Auto counterweight issues

[SiH]

Hey all - bit of an odd one.

The auto counterweight I have to fit my engine is causing huge headaches. When the main rear bolt is torqued up, it appears to be forcing the counterwight against the rear housing, and the whole rotating assembly is binding up.
I wa sold it as an FD counterweight - are there different types?
Could I have an FC counterweight?

Anyone had this problem before?
Cheers
Si

[bumpstart]

they all fit the same

the only time i have seen an issue is when adding the 6 flywheel bolts,, and having them too long
they protrude through and hit the stat gear bolt heads

you must select these bots carefully,, they must be hi tensile and the correct length

[SiH]

Cheers for that, so all the same though all FB, FD, FC, Cosmo?

We used random bolts to bolt up the fly, but we were only using them to fit the FW for assembly purposes (i.e. so we could lock the fly up to torque up the e-shaft) and theywere only jsut threaded in, and then nute were used further up the thread to ensure they weren\'t set too deep. We looked down between the CW and the housing/e-shaft/seal, and you could see that there was clearance between the bolt ends.

The engine has gone together using exactly the same components as it came apart with, with the exception of the CW. Engine had no issues before hand and 0.05mm of end float.

The strange thing is that we bunged a manual stock fly on there and torqued it up, and the end float was bob on 0.05. Thought we may have overtorqued the big nut on the rear, so loosened it and tightened it, but it still bound. It\'s got to be the CW, surely? Can\'t see what else it could be :confused:

[clive]

As bumpstart says, all counter balance weights whilst different weights are all the same dimensionally including FE

Only thing I can think of is that you have a S/H one thats come loose and its worn letting it fit further onto the taper,  

If the stock flywheel fits O/K then I would suggest you get another weight, however a word of warning is that you need an FD one because as said, the weights are different.

Quite honestly unless you buy new with a part number on the box you are risking an inbalence with your new engine because it\'s damn near impossible to see the difference between FC/FD and FE

Hope this helps

[bumpstart]

s5 FC and FD and cosmo 13b re all use the same rear counterweight part
( they all use the same mass 9.0:1  rotors ) ( including s5 NA = same mass rotor but 9.7:1 )
[ FD front weight uses the larger torrington race size ]

to identify the part you measure the inside rim edge flat ( without the chamfer edge )
metricated and measured thus -






89-95 13B
-N351-11-5210---------12.52 to 12.85 mm


86-88 13B
-N327-11-521A--------13.23 to 13.92 mm


76-85 13B
-1029-11-751A--------11.68 to 12.14 mm
( NB older versions may be stamped 1029A, 1029 or 29 )


83-85 12A
-N226-11-751A---------6.07 to 7.01 mm



79-82 12A
-1883-11-751A-------- 8.25 to 9.17mm

and PS,, rear counterweight and the nut TQ has no effect on engine endfloat
-- the endfloat is all set relative to the front stack component height and front stat gear position
and as such its not uncommon for race old school 12a/13b that has had plates faced many times to be short in the block
- requiring ovalling of manifold stud spacings,, and shimming the starter motor backwards to clear the ring gear
( cause the crank effectively sits further out the bum of the assembled \'shorter\' block )

[SiH]

Cheers guys, some awesome info there! - I\'ll go get my plastic verniers on it for a rough approximation!

Yeah, the endfloat setting using hte washers is what I\'m talking about, and we  knew it shouldn\'t have any effect, but were starting to run out of ideas!

[bumpstart]

try fitting the current C/W without the flywheel or bolts
see if it turns,, i still have my suspicions the flywheel bolt threads are hitting the stat gear bolt heads unseen

the only other thing i have seen lock the engine up is early open extend porting that fails to support the side seal fully
-- when rotating backwards the seal closing end can strike the bottom of the port pattern
( if the port isnt chamfered to help the seal ride home )

[DRAGON]

s5 FC and FD and cosmo 13b re all use the same rear counterweight part
( they all use the same mass 9.0:1  rotors ) ( including s5 NA = same mass rotor but 9.7:1 )
[ FD front weight uses the larger torrington race size ]

to identify the part you measure the inside rim edge flat ( without the chamfer edge )
metricated and measured thus -






89-95 13B
-N351-11-5210---------12.52 to 12.85 mm


86-88 13B
-N327-11-521A--------13.23 to 13.92 mm


76-85 13B
-1029-11-751A--------11.68 to 12.14 mm
( NB older versions may be stamped 1029A, 1029 or 29 )


83-85 12A
-N226-11-751A---------6.07 to 7.01 mm



79-82 12A
-1883-11-751A-------- 8.25 to 9.17mm

and PS,, rear counterweight and the nut TQ has no effect on engine endfloat
-- the endfloat is all set relative to the front stack component height and front stat gear position
and as such its not uncommon for race old school 12a/13b that has had plates faced many times to be short in the block
- requiring ovalling of manifold stud spacings,, and shimming the starter motor backwards to clear the ring gear
( cause the crank effectively sits further out the bum of the assembled \'shorter\' block )

Good post thanks.
Wdo you know what weight the low compression turbo 2 rotors are?

[AtomicRex]

Ross as standard they are about 4.6kgs
 
I have a set of balanced ones in stock if you want them

[SiH]

try fitting the current C/W without the flywheel or bolts
see if it turns,, i still have my suspicions the flywheel bolt threads are hitting the stat gear bolt heads unseen

the only other thing i have seen lock the engine up is early open extend porting that fails to support the side seal fully
-- when rotating backwards the seal closing end can strike the bottom of the port pattern
( if the port isnt chamfered to help the seal ride home )

We could clearly see space between the bolts and the stationary gear - pretty sure they weren\'t hitting the heads as it was a constant drag, rather than a solid feel of resistance/\'indexed\' feeling.

Just measured up the CW outer lip without flange and it\'s around the 12.5 mm mark. Will get a photo up shortly and you can sort of see where it was dragging.

Only other thought was that the stationary gear bearings (I had new ones pressed in) weren\'t all the way home, but they aren\'t proud of the gear.
 
As soon as the CW is removed the engine rotates freely, so I don\'t think it\'s a build issue in that respect.

Only thing is the manual isn\'t 100% clear - with the e-shaft in and the motor built up, it is simply stationary gear > CW, with no shims/spacers between, yeah?

Thanks again for the help peeps, much appreciated At the end of my tether with the heart of Christine atm

[SiH]

OK, piccies:


And you can see the binding here:

[bumpstart]

Only thing is the manual isn\'t 100% clear - with the e-shaft in and the motor built up, it is simply stationary gear > CW, with no shims/spacers between, yeah?

correct

and it does appear that the CW is dragging on the rear stat bearing, me thinks i would take that rear stat out and look closer at it
( in fact i rather suspect there is an issue in the front stack assembly that has pulled the crank to far out,, and you will know when its time to fit the serp belt )

this morning i put a s/h stat and counterweight together
( so that the rubbing mark on the CW sat on the lip of the rear seal )
and there should be 8- 10 mm approx of space between CW and rear stat bearing end
( at least enough to squash my finger tips in there )

please tip the motor with crank snout up and redo the front stack assembly to be sure
( and remove and inspect that rear stat,, something is amiss ! )

[SiH]

Cheers again for the input
The thing I don\'t get though, is why does it work ok with the manual flywheel? That\'s what has me confused!

We\'ve redone the front stack several times to  no avail

Just checked the FSM and I\'m pretty positive that\'s how it\'s gone back together - only thing that\'s changed is the counterweight, new Apex and side seals (but it can\'t be them, otrwise the motor wouldn\'t turn without the large nut done up, surely?) and new sationary gear bearings.
Is there any way that the stationary gear bearings could cause this?

[clive]

Slide the old stock flywheel on and measure how far its going onto the shaft then do the same with the counterweight and I feel your going to find that the counterweight is going up the taper too far,

I think logically your going to end up getting another counterweight because as you say, every thing is fine with the stock flywheel

[FD3UK]

Have you set end float?

Thrust bearing dropped?