Official Caterpillar3116/3126 Thread

On my BMW 335i N54 the twin turbos kick in around 3,000 RPMs. When do they kick in on the 3126 cats?
 
Oh you’ll know! you’ll feel it in your seat!

Diesels are a little different than gas, push the throttles up together until you hit about you target cruise RPM. The boat will accelerate and come up on plane. No need to go to full throttle to “get up over the hump” and then back down.
 
The thing you will enjoy most about the diesel powered 380 is the ability to maneuver in close quarters. When you put her in gear, be sure where you are headed because she is going to squat and go there right now. With Cat's torque, be sure passengers are seated or holding on to something when you put the boat in gear or you may need to help them up off the deck.

Enjoy the boat and engine package………….

Frank
 
CAT 350 hp #'s. This is published in in. Hg to convert to psi is roughly divide by 2.

So looks like if all is running as it should, boost is about 0 at 1200, start to build at 1400, and takes off above 1600.

upload_2022-3-12_16-45-47.png
 
Interesting table. I’m somewhere between prop demand curve and max limit. About 19psi at 2200

 
Last edited:
Finally, something I understand, boost ;-) I've been slowly increasing the boost on my N54 335i with bolt on and mods. Last time I did a pull I was around 17 psi.
 
mrsrobinson said:
Finally, something I understand, boost ;-) I've been slowly increasing the boost on my N54 335i with bolt on and mods. Last time I did a pull I was around 17 psi.
Click to expand...

diesel boost was an eye opener for me after living in the gas powered car world. Even my little 3 liter duramax makes 29psi under normal driving
 
Don't be like me... Doing zincs today and it didn't end well. Started the engine and this one was dripping a little so I tightened it up and split the end cap.

2022-03-12 14.33.38.jpg
 
I always put some sort of sealent on the threads. Despite old wives tales, it has never never raised the resitance to ground. Easily checked with ohm meter. Your boat your choice of course.
 
Njlarry said:
I always put some sort of sealent on the threads. Despite old wives tales, it has never never raised the resitance to ground. Easily checked with ohm meter. Your boat your choice of course.
Click to expand...

Brass going into a plastic/composite sealant is totally okay
 
So it's Sunday, I thought today would be a good day to tackle the impeller replacement on the 1996 450DA with CAT 3126

The plan: Do the port side, the easy side first, then you'll know exactly what tools to bring along when you squeeze yourself into the stbd side.

OK- the port side goes really nice and easy. Used all of Franks recommendations, including sanding down the new key.

Now on to the port side.

Impeller shaft is at 4, almost 5 o'clock

After removal of the impeller, I noticed there was no shaft key attached to it.

Couldn't feel the key inside the pump.

Took photos of the pump cavity (can't get your head in there) and found no key - O.K. must have fallen out, not in the parts bucket, must have ended up on the oil zorb pad...... no big deal, right?

I used some synthetic grease to hold the new key (this pump has the short style, the port side had the long style)

Time to install the new impeller, it won't go in all the way.

Attempted this twice.

Decided to remove the key and in the process, dropped it in the pump cavity.

Can't find it

Can't see it

Can't feel it.

I'm wondering if both keys are somehow in one of the recesses (likely the bottom one)

There's an oil leak at the bottom of the pump mounting. I WAS going to tighten the two mounting bolts, but it now looks like I need to remove the entire pump.

Took a break for lunch as I write this.

Going to first scour the engine room floor to make certain there aren't TWO keys down there.

Assuming the keys are in the housing, would removing the bottom elbow alone perhaps release the keys?

Looking at the parts manual it appears that the gear on the pump does not need to be removed to R&R the pump. Can't find any reference to the raw water pump in the service manual.

Well, I'm off to see what I can see.

Hope to get some advice here soon.

BEST !

RWS
 
Maybe A Dancer said:
So it's Sunday, I thought today would be a good day to tackle the impeller replacement on the 1996 450DA with CAT 3126

The plan: Do the port side, the easy side first, then you'll know exactly what tools to bring along when you squeeze yourself into the stbd side.

OK- the port side goes really nice and easy. Used all of Franks recommendations, including sanding down the new key.

Now on to the port side.

Impeller shaft is at 4, almost 5 o'clock

After removal of the impeller, I noticed there was no shaft key attached to it.

Couldn't feel the key inside the pump.

Took photos of the pump cavity (can't get your head in there) and found no key - O.K. must have fallen out, not in the parts bucket, must have ended up on the oil zorb pad...... no big deal, right?

I used some synthetic grease to hold the new key (this pump has the short style, the port side had the long style)

Time to install the new impeller, it won't go in all the way.

Attempted this twice.

Decided to remove the key and in the process, dropped it in the pump cavity.

Can't find it

Can't see it

Can't feel it.

I'm wondering if both keys are somehow in one of the recesses (likely the bottom one)

There's an oil leak at the bottom of the pump mounting. I WAS going to tighten the two mounting bolts, but it now looks like I need to remove the entire pump.

Took a break for lunch as I write this.

Going to first scour the engine room floor to make certain there aren't TWO keys down there.

Assuming the keys are in the housing, would removing the bottom elbow alone perhaps release the keys?

Looking at the parts manual it appears that the gear on the pump does not need to be removed to R&R the pump. Can't find any reference to the raw water pump in the service manual.

Well, I'm off to see what I can see.

Hope to get some advice here soon.

BEST !

RWS
Click to expand...

the gear has to come off if you buy a new Sherwood, it won’t come with the new gear. I’m pretty sure the gear is $300 or so from cat so it’s worth transferring. I was able to pop it off by striking the old pumps shaft with a hammer, harmonics broke it loose

if it’s dripping oil from the shaft area, just replace it. Rebuilding it is a PIA but if you feel compelled to rebuild it after replacement you’ll have a nice spare
 
You must log in or register to reply here.

Forum statistics

Threads
113,241
Messages
1,429,111
Members
61,122
Latest member
DddAae
Back
Top