boost).

So, stuff you'll need:

Engine harness for an LH 2.2 240 (I'd go with either a replacement harness, or find one from an '88 car, since it'll have no rot)
LH-Jetronic ECU (last three digits either 517 or 541)
EZK ignition module and wiring from a 1988-89 740 Turbo (likely no rot)
1985-88 B230F distributor from a 240
Ballast resistor pack and greentop injectors from the 740 donor car (or find compatible injectors that have the desired flow rate)
B21 head gasket set
A machine shop to do the aforementioned guts swap into and rebuild of LH-Jet head.

-J
 
From what I was reading when I looked up the numbers off my Bosch Ecu in my car it showed LH 2.1... Are you sure it's a 2.0? I read the 2.0 is pretty rare, and only available on earlier 81-82 cars.
 
John242Ti said:
Yes. You are missing something. A 1984 245DL or GL has LH 2.0, not 2.1. LH 2.1 is turbo compatible, since it came only in turbo cars, namely the 1984 760 Turbo.

It'll be easier to update to LH 2.2 and use the 700 Turbo EZK system with a B230 LH 2.2 distributor. Head-wise, I'd stick with the turbo head, but have it rebuilt and the injector holes plugged. Either that, or take both heads to a machine shop and have them swap the guts of the 398 head into the 160 head. Turbo heads have sodium filled valves, which are nice to have (albeit not really necessary if you're running stock boost).

So, stuff you'll need:

Engine harness for an LH 2.2 240 (I'd go with either a replacement harness, or find one from an '88 car, since it'll have no rot)
LH-Jetronic ECU (last three digits either 517 or 541)
EZK ignition module and wiring from a 1988-89 740 Turbo (likely no rot)
1985-88 B230F distributor from a 240
Ballast resistor pack and greentop injectors from the 740 donor car (or find compatible injectors that have the desired flow rate)
B21 head gasket set
A machine shop to do the aforementioned guts swap into and rebuild of LH-Jet head.

-J
Click to expand...

Actually, I see what you mean. The numbering is so confusing to me. What technically would be the issue with running my current 160 head with the LH 2.0 on the B21FT (with the dizzy from my b23) I don't see why It wouldn't work unless there's a fuel issue I don't understand.
 
The only difference besides the k-jet injector holes are the possibly the size of the cooling ports, the 398 may have the smaller cooling ports which are less likely to deform during a detonation event. I don't think it's as big an issue on the b21 blocks, I've been using a 160 head on my B21F+t but I've had it rebuilt with stainless valves. I wouldn't worry about it for stock boost levels though.
 
Some 398 heads have BCP, some have SCP. Same with the 160 heads. The change in coolant passage size occured sometime during the 1984 model year. The 398 heads were introduced in the late '70s when the early 160 heads had erosion problems. At the same time, Volvo started using the updated aluminum alloy on the 160 heads. So, there really isn't any difference between the two, except for the casting number.

LH-Jetronic versions and years:

1.0 - Some 1982 B21F engines, typically late production, and California spec.
2.0 - 1983-84 B23F with 503 or 510 ECU. Uses cube relays for fuel system and fuel pump. Chrysler ignition box (Volvo p/n 1317295 - high compression B23, 1346105 - low compression B23)
2.1 - 1984.5 B23FT with 507 ECU and EZK102K, first version with white fuel system relay.
2.2 - 1985-88 B230F, 1985-89 B230FT, various ECUs used. 511, 544, 554 are non-turbo, 517 and 541 are turbo. 240 used Chrysler box - two or three different part numbers on these as well. 700 used EZK115K or 117K. 2.2 was also used on the B280F in the 760/780/very early Euro spec 960 (like 1990-91), which used the B280 instead of the B6304 engine.
2.4 - 1989-98 B230F, 1990-98 B230FT, 1989-91 B234F (probably B204FT/GT as well, in addition to B200F/FT, etc), again, various ECUs used. EZK116K ignition.
3.1 - 1990-93 B230F with M47, typically in 240 with M47. Uses heated film AMM.

Benefits of upgrading to 2.2 from 2.0:

Cheaper and much more common AMM that's also more reliable
One single fuel system relay, instead of the two power window relays that are used for the fuel system and the fuel pumps
Gets away from the Chrysler ignition system that doesn't seem to work as well in turbo applications

There are some other improvements that you'd notice by upgrading. Not to mention the fact that Dave Barton already has a conversion harness that can be used for turboing an LH 2.2 240.

-J
 
John242Ti said:
Some 398 heads have BCP, some have SCP. Same with the 160 heads. The change in coolant passage size occured sometime during the 1984 model year. The 398 heads were introduced in the late '70s when the early 160 heads had erosion problems. At the same time, Volvo started using the updated aluminum alloy on the 160 heads. So, there really isn't any difference between the two, except for the casting number.

LH-Jetronic versions and years:

1.0 - Some 1982 B21F engines, typically late production, and California spec.
2.0 - 1983-84 B23F with 503 or 510 ECU. Uses cube relays for fuel system and fuel pump. Chrysler ignition box (Volvo p/n 1317295 - high compression B23, 1346105 - low compression B23)
2.1 - 1984.5 B23FT with 507 ECU and EZK102K, first version with white fuel system relay.
2.2 - 1985-88 B230F, 1985-89 B230FT, various ECUs used. 511, 544, 554 are non-turbo, 517 and 541 are turbo. 240 used Chrysler box - two or three different part numbers on these as well. 700 used EZK115K or 117K. 2.2 was also used on the B280F in the 760/780/very early Euro spec 960 (like 1990-91), which used the B280 instead of the B6304 engine.
2.4 - 1989-98 B230F, 1990-98 B230FT, 1989-91 B234F (probably B204FT/GT as well, in addition to B200F/FT, etc), again, various ECUs used. EZK116K ignition.
3.1 - 1990-93 B230F with M47, typically in 240 with M47. Uses heated film AMM.

Benefits of upgrading to 2.2 from 2.0:

Cheaper and much more common AMM that's also more reliable
One single fuel system relay, instead of the two power window relays that are used for the fuel system and the fuel pumps
Gets away from the Chrysler ignition system that doesn't seem to work as well in turbo applications

There are some other improvements that you'd notice by upgrading. Not to mention the fact that Dave Barton already has a conversion harness that can be used for turboing an LH 2.2 240.

-J
Click to expand...

Great information! If worse came to worse though, would I technically be able to use my current LH 2.0 setup?
 
I have an LH 2.2 Ecu and 007 mass air flow in my garage, I'm going to try converting my B23F first. After I do that, will that set up work with the B21FT?
 
Let's go back to basics for a minute using an overly simplistic example.

Standard atmospheric pressure at sea level is 1 bar or 100 kPa or 14.5 psi. This is the pressure that a NA engine has to work with. Now, for discussion, let's say that you add a turbo with 14.5psi of boost and a [fictional] intercooler that drops the boosted air temperature back to ambient. With this, you're running twice the airflow as a NA engine! Wow, double the engine size under boost, no wonder folks love turbos!

So, for our 2x boosted engine, we need:
- An ECU that's programmed to handle 2x boost and associated airflow. NA ECUs don't go this high.
- Injectors that can supply 2x fuel compared to NA
- A fuel pressure regulator that can supply 2x the fuel with 2x intake pressure
- A fuel pump that can keep up
- An ignition system (EZK) that's programmed to handle 2x boost. NA EZKs don't go this high.

If you convert your NA B23 to NA LH2.2, that's an OK start but you'll still need to upgrade to Turbo ECU, EZK, injectors, fpr, pump. A chart of Volvo ECUs is here (among other places):
https://www.volvoclub.org.uk/faq/EngineFIComputer.html#ECUAMMReferenceChart

Yes, a megasquirt conversion may be easier for you. MegaSquirt can be challenging to setup and tune on your own without help. I'd post in wanted for someone local who can show you their megasquirt install and talk you through all the steps. Maybe it's for you, maybe not.

[On other stuff, STSmachining offers nice KJet injector plugs so you can keep your KJet head and add a B230 intake manifold with its own injector holes.]
 
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