Bought a new long block and wondering about the coupling and gimbal bearing.

[AKJohne]

I know, I know... I only get on here when I need help and am thankful you guy's are here.
I am working on a 1997 5.7 LX Alpha 1 Gen II.
The existing motor was pre-vortec and rebuilt by others, I tuliped a valve last year and had the heads rebuilt. After I got it back together I realized it was severely burning oil, assume the rings are collapsed. Decided to replace rather than rebuild and bought a new 5700 long-block from Michigan Motorz and a new intake. I Will be reusing all the original accessories to include Weber 750 and TB V ignition. I am converting to a electric fuel pump as well.
The motor and gimbal bearing have about 600 hours on them, the coupling has maybe 800 hours.
I have a couple of questions, should I reuse or replace the coupling? Is there a way to evaluate it?
The gimbal bearing feels fine and I have greased every 100 hours, should I replace just because I have the OD off (I checked the alignment before I pulled to old motor and it was spot-on).

Some pics for fun..... it was a bit frozen in

 

[kenny nunez]

You can always change the gimbal bearing and since it is smooth it should last. The coupling is worth changing now with that many hours. That is something that you never know when it will leave you like propeller hubs are known to do.

 

[Bondo]

I have a couple of questions, should I reuse or replace the coupling? Is there a way to evaluate it?
The gimbal bearing feels fine and I have greased every 100 hours, should I replace just because I have the OD off (I checked the alignment before I pulled to old motor and it was spot-on).

Ayuh,..... The splines should have nice flat tops, not worn pointy,.....
'n a general visual inspection, on the coupler,......

If the gimbel bearin' is Good, leave it alone, it's yer baseline for alignment,......
It's done from behind the boat anyways,....

 

[AKJohne]

Ayuh,..... The splines should have nice flat tops, not worn pointy,.....
'n a general visual inspection, on the coupler,......

Splines are flat, not pointy, the coupler visually looks ok, and doesn't look like the rubber is bad, is there something specific I should be looking at or are you saying I should just change it?

 

[alldodge]

Agree with Bondo inspect it, the coupler will last forever if taken care of

 

[Lou C]

Interesting my old boat still has the original one.

 

[achris]

...The motor and gimbal bearing have about 600 hours on them, the coupling has maybe 800 hours.

Still relatively new then.

I have a couple of questions, should I reuse or replace the coupling? Is there a way to evaluate it?

Visual inspection, check the splines for wear, Bondo has that covered.

The gimbal bearing feels fine and I have greased every 100 hours, should I replace just because I have the OD off (I checked the alignment before I pulled to old motor and it was spot-on).

If the bearing is still smooth, leave it.

One of my pet hates (yes, I have plenty) is people with this 'while I have access I'll replace it' attitude.. It's a complete and utter waste of money and more importantly, resources. We need to end the 3 Bs.... And not replacing parts that are still perfectly serviceable is one of them.

Chris......

 

[AKJohne]

Thanks all, I am not interested in replacing parts just cuz...
If so I wouldn't have rescued a 40 year old boat that had seen better day!

The spline looks good with little wear, alignment was good and coupling looks fine, now that I understand what misalignment will do I know what to look for. One of the U-joints has a couple of tight spots and I think Ii need to address that. And that might explain the vibration I noticed last year, especially noticeable at 2000 RPM.

 

[AKJohne]

New motor is in, a few minor details such as the boss on the new water pump was not machined and skewed the idler. Got a minor education in SBC water pump bypass. Waiting to get the OD back and should be ready to fire up. Spring is coming!

 

[achris]

Looks sweeeeeet....

Chris.......

 

[tpenfield]

Full closed cooling system

 

[Scott Danforth]

New motor is in, a few minor details such as the boss on the new water pump was not machined and skewed the idler. Got a minor education in SBC water pump bypass. Waiting to get the OD back and should be ready to fire up. Spring is coming!

you can just shove a hose up the hole in the gimbal housing to run it.

 

[Lou C]

looks great, everything is very neat and shiny!
even the markings on the harmonic balancer!
that's usually the darkest dirtiest part of a SBC lol.

 

[AKJohne]

New LB came with new balancer, took a degree wheel and marked it. Good idea on the hose for water, I have to attend to another project before breakup, if no OD by next weekend I will give it a go with the hose. Motor has been primed but will crank it over with the plugs out to get fuel through the new filters and get it ready to fire. Having a issue with water pump gaskets, on the third one and still weeping. These gaskets had 2 small rivets on each side, thinking I will use a paper gasket from Napa?

 

[tank1949]

I assume you have knock sensor, but does it work? If valves went bad due to pre-ignition, KS may be defective. Don't repeat same problem. That old of boat, I'd check for transom rot too. Trust me!

 

[Scott Danforth]

New LB came with new balancer, took a degree wheel and marked it. Good idea on the hose for water, I have to attend to another project before breakup, if no OD by next weekend I will give it a go with the hose. Motor has been primed but will crank it over with the plugs out to get fuel through the new filters and get it ready to fire. Having a issue with water pump gaskets, on the third one and still weeping. These gaskets had 2 small rivets on each side, thinking I will use a paper gasket from Napa?

use the grey RTV for waterpumps

 

[achris]

.... Having a issue with water pump gaskets, on the third one and still weeping. These gaskets had 2 small rivets on each side, thinking I will use a paper gasket from Napa?

No, those rivets are for grounding, and quite necessary.

Chris....

 

[AKJohne]

I assume you have knock sensor, but does it work? If valves went bad due to pre-ignition, KS may be defective. Don't repeat same problem. That old of boat, I'd check for transom rot too. Trust me!

Good thoughts for sure, transom was redone, has a knock sensor, verified that it works with a timing light and fluke scope. Tapping on the block retarded the timing and scope could show us how many milliseconds it was retarded.
Motor was rebuilt by prior owner of motor for his own use. He bought some used heads, lapped the valves and ran it for 30 hours. Rolled the boat over. We bought the motor and drive and ran it for 500 plus hours. Intakes were thin, it was just a matter of time, but yeah, I was concerned about detonation as well.

 

[AKJohne]

No, those rivets are for grounding, and quite necessary.

Chris....

What is their function?

 

[Bondo]

What is their function?

Ayuh,.... The ground the housing, so the temp sensor can work,....