LPG question

[73GreenMachine]

I had a bit of a look round on the net and it seems the coils are actually different. People seem to think the HEC stands for high energy coil and MEC stands for medium energy coil. It makes sense but may be too simple of an analogy. Most people seem to get the HEC716 and just modify the coil lead so I might do that aswell.
It seems that this may have been the primary cause of what I thought was valve bounce on the dyno. It would make sense that with the wrong coil with a low voltage it was not able to provide a strong spark or recharge quickly enough as the rpm increased. Oh well lesson learned the hard way..again.

 

[addo]

I went and browsed the Bosch Coils PDF.

XD, XE are listed with MEC-717. XF gets the HEC, which I suppose is supposed to tie in with the different ignition modules employed.

BIM 024 is the module found in the XD/XE distributors, Corollas, Magnas and many other cars. BIM 032 came with the XF EFI Falcons and is listed right through the EL series.

Look here for a list of cars with this module, you can raid when seeing an abandoned one.

So - perhaps, mnemonics aside, the HEC is matched to the BIM 032 but I can assure you that it's run fine under very trying conditions with the earlier style dizzy.

 

[73GreenMachine]

Thanks for the research. I think I will go with the HEC716 and just modify the lead. Can't wait to see what it runs like with a proper ignition system! It might actually run properly(Gasp)!

 

[addo]

Oddly enough, it's a shade cheaper than the MEC, too. Possibly just reflects volume of sales.

 

[73GreenMachine]

Got the head back today FINALLY!!!! Its only been 8 weeks Its still not right yet though so I am taking it to another shop to have things fixed. After talking to the machinist, I found out that I will have to pull the engine out of the car again to get the compression I want for LPG (9.5-9.7:1). Deck height is being taken from 56 thou down to about zero, the block is being grouted and I may swap to some new pistons. This time, the engine will be a sealed unit for me to drop back in my car so less for me to stuff up!