candpdoyle Posted January 11, 2013 Share Posted January 11, 2013 Hi All Wonder if I could reap some forum expertise? This will be a long post as I have an ongoing fault that is doing my head in :-( vehicle is a series 3 swb fitted with a 3.5 v8 engine number starts 38A has twin strombergs and dizzy is the 38dlm8 with 2 lucar pins was running and starting well when i bought it so started renewing ignition bits. red rotor arm, powerspark blue 8mm ht leads, new dizzy cap, new set of ngk bpr6es (i think) plugs gapped to 0.08mm had an lpg system fitted (second hand) By Gordon Findlay and all was good bar a little fluffiness on lpg decided to renew dizzy with a simonbbc unit and matching coil which is where my problems started. after lots of cocking around I have sent the simonbbc parts back as i could get no joy( would not start on gas at all and felt gutless. also down to 8-10mpg from 17mpg) and the old parts seemed to work better been ok except for intermittent spark issues. spark is not very strong and appears to be intermittent ?? will spark for a second and then goes away. 12v at the coil, but does seem to drop on cranking. have tried direst feed from my battery and from another spare battery while cranking and still carp spark. tried 2 spare coils I have and same(except 1 was dead) have tried jumper cable to various different earthing spots on starter, engine and chassis with no difference there is no ballast resister and coil is a 12v item switch to petrol and it starts and runs as it should.. struggles to fire on change to gas but will do so after a second or 2 and then runs but i think not on all cylinders...seems smooth enough but sluggish... still faster and more powerfull than a 2.25 but definately not like it normaly runs sorry for the essay, but not sure what to check next??? thanks in advance Chris Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 11, 2013 Share Posted January 11, 2013 Ignition amplifier on the dizzy - it *grounds* the other leg of the coil to make it work, so even if you have a solid +12v on one side that's not a guarantee of working. Quote Link to comment Share on other sites More sharing options...
taz90 Posted January 11, 2013 Share Posted January 11, 2013 put the old plugs back in or try another set of plugs Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 11, 2013 Author Share Posted January 11, 2013 amplifier is wired up correctly I think... the problem seems to start before the dizzy though... I have been testing with a spare plug in the king lead, and the spark is carp from the coil??? my tester has blown up now, so have resorted to old school checks :-) Chris Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 11, 2013 Author Share Posted January 11, 2013 old plugs were bp5 ngk's, but they looked to have been in there since noah built the ark Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 11, 2013 Share Posted January 11, 2013 Who said it's wired up wrong? I mean it may be faulty - they die quite often, usually getting worse when hot first. Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 11, 2013 Author Share Posted January 11, 2013 Ah I see what you mean... only problem with that theory is It was worse with the new simonbbc one? is there any way of testing them? might pop down to the local landy specialist and see if he has any spare 2nd hand units i can try :-) Cheers Chris Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 11, 2013 Share Posted January 11, 2013 Starting at Page 1 of the V8 problem solving book - the best thing you can do is replace all the ignition bits with genuine ones. It sounds like you're running non-gen leads & rotor at least. LPG puts extra strain on the ignition system and the standard setup isn't that great to start with. Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 11, 2013 Author Share Posted January 11, 2013 Cool, sounds like a good start :-) Genuine as in Lucas?? Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 11, 2013 Author Share Posted January 11, 2013 would you call these genuine?? they are marked Lucas and states oem? http://www.ebay.co.uk/itm/280607607297?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 have noticed other sites charge up to £300 for "genuine" HT leads have ordered a dizzy cap, rotor arm and coil from matford, but could not bring myself to pay what they want for ht leads Chris Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 12, 2013 Share Posted January 12, 2013 Lucas or Bosch, last set I bought was from a motor factors for not so very much. Just beware all the after-market shiny stuff / Britpart etc. Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 12, 2013 Author Share Posted January 12, 2013 looking through all the other v8 posts, i see i should have gapped at 0.6mm ... hopefully get a chance tomorrow afternoon to regap and tidy ht lead routing.... as a free start while I wait for parts to arrive Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 14, 2013 Author Share Posted January 14, 2013 me thinks we are on the right track :-) took all the plugs out, cleaned and regapped them at 0.6mm.. replaced the powerspark rotor arm with the old lucas one, and tidied up the ht leads using nige's nice pic on the routing (thank you) started and sounded sounded a bit better, so i advanced the timing to the old mark on the dizzy (where it was before all my troubles) reset the idle and took it for a blast around the block much better.. picks up revs quickly and barks like a goodun... nice and wheel spin happy again as well which has been lacking lately so will definately replace and renew all ignition components with genuine over the next week.. have also ordered some new earth cables which i will fit over the weekend hopefully cheers Chris Quote Link to comment Share on other sites More sharing options...
bluespanner Posted January 16, 2013 Share Posted January 16, 2013 I'd try a set of plugs without resistors. Quote Link to comment Share on other sites More sharing options...
candpdoyle Posted January 20, 2013 Author Share Posted January 20, 2013 I think the culprit has been found :-) I Fitted the new earths yesterday, and while removing the battery to chassis cable I discovered the po had spliced the cable to extend it... was a good 3/4 inch gap in the splice Ran a nice shiny new cable to chassis, and from there to bellhousing. Have another from engine to front panel and another chassis to gearbox.. should cover it I think cleaned up all the mounts with wire brush as well. turns over much quicker now and spark is nice and strong, even runs better... muchly happy and will sort the vacuum advance next Cheers Chris Quote Link to comment Share on other sites More sharing options...
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