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| Lean Burn to HEI conversion https://www.slantsix.org/forum/viewtopic.php?t=60845 |
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| Author: | afastcuda1970 [ Mon Feb 27, 2017 3:57 pm ] |
| Post subject: | Lean Burn to HEI conversion |
I just finish the LB to HEI swap and it runs. However when I set the initial timing to get a good idle, the timing light reads 43* advanced. Did I put the distributor in off a tooth or two? |
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| Author: | DadTruck [ Mon Feb 27, 2017 4:23 pm ] |
| Post subject: | |
its running, so i think that you have the distributor meshing with the cam close enough.., however with 43 degrees of initial timing being registered.. 1) are you sure that you are picking up on #1 spark plug 2) it is possible that the ring has slipped on the damper, was the timing indicating something more correct, something like 8 to 12 degrees advanced just before you made the conversion? 3) do you have the vacuum line to the advance can disconnected and plugged? 4) what does the motor do when you dial the timing back to 8 to 12 degrees? |
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| Author: | afastcuda1970 [ Mon Feb 27, 2017 4:56 pm ] |
| Post subject: | |
Quote: its running, so i think that you have the distributor meshing with the cam close enough..,
I am on #1 cylinder.however with 43 degrees of initial timing being registered.. 1) are you sure that you are picking up on #1 spark plug 2) it is possible that the ring has slipped on the damper, was the timing indicating something more correct, something like 8 to 12 degrees advanced just before you made the conversion? 3) what does the motor do when you dial the timing back to 8 to 12 degrees? I don't think the ring has slipped, I checked it by TDC a few monthes ago. It called for 15* btc with the LB and that's where I had it set before the swap. If I dial it back it tries to stall. The idle speed has decreased to 500 rpm after the swap. I couldn't locate the curb idle screw on this carb. I found the fast idle screw but it started getting dark out. I will research this carb and find the idle screw. I don't understand why I lost idle speed. |
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| Author: | DadTruck [ Mon Feb 27, 2017 5:33 pm ] |
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my experience has been that if the distributor and cam are not timed together properly the spark from the spark plugs may occur when an intake or exhaust valve is not closed,, and you will get popping out of the carb or a backfire out of the exhaust and or the engine will run poorly or just not start at all. take another look in the daytime. |
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| Author: | afastcuda1970 [ Tue Feb 28, 2017 1:07 pm ] |
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I found a vacuum leak to be the cause of the low idle. The reason I couldn't find the curb idle screw was because it is not there. I found a threaded hole where a screw should be but there was nothing for the screw to push off of. The carb has a remanufactured by Holley sticker on it. I think a previous owner/mechanic has been in it. I know a junkyard where there is a '79 slant truck that I will get a complete carb from. I was able to set the timing at 13* btc and it idles at 500 rpm, a little rough but idles for now. |
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| Author: | DadTruck [ Tue Feb 28, 2017 5:06 pm ] |
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Great Progress! |
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| Author: | afastcuda1970 [ Sun Jun 04, 2017 3:51 pm ] |
| Post subject: | |
OK, since I have done this HEI conversion, I have burned up three BWD select modules. They have been covered under warranty but after the second one, I bought a duralast to put in the glove box. The third one burned out today. I used the GM bracket and coil with aluminum heat sink from a late 90's Chevy truck to mount the module. I ran 12 volts through a relay and put an extra ground wire to the module. Is anyone else having trouble with the BWD select modules? Any other ideas as to what I could have done wrong? I don't know why these modules keep burning out. |
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| Author: | Charrlie_S [ Sun Jun 04, 2017 6:13 pm ] |
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Did you either remove the plastic "tit" from the back of the module, or drill a locating hole in the heat sink? The module must sit flat on the heat sink. Must also use heat sink compound, not dialectric grease. |
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| Author: | afastcuda1970 [ Sun Jun 04, 2017 6:28 pm ] |
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Quote: Did you either remove the plastic "tit" from the back of the module, or drill a locating hole in the heat sink? The module must sit flat on the heat sink. Must also use heat sink compound, not dialectric grease.
I did remove the tits. I used the compound or grease that came with the module. The BWD select module came with some clear greasy stuff. The duralast module came with some white pasty stuff that looks more like what GM had on there. Both were included in the box the modules came in and were unlabeled. |
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| Author: | enrique lopez [ Mon Jun 05, 2017 2:24 pm ] |
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That also happened to me. I finally fixed the problem by rewiring. Turns out I was using the wrong wire to feed my module. Too much juice upon acceleration. So I ran a wire from my battery, installed a relay, and no problems since.. |
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