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240 B230F+T, LH2.2, Swap into 78' 242 - Issues

Joined
Sep 26, 2016
Location
Clawson, MI
First off, I would like to say thank you to anyone who takes the time to help me think on this.

Background
I had a well-running 1987 740 turbo that I had in good stage 0 condition, until I decided I wanted to swap a V8 or similar. Engine was a 95' vintage NA squirter block with a stock head, turbo, injectors, etc... Ran very well for several thousand miles and rallycross events before pulling. Engine and transmission was pulled and a nice 242 came up for sale, so I bought it to stuff the B230F+T into. The engine has been converted to a block mounted LH2.2 distributor, and the 740 harness has been made to work in the 242.

The problem!
After swapping and LH2.2 B230F+T into a 1978 242 project, I am having problems getting it to start and run with correct timing. The spec for these engines is 12? +/-2 at idle. So far, the car doesn't want to start until the timing is advanced to about 18-20?. During cranking, it acts as if it is getting either no spark or no fuel until I advance the timing to this point. Sometimes after the starter is let go it will sputter once or twice, when the timing is lower than 18-20?. Once it starts, it also seems to have a miss at idle. Does this sound like something in the electrical system is funky?

What have I checked?
  • Timing of cam, intermediate shaft, and crank are correct
  • Timing mark on crank pulley matches timing cover when at TDC

I would really appreciate any thoughts, or ideas that you may have. Cheers, and thank you.
-Joe
 
Are you sure that the distributor was installed in the block correctly? The rotor needs to be rotated ~60 degrees away from the alignment mark on the housing so that when the gear teeth engage it will rotate back to be in alignment. In other words, if the distributor is installed with the rotor lined up with the mark on the housing, it will not be aligned correctly when it is fully seated in the block.

1GeRcZBl.png
 
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To be honest, I'm not completely sure that the distributor is aligned correctly. I found this same picture that you linked, but can't find any corresponding mark on my distributor housing (I wish the picture in the manual was better). I can take a picture when I get home to show what mine looks like. Have you done this on your car and have a mark? Could you share what it looks like, if so?
 
Yea I had to do this procedure and got it wrong the first time. IIRC the mark is under the plastic shield below the rotor on the top edge of the housing. I’ll try to get a pic for you.

Are you also running EZK ignition? Or breakerless?
 
I would very much appreciate if you could do that. If you got it wrong, it's very possible that I got it wrong! I would be happy to find something that was actually done incorrectly at this point!

Right now I'm running a 591 LH2.2 ECU and a EZK 117 that came out of the 740 (can't recall the model of the EZK 117). In the 740, the engine ran great and pulled very strong. Since then, the only components that have changed are really the intermediate shaft and the block mounted distributor.
 
My #1 wire is close the where the hall pickup wires go through the side of the distributor. I set it so once it rotates intro position on the way in so that the rotor is 1/2-3/4 of the way past the hall wiring grommet.
 
Thanks for taking that picture! Apparently mine doesn't have this mark on it. Unless it's the faint smudge appearing thing near the same location. Either way, I'm going to set it to match yours today and see what that does. From memory, it would appear to be about where I set the rotor during installation.
h8KIPURl.jpg


What about the adjustment slot? Is yours in the middle or adjusted more towards one end?

Thanks again for your help.
 
Just wanted to report back in. All timing marks were checked again today and were looking correct to my eye. My rotor pointed in the same direction as oldshoolvolvo shows above. I tried to start the car again, but it refused to start with anything less than 20? of timing advance. I decided it was time to start throwing random ignition related parts at it to see what happened. I swapped out coils and this did nothing. I replaced the rotor and cap to no avail. Next I replaced the power amplifier and this seems to have been (fingers crossed) the culprit. With this swapped in, the car will start with timing at the correct 12? BTDC and seems to run just like it did prior to the swap.

Does this make sense? My thoughts are that the power amplifier may have been providing too little voltage and incorrect spark signals to the coil. I'm not sure why adjusting the advance would play a role in this. Thoughts?
 
Glad you got it sorted out.

On my setup the distributor bolt is towards the left end of the slot.

FWIW, I'd recommend taking the power stage off of the heat sink, cleaning and reapplying some thermal paste between the two. The power stage generates some heat during normal operation and I've found that the factory thermal paste is pretty deteriorated by now. I used some "Arctic Silver" brand from amazon.
 
I'm glad to have hopefully figured this out. It seems to be running just like it was before the swap. The idle still isn't perfect, but I was never able to get it to be rock-steady. Just a very minor sputter here and there. Once it's warm, it tends to hang rpm slightly after coming to a stop. That was something I wasn't really able to figure out in the past. The car's going to be primarily a rallycross toy, so I'm not too concerned about that one.

FWIW, I'd recommend taking the power stage off of the heat sink, cleaning and reapplying some thermal paste between the two. The power stage generates some heat during normal operation and I've found that the factory thermal paste is pretty deteriorated by now. I used some "Arctic Silver" brand from amazon.

Great idea! I noticed that the heat sink on the bad one was not get very warm, while the one that is working is quite hot to the touch after driving around. That must be a sign that it's actually pulling heat out of the power stage. I think I have some thermal paste at work that I can borrow :).
 
I'm glad to have hopefully figured this out. It seems to be running just like it was before the swap. The idle still isn't perfect, but I was never able to get it to be rock-steady. Just a very minor sputter here and there. Once it's warm, it tends to hang rpm slightly after coming to a stop. That was something I wasn't really able to figure out in the past.

Ha that sounds just like how mine runs.
 
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