oLDSKI-DOOSLEDS

Vintage Ski-Doo Site Since 1999!

Restoration Resources

If you can't find it below, please see the oldski-doosleds message board.

oldski-doosleds help desk(s) message archives 

Got a bad piston? 
Motor Rebuilding and Basic Info
Calculate Engine Displacement 
Gas/Oil Mix Ratios 
Polycarbonate Hood Cleaning / Polishing ?? 
Mikuni Info and Jetting Info 
CDI to Points (Help); Setting Timing and CDI-to-points 
Tillotson Carburetor - Diagrams / Rebuild Help / Parts 
Weak Spark One Side Troubleshooting
Flywheel Pullers (and where to buy) 
Link Plate Spring Removal Tool 
NGK CHAMPION BOSCH Xref 
Info available from Bombardier Museum, Manuals etc  
E
ngine Compression Tables  
1970-1973 blizzard numbers 
blizzard (and others) slide instructions (torque reaction suspension sleds  from ~ mid `70s to ~ mid `80s)


GOT A BAD PISTON?
1970TNT--CHECK THIS OUT  LOTS OF INFO ON BURNT/BAD PISTONS AND WHY.  http://www.smellofdeath.com/lloydy/piston_diag_guide.htm 
luckyketch--Here is some more info.http://www.snowridermag.com/snowmobiles/snowmobile-piston.html 
luckyketch--More piston info http://www.dansmc.com/pistons.htm


Motor Rebuilding and Basic Info
luckyketch--
This site is about motorcycles but applies to any two stroke. Great stuff here. http://www.dansmc.com/indexindex.htm


Calculate Engine Displacement
luckyketch--For those of us that are math challenged, here is a great place for calculating engine displacement. Just plug in bore and stroke and away you go. If you are over boring, add oversize dimensions to original and get your new displacement. http://www.nightrider.com/biketech/calc_displacement.htm 


Gas/Oil Mix Ratios 
Vintage Elan Guy--see many many threads come up over time asking about gas/oil mix ratios for specific machines. I have made this sticky to help answer that question.

Your gas/oil mix ratio has nothing to do with what machine you have. It has everything to do with what oil you are using. If you have managed to come across a case of oil that was manufactured in the late 60s or early 70s then it will likely tell you on the container to mix it at 20/1.

If you don't have that stash of old oil then get a bottle of new oil, buy the best you can find or afford within your budget, read the label and mix accordingly. Most new oils will work best at 40/1 or 50/1 mix ratio. However, if you feel the need for whatever reason to mix it heavier, then you are in luck sort of as new oils leave much less carbon deposits than old oils so other than more smoke, you probably won't foul more plugs.

Summary, buy the oil, read the label and mix away!

Here are some links for different types of oil. Most oil mfg have their own web site filled with info.

http://www.amsoil.com/
http://www.castrol.com/castrol/multipleproductsection.do?categoryId=82915526&contentId=6003635
http://www.bluemarbleoil.com/
http://www.pennzoil.com/products/outdoor/snowmobile.html
http://www.petro-canada.ca/pdfs/IM7882E.pdf
http://www.valvoline.com/pages/products/product_detail.asp?product=62
http://www.redlineoil.com/products_motoroil.asp?productID=24&subCategoryID=3&categoryID=3
http://www.valvoline.ca/pages/products/cycle.asp
http://klotzlube.com/storeCats.asp?ci=5

cdem72--My '70 340 blizzard motor was on the dyno for major testing and it seemed to like 20:1 mix best. Plug was chocolate brown and nice and clean after racing weekend using VP fuel and blue marble. Rather have the motor run at 8000 rpm without issues than burn down.

75 Elan--Here is a site that gives metric and standard amounts for all types of mixtures: http://www.csgnetwork.com/oilfuelcalc.html

snowcruiserman6566--I run 32 to 1 Shell Advance machines running from 65 to 73 seems to be alright. I burn premium if I am racing.

olympique_mike--Here is another site with some good info like oil ratio charts and FAQ's about mix ratios. They talk about richer oil ratios lowering the total mix octane and how a richer oil ratio can actually be the cause of detonation and a burndown on higher compression engines.
http://www.spectro-oils.com/synsno_oils.htm

Blizz--If your spinning the motor hard or harder than what stock should be then the extra oil is good but for a stock sled most of todays oils can be mixed at 50:1 maybe 40 if you want extra security and running premium in your old sled is not really a great thing either as it was designed to run on regular gas. It can hurt some sleds more that it can help at least on stock.

ds33gt--Those ratio rite things work really well.  There's like 5 or 6 different types.  From1 to 5 gallons and 12 to 100:1.  There only like 8 bucks too...

nukemech1--found a chart that said all 73 elans were 40/1.

Vintage Elan Guy--Here is a chart that will give you a multitude of options for the ratio you want to use. Just click the link and navigate to the full size view and save it to your computer. Hope it is usefull.
http://inlinethumb45.webshots.com/21676/2550969410063439709S600x600Q85.jpg 


Polycarbonate Hood Cleaning / Polishing ??

Sledder Al--Hey all -  I know this was discussed once before, but I seem to have lost my notes on it.  I want to bring back my 1974 Elan 250 Twin Deluxe Hood (black) back up to a nice shine.  It is a bit dull.  Any suggestions greatly appreciated. Also - would the same apply for a 72 Oly hood?  Thanks!

1970 TNT--ZEKE513 TOLD ME TO USE 400 THEN 600 THEN 800 THEN 1000 WET SAND PAPER. I WAS GOING TO USE WHITE POLISHING COMPOUND.

775--Sanding is a pain, and takes a lot of time and patience. I had to use 1000, 1500 and 2000 grit and wet sand my 75 SS. Finished off with Meguiars plastic polish. Still not 100% satisfied, but looks better than it did.

RV440--Have you ever noticed the chevys and fords that have their headlight lense's a dull yellow or they are cloudy? Well most of them are made of polycarbonate.

I have polished a few and they have turned out nice. I used 2000 to 3000 wet or dry sand paper and then a buffing pad with 3m compound,

http://solutions.3m.com/wps/portal/3M/en_US/Automotive_Aftermarket/Home/Products/Solutions/Lens_Repair/

http://superiorcarcare.net/headlight-lens-care.html

But I have not tried it on a skidoo hood yet. Since they are made of the same material it should work.

But it can get costly so maybe a new paint job might be the best way to go.

olympique_mike--I just polished up two '72 oly hoods with motorcycle windshield polish and it worked really well. i got out some scuff/smudges with careful use of a contact cleaner then the polish.

73ss--Meguiar's "PLASTX"  from Canadian Tire.  Removes fine scratches, oxidation and grime, haze and cloudiness. 10 ounces for around $12

Catsn'Doos--Theres also stuff available (meant for headlights) from autopro for $30  works great on anything plexiglas, or polycarb that ive seen it used on...

Blizz--Use Flitz, the stuff is amazing we use it to polish aircraft parts it will not harm any plastic fiberglass or painted surface.

73ss--my favourite is ""gunk" engine brite", it comes in a white can with an orange logo, best stuff ever for grease and the like. just spray it on, let it sit, and pull out the garden hose-safe to leave the hood right on the machine

Sledder Al--Best bet is to take the hood off and remove the fuel tank, then start cleaning...better safe than sorry...To clean the inside of the hood - good old elbow grease an brush and some water with soap....Spray Nine will work on many surfaces and is not a solvent....I have used it on plastic hoods before with no noticeable issues...

Hermit--I've had great success with cleaning with WD40 or the like (generic brand works also, and is less expensive, but doesn't come in the gallon size) It cleans grease, and doesn't damage the plastic or paint. Also treats aluminum and bare metal nicely. I like to use it on the bases and aluminum engine parts with an old toothbrush. As far as polishing the NOVUS brand No2 plastic polish does a fab job, is not watery, and doesn't gum up. The more times you do it the better. I've seen some fogged windshields look optically clear after. I buff it by hand but some like a wheel. The plastic is prone to overheat so I'd careful on that one. The NOVUS also works great on the hoods, lenses and all paint in general. Dave if you aren't happy I'd try a bottle of this and would be really surprised if you were still unhappy.

timmytorco--I hate to say the word, but Arctic Cat makes an awesome plastic polish. Sorry, but it does work. It's the only good thing I've found with AC on it though.

RV440--3M just came out with a new polishing kit. http://solutions.3m.com/wps/portal/3M/en_US/3MAutomotive/Aftermarket/Products/Featured_Products/Headlight/

miller man--castrol superclean i have found works really well on my boat ,truck, sled ,4 wheelers, might want to dilute it first see how it works for you then go to full strenth.it really is a good product. hope it works for you.


Mikuni Info and Jetting Info

1970 TNT--GO TO THIS WEB SITE FOR MIKUNI INFO   http://www.mikuni.com/pdf/vmmanual.pdf    GUYS JUST FOUND A CONVERSION SITE TO CHANGE JUST ABOUT ANY TILLY TO MIK http://www.bayshorecad.com/Sleds/Literature/Carbs/MikuniVM/Mik_Conversion_Specs.pdf

stilldoonit--Probably the best explanation on jetting I have found yet:  http://www.snowtechmagazine.com/articles/2001/baseline/baseline.php  and also this: http://www.650motorcycles.com/CarbTuning.html


cdi to points (help); Setting Timing and CDI-to-points

440tnt--hi would like to switch my 1975 tnt 440 f/a over to points from the polar fire cdi because ive been havin alot of trouble with them  and i need to know witch sled would have tha points stater and magneto that would fit my tnt Thanks

Bones--Howdy 440tnt.  You must believe in magic doo you
`cause it would be a miracle if there is another hub that will work other than one from a `73 - 340 T`nT F/A or a BSE type 399 or type 439 F/A   ou will not find one from any other engine !!! When / if you find one of them i`ll walk `ya through what `ya need to doo. There is several different `70s stators that will work.
The mag stub end on a `73/75 T`nT F/A engines ( types 346, 396 & 436 ) is very large, bigger than any other that I know of, thus the limited options for a hub  
Place a "wanted" add on this & some other sites, see if `ya find one

Bones--Stator from a 340 F/A with a hub that is too small to fit a `75 crank & engine has a single carb....You most likely got the hub froma `77/78 - 340 F/A, doo you have the whole engine  The stator from that engine would work great in a `73/75 conversion.

Bones--900 magnetos, you are gonna` have to look through a bunch aren`t `ya  ( yeh I know)  
The magneto hub/magnet ring you need has the numbers 212 416 028,  12V 75/23W stamped on the magnet ring. On the hub is 865 460, (same number as on the CDI hub). On inside of the hub it will look similar to CD hub, the CD hub has a sleeve in the center with a prong on it that excites the CD trigger as it passes it. The Bk Pt hub also has a center sleeve type thing but is a "encentric" to operate the points where as the other conventional Rotax systems have a encentric sleeve that slips over the crank shaft that locks into a centrifigal advance lever to operate the points.
FYI: there is not a encentric sleeve big enough to fit over the "big" 75 crank stub !!!!
Using the stator from any `77/78 F/A 340 - 440 is a great choice or a stator from any `74/79 type 440 engine is also great as these stators have wires that are the right length to work good. Also on the `77/78 F/A engines or the `74/79 type 440 is a bracket that bolts to the crank case below the carb that the coils mount to, this bracket will bolt to the `75 case to mount the coils to.
Once you have the above equipment. Get some "NEW" Bosch points, the aftermarket points are not worth a damm. Install the points on the stator. Install stator & mag hub into engine. Set the breaker points to max opening of .014 TO .018" ( preference to .016" ).
Now get a TDC ( top dead center ) gauge. Install the TDC gauge into one of the spark plug holes ( either one ).
Rotate engine to find TDC, ( looking at engine from the mag end ), rotate engine counter clock wise to get the piston at .119" BTDC (before top dead center ). On the end of the crank case ( the part that the magneto is in ) there is a hole that you can see the fly wheel through. Around this hole is 3 marks, using the center mark as a main giude, is there now a mark on the flywheel that lines up with the center mark   ( while holding at .119 " BTDC), if yes good, if not make a mark on the flywheel coresponding to the center hole mark. Repeat this procedure for the other cylinder, it will be 180 degrees different on the fly wheel. Making the marks is optional, you can & should go by the dial when setting timing, but marks are good for future if you don` have a guage.
Now you need a signal device of some kind. You can buy audible tone signal devices etc. I simply use a sled head light bulb & a tiny 12V trickle charger for power ( 12V battery works fine).
OK, on the stator, from one set of points is a blue wire & from other set is a Blue/red wire ( in run mode these wires are connected to the high tension coils ), the wires at this time are not connected to the coils.
Assuming you are using a light bulb...You need a wire from the positive side of the bulb & a wire from the ground side of bulb.
Connect the power supply + to + side of bulb, - side of bulb to the blue wre ( blue is mag side, upper set of points, if you get the stator in as normal ) from stator, - side of power to engne case ( grd) . Now slowly rotate engine, light will be dim for part of rotation & bright for part of rotation, one set of points is now functioning as a "switch". After a couple of test turns to get the feel of the light. Install the TDC gauge in the mag side plug hole, find TDC, rotate engine counter about 1/4 turn, light sould be bright, now slowly rotate to right, when bulb dims, the points have opened & spark occures !!!
When the bulb went dim, take note of where the TDC gauge is ( maybe at .150" BTDC ? ). Do not make any adjustments yet. Install TDC gauge in PTO side plug hole. Connect the blue/red wire to bulb & repeat same procedure as above. Lets assume it also was at .150" BTDC, then you loosen the two screws holding the stator plate in place & rotate the stator to the right ( all rotate directions are looking at engine from mag end). If both sides were the same ie;.150", then you will only need to check one side after rotating stator until you think you have that side at the .119" BTDC, then check/confirm other side.
BUT...If when you first checked each side you found them different from each other.....You open or close a set of points to get them both the same. Decreasing point gap will retard spark, increassing gap will advance spark, but both sets of point MUST STAY WITHIN THE .014 - .018" range.
Point gap has the .014 - .018" range & the timing has a range / tolerance of +/- .010" ie 110 - 129" BTDC.
Other / partial method.....As above setting stator rotation & point gap to get timing in spec is some what trial & error, that is how I personally doo it all the time, but you can get you engine rtation at the spec .119" BTDC then open/close point gap to to get light to dim at that time, then tighten all & re-check. I have never had much luck at that my self.
The equipment I recomended using is stuff that was made by Doo/Rotax. You can take thngs to a machine shop, maybe even use stuff from a different manufacture etc, & possibly come up with several different combinations, but it will take some though  
Good luck.  Bones.

Bones--A complete magneto from a `74-79 type 440 engine is identical to a `77/78 340/440 F/A magneto & as mentioned in previous post, that is a excellent stator to use for the conversion, but you still need the other hub.

Bones--Bones. Will the Polar fire from the 75 Everest retrofit into other non 75 motors? 440 and 640 etc?  Reese
Howdy Reese.
I can tell you for certain, the Polar fire system from a `75 Everest WILL fit/work on any `74 to `79 "type - 440" engine. Actually you can use a Polar fire stator from any T`nT F/A or RV, but you "MUST" use the hub from a `75 Everest !!
The mag end of the crank on a `73 down engine is different & as far as I know there is no hub to fit.
640 engines retro   I have not had too many 640 engines around. I know the 640s up to inc `72 have a smaller mag end stub than the type 440 engine so again there is no hub to fit that I know of, but the `74 Nordic had Polar fire & I have never seen what the hub or crank end looks like so I really can`t tel you for sure about the post `72 engines   If you found a hub to fit with the exciter prong then I am almost certain you could use any polar fire stator, but then you need to watch which CD box you use.

stilldoonit--This is a great post for setting timing that I don't think a lot of people are reading because it is titled cdi to points. If someone were to re-word it to say maybe "Setting Timing and CDI-to-points" It may be found more easily by people just looking for a great explanation on timing an engine. Just a thought.   I've got this printed out and pinned to the wall above my workbench


Tillotson Carburetor - Diagrams / Rebuild Help / Parts

Sledder Al and 1970 TNT--Everything and anything you need to know about rebuilding a Tillotson Carburetor can be found:
http://www.aerocorsair.com/id27.htm
http://www.tillotson.ie/
http://www.eccarburetors.com/
http://www.mercurysnowmobiles.com/carbs.htm
http://www.mfgsupply.com/SnowTillCarbRepair.html
http://www.KIMPEX.com

jax--Haven't seen this one yet thought I'd add to the list http://www.bayshorecad.com/Sleds/CarbManuals.html  It does have an application sheet that is good info


Weak Spark One Side Troubleshooting

luckyketch and bliz340--Switch the primary wires at the coil. if spark stays weak on the PTO side then it is the coil, wire or plug or plug boot. if weak spark switches sides then the problem is in the MAG area.


Flywheel Pullers (and where to buy)

luckyketch--Flywheel Pullers can be purchased at the following URL's
Singles
http://www.parkeryamaha.com/browseproducts/SeaDoo-Puller-420976235.html
Twins
http://www.parkeryamaha.com/browseproducts/SeaDoo-Puller-529035547.html
Holder for Twins (needs slight modification for smaller twins)
http://www.parkeryamaha.com/browseproducts/SeaDoo-Flywheel-Holder-420876081.html

I have used all of the above and they work great.  Reasonable prices and shipping.

stomper--just ordered 2 of them from my local dealer he gave them to me way under list price


Link Plate Spring Removal Tool

luckyketch and bliz340--Here is a spring removal and installer tool I made form 12"piece of 1/2" water pipe and a T connector wit a slot cut in it. I would like say it was my idea but I have to give the credit to bliz340.
http://i39.photobucket.com/albums/e156/luckyketch/Spring%20Removal%20Tool/DSCF2849.jpg 

Tackle--You mean I don't have to hurt my hands doing this?  I guess now you are going to tell me you have some easy way to avoid pinching your fingers when you replace the metal slider on the skis (ouch).
I thought half the fun was showing all the bruises and cuts to your kids.  "wow nice bobo Dad"

luckyketch--I know this is cheating and there is probably a better way, but I bend them just a little in a vise. When you tighten them down you will never know it. Still get my fingers once in awhile but it doesn't seem to hurt quite as much.


NGK CHAMPION BOSCH Xref

luckyketch--Here is a real good cros referance for plugs. www.bayshorecad.com/Sleds/Literature/SparkPlug%20HeatXref.pdf 


Info available from Bombardier Museum, Manuals etc

westbranch--just got these 2 replies re info on my 1972 Oly... 

I've transfered your request to Guy Pépin the Museum Conservateur-restaurateur who will answer the production part of your request.
"Further to your request for technical publications for your Ski-Doo® Snowmobile Olympique 399cc 1972, the Museum have a copy of the  Parts Catalog (36$), Shop Manual (36$), Owner's manual (7$) and the Sale Brochure of the 1972 all models (5$) at a total cost of 84$.  All fees cover reproduction costs, postage, handling and taxes. If that interests you, we will forward you a copy of the technical publication requested.

The Museum requires receiving the complete payment before the sending of the document(s).You can pay by credit card (Visa or MasterCard accepted) or by check or postal money order made to "Fondation J. Armand Bombardier" and send it to my attention at the address below.

The Museum also asks you to send us your complete postal address so we can send you the requested material.  "
AND
"Concerning your request for information on your sled : here at our museum we have photos, technical publications, paint codes...etc on a 1972 Olympique* 399 cc model. 19120 were produced of this model.
If you require any further information, please do not hesitate to contact us"
Contacts are  via:
www.museebombardier.com  and g.pepin@fjab.qc.ca
Hope this helps someone else... 

moxymech1--Manuals also available online at BRP (huge 13 meg files)
http://www.operatorsguide.brp.com/login.aspx?ReturnUrl=%2fdefault.aspx%3fbrands%3dskidoo%26lang%3de%26type%3dog&brands=skidoo&lang=e&type=og

Poidy--I see that David has posted up some doo manuals here's the link
http://www.vintagesnowmobiles.50megs.com/VINTAGE_SNOWMOBILE_MANUAL_PAGE_FEB_2006.html

Warrior--Lots of stuff here, owners manuals, service manuals, clutch carb data etc.    http://www.vintagesnow.com/Home.html


Engine Compression Tables  

kingdavid--Anyone know a good source for compression level charts for 69-73 doos?  Specifically 299, 318, 335 singles and 340, 399 and 440 twins.  Thanks.

Jimbo Jessup--
Singles
(I don't have the numbers for the 318)
1970
299- 6.5:1
335- 7.5:1

1971
299- 7:1
335- 8:1

1972
299- 7:1
335- 9:1

1973- No changes

Twins
1970
399- 8.75:1
399(TNT)- 10:1

1971
399- 8.75:1
440(TNT)- 10.5:1

1972
399- 9:1
340(TNT)- 11.8:1
440(Nordic)- 9:1
440(TNT)- 11.8:1

1973
340(Olypique)- 9:1
399- 10:1
440(Olypique)- 10:1
440(TNT)- 10.5:1

gspaulding--Hello!  Just a few added notes.  If your altering compression ratio along with any exhaust port timing changes, these compression values are calculated as full stroke ratios not effective ratios.  Just wanted to mention that.

kingdavid--Great info!  Thanks.  I just picked up a compression tester and I have been testing all of my engines.......that turn over.   I am getting readings around 150 psi on all my one lungers.  Is that pretty standard and within effective specs?  I have one 400 with one cylinder at 150 and the other at 140....any concerns?  Thanks again.

lowtekrednek--Greg,  I would love that info- I think a lot of other guys would too.  if you email it to me I will post it- I think I can make it permanent

gspaulding--Hello!  I think I can fit it in right here.
Basically compression ratio is how many times the trapped cylinder and head volume at top dead center, will go into the cylinder and head volume at bottom dead center.  This is full stroke ratio and will be much higher than effective ratio because the entire cylinder volume (engine stroke) is being used for the ratio calculation.

But a 2 stroke doesn't start compressing mixture until the piston closes the exhaust port, and changing exhaust port timing (raising, lowering) can have a big effect on performance and of course compression ratio.  So if you raised your exhaust port 1mm, true (effective) compression ratio has changed but using the full stroke calculation (like a 4stroke) you will always show the same compression ratio.

So in the calculation, stroke (full stroke) should be used for a 4 stroke, and port height which is the distance from top of cylinder to top of exhaust port opening should be used (effective).

So the ratio calculation is pie (3.1416) times bore, times bore, times stroke, (full stroke) or times port height, (effective) divided by 4, divided by the combustion chamber volume at TDC not counting the plug threads equals ratio. (Move the decimal point to the left 3 places)

Example would be an engine with a 66.5mm bore, and a 63mm stroke, with an exhaust port height of 30mm and a combustion chamber volume of 17cc. using the calculation, this configuration would have full stroke compression ratio of 12.87-1 regardless of any exhaust port timing changes whereas the effective ratio would be 6.13-1 and would change with port timing changes.

The combustion chamber volume needs to be known of course and I can go over that also if anybody wants to know. But I think I've used up enough space for now.

Thanks!
Greg

luckyketch--Greg, I would be very interested in how to figure figure out the combustion area volume. We used to fill fill the head chamber with liquid (water), after removing it of course,  and approximate the volume that way,  but I am sure there must be a more accurate way.

I found this site and his method is exactly the way we used to do it when working on race engines. Did not know about the food coloring or the alcohol then. Wish I would have.

Here is the site:  http://www.merkurxr4ti.com/chambervolume.html

Tony

luckyketch--Not a problem. You can also find the squish area of a domed or stepped piston by using the same method only slightly modified.

Drop the piston down exactly 1" or 2.54cm from top dead center. Calculate the cc's at this distance. Then fill with liquid and and measure the amount of liquid required to fill cylinder up to plexiglass plate. Subtract this from the cc's calculated in previous step and you now have the volume filled by any irregular shaped piston, measure the thickness of a previously install gasket and calculate the volume this takes up. You now have all the info required in Gregs formulas.

The idea was to find out what the difference between all cylinders was. I can't remember for sure but I think was 1 to 1.5 % was acceptable.

This should all be calculated prior to final assembly cause it could get a little messy.

gspaulding--Hello!  Here's how I have always found combustion chamber installed volume to use with the compression ratio calculation.  You'll need a cc buret which is an accurate liquid measuring device,  dial indicator for finding TDC, measuring liquid for the buret, and a little grease.
A 50/50 mix of marvel mystery oil and parts washing solvent or gas works well for the liquid. It shouldn't be too thick or the liquid clinging to the sides of the buret after filling the combustion chamber can give you an inaccurate reading of volume.

First remove the cylinder head, wipe a thin film of grease around the upper area of the cylinder bore. Rotate the piston to TDC, then wipe any excess grease from around the piston.  This grease seals the ring end gap so your volume remains stable. Install the dial indicator and get exactly TDC. Lock the crankshaft/flywheel etc. in place somehow so the piston stays at TDC.

Install the cylinder with gaskets if any, and torque correctly. Use the buret to fill the combustion chamber with liquid up to the bottom of the spark plug threads.
Let the buret settle for a few minutes, read the volume used from the buret, and you have your combustion chamber volume needed for the compression ratio calculation.

Filling the combustion chamber to the bottom threads is fairy accurate, but to be dead on you need to measure the actual volume the plug displaces and then fill the liquid to the top of the plug threads and subtract the value the plug displaces.  That's another process called flat plate cylinder head volume measurement. But the process above will be very close.

Thanks!  Greg

luckyketch--1971 TNT 640 10:1 and 1970 Nordic Alpine 9:1

1970TNT--FYI  Compression Ratio Compression (psi) Range (psi)
6.5 96-114 18
6.6 98-116 18
6.7 100-119 19
6.8 102-121 19
6.9 104-124 20
7.0 106-126 20
7.1 107-129 22
7.2 109-131 22
7.3 111-134 23
7.4 113-136 23
7.5 115-139 24
7.6 117-142 25
7.7 119-144 25
7.8 121-147 26
7.9 123-149 26
8.0 125-152 27

SO YOURS IS 8:1 SO YOU SHOULD HAVE ABOUT 127 TO 154 IBS ON YOUR COMPRESSION TESTER OR WHAT I DOO IS TO MULTIPLY THE 8 NUMBER BY 14.7 AND ADD 20 IT WILL GET YOU CLOSE


1970-1973 blizzard numbers

decoy706--Bones, lost my Blizzard numbers could you either send them or post some for me.

bones--Hi decoy706. Here is what I have for F/A Blizzard #s.
1970s
7051 - 292,  292 units
7053 - 340,  308 units
7055 - 250,  20 units
7060 - 440,  311 units
7062 - 640,  290 units
7064 - 776,  354 units
1971s : For `71 there is two model series, 7100 - 7109 which are cleated track, & series 7150- 7159. I only have one set of prod #s & doo not know which series they are, I really suspect the 7100 - 7109  
250,  198 units
292,  262 units
336,  234 units
397,  113 units
437,  280 units
645,  245 units
797,  251 units
1972s
2501 - 300,  339 units
2502 - 340,  349 units
2503 - 395,  101 units
2504 - 438,  346 units
2505 - 645,  349 units
2506 - 797,  251 units
1973s
3501 - 298,  150 units
3509 - 345,  150 units
3503 - 441,  107 units
3504 - 645,  93 units
3505 - 797,  62 units
The model #s for `73 are the "GR" model #s & I really question if there was that many GRs built  I really wonder if those prod # are for the winter sleds model #s 3521 - 3525  
Bones


blizzard (and others) slide instructions
torque reaction suspension sleds  from ~ mid `70s to ~ mid `80s

rv340--Hello All,  I asked this before,  but I need more help.  Can one of you tell me how to change the slides on my 1981 Blizzard 5500.  I know you have to drop the suspension but I really don't even know how to start.  Any help would be appreciated.  I hope to start on this tomorrow......Thanks

bones--Howdy rv340. The removal & installation of that type of suspension has been a real nightmare for some  
But.....Please follow this method (do not varry it) & you will find it very, very easy to remove / install your suspension.
You will need to remove just 2 bolts on each side, the ones in the front & rear arms, you will not need to remove the center idler shaft.
First, fully loosen of track tension. Next, make sure you can loosen each bolt. Often you loosen one side, then go to other side, the cross shafts turns & will not loosen the bolt. You may need to loosen one side, back it out 1/2way, oil the threads, then thread it back in, snug it up, then go to other side & loosen bolt, go back to first side & loosen bolt by "snapping" it. A air wrench is a big help, but not required. Once you get the 4 bolts loose...
Tip sled on its side. Loosen the bolt in the limiter strap, leave on by a couple of threads. Remove the cotter pin from the pin in the top of the rear shock. postion sled back to track on floor. Set the load spring tension to lowest position on all 4 springs. Continue to fully remove the nut from limiter strap bolt & remove bolt. Pull strap off the lower shaft, leave strap hang on upper arm. Lay across rear of seat & push down on rear of sled, reach under sled & remove the pin from the rear shock. Lift up on rear of sled, suspension arms will stand up with no spring tension. Block rear of sled apx 1 ft higher than normal, to have rear arms straight up but not lifting track. Remove the bolts from either side of rear arm, push arm forward to make it fall down Lift rear of sled apx 2 ft higher than normal. Remove bolts from front arm, push arm forward to make it fall down. Pull suspension from under sled.
Change the slides......
Slide suspension under sled. With rear up apx 2 ft, swing the front arm up into position & install bolts, not tight. When you swing the arm up, ensure you have the springs in position, with the arm up, there will be No pre - load on spring at this time. Lower rear of sled, you will likely need to push down & forward some what as this pre loads the front spring a little. With rear of sled up apx 1 ft, raise rear arm into position, again make sure the springs are in place. Install the two bolts, not tight. Push down & forward on sled to load springs. Lay across the seat, reach under sled & insert the pin into the top of rear shock. Thread limiter strap back to normal. Install the bolt in limiter & start nut on. Tip sled on side. Tighten limiter strap bolt. Install cotter pin in shock pin. Tighten cross shaft bolts. Set spring ride adjustment to desired. Tighten track.
If you under stand the above procedure & follow it correctly, you really should have no trouble. Many guys want to leave the spring not in position when the install the bolts in the arms, then try to "FIGHT" the spring into position after, don`t doo that, it just makes it harder   I can usually install one of them suspension into a sled by my self in about 15 minutes, with no choice words, not skinned knuckles etc  
Good luck.  Bones

P.S. Fellas, this method works for "all" the torque reaction suspension sleds. From ~ mid `70s to ~ mid `80s  

Canadian RV--I can personally  vouch for Bones' method, he typed it up for me last yr...I followed it to a "T" and it worked no problem...

lshobie--same for the 300SS I suspect? thanks. Louis

bones--NO.....The Elan SS has a 2nd version of the ground leveler & is different from the torque reaction suspension.
For the ground leveler you leave it all together in the suspension frame & install it, then install the rear link plates.  Bones