Tips for removing engine zincs?

[Tree]

Hi all. I've currently got FP2 on the hard for annual maintenance and this afternoon went to change the engine zincs only to have a bit of a problem - some of them are locked in solid! I've managed to do the oil cooler despite the end cap spinning but I cannot for the life of me remove the others. I've applied plenty of penetrating fluid on them to leave soaking overnight. Does anyone find that they're easier to remove on a warm engine as this is the first time I've changed the zincs myself. Oh and how on earth do you change the zinc on the fuel cooler? I can't see any practical way to get to it with it being so tight to the bulkhead?

Engine is a 6LP.

Cheers

Lee

[mike66]

Do you have trouble loosening the bolts, or are the zincs stuck in the cooler while the cap comes out?

[Tree]

Both actually. The ones I have removed the zinc was stuck in the cooler. I know they're free of any loose zincs as the coolers were stripped around 200 hours ago.

[Tree]

Well I managed to finally access the fuel cooler zinc despite having my hands ripped to bits from hose clamps and zip ties but that still leaves me trying to get the zincs out of the CFW cooler and the air cooler. Despite them being the easiest to access they're the ones that are solid. Anyone else experienced this with these ones as I really don't like the idea of putting too much weight on them and possibly destroying the thread.

I've given them another liberal soaking of penetrating fluid this evening and I'll give them another go tomorrow.

[Carl]

I have changed mine every year for 8 years and have never had to deal with a frozen one. I would not worry about the threads at this point, if they truly were installed too tightly, damage most likely is done. I bet when you get down on them they brake free with no issues. Good luck!

[Tree]

Carl, my thoughts are since they are tapered threads they should move easily but they're just not budging! If they don't shift tomorrow, I think I'll wait till I've got the engine hot and give them a go then.

[RobS]

Never experienced and never heard of the brass caps being frozen. Are you using a slight smear of grease on install? Sounds like they are getting installed dry and way too tight. Not sure if the cold side of the coolers will got hot enough to make a difference. I would deal with it now rather than later. Be sure to hold the casting when putting pressure on them. If you think heat will help maybe you can get a torch on the area. Probably a good time to pull those coolers for a full service so you can work them on the bench.

[Tree]

Rob,

remember when I had the issue about 2 years ago with the core plug for the oil pump? I had the engine out then to do a decent paint job on it then and all coolers were pulled and cleaned at the same time. I've had the end cap off the oil cooler to remove a broken zinc and there is little if any build up of lime in system.

One other thing i found strange was the zinc kit i bought from yanmar only had 4 small zincs in it when there appears to be five on the engine and one bigger zinc for the air cooler. I've machined enough zincs now so i can change them every 3 months to stop any zincs breaking off in future - just need to get three of them out!

[Carl]

If and when you get them out, you may want to use this. It will enhance the connection as well. Use sparingly, it is messy stuff and doesn't wash out of cloths very well.


http://www.mscdirect.com/product/details/00129189

[Tree]

Bruised knuckles aside I've got them! The zincs had jammed in the bores and were gripping causing the thread of the zinc to lock against the thread of the brass plug. 3' bar took care of that. Now to remove the zinc that's in the hole!

[RobS]

Good to hear. You may want to chase the female threads in the coolers with a tap to be sure all is right. And some thread sealant, like rectorseal, on reinstall.

[Tree]

Wouldn't thread sealant defeat the object of a metal to metal bond?

The plan is now I've got a bag full of zincs to pull them every three months. I don't anticipate this problem happening again and I'll minimise the chance of any zincs ever falling off again.

[RobS]

No, you'll still get the metal to metal interference fit of the tapered pipe threads but the pipe dope will fill any tiny imperfections between the threads. If you want to "feel good" afterward, just check it with an ohm meter after install.

[Jeremyvmd]

My engine zinc was frozen in(us peninsular guys only have one to worry about;)) but that's cuznit sat for two years unused. So I suspect it didn't like that. I just threw a lil dielectric grease on the threads and called it a day

[RobS]

Yup, the "conductivity" is the result of the metal to metal conduct, not whatever product we decide to use. Any "product" is displaced and simply fills the voids and protects the connection from the environment. The pipe dope may be especially helpful in Trees case since the threads may be less than perfect after that "3ft bar"