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Message |
    
nar
Advanced Member
Username: nar
Post Number: 31
Registered: 04-2007
| | Posted on Tuesday, December 18, 2018 - 01:27 pm: | 
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Hi, I’m posting for a friend that has a twin cylinder Vim “high-speed” engine made in Sandusky, Ohio. The crankshaft was out of this engine when he got it & he was wondering if anyone here could answer a couple questions about the crankshaft throws in it.
Being a twin cylinder, it’d seem like the crank throws should be 180 degrees apart but this engine has throws that are about 150 degrees apart. (30 degrees off from where they should be, see pics below)
Has anyone had one of these engines apart or know if the crankshaft should be 180 degree throws instead?
The ignition timer has pick-ups that are 180 degrees apart which means the crank throws should probably be 180 degrees apart but my friend has had the crank to about 6 places & all have said it isn’t twisted.
He just wants to positively confirm one way or another if this crank is right or wrong before putting the engine back together.
Thanks & any replies or info is appreciated,
-Nick
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giii
Advanced Member
Username: giii
Post Number: 37
Registered: 04-2010
| | Posted on Tuesday, December 18, 2018 - 02:30 pm: |
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Are the timer terminals at 180 or 150 degrees?
George |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1401
Registered: 07-2002
| | Posted on Tuesday, December 18, 2018 - 07:11 pm: |
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That crank was cut from flat plate, it was flat at one time, probably both throws on the same side to save metal. I would say it should be 180, don't know if they didn't twist it enough or if it got damaged. |
keith
Senior Member
Username: keith
Post Number: 527
Registered: 02-2002
| | Posted on Wednesday, December 19, 2018 - 09:32 pm: |
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I have a 3 cylinder, high speed Vim. I’ll check the crank timing on it but I would bet they fall an equal 120 degrees apart. If the the timer is, as you stated, 180 degrees apart, the crank is incorrect. 30 degrees additional advance? Wow |
keith
Senior Member
Username: keith
Post Number: 528
Registered: 02-2002
| | Posted on Saturday, December 22, 2018 - 09:05 pm: |
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I checked. My 3 cylinder falls at 120 degrees. The timer is a Unisparker. Any chance the crank throws are 120 and it's a cut off 3 cylinder crank. I suppose with the proper degree timer it would run something like a John Deere. |
nar
Advanced Member
Username: nar
Post Number: 32
Registered: 04-2007
| | Posted on Tuesday, December 25, 2018 - 02:40 pm: |
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Thank you for everyone that posted & supplied info, I appreciate it & my friend said thanks as well.
George, on the ignition terminals, the spark plug connection terminals are 180 degrees apart on the timer which should mean the crank throws should probably be 180 degrees apart.
Not a Vim but my dad is currently working on a stationary twin cylinder in-line 4-stroke engine with 180 degree crank throws that has a mag with spark plug wire connection terminals coming out of it at 130 degrees (which doesn’t seem to be right for 180 degree crank throws but it’s the original mag). We’re guessing it has extensions on the terminals inside that pick-up the spark at a different angle than we’re seeing on the outside. (Maybe a rare case but the degree of the spark pick-ups inside is different than the spark plug terminals outside).
JB, thanks for the info on the crank & like you said it might just be damaged. For some reason the crank & flywheel had been taken out of the engine when he got. Everything else was together.
Keith, thanks for checking your Vim, we appreciate it. The crank could be out of another Vim but it’s odd with the 150 degree throws.
Thanks again & if he finds out anything else I’ll let you know.
-Nick
Since this is a Vim related I’ll post it; it’s a couple Vim’s my dad bought a while back. Both came from the same place & were like new. The one with the transmission is serial #997 & the other is serial #1860.
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jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1403
Registered: 07-2002
| | Posted on Tuesday, December 25, 2018 - 10:33 pm: |
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On a 4 stroke with a 180 crank the distributor fires 90 degrees apart, skips 270. Look at the point cam to see when it's actually firing. |
