jagwit Posted October 18, 2011 Share Posted October 18, 2011 Hi all I'm sure my question must have been asked before and the answer is here somewhere, but I did look and can not find it.... I'm implementing an MS2 on a Thor V8 and I want to use the OEM Crank Position Sensor for my trigger input and 4 coil outputs for wasted spark direct coil control. I know "the 2 missing teeth are at 60 degrees BTDC" but I need to understand more accurately than that exactly where that "60deg point" is. I'm sure you "squirters" will understand what I'm after. Eg: Is it (60BTDC exactly) in the centre of the first hole? Is it in the centre of the 2nd hole (ie exactly halfway between where the two missing teeth would have been)? Is it in the centre of the 3rd hole? Is it where the the first missing tooth would have been? Is it where the 2nd missing tooth would have been? Other? Best regards Philip Lochner South Africa My web site: www.jaguardiy.net Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 18, 2011 Share Posted October 18, 2011 It's not super-critical as you have an offset/trim value to adjust it in software. Here's mine: Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 18, 2011 Share Posted October 18, 2011 From what I remember the 60 degree point is at the first tooth after the gap but the MS starts counting at the first missing tooth. I have an MS1-Extra msq file for a Thor V8 using OEM crank sensor if it'll help. In the back of my mind I have a vague feeling that I had to do something a bit odd to get it all to work - something like offsetting the coil firing order but it's 3 years + since I did my last Thor MS install. On an MS1-Extra the settings are: 60 teeth missing -2 Trig positions are: 2 17 32 47 60 degree timing angle An assistant and a timing light are your best friend Quote Link to comment Share on other sites More sharing options...
jagwit Posted October 19, 2011 Author Share Posted October 19, 2011 @Fridgefreezer: I want to use the original trigger wheel on the flywheel, not an aftermarket added trigger wheel @oldhand: I would appreciate your MSQ, I'll send you a PM with my email address. A timing light is of no use on the THOR!! It does not have timing marks on the crank pulley and no reference against the timing cover. I will attempt adding them while I build the engine. Unless someone comes with 100% accurate info on this thread, Plan B is to use a dial gauge to find TDC (add the timing marks) and to then check through the CPS hole to see where the missing teeth are.... Quote Link to comment Share on other sites More sharing options...
Dave W Posted October 19, 2011 Share Posted October 19, 2011 Sorry, should have added about the timing marks. Whenever I set up an engine that I don't know I put my own timing marks on the crank pulley at TDC and at 90 degree intervals having checked TDC through number 1 spark plug hole. You can never fully trust the factory timing marks on an RV8 anyway. I then set the cranking advance to 0 and put a timing light on each coil in order while cranking the engine over (fuel pump disconnected or off) and make sure that the appropriate timing mark looks to be at the pointer/reference mark. It doesn't have to be 100% accurate at that point but it's the easiest way of confirming that it's somewhere in the right ballpark and that you haven't stumbled upon one of the "bad" trigger wheel settings that causes MS to fire erratically. You can fine tune a more precise angle once you have the engine running. Don't forget though that timing guns with adjustable advance don't work correctly on wasted spark and have to be set to 0 degrees. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 19, 2011 Share Posted October 19, 2011 Personally I would mark the TDC by using a solid tool through the spark plug hole #1. I hollowed out an old spark plug and stuck a cap head bolt through it with a turned down (with a grinder) nut on the spark end. Screwed this in and marked a point on the pulley where the piston had hit the tool, then turned it backwards and marked another position on the pulley. Halfway between this is TDC. Adjust the length of th ebolt with washers/file/whatever so the gap between the points is small. I tried dial gauge but couldn't get it reliable, for some reason there was quite a float on the position, whereas the above method gave me within 10% accuracy over about an inch or so of crank pulley. Quote Link to comment Share on other sites More sharing options...
jagwit Posted October 19, 2011 Author Share Posted October 19, 2011 I tried to figure out what the meaning is of "Trigger positions" 2, 17, 32, 47 of Dave's config read in conjunction with "Trigger angle" =60 in "spark settings" and thus to conclude where exactly 60deg BTDC would be but concluded that it would take substantial study - my energy levels too low for that...today. It is interesting that its not 0, 15, 30 and 45 though. Quote Link to comment Share on other sites More sharing options...
jagwit Posted October 19, 2011 Author Share Posted October 19, 2011 According to Matt(http://tinyurl.com/6j6fxzf), based on Dave's MS config, the first tooth after the two missing teeth is at exactly 60deg BTDC. Quote Link to comment Share on other sites More sharing options...
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