Harmonic Balancer bolt thread/size for removal.

[AgentSBond]

Hi mercruiser boaters,
I'm trying desperately to remove the harmonic balancer from my 470, as I need to change the Circulation Pump gasket behind it.

Does anybody know what thread/size bolts to use for a puller? Most likely they are imperial and the cheap puller I bought from an auto shop only has metric thread on the bolts.

Picture attached.

I'd appreciate any advise.
Thanks
Si

 

[Scott Danforth]

yes, imperial. should be 5/16-18 or 3/8-16

 

[AgentSBond]

yes, imperial. should be 5/16-18 or 3/8-16

Thank you. That is super helpful. you're a star

 

[kenny nunez]

It is definitely 3/8” 16 . Try to get a tap that size to clear the threads if you can. If possible get a 1/2” 20 bolt at least 2-3” long to help reinstall the balancer along with some 3/8” and 1/2” flat washers.

 

[AgentSBond]

It is definitely 3/8” 16 . Try to get a tap that size to clear the threads if you can. If possible get a 1/2” 20 bolt at least 2-3” long to help reinstall the balancer along with some 3/8” and 1/2” flat washers.

Okay that's sound advise. I know exactly what you mean about getting a longer centre bolt to reinstall the balancer. Thanks alot for the great help. I'll crack on tomorrow morning.

 

[Grub54891]

Okay that's sound advise. I know exactly what you mean about getting a longer centre bolt to reinstall the balancer. Thanks alot for the great help. I'll crack on tomorrow morning.

I use this, no risk of messing up the threads on the crankshaft.

 

[todhunter]

I use this, no risk of messing up the threads on the crankshaft.

Agreed - I've got the Moroso harmonic balancer installer tool - similar concept. The thing I like about the Moroso tool over using a long bolt is that it has a bearing to reduce friction while turning the nut - this reduces the chance of snapping the bolt off in the crank snout. Looks like the kit you posted has a bearing in it too.

 

[Grub54891]

Agreed - I've got the Moroso harmonic balancer installer tool - similar concept. The thing I like about the Moroso tool over using a long bolt is that it has a bearing to reduce friction while turning the nut - this reduces the chance of snapping the bolt off in the crank snout. Looks like the kit you posted has a bearing in it too.

Yeah, the one I actually have does have the bearing; I just posted the first one I saw online. Wish I would have got it years ago.