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  Anyone done a modern CD conversion in a single?
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Blizzard GR
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Anyone done a modern CD conversion in a single?
« on: February 23, 2011, 09:02:19 AM »
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I am doing a rebuild of 1970 340 single Blizzard for friend.  His original CD ignition is gone and instead of points he would like me to check into doing a modern CD conversion.  I see the mid 1980's Citation LS is CD, has anyone tried that or?????????

Thanks!

John
« Last Edit: February 23, 2011, 11:17:07 AM by Blizzard GR » Report to moderator Logged

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# Larry Rugland's factory 1976 Ski-Doo 440 liquid Sno-pro, starting resto
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Nico
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Re:Anyone done a modern CD conversion in a single?
« Reply #1 on: February 24, 2011, 06:30:39 AM »
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Hi John,

I've been thinking about this! There's 2 problems. First is easy, the CDI stator plate won't bolt onto the crankcase but drilling some new holes will fix that. The diameter should be the same. It may even be possible to bolt the CDI parts onto a points plate.

Next problem is the flywheel won't fit on the crank either. What I'm thinking is take the center from a points flywheel that will fit on the crank, and the magnets off a CDI flywheel, and hope you can bolt them together. Then figure out a way to get both of them in the correct position and it might just work
« Last Edit: February 24, 2011, 06:31:22 AM by Nico » Report to moderator Logged

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Blizzard GR
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Re:Anyone done a modern CD conversion in a single?
« Reply #2 on: February 24, 2011, 07:04:30 AM »
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Hi Nico,

Good to hear from you!  I know the guys in vintage racing that have done ND conversions to their twin and triple Rotax engines have the case milled to accept the ND stator and then they have the hub cut out of the Bosch flywheel and pressed into the ND flywheel so it will go on the crank.  I would assume this could be done here also?

John 
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My stuff:
# Phil Mickelson's Open Class alky Blizzard he ran from 1970-'72.
# Larry Rugland's factory 1976 Ski-Doo 440 liquid Sno-pro, starting resto
# 1999 Mini-Z for when the grandkids visit
# 1975 Can-am 125 T'nt
Nico
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Re:Anyone done a modern CD conversion in a single?
« Reply #3 on: February 24, 2011, 08:05:16 AM »
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That's pretty much what I was thinking, yes.
I'm not sure if it needs to be all that complicated though, the flywheel is attached to the hub just with a couple of bolts and it may be possible to just move it to another hub. It kind of depends what kind of ignition you want to use, I guess.

Once you have a flywheel that will fit on the crank, the stator plate should be easy I know that for the 277 CDI you are thinking of, the stator plate has the same diameter as the Bosch points plates, but they don't use the same bolt holes in the housing. If you can fix that by drilling a new hole or 2 in the plate, it should bolt right on without having to do any machine work on the case.
« Last Edit: February 24, 2011, 08:06:18 AM by Nico » Report to moderator Logged

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j3greg
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Re:Anyone done a modern CD conversion in a single?
« Reply #4 on: February 24, 2011, 08:17:50 AM »
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Bosch and ND flywheels are both 4 magnet - should be no issues using 

Problem is relation of keyway to magnets to TDC -  need to re-key flywheel (use 1 existing mtg hole and drill 1 )  or properly position Stator using two new holes

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hermit
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Re:Anyone done a modern CD conversion in a single?
« Reply #5 on: February 24, 2011, 08:20:05 AM »
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lowtek may be the guy to talk to. I think he may have dabbled with the twins and might know about the singles. The blizzard bases have been machined differently than tnt and oly so may accept the cdi stator more readily seeing they had a form of cdi to start with if his base was original Blizz. I know my 246 looks very different than a tnt style. I may snap a pic later.
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'65 Olympique
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Re:Anyone done a modern CD conversion in a single?
« Reply #6 on: February 24, 2011, 08:30:33 AM »
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I have a couple of leads on a Citation CD system and if they come through I will take some photos and document it on here.  If the stator is the same size as the old points unit, that would take the milling out of the equation which would be great. 

j3greg, thanks for your input also.  Just so I understand, are you saying that the Bosch flywheel can be used with the ND stator (but re-key it), or did I understand that wrong?

Neat stuff!  John
« Last Edit: February 24, 2011, 08:36:45 AM by Blizzard GR » Report to moderator Logged

My stuff:
# Phil Mickelson's Open Class alky Blizzard he ran from 1970-'72.
# Larry Rugland's factory 1976 Ski-Doo 440 liquid Sno-pro, starting resto
# 1999 Mini-Z for when the grandkids visit
# 1975 Can-am 125 T'nt
hermit
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Re:Anyone done a modern CD conversion in a single?
« Reply #7 on: February 24, 2011, 09:11:31 AM »
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Cool. There are some great resources here and guys have done some neat retrofittings. I would imagine the single has to be amongst the easiest to make work.
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'65 Olympique
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Re:Anyone done a modern CD conversion in a single?
« Reply #8 on: February 24, 2011, 09:20:02 AM »
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This site is soooo awesome.  I can't thank Monty, you Tim, and the others enough for your hard work and help.  First class all the way

John
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My stuff:
# Phil Mickelson's Open Class alky Blizzard he ran from 1970-'72.
# Larry Rugland's factory 1976 Ski-Doo 440 liquid Sno-pro, starting resto
# 1999 Mini-Z for when the grandkids visit
# 1975 Can-am 125 T'nt
decoy706
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Re:Anyone done a modern CD conversion in a single?
« Reply #9 on: February 24, 2011, 01:29:31 PM »
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John
Please remember to save the project for the rest of us as I don't want to use my NOS CDI for the Blizzard singles unless I have to. Been saving it for a long time
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Blizzard GR
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Re:Anyone done a modern CD conversion in a single?
« Reply #10 on: February 24, 2011, 01:45:18 PM »
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Will do, Decoy! 

The owner is working on finding a Citation CD system and I will post some pics once he gets one over to me and then I will start the process on here (unless someone else wants to start it on here, which would be great also).

Thanks!

John
« Last Edit: February 24, 2011, 01:47:59 PM by Blizzard GR » Report to moderator Logged

My stuff:
# Phil Mickelson's Open Class alky Blizzard he ran from 1970-'72.
# Larry Rugland's factory 1976 Ski-Doo 440 liquid Sno-pro, starting resto
# 1999 Mini-Z for when the grandkids visit
# 1975 Can-am 125 T'nt
j3greg
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Re:Anyone done a modern CD conversion in a single?
« Reply #11 on: February 24, 2011, 05:18:33 PM »
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OK - Had been holding on to this thinking it might be a business opportunity - but what the hey who says I’m a good business guy …..  And in full disclosure mode - I have not done this on a 335 yet but have done it on a 277 and everything looks to measure up correctly on a 335/340 and most likely all singles using a Bosch point system

The Ultralight community has been converting 277 Bosch point systems to ND CDI for years

There is a company in Arizona - Airscrew performance Sells the complete conversion kit  $275 (last year) Its a proven system and if fly guys run it should be ok on track or trail.  I feel worth the money

however if you would rather gather parts yourself keep reading

The 277 point flywheel magnet  ring  is the same diameter as the 335/340  and other singles It may actually be the same - but I have haven't dug into part numbers

The 277 point flywheel uses 4 magnets same as  335/340 point and  277 ND CDI  flywheel


What you need  - but what's in the kit  may not be what I reference from aftermarket snow suppliers

Item               rotax #        aftermarket

1) CDI  box            Rotax 420-866-595    Kimpex      01-299
2) stator gen coil         420-866-635      Marshall    11-1347
3) external ign coil      420-866-660      Mfg supply  01-113
4) roll pin                  NA                                  5/32  pin

Or get yourself a few used parts.  The stator coil and the CDI box are the same that were used on most trail sleds between mid 80's and early 90s  The key to identifying a ND stator - is the horseshoe shaped lighting coil. When you look up these parts you will see how one size fits all they are

The first part is pretty easy -  the CDI trigger coil assembly is the same size and shape as the ignition coil on a point Stator   

Take your coil off the point stator (internal ignition or charging coil if external ign).  Bolt in the CDI coil    Your lighting coil stays

On the outside find a place to bolt the coil and box

Run the wires between the three pieces ( if you are using new parts you will need to hard wire the stator coil to the box  it does not come with the plug ) 

Part two not really hard but kinda a PIA

Put the flywheel on  - loose nut no key    find a convenient place to put a mark on the case  -  rotate the flywheel  to top dead center  -  mark the flywheel opposite the mark on the case .

Now here comes the tedious part .  Spin the engine by hand  - like you were starting it  -  with a timing light see where it is firing in relation to the TDC marks  Move the flywheel to get it closer  try again

Ultimately what you are trying to do is get  the engine firing at TDC  “AT CRANKING SPEED”.    The beauty is - the CDI box will advance it automatically from there when the engine is actually running.

Step Three -  The hard part  -  Once you know where the flywheel needs to be - you need to lock it down.  One way is to re-cut the keyway in the flywheel in the correct spot

The other way is what the Arizona kit does -  using a drill bit - drill straight into the crankshaft where the current flywheel keyway  is -  insert a roll-pin in place of the true key. Put the nut back on and away you go.

That’s it your done  -  Royalty payments can be sent to me 


The Stators

The "Kit from Arizona"
« Last Edit: October 31, 2011, 05:00:28 AM by j3greg » Report to moderator Logged
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Re:Anyone done a modern CD conversion in a single?
« Reply #12 on: February 24, 2011, 05:36:57 PM »
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Very cool. I've read several articles those ultralight guys have written and truthfully discredited much due to the 277 thing and having "old school" engines and a very good portion is like reading Greek to me with limited knowledge of what they're talking about. Also the Kimpex cdi's always scared me. But obviously you've done your research and that's apparent. There is still no reason why you couldn't assemble the same essential parts and sell your own version of these to people interested. Many guys(myself included) really don't want to have to think about what items to get parts etc so is easier to just go to a guy and lay out the money for what he has. I've done it many times with the Tillotson parts and some Bosch parts, but remembering which cdi box and coils part numbers for this project would be more than I want to remember. It is a great thing that you've shared and really will apply to a small percentage who are after more than the standard points and condenser have to offer. Almost seems enticing for my 246 engine but am not racing nor even looking for any addl power so the points conversion will suffice. Thank you for sharing.
« Last Edit: February 24, 2011, 05:38:23 PM by hermit » Report to moderator Logged

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Re:Anyone done a modern CD conversion in a single?
« Reply #13 on: February 24, 2011, 05:59:33 PM »
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Hey Hermit- Really not worried about the business side of this- cuz any profits would just be plowed back into some thing old and yellow anyway

Real concern for not posting sooner was I haven't actually done it on my TNT yet .  I have all the parts  - did all the homework - am 99.99% sure  - but you never know till you fire it up

Rotax never offically sold any aircraft engines with CDI untill they brought out the redudant systems.  Lots of guys converted to snowmobile systems on their own.

I never flew behind one for the reason you mentioned- snow guys complainig about Kimpex electrics. Points served me well.  On the other hand never had anybody in our club lose a 277 CDI ignition  mid-flight either.

But when we started running citations was not at all impressed with the fact there is no advance mechanism. Lots of compression, full advance when pulling the rope - doesn't sit well with flimsy plastic recoil parts    And they just seem to start and idle better 

Can't say they are any faster ...
« Last Edit: February 24, 2011, 06:22:33 PM by j3greg » Report to moderator Logged
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Re:Anyone done a modern CD conversion in a single?
« Reply #14 on: February 24, 2011, 07:12:57 PM »
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I have the original Bosch cdi for my 246 and it did spark when I got the engine. I will have the external box mounted with the appearance it's functional but have a new points stator from a twin I will be using for fire. One issue with these machines is the crank taper is different from the singles and twins. The Blizzard singles actually hav ethe same taper as the twins, but not the same as singles? so you have to run the twin flywheel when converting over to points IF you have the orig Blizzard crank. Lucky for me I do. I've thought maybe I'd try the orig cdi but I don't want to be messing with it. I'd rather sacrifice the little possible rpm loss with points in favor of reliability. MAny guys have confusion and feel points aren't as reliable as cdi so they want to change them. My understanding is the points aren't as capable of achieving the high rpm without floating and ignition curves are not as controlled as with electronics. Anyhow I'll be curious how it all works out.
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Re:Anyone done a modern CD conversion in a single?
« Reply #15 on: February 25, 2011, 03:12:54 AM »
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Hermit -

the amazig thing about converting ths way is that it APPEARS almost any Bosch points stator can be converted in this manner    it makes no difference twin or single

the only change to the point stator  is changing the ignition coil

the only change  to any flywheel is the new keyway

I know it works on a 277 or 377

the twins use a different external coil because it has two plug wires - but the CDI unit and stator coil is the same 

If you find the used parts from any 82-89 sled you have all the parts.  Even the twin coil can be used on a single - just use one plug wire

Again there really is no huge improvement in using this system over a PROPERLY working point system

point float is an exageration - old v-8 cars povide 16,000 sparks a minute -  sleds are doing 8000

It does provide a much stronger- hgher voltage spark  so you can run richer (cooler) and not run foul plugs

this vintage CDI does not help perfomance much because the timing curve is really no different than a point system  Fully advanced at a certain RPM usually 6000

Modern systems actually RETARD the timing  giving as much as 25-30 advance at low rpm and then backing off to around 10 degrees at 8500 rpm

Let us know what you do with the 246



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lowtekrednek
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Re:Anyone done a modern CD conversion in a single?
« Reply #16 on: February 25, 2011, 11:37:00 AM »
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the nippondenso ignition system bolts on and works for most of the free air twins, with the exception of the 72 400 tnt fa, and the 77-78 tnt free air.

I honestly do not know if it works on the RV free air engines.

the difference is in the crank stub diameter, the ones that are not a direct fit have a smaller stub on the ignition side.

one possible way around this would be to find the early nippon ignition out of a 9500 blizzard, as they have a smaller flywheel hole, I am still researching that.

the above may work for the singles too...???

j3greg, after talking to you at st germain, I went home and tried the nip flywheel on a 292 crank, and the hole in the flywheel is larger than the stub on the crank.

there are two things that need to be done when converting the points to CD on the twin (I know, wrong section)
you will need to make the hole in the crankcase larger to fit the CD plug thru, and you need to make new timing marks.

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lowtekrednek
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Re:Anyone done a modern CD conversion in a single?
« Reply #17 on: February 25, 2011, 02:20:18 PM »
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ok.... heres the deal,
the single cyl crank is smaller than the early type 454 nippondenso flywheel hole.

some machining will be necessary
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Vintage Elan Guy
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Re:Anyone done a modern CD conversion in a single?
« Reply #18 on: February 25, 2011, 02:32:12 PM »
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I made the topic a sticky so it won't get lost or deleted, hopefully.
Always best to save it on your computer if you want to preserve the info for yourself.
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Rob Noakes
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Re:Anyone done a modern CD conversion in a single?
« Reply #19 on: February 25, 2011, 02:54:13 PM »
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I know about nothing about Ski-Doo/Rotax CD systems after 1980 ( that dates me  )
What triggers the spark on the (say ) Nipp ignition from the 377 
If the 277/377 hub fits the early TnT F/As then it ain`t gonna fit on any other `70s Rotax, other than maybe the early F/A blizzards, I doo not know about them. The `73/75 F/As have the biggest crank stub of all the `70s engines. The 340 RV is a fairly tiny stub.
On the `70s engines there is a few different crank stub sizes, several different locations for key way in relation to piston(s) TDC & 2 different key sizes.
If the 277/377 ignition triggers from the magnet ring then you might ? be able to mount the 277 mag ring onto the hub from the engine you are converting to 
If it triggers from the hub, well then the ring swab ain`t gonna work.
Bones
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