Topic: Tight Motor ,Starter wont crank it, Please help!!

[mowterin']

well i finally got around to building my 16 hP Opposed today, jusat putting it back together, nothing fancy. I used all the original parts that came out of it. torques are right, but the motor is so tight i can barley spin the flywheel by hand. thew starter wont event get a revolution out of it. does anybody know anything, there all the original rings rods, the crank was never taken out.

[hoserrb]

take the bottom "pan" off. if it is still hard to turn, then it's likely a crank/rod issue. if it now spins freely, then you may not have a thick enough gasket and therefore not enough end play.

if you never took the rods/pistons/rings and crank out, what the heck did you rebuild?

if you took out the rods/pistons you can bolt the cap on the wrong way, then you will have trouble.
When i put together a twin i always spin the crank after each rod/piston install to make sure there is no problem before complete re-assembly. every time you put in another part, spin it. then you know if there is a problem

[mowterin']

it was torn down to just the crank installed. all i did was replace an exhaust valve, put the starter on, put the rods in, and heads. please explain the right and wrong way to put rod caps on. how are the supposed to mate up. im thinking that is what i did wrong, it spun perfect without the rods in. thanks for the help too!!- i dont have a book , or i wouldnt be asking these simple questions, i dont get it ,i can build 10,000 HP jet engines and propellers in my sleep, but a 16 HP opposed will kick my butt every time!!! LOL

[mowdak1]

The right way is to mark the rods and rod caps before taking them apart, so that you know which rod and which cap go together in which orientation. Each rod/cap combination will stretch a little differently when tightened down the first time they're bolted together; each will wear a little differently due to the forces encountered under load.

If you reverse the orientation the cap was bolted on, or mismatch the caps and rods, you may have moved a few thousandths on the cap in a direction opposite of the same few thousandths on the rod side of the journal, the end result of which is a weee bit more than a few thousandths! Wherein you got one (or two) very tight rod cap(s)!!

As for how to figure out which one goes where, since that's gonna be the next question, are you by chance familiar with the Rubik's Cube??? Same theory, kinda!!

[mowterin']

ok, i can solve a rubiks cube, so ill give it a go!!

[mowdak1]

About all you can do is take them off, or at least loosen both up and start over. Torque one down see if it gets tight. If it does turn the cap the other direction. If it still gets tight, swap the caps, torque it down, see if it gets tight, turn the cap if it does. Upon finding the right combination, install the other, torque, test, turn it around if it's tight. While in the process, keep repeating over and over... "I'm glad I wasn't building a V-8!"  :wink:

[Squidd]

Don't those rod ends have a Dado and a Rabit notch, so they only go on one way...??

Then your just down to rod to rod switching...

[mowdak1]

Randy's comments did make me think, (now that I'm awake) and I thought... Why didn't I look at my Briggs Interactive CD to see if there was a picture of that there. And, there is sorta, but it doesn't show the dado and rabit. It does however make a few other critical points in there that should maybe be addressed like location of the oilling holes on the rods and such...






Found the CD on E-Bay for about $10 - $12 with shipping, it only runs through 1999 though.

Different CD than I have you might want to check on year models covered

[Mowindown]

modak1 does the program run on Windows XP  i seen some on there that only run on widows98.  If it does run on xp I need one   thats not a bad deal.  Thanks

[mowdak1]

The copy I have indicates it will work in all MS Operating Systems -95, 98, ME, 2000, and XP. XP has the ability to open many 98 and early ME programs that even 2000 won't, and if it's good for 2000, it'll work on XP. The drivers are both set up for NT partition there, and thus essentially the same.

If you look closely at the larger image bottom of the link posted above it appears the CD is copyrighted 2003 or 2005, can't quite make the last number out there, but definitely after 2000, in which case I wouldn't have any reservations about it running on XP.

Actually a very nifty program, has loads of good info, you can elect motor type... L-Head, OHV, V-Twin, 180* Opposed Twin, search by model number, look up by part name, use the menu to move directly to chapters within the manual, etc. etc. The only drawback I've found is it locks you in the program when open, so you can't copy and paste info like I did above! Well... at least most folks can't. There are ways!!  :wink:

[nor66]

I also have that cd it is a really good deal, it says on the the cd that it will run on xp,2000.ME,98,and95 so it should work it is worth the try  

[mowterin']

SWEET, i only had 1 cap backwards and it was the first one i picked, so it runs great now, but i can hear a slight knock, like a little slop in one of the rods, it may be time for some new ones, huh, thanks for all your help, you guys saved me a bunch of headaches! now if only building my drag car was this easy LOL

[hoserrb]

not saying this will happen to you but....
i once put a cap on backwards on a twin, torqued it down, then changed it to proper once i realized. it must have bent the cap a bit because it was just a little tight when put on right. ran fine for about 10 minutes, then siezed, and gouged the crank enough to ruin it too. not good.