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T O P I C    R E V I E W
rannsachairPosted - 03 Nov 2012 : 11:51:17
Thought I would start a new thread in response to 1970V4:

"Nice bikes!

You should keep your eyes out for a 95 or 96 two-stroke car with a blown engine. A bullnose is even better, less weight up front (less sheet metal)and quicker ratio steering rack. Check out my '64 that I recently got going: http://saab-v4.co.uk/speedball/topic.asp?TOPIC_ID=3135&whichpage=1

Strokers are fun but a totally different animal than the V4.

Is the gearbox a 3- or 4- speed? Does it have the drivers that are cups or the ones with flexible rubber bits in them?
"
Gearbox is four speed with cups:
Engine had been put away with lots of oil - even carbs were full of oil. No visible wear on any compnents: bores perfect as is distributor, carb internals and starter gear looks like new.


Going to paint engine and get all brackets and air filter epoxy coated. Was ready to order gaskets and seals yesterday but Erik's site is down.
15   L A T E S T    R E P L I E S    (Newest First)
rannsachairPosted - 02 May 2013 : 20:24:14
quote:
Originally posted by john wyatt
I have a set of ht eads with correct SAAB caps I would be happy to send you

Very kind offer, i have emailed you.
john wyattPosted - 02 May 2013 : 19:43:31
I have a set of ht eads with correct SAAB caps I would be happy to send you
rannsachairPosted - 01 May 2013 : 22:06:52
Engine was rebuilt a few months ago, just gearbox to checkover.


rannsachairPosted - 12 Jan 2013 : 16:33:43
quote:
Originally posted by rsimps
Usually you can make some measurments on how much the rod can flop from side to side at an angle (I will have to get a measurment from either the service book or the tuning books for you).

No you can have a very worn bore without any marks at the top. the liner expands around the exhaust port and then wears when hot. What I found is that you get alot of wear around the port areas, not much at the top and a tapper below the ports. At one point I had a max difference of 0.12mm on one bore. You need a bore gauge though to measure at different points down the bore. At this point the engine was blowing past its rings and effecting the crankcase.
Also do a compression test, a std used engine seems to be around 120 psi.

Finally got a new original gasket from Erik. He threw in a new fuel pump diaphragm for the hassle

Measured bores .04 to .05 mm difference between top of bore and at ports and up to .015mm difference at ports 90 degrees appart, does this appear ok?

Thanks
rsimpsPosted - 13 Dec 2012 : 12:36:41
Usually you can make some measurments on how much the rod can flop from side to side at an angle (I will have to get a measurment from either the service book or the tuning books for you).

No you can have a very worn bore without any marks at the top. the liner expands around the exhaust port and then wears when hot. What I found is that you get alot of wear around the port areas, not much at the top and a tapper below the ports. At one point I had a max difference of 0.12mm on one bore. You need a bore gauge though to measure at different points down the bore. At this point the engine was blowing past its rings and effecting the crankcase.
Also do a compression test, a std used engine seems to be around 120 psi.
rannsachairPosted - 11 Dec 2012 : 20:24:55
quote:
Originally posted by rsimps
If you go down the solid gasket route you will need the block and head grinding to a very high level of finish, then get a can of spray Hylomar and spray 2-3 coats each side.
Have you checked the bores for wear, they seem to wear around the exhaust ports (probably due to bore expansion). You need to get a bore gause down there and measure at set distances and angles to get a picture of the bore wear. On the engine I an rebuilding at the moment it was so bad I had to go up a full 1mm in piston size, 0.5 would be hit and miss. Also is the crank OK?

I am awaiting a new composite gasket from Erik.

Last 2 stroke my dad rebuilt was a BSA Bantam and only manual I could get hold of is by Autopress Ltd, so not much advice on checking. For Crank just degreased it, firm pull and push on con rods - no discernable movement and span bearings - no noises. Is there much more you can do to check?

I know there was no visible bore wear, will check at ports with internal mic before head goes back. Do you not get a step at the top of the bore like on a worn 4 stroke?

Thanks for advice.

rsimpsPosted - 11 Dec 2012 : 08:05:15
If you go down the solid gasket route you will need the block and head grinding to a very high level of finish, then get a can of spray Hylomar and spray 2-3 coats each side.
Have you checked the bores for wear, they seem to wear around the exhaust ports (probably due to bore expansion). You need to get a bore gause down there and measure at set distances and angles to get a picture of the bore wear. On the engine I an rebuilding at the moment it was so bad I had to go up a full 1mm in piston size, 0.5 would be hit and miss. Also is the crank OK?
rannsachairPosted - 23 Nov 2012 : 12:44:20
Erik has found a problem with his current batch of gaskets, he is speaking to his supplier today.
dansp1Posted - 22 Nov 2012 : 18:02:05
Or i have got a solid alloy head gasket 1mm from Niklas if you are interested.............
dansp1Posted - 22 Nov 2012 : 17:58:12
That gasket looks diabolical!
try these folk
http://www.classicsaabparts.nl/c-458340-4/motor/
rannsachairPosted - 22 Nov 2012 : 17:07:43
I purchased a new Head Gasket from Erik, does not look right - to get the gasket central on the bores I will have to elongate the bolt holes and will have about 1/2 the gasket width across some sections near the waterways. Erik has agreed to take it back.

Anyone else experienced this, I would be happier finding another head gasket that fitted better.

See:


TristaredPosted - 21 Nov 2012 : 14:30:47
Cor blimey – look at that!

Nicely done.
James RanaldiPosted - 19 Nov 2012 : 23:06:34
Looking good. Green and black, real "old school" . Luvvin it.

Cheers
rannsachairPosted - 19 Nov 2012 : 22:47:07
quote:
Originally posted by Woody
Looking good.

Can I ask the dimensions of the gaskets in the poly packet?
ie size of large hole and distance between small holes centre to centre.

Was not quick enough, measured the old gaskets: 69.8mm between centres and main bore 46.7 mm - was already assembled:



rannsachairPosted - 18 Nov 2012 : 22:32:26
quote:
Originally posted by Woody
Looking good.

Can I ask the dimensions of the gaskets in the poly packet?
ie size of large hole and distance between small holes centre to centre.

I will be up at my parents tomorrow night, will measure then and let you know.

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