Official Caterpillar3116/3126 Thread

[Njlarry]

Didnt know aluminum worked in brackish and even salt. Good to know, they look to be less cost too.
What is the advantage of stainless plugs and are they all the same size? I have not yet changed mine but was surprised the set of zincs I received from boat zinc had some with the plug on and some off. Can aluminum be used with bronze plugs?

 

[Thomas Griffith]

https://www.glendinningprods.com/store/Synchronizer-c3154908

On order along with a Flexshaft. Once I learned what that is, made perfect sense just to do it. Thanks! Hopefully by this weekend we will have a fully functioning starboard engine again!

 

[dtfeld]

Didnt know aluminum worked in brackish and even salt. Good to know, they look to be less cost too.
What is the advantage of stainless plugs and are they all the same size? I have not yet changed mine but was surprised the set of zincs I received from boat zinc had some with the plug on and some off. Can aluminum be used with bronze plugs?

The CAT after cooler caps are a strait thread and require the o-ring to seal. The Stainless can be thrown into rydlym over and over and dont discolor. I had to change the After cooler much more ofter than the other anodes, hence the 2 sets.

The other anodes are in a Pipe thread cap, so they seal as you tighten them, no o-ring. I do have the pipe thread versions for the other anodes as well, and use the same rydlyme method

 

[Steve S]

The CAT after cooler caps are a strait thread and require the o-ring to seal. The Stainless can be thrown into rydlym over and over and dont discolor. I had to change the After cooler much more ofter than the other anodes, hence the 2 sets.

The other anodes are in a Pipe thread cap, so they seal as you tighten them, no o-ring. I do have the pipe thread versions for the other anodes as well, and use the same rydlyme method

View attachment 114792

Dave,
As in expert in threads, i need to point out that standard NPT tapered pipe threads do not seal without Teflon tape or pipe "dope". This is because the roots and the crests of the threads are truncated and do not provide an interference fit when mated. NPTF "Dry Seal" threads provide the interference fit, as they are not truncated and the roots and crests provide a "crush fit" to form the seal. NPTF threads are technically only good for one use as a "Dry Seal", then they become an NPT thread.

 

[dtfeld]

Best of my knowledge the pipe threads are NPT, and are used in low/no pressure application. Teflon pipe tape can be used as necessary...I don't though.

CAT does like to use strait threads with an oring or gasket in a lot of places, so you do have to be careful

 

[ttmott]

Dave,
As in expert in threads, i need to point out that standard NPT tapered pipe threads do not seal without Teflon tape or pipe "dope". This is because the roots and the crests of the threads are truncated and do not provide an interference fit when mated. NPTF "Dry Seal" threads provide the interference fit, as they are not truncated and the roots and crests provide a "crush fit" to form the seal. NPTF threads are technically only good for one use as a "Dry Seal", then they become an NPT thread.

However for the anodes the NPT threads need to be dry fit so the zinc anodes are electrically bonded. All of our applications are very low pressure; I've never had any leakage and all are installed without sealant. It would be better if they adopted a MS Boss arrangement so we would have both an O-ring for seal as well as metal to metal contact through the threading. The other observation on this arrangement is the anodes should be reverse threaded in the caps which would fix the other issue with them unthreading during disassembly.....

 

[Strecker25]

However for the anodes the NPT threads need to be dry fit so the zinc anodes are electrically bonded. All of our applications are very low pressure; I've never had any leakage and all are installed without sealant. It would be better if they adopted a MS Boss arrangement so we would have both an O-ring for seal as well as metal to metal contact through the threading. The other observation on this arrangement is the anodes should be reverse threaded in the caps which would fix the other issue with them unthreading during disassembly.....

it drives me nuts that they're not reversed, such an easy fix. I think it was frank who recommended a little loctite on the threads of the new ones and that has worked for me (along with just changing them well before they are deteriorated)

 

[ttmott]

it drives me nuts that they're not reversed, such an easy fix. I think it was frank who recommended a little loctite on the threads of the new ones and that has worked for me (along with just changing them well before they are deteriorated)

Yes but again you wouldn't want to insulate those threads either; it must all be electrically bonded to the boat or the zinc's are for not.

 

[Saverio]

DT,
can you tell me the correct number to order for each engine. I don't want to confuse my self the first time. I know i need 11. so 22 for both. you ordered over 40

thanks

Zincs are a pretty easy job with a little prep work before you go to the boat. I make up all mine before I head down and then its about an hour job for both engines (unless as Frank calls it Zinc diving) once you get a system going (and don't let them go too long).

A couple points to make this job easier.

1. Buying anodes- You might consider Aluminum (they call this material Navalloy) anodes. They work in all types of water fresh, brackish salt, doesn't matter, and they claim to last longer than zinc. Buy here --> https://performancemetals.com/. Email barbara@caldwellcasting.com.

These are the ones for a 3126, and you can get ones for the Westerbeke as well (that might be the AE-0).

View attachment 114732


2. I bought 2 sets of Stainless Steel Hex Plugs --> https://www.boatzincs.com/114-9096-Cat-Plug.html

When I swap out, I get as much of the old anode off the plug, and throw the whole cap in a cup of rydlyme. Rydlyme will eat what is left up in the cap and leave the threads ready for a new anode. Add just a little blue Loctite to the new anode right at where the shoulder of the anode touches and that prevents the anode from unscrewing in the aftercooler as you unscrew the cap. New orings come from CAT.

I make these 10 at a time and let the Loctite cure. So far this make for a really easy job.

View attachment 114733

 

[ttmott]

DT,
can you tell me the correct number to order for each engine. I don't want to confuse my self the first time. I know i need 11. so 22 for both. you ordered over 40

thanks

Here you go; complete kit for 3126.
https://www.boatzincs.com/CAT-3126-AnodeKit.html

 

[Saverio]

Here you go; complete kit for 3126.
https://www.boatzincs.com/CAT-3126-AnodeKit.html

Thanks !!

 

[Riptide III]

Can someone explain why you need an “electrical” bond on the end caps. They are plastic. The only bronze is the threaded insert for the plug.

 

[ttmott]

Can someone explain why you need an “electrical” bond on the end caps. They are plastic. The only bronze is the threaded insert for the plug.

Yes - the bronze threaded bungs for the zinc's in the plastic caps have a metal strap to the cap bolts embedded in the plastic. I was perplexed also so when I had them off I measured with a DVM and found them bonded. What good would a sacrificial anode be if there wasn't electrical bonding?

 

[dtfeld]

DT,
can you tell me the correct number to order for each engine. I don't want to confuse my self the first time. I know i need 11. so 22 for both. you ordered over 40

thanks

Saverio

The stainless caps with the o-ring are only for the aftercooler anodes. There are 5 per engine, x 2 so 10 total for a twin engine setup. These will not work in the other anode locations.

There are 11 anodes per engine. 5 in the aftercooler, 3 in the heat exchanger, 2 in the transmission cooler, and 1 in the exhaust elbow.

I have spreadsheet because it can get confusing. Let me see if I can find it…

 

[Thomas Griffith]

Hey DT and Frank, getting ready to switch these belts out. Is there a specific amount of tightness they need to be?

 

[The Bill Collector]

Hey DT and Frank, getting ready to switch these belts out. Is there a specific amount of tightness they need to be?

Get them tight and then re-check after 5 hours run time as they'll stretch a little.

 

[fwebster]

Be sure you only use Caterpillar belts. Aftermarket belts will keep you busy tightening then so they dpon't slip. Tight enough so they won't slip but loose enough so the normal vibration of the dsiesel engines won't throw the belts off the pullys.

 

[920richardf]

FWIW: 1/64" deflection per inch of span between sheave centers

 

[cwiert]

I just drained all my coolant and bought 16 gal of new CAT ELC coolant to replace. Before I do that, is there any recommended maintained or things I should check out while the engines don't have coolant in them?

 

[ttmott]

I just drained all my coolant and bought 16 gal of new CAT ELC coolant to replace. Before I do that, is there any recommended maintained or things I should check out while the engines don't have coolant in them?

Absolutely - flush the engine cooling passages. The ELC if not changed per schedule will leave a film on the metal surfaces and inhibit heat exchange. I think my mechanic filled the engines with a solution of some type and ran them to circulate then drained then filled with the ELC.