hey i have a sled here that only runs on two cylinders they are 1 and 2, it has good spark on all 4, carbs have been gone through, and has good comp. on a 4, so it has fuel spark and compression on all cylinders but only 1 and two are firing. now when cylinder 1 is at tdc 2 is bdc 3 is bdc and 4 is tdc is the crank timing off what is the 90 or 180d engines?
crank question
- Thread starter lucky7ms
- Start date
AL P
Moderator
so the plugs on the right two cylinders are wet when you pull them?
just for poops, and giggles, have you switched the left two plugs, for the right two?
hope the crank aint twisted?
if this motor has`nt been re-set to other then stock settings IE has`nt been pulled apart, and set to 180..then you defiantly have a twisted crank..but again, it seams VERY odd, that it would twist, and end up perfectly like a 180`d motor would be?
can you talk with the previous owner, and check on that??
AL P
just for poops, and giggles, have you switched the left two plugs, for the right two?
hope the crank aint twisted?
if this motor has`nt been re-set to other then stock settings IE has`nt been pulled apart, and set to 180..then you defiantly have a twisted crank..but again, it seams VERY odd, that it would twist, and end up perfectly like a 180`d motor would be?
can you talk with the previous owner, and check on that??
AL P
ive switched the plugs around coils around, 3 and 4 act like they want to fire but just pop, and load the exhaust(psi quads) with gas maybe someone rebuilt it wrong? i just got the motor out of the sled so im going to have a look at it when the piston is at tdc what is the piston position supposed to be
AL P
Moderator
okay...first off, so as to save posible confsion..lets call the cylinder nearest the clutch, cylinder #1..
okay, in stock form..90 degree`s..
cylinder #1 would be at TDC, cylinder #2 would be at BDC, and cylinders # 3 & 4, would both be even at half stroke..with cylinder #3 on its way up, and cylinder #4 on its way down...not...don`t forget the motor n a vmax4 rotates in the opisite direction as any other sled motor that I know of..
Here`s a couple pcs I drew a while back to help explain/describe..
okay, in stock form..90 degree`s..
cylinder #1 would be at TDC, cylinder #2 would be at BDC, and cylinders # 3 & 4, would both be even at half stroke..with cylinder #3 on its way up, and cylinder #4 on its way down...not...don`t forget the motor n a vmax4 rotates in the opisite direction as any other sled motor that I know of..
Here`s a couple pcs I drew a while back to help explain/describe..
AL P
Moderator
Yeah it does`nt sound good...unless....
someone did rebuild it, and set it to 180 degree`s???
Lucky..are you sure, or relatively sure..that those TDC`s, and BDC`s, are correct?? I mean, do you feel confident that their truley at TDC/BDC??
I`d still think about trying to get ahold of the previous owner, to see if they rebuilt the lower, and how they set the crank??
Good looking out on the CDI jamie!
Lucky, almost forgot to add an answer to this..
what is the 90 or 180d engines?
a 90 degree motor, would be like the pic i posted..every 90 degree`s of crank rotation, a piston would fire/come up to TDC..
A 180`ed motor, TWO piston would fire every 180 degree`s of rotation.
either piston 1 & 4 would run together and both hit TDC at the same time (like wise with pistons 2 & 3), or i believe on some setups, pistons 1 & 3 would run together and hit TDC at the same time (like wise with pistons 2 & 4)..
so on a 180`ed motor, every 1/2 crank turn, two pistons would fire/reach TDC..
someone did rebuild it, and set it to 180 degree`s???
Lucky..are you sure, or relatively sure..that those TDC`s, and BDC`s, are correct?? I mean, do you feel confident that their truley at TDC/BDC??
I`d still think about trying to get ahold of the previous owner, to see if they rebuilt the lower, and how they set the crank??
Good looking out on the CDI jamie!
Lucky, almost forgot to add an answer to this..
what is the 90 or 180d engines?
a 90 degree motor, would be like the pic i posted..every 90 degree`s of crank rotation, a piston would fire/come up to TDC..
A 180`ed motor, TWO piston would fire every 180 degree`s of rotation.
either piston 1 & 4 would run together and both hit TDC at the same time (like wise with pistons 2 & 3), or i believe on some setups, pistons 1 & 3 would run together and hit TDC at the same time (like wise with pistons 2 & 4)..
so on a 180`ed motor, every 1/2 crank turn, two pistons would fire/reach TDC..
Last edited:
Kaw550
New member
Did you just buy this sled or were you running it? If you were runnin it I'd say the cranks spun and are looking like a 180'd motor, if someone just bought it like this I'd say someone needed the 180 box. When you say where the non runnin cylinders are, are you checking that with a degree wheel, meaning they are exactly 180'd or did you do the quick and easy check.
AL P
Moderator
Dang, you don`t mess around..kick butt man..
so what`d everything look like? i take it the dots on the center gears were lined up, but the pistons were in the wrong position?
There`s a place down here in flint, that has been around forever, and has a VERY good reputation, that can do it..they`ll set it, and weld it..
only thing is, they won`t quote you a price, until they see your crank..reason is..they don`t want to tell someone a certain price..then see the crank, and its got some kind of damage or whatever (outside of the twist of course)..
anyway, I`ve delt with ths place ALOT over the years, and have always been VERY happy with thier work..plus..they`ve always been very competitive on pricing..
so what`d everything look like? i take it the dots on the center gears were lined up, but the pistons were in the wrong position?
There`s a place down here in flint, that has been around forever, and has a VERY good reputation, that can do it..they`ll set it, and weld it..
only thing is, they won`t quote you a price, until they see your crank..reason is..they don`t want to tell someone a certain price..then see the crank, and its got some kind of damage or whatever (outside of the twist of course)..
anyway, I`ve delt with ths place ALOT over the years, and have always been VERY happy with thier work..plus..they`ve always been very competitive on pricing..