3116 Cats - Frank - need a refresher course

[WFYB]

Frank, I hope you have your 3116 Cat primer saved. Several months ago we discussed a 33 EC w/ 3116 cats a friend is considering. Well he is getting close again, 97 33EC / 3116 Cats, 1100 hrs. Here are some CAT pressure points that I believe need attention during an engine survey.

1. FAPS block - avoid
2. Look for cracks / leaks in expansion bottle
3. Boat should obtain 2800 WOT.
4. Only use an authorized Cat dealer for survey.
5. Confirm the warranty and upgrade history through Cat.
6. Cat dealer ---> combustion blow by test.

what am I missing? I have read on Boat diesel that this engine has an expected life of around 30,000 gal of fuel. Some "experts" calculate this between 2400 - 3000 hrs, (12.5 gph or lower). what do you think? Anything else?

Thanks for your help. This time I will save the reply.

 

[Sea Gull]

While Frank takes one last bite of turkey I'll chime in. My last boat had the 3126 mechanicals. These - along with the 3116s are great engines.

You have pretty much covered the major stuff. Be sure to take oil samples from engines and transmissions - CAT can supply the kits and run the analysis for you. The biggest tell is the condition of boat and engine room. If the engines have been well maintained, they will last a long time. Get the service records and make sure that major services have been done. Check that oil was changed at recommended intervals.

Also, check with the tech. They always told me to set the props so that the engine reached 2850 - in other words you are better off a bit high than a bit low on WOT RPM.

good luck.

 

[never monday]

what am I missing? I have read on Boat diesel that this engine has an expected life of around 30,000 gal of fuel. Some "experts" calculate this between 2400 - 3000 hrs, (12.5 gph or lower). what do you think? Anything else?

That sounds low to me.

 

[WFYB]

3000 hrs sounds low to me as well.

I understand the greatest life shortener to marine diesels is over propping. I agree 2850 is better.

 

[osd9]

Frank's probably eating some Pumpkin pie right now...and then back for seconds of turkey.....

Just to jump off topic a little, this past summer, because of personal reason, I couldn't use my boat for about 3 -3 1/2 weeks in the hottest part of August...when I finally got back out I noticed a MAJOR difference in performance....I dove under the boat and spent almost an hour cleaning props, shafts, and what have you....

That said, and from some of the comments above, it sounds critical to run the boat upto full throtle for short periods, on every outing. Otherwise, you may be running over propped without knowing it...

later,

 

[tc410]

Frank must have passed out from too much triptofan in that white meat.

Back to those CAT's...

One other known issue to add to your original list was a run of bad valves from TRW. That being said, those engines having 1100 hours probably would have either failed long ago, or had the valves replaced to prevent failure. The CAT historical data from the serial numbers should clarify that.

 

[fwebster]

You are all a bunch of smart allecks........ I had to drive 120 mile to get to the turkey today....I have eaten too much, but I have not been eating all day!


You list is pretty complete. However, I followed my own advice first hand last week and surveyed a 370EC with 3116's for a friend of mine. We did the whole number....hull survey (didn't need the professional, we caught more than he did, but the insurance co, required it), mechanical survey by a Cat dealer and about 4 hours on the water with the boat.

We learned that the 3116 is not subject to the soft block issue, only the 3126. We asked for written confirmation and its on the way. I've never seen a 3116 with a soft block but have see a few 3126's and this explains why.

At 1100 hours, the engines are well past the time that the soft TRW valves would have been an issue, so you can forget this one. But, at this running time you are probably ready for some kind of expensive maintenance.....cleaning heat exchangers, cleaning transmission oil coolers, new sea water pumps, reset the engine overheads (valve and injector timing). Complete service records will give you an idea of what has been done and what you can expect to have to do.

The 30,000 gallons of fuel is not the life expectancy of the engines.......that is some boat owner's misinterpretation of the Caterpillar Operation and Maintenance manual. In the section on recommended maintenance Cat does recommend an engine overhaul at 30,000 gallons of fuel, but the paragraph following that statement is full of qualifications and ends with this:

"An overhaul is generally indicated by increased fuel consumption and reduced power. This option consists of completely reconditioning the cylinder head but the cylinder components are not worn enough to need repair" S

So what Cat is saying is that you may need a valve job and the injectors reseated at 30,000 gallons of fuel burned, not that the engine has a useful life of 30,000 gallons. I have friends who run 3116's in a charter boat and he was at 6500 hours in October and had never had more than an injector or 2 fail.

The full power or WOT rpm's on this motor is 2800 and they should never be run faster than that. You can either prop the boat for 2800 with full load or prop it for something higher and pull the throttle back to 2800 when the boat is light......but 2800 is it.

From my standpoint, if you an run the boat for 3-4 minutes at WOT and see 2800 RPM's.....there isn't much if anything wrong with the engines. An engine with problems will either not run up to 2800 smoothly or if it does, it will show symptoms of a problem.

Also, if they are right, these engines are usually very clean.....they don't leak, don't have a lot of blow by, they don't smoke on start up, and they won't soot up a transom. If you see an engine room with diesel oil in it, soot on the transom, or oil film in the engine spaces, then start looking for the problem and be careful of the boat.

The Cat oil sample is almost a given for me, its cheap and easy, so spend the $40.

There have been several minor recalls or upgrades on this engine so get the Cat dealer to run down the serial numbers thru the Cat service system and see what has been reported to have been done.

No I gotta go find a Zantac...............

 

[WFYB]

Thanks guys, he is looking at the boat tomorrow. I'll post if there is anything that seems interesting.

 

[Dancin Dave]

I would just add that if the engines did not have Air seps on them, there will be some oil that is not recovered , and easily addressed with a folded up diaper placed at the breather tube to collect any drips. This will keep it from going all over the alt and or anything else below.

 

[WFYB]

We looked at the boat yesterday. The boat was real clean and appeared to be well maintained.

Observations:
1.There was some slight evidence of dampness in the cabin. The dehumidifier was not being run so this clearly contributes to dampness in Florida this time of year, (cool nights & warm days).
2.There was some evidence that there may have been a leak around the port forward window at one time, the vinyl was slightly discolored. The discoloration could be from using too strong a cleaner.
3.One of the rudder posts was leaking a bit and was corroded.
4. One of the shaft couplers was corroded where it attached to the transmission, It appears both shaft seals and maybe the shafts are new.
5. The bottom was filthy - the boat has clearly not moved for quite a while.
6.The engines were clean, no evidence of leaks. The starboard engines valve cover appeared to have been painted - evidence that it was removed at one time.
7.There was no excessive water in the bilge, the water was reasonably clean with no evidence of oil.
8. The bilge was clean - no oil etc.

My friend is going to run the engine serial numbers and try to get the maintenance records. If it checks out he will proceed with an offer contingent upon engine & hull survey and sea trial.

 

[fwebster]

Observations.......the rudder posts will leak if the packing nut is not tight enough. It is unusual for it to need more than a tightening.

Valve covers have to be removed to do adjust the valves and retime the injectors which is a required service at 250 hours.

To replace the Strong Seals you will destroy the paint on the couplers, but you will also have to polish the shaft from the running surface forward which is the part inside the boat that you see....all normal if the seals were recently replaced, but most of us just go ahead and bead blast the couplers while they are off so they can be repainted when done.

 

[WFYB]

Thanks Frank