OAF
Well-Known Member
Im currently looking at a second hand boat with a pair of Cats 3126TA with around 450 hours on them, any advice on these engines from the experts out there?
Caterpillar engine experts?
- Thread starter OAF
- Start date
starfire
Well-Known Member
Simple answer with Cats.
If they start, they are Ok.
If they don't start, its something serious.
If they start, they are Ok.
If they don't start, its something serious.
sarabande
Well-Known Member
the search engine works quite well for a change.
Previous discussion
http://www.ybw.com/forums/showthread.php?t=132676&highlight=Caterpillar
Previous discussion
http://www.ybw.com/forums/showthread.php?t=132676&highlight=Caterpillar
PaulGooch
Well-Known Member
Probably not much point reposting the same question, just because you didn't get an answer inside 24 hours. It might be that anyone familiar with this particular engine is away for the weekend, or just busy.
Patience grasshopper.
Patience grasshopper.
Bilgediver
Well-Known Member
We used these engines offshore along with others and built in defects were not a problem.
I would suggest you ring Finning in Aberdeen and speak to the service department. Providing it is a quiet time I m sure they will give you some time. They service these engines and will be familiar with their good and bad points.
Finning Aberdeen
Workshop & engineer callout
01224 820000
volvopaul
Well-Known Member
I dont think so.... 3126, early ones had a french built "soft block" many went pourous and were changed under warranty.
Then there was the issue with the cylinder heads and valve problems which were also changed under warranty, you can find out if warranty was carried out by contacting finnings with the serial numbers.
Then theres cats own fuel injection system which only cat can work on, ie setting up of pump and injectors, all the tools that are req etc.
To change the alternator belt you have to remove the crankshaft damper as its diameter is larger than the belts circumference, on some boats its nigh on impossible if the engines are situated far forward in the engine bay.
Then theres the price of spares, impellers and anodes are nearly twice the price of even volvo, lastly servicing, the valves haveto be set by deler as yet again more specialist tools are req.
OAF
Well-Known Member
Thanks for the useful replies chaps,
Do you think that it will make the boat worth less than if it had the Volvos in?
Do you think that it will make the boat worth less than if it had the Volvos in?
Renegade_Master
Well-Known Member
To change the alternator belt you have to remove the crankshaft damper as its diameter is larger than the belts circumference,
Access to the damper on mine is ok, how long would it take to remove the damper do you think oh and put it back
Access to the damper on mine is ok, how long would it take to remove the damper do you think oh and put it back
Latestarter1
Well-Known Member
The 3116/3126 marine engines have a colourful history in the US, and the reputation they have earned has not yet reached these shores. Any motor which requires removal of the crank damper to change the alternator belt and $$ in special service tooling as others have stated would not be on my shopping list.
I have been examining two vessels, which have had repeat turbo failures and what I have discovered does not impress. Sadly the engineers at CAT who did 3116/3126 were not of the same calibre as those who did the 3208 typical marine type couch engineering is mixed with poor design of salt water cooled wet riser that is designed to fail the turbo.
Original factory risers were made of Stainless Steel with the salt water inlet at the bottom of the riser. Two things happen over time, because the riser outlet at the top was designed at such a shallow down angle water drips back down the riser during cranking and after shut down damaging the turbo.
.
After about 400 hours in service, the riser fails internally leading to total failure of the turbo and often failure of the #6 cylinder exhaust valve. CAT later changed from Stainless Steel to Bronze construction for this design (that solved the rotting out internally part of this poor design) only to have the shallow angle of the outlet to still come back and bite them.
It took CAT engineers about 7-8 years to understand the issue (gravity being the main culprit) and they finally dumped the entire design with the last generation of 3126 and the newer C-7's. Owners left to pick up the pieces.
I have been examining two vessels, which have had repeat turbo failures and what I have discovered does not impress. Sadly the engineers at CAT who did 3116/3126 were not of the same calibre as those who did the 3208 typical marine type couch engineering is mixed with poor design of salt water cooled wet riser that is designed to fail the turbo.
Original factory risers were made of Stainless Steel with the salt water inlet at the bottom of the riser. Two things happen over time, because the riser outlet at the top was designed at such a shallow down angle water drips back down the riser during cranking and after shut down damaging the turbo.
.
After about 400 hours in service, the riser fails internally leading to total failure of the turbo and often failure of the #6 cylinder exhaust valve. CAT later changed from Stainless Steel to Bronze construction for this design (that solved the rotting out internally part of this poor design) only to have the shallow angle of the outlet to still come back and bite them.
It took CAT engineers about 7-8 years to understand the issue (gravity being the main culprit) and they finally dumped the entire design with the last generation of 3126 and the newer C-7's. Owners left to pick up the pieces.
volvopaul
Well-Known Member
Ahhh reality at last..
You wont go wrong with 63p 370s a proven block base unit with all the last of its evolution heat exchangers and intercoolers, coupled with a decent injector pump and sea water pump.
Only a few gripes, mainly seizure of its turbo wastegate, numerous oil leaks which you get its a volvo!, and intercoolers that scale up causing overheating at WOT, if properly serviced a great unit, again a mechanical survey and sea trial are a must on a boat and machinery thats that vintage.
There is a 420 in teneriffe, thats got engine borne history pm if you want to know its history, or leave well alone.
OAF
Well-Known Member
Thanks Latestarter and Paul for your excellent replies, Thanks Paul re the one in Tenerife, I had been considering one over there as a possible candidate.
I'm not too worried about the special tooling required to work on the engines or the crank damper removal to change a belt, all engines have idiosyncrasies and while it is not perfect i could live with it, what I don't want is a pair of engines that are going to be problematic
The issue with the down angle on the risers, was it it ever sorted out or was it just left as a poor design and what year did they start fitting bronze risers?
I have seen the engines up and running and they sounded superb, not sea trialed it or had it surveyed yet, that is still to come if i decide to put in an offer.
I'm not too worried about the special tooling required to work on the engines or the crank damper removal to change a belt, all engines have idiosyncrasies and while it is not perfect i could live with it, what I don't want is a pair of engines that are going to be problematic
The issue with the down angle on the risers, was it it ever sorted out or was it just left as a poor design and what year did they start fitting bronze risers?
I have seen the engines up and running and they sounded superb, not sea trialed it or had it surveyed yet, that is still to come if i decide to put in an offer.
Latestarter1
Well-Known Member
The bronze risers just eliminate the the rot though issue turbo will still be on borrowed time with the bronze version. If you PM me I can send you photographs and indications of what to look for.
Last year of 3126 production was the transition to the improved C7 manifold/riser set up.
OAF
Well-Known Member
PM sent
what was the last year of production for the 3126 ?
what was the last year of production for the 3126 ?
volvopaul
Well-Known Member
Whats the location of the boat with cats in? if uk think ive come across it before.
OAF
Well-Known Member
cat engines
PM sent Paul
PM sent Paul
OAF
Well-Known Member
Thanks to Paul and Paul for their help and advice, very much appreciated guys
Simon
Simon
oldgit
Well-Known Member
If you are at a loose end with an hour or two to spare have a rummage through this site.
http://www.yachtsurvey.com/exhaust_risers.htm
Renegade_Master
Well-Known Member
After about 400 hours in service, the riser fails internally leading to total failure of the turbo and often failure of the #6 cylinder exhaust valve. CAT later changed from Stainless Steel to Bronze construction for this design (that solved the rotting out internally part of this poor design) only to have the shallow angle of the outlet to still come back and bite them.
__________________________________________________________________________
Hi Latestarter you will remember my tales of woe back in August when the 3126 on my jet boat failed. I had many problems with the intercooler coking up which meant removing and cleaning it many times. What seemed to stop it in the end was redirecting the breather pipe which comes from the crank and onto the air filter. No the air filter does in fact go straight through to the turbo, there is no filter in the centre as such, however this goddam breather pipe was connected to a so called filter around the edge of the AF, I imagine for "environmental" reasons so the air from the crank breather went back into the engine.
I am now convinced it was the s**t from the breather blocking the intercooler.
Anyway I digress, you mention above 400 hrs of service and the No 6 exhaust valve failing.
Coincidently mine had done 470 hours approx in august and the No 6 exhuast valve seating failed, not the vlave itself. Examination of the head revealed several cracks there and elsewhere so I had to fit a new head and valves. I have lost faith in this engine as it failed me on my first season of commercial use.
__________________________________________________________________________
Hi Latestarter you will remember my tales of woe back in August when the 3126 on my jet boat failed. I had many problems with the intercooler coking up which meant removing and cleaning it many times. What seemed to stop it in the end was redirecting the breather pipe which comes from the crank and onto the air filter. No the air filter does in fact go straight through to the turbo, there is no filter in the centre as such, however this goddam breather pipe was connected to a so called filter around the edge of the AF, I imagine for "environmental" reasons so the air from the crank breather went back into the engine.
I am now convinced it was the s**t from the breather blocking the intercooler.
Anyway I digress, you mention above 400 hrs of service and the No 6 exhaust valve failing.
Coincidently mine had done 470 hours approx in august and the No 6 exhuast valve seating failed, not the vlave itself. Examination of the head revealed several cracks there and elsewhere so I had to fit a new head and valves. I have lost faith in this engine as it failed me on my first season of commercial use.
Last edited:
Renegade_Master
Well-Known Member
OAF engines aside, if its a mid nineties Princess 410 420 560 etc watch out for corrosion of the window frames. Princess in their wisdom at that time, used a SS frame with an aliuminium "E" shaped extrusion insert which acted as the glazing bead.
Problem was two different metals side by side meets salt water = electrolosis
On my 560 the previous owner had in a futile attempt to stop the ali from turning to powder, put little earthing wires between the window frames internally.
I kid you not there was a constant dusting of aliuminium powder from the fast corroding extrusion all over the dash etc and water ingress through the frames.
I had the three front and two forward side windows remade in total aliuminium by Seaglaze.
Problem was two different metals side by side meets salt water = electrolosis
On my 560 the previous owner had in a futile attempt to stop the ali from turning to powder, put little earthing wires between the window frames internally.
I kid you not there was a constant dusting of aliuminium powder from the fast corroding extrusion all over the dash etc and water ingress through the frames.
I had the three front and two forward side windows remade in total aliuminium by Seaglaze.
Latestarter1
Well-Known Member
Do you or perhaps in view of your comments did you have the Walker Airsep CCV option?
Walker Airseps were the bee's knees on a Detroit stroker, on other engines they can prove to be a nightmare. Instead of returning the condensed fumes to the oil pan which I hate anyway, a stuck valve will result in the condensate being circulated though the induction system instead, clagging up the charge air cooler.
Re; your head failure I would suggest that the head may have cracked due to sea water dribbling back into the cylinder head following hot engine shut down.
Havent you had repeat turbo failures on yout CAT 3126? The post sprang to mind when I was examining the failed riser (poor description) removed from the vessel undergoing survey.
Walker Airseps were the bee's knees on a Detroit stroker, on other engines they can prove to be a nightmare. Instead of returning the condensed fumes to the oil pan which I hate anyway, a stuck valve will result in the condensate being circulated though the induction system instead, clagging up the charge air cooler.
Re; your head failure I would suggest that the head may have cracked due to sea water dribbling back into the cylinder head following hot engine shut down.
Havent you had repeat turbo failures on yout CAT 3126? The post sprang to mind when I was examining the failed riser (poor description) removed from the vessel undergoing survey.
