Official Caterpillar3116/3126 Thread

Steve S said:
Thanks Tom. They are saying the belt order is opposite with the alternator inside. They did say a bracket but they made it sound like a cover.
It's the 15 hours of labor that has me going...
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A bit of a better picture. You can see the water pump pulley and idler pulley/tensioner just below it. The alternator isn't installed but it mounts to that bracket to the left with the empty bolt hole. The little stud in the middle of the dampener is for the synchronizer cable - a holding bracket goes over that. Now that I see this it is that cable support bracket that needs to be removed for the inner belt removal/installation.
CAT-R_3116M-4.jpg
 
Strecker25 said:
and from what I've read a weak point on these engines? I'm not sure if that's referring to the belt itself or the pump but I know I've read of pump failures causing rapid overheat
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The only thing is the impeller is press fit on the shaft for that pump. There have been situations where when the engine is cold everything is good but when it heats up the impeller slips then when overheating slips even more - thermal expansion. Self-eating-watermelon. Rare though - my mechanic has only seen it once. Just like everything else the water pumps should be changed after XX hours.
 
ttmott said:
The only thing is the impeller is press fit on the shaft for that pump. There have been situations where when the engine is cold everything is good but when it heats up the impeller slips then when overheating slips even more - thermal expansion. Self-eating-watermelon. Rare though - my mechanic has only seen it once. Just like everything else the water pumps should be changed after XX hours.
Click to expand...

makes sense. I suspect mine are original and at 1000 hours, probably time to do them. They look like a bit of a nightmare to change just based on the stuff in the way, though
 
ttmott said:
A bit of a better picture. You can see the water pump pulley and idler pulley/tensioner just below it. The alternator isn't installed but it mounts to that bracket to the left with the empty bolt hole. The little stud in the middle of the dampener is for the synchronizer cable - a holding bracket goes over that. Now that I see this it is that cable support bracket that needs to be removed for the inner belt removal/installation.
CAT-R_3116M-4.jpg
Click to expand...
F7038.jpg
 
Steve S said:
So as part of my winter layup, the marina inspected my 1998 400 Sedan Bridge and recommended that the alternator belts be changed. I purchased the belts from Cat per my 3116 engine serial numbers.

The marina just called me and said that they cannot quickly change the belts. There is a second set of belts in front that needs to be removed also PLUS a cover and a coolant pipe. They are saying it will take two days and about $3 Boat Bucks to get this done.... Is this crazy or what it would cost? Should I find another mechanic to come in after the boat launches and I am not tied down to the marina (Skipper Bud's) staff?
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Wait, what? Assuming they are the same as my 3126s, both belts on one engine took about 45mins for the first one, first time doing it, 30 for the 2nd. A real pain in the butt to get to, but doable. Only thing removed was the synchronizer cable.
 
Strecker25 said:
makes sense. I suspect mine are original and at 1000 hours, probably time to do them. They look like a bit of a nightmare to change just based on the stuff in the way, though
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He replaced mine at around 1800 hours. Complete block flush and clean as well as new hoses, belts, idler pulley, expansion tank cap, and thermostat. That's also when we tank'd the Hx and pressure checked the Hx and expansion tank. Everything got cleaned with a brilliant coat of paint.
 
I'm not a CAT mechanic who does this day in/day out, just an old guy with mechanical experience.

I did all the belts at once, didn't take very long, nor was it difficult.

Make sure you mark the different spacers on the belt guard.

By the way, I rightly chose to leave the belt guard off of the port engine, but it is truly needed on the stbd side.

BEST !

RWS
 
The weak point is the belts require constant vigilance or they will work themselves loose and start slipping. I changed my 3116 belts about every 3rd year because we cruised our boat and I never wanted to break or to throw a belt off away from home where I did not have the time or the tools needed to remove the guards and change the belts. To avoid a belt failure I checked and tightened the belt tension about once a month until the belts maintained their adjustment.

What screws up mechanics and quoting belt change times for mechanics not familiar with how Cat builds engines is that the entire belt guard must be loosened or removed to get to the idlers or adjustment bolts to remove and retension the belts. It took me about a half a day to pull the guards off and replace the belts the first time I did it……but this isn't my first rodeo. The belt guards are all a part of the accessory mounting bracketry for the alternator, water pump idlers, adjustment cams, etc., so if you remove them be very sure you or the mechanic keeps up with where the spacers and washers go. They are all important

After my second belt change, I said: "There must be a better plan" and I removed the entire Cat Belt guard assembly and made I made a smaller belt guard that just covered the alternator belt on the stbd engine so I could remove the Cat guard and that facilitated a very easy belt change on the 450DA because the front of th e engines are positioned againbst the. rear engine room bulkheadwhich kees me or a mechanic from accidently backing into the alternator pulley or either of th e rotating belts on either engine. Disclaimer: I cannot recommend this for you because I am not familiar with the 2000 400DB engine room layout or working room space in front of the engines. Removing the entire belt guard was possible on the 450DA with Cat engines because the working space on the 450DA in front of the engines and the sides were so tight that the belts and pulleys were fully protected and impossible to accidently contact except for the inboard side of the stbd engine, which is where I added the belt cover. I'll look for a photo today………..

As far as your 30 hour quote to change the alternator belts……that one is from a mechanic who doesn't want the job. I work on diesel engines all the time and this was easy for me. I removed the belt guards and replaced both belts on 2 engines the first time I changed the belts and made it home for lunch.
 
So it's for the stupid people...

I guess it makes sense, I may jump in there to do something while the engine is running.

Same on my 380, maybe a small monkey can get in there, but not me:

"Removing the entire belt guard was possible on the 450DA with Cat engines because the working space on the 450DA in front of the engines and the sides were so tight that the belts and pulleys were fully protected and impossible to accidently contact except for the inboard side of the stbd engine, which is where I added the belt cover."
 
fwebster said:
The weak point is the belts require constant vigilance or they will work themselves loose and start slipping. I changed my 3116 belts about every 3rd year because we cruised our boat and I never wanted to break or to throw a belt off away from home where I did not have the time or the tools needed to remove the guards and change the belts. To avoid a belt failure I checked and tightened the belt tension about once a month until the belts maintained their adjustment.

What screws up mechanics and quoting belt change times for mechanics not familiar with how Cat builds engines is that the entire belt guard must be loosened or removed to get to the idlers or adjustment bolts to remove and retension the belts. It took me about a half a day to pull the guards off and replace the belts the first time I did it……but this isn't my first rodeo. The belt guards are all a part of the accessory mounting bracketry for the alternator, water pump idlers, adjustment cams, etc., so if you remove them be very sure you or the mechanic keeps up with where the spacers and washers go. They are all important

After my second belt change, I said: "There must be a better plan" and I removed the entire Cat Belt guard assembly and made I made a smaller belt guard that just covered the alternator belt on the stbd engine so I could remove the Cat guard and that facilitated a very easy belt change on the 450DA because the front of th e engines are positioned againbst the. rear engine room bulkheadwhich kees me or a mechanic from accidently backing into the alternator pulley or either of th e rotating belts on either engine. Disclaimer: I cannot recommend this for you because I am not familiar with the 2000 400DB engine room layout or working room space in front of the engines. Removing the entire belt guard was possible on the 450DA with Cat engines because the working space on the 450DA in front of the engines and the sides were so tight that the belts and pulleys were fully protected and impossible to accidently contact except for the inboard side of the stbd engine, which is where I added the belt cover. I'll look for a photo today………..

As far as your 30 hour quote to change the alternator belts……that one is from a mechanic who doesn't want the job. I work on diesel engines all the time and this was easy for me. I removed the belt guards and replaced both belts on 2 engines the first time I changed the belts and made it home for lunch.
Click to expand...
Thanks for the detailed answer Frank. Looking at this picture, this side of the engine is near the bow side of the engine room. The starboard engine would have the alternator towards the starboard side of the boat. The port engine would have the alternator in the walkway area between the engines.

CAT-R_3116M-4.jpg
 
Our boat's with straight shafts (DB and Express) need the belt guard as there is much more exposure to the rotating parts there. The DA boats I don't see the need except for the Starboard alternator as Frank alludes. My 400DA didn't have any guards BTW.
 
ttmott said:
Our boat's with straight shafts (DB and Express) need the belt guard as there is much more exposure to the rotating parts there. The DA boats I don't see the need except for the Starboard alternator as Frank alludes. My 400DA didn't have any guards BTW.
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Tom, wouldn't that guard be needed more on the port side? Isn't the alternator on the "outside" of the boat on the starboard side?

As an aside, Why would I be in the engine room with the engines on? The only time I can remember having the engines on and the engine room open was after changing the oil and while I was checking the coolant tanks for leaks.
 
ttmott said:
Our boat's with straight shafts (DB and Express) need the belt guard as there is much more exposure to the rotating parts there. The DA boats I don't see the need except for the Starboard alternator as Frank alludes. My 400DA didn't have any guards BTW.
Click to expand...

=======================

I'll second that motion on the 450 - stbd guard is important, on the port side there is little advantage.

BEST !

RWS
 
Steve S said:
Tom, wouldn't that guard be needed more on the port side? Isn't the alternator on the "outside" of the boat on the starboard side?

As an aside, Why would I be in the engine room with the engines on? The only time I can remember having the engines on and the engine room open was after changing the oil and while I was checking the coolant tanks for leaks.
Click to expand...
I have done it many times, checking temps for example with a laser temp gun, checking for water leaks after replacing a hose (especially a raw water hose), tightening a water clamp on a hose that is dripping enough until the drip stops, etc. And ironically, checking the belts after installing the new ones.

With these loud Cats these will be your best friend:

https://www.amazon.com/gp/product/B07MNZ7C1M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
mrsrobinson said:
I have done it many times, checking temps for example with a laser temp gun, checking for water leaks after replacing a hose (especially a raw water hose), tightening a water clamp on a hose that is dripping enough until the drip stops, etc. And ironically, checking the belts after installing the new ones.

With these loud Cats these will be your best friend:

https://www.amazon.com/gp/product/B07MNZ7C1M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Click to expand...


=========================================

Hanging on the engine room ladder, next to the knee pads !

After the ER floor paint, I'll add the foam rubber floor padding between the center stringers as Dr. Webster has recommended.

BEST !

RWS
 
Maybe A Dancer said:
=========================================

Hanging on the engine room ladder, next to the knee pads !

After the ER floor paint, I'll add the foam rubber floor padding between the center stringers as Dr. Webster has recommended.

BEST !

RWS
Click to expand...
Added the floor pads year 1
 
It's out on 450DA string but I will post here too, anybody who makes it out to the left upper coast gets a cruise on Puget Sound...
 
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