5.7LX rebuild question

[AKJohne]

1996/97 5.7LX A1 gen 2, closed cooling 0K158784
Severe blow by and time to to rebuild. ~ 580 hours on a rebuild (PO), not original block.
Had head issues last season and tuliped a valve, replaced all the intake valves. Compression and leak down test were ok and piston (#3) looked ok.
Not original heads either.
However I suspect the oil rings have collapsed due to heat. Now burning oil... severely!
Going to pull the motor, and see if machine shop can bore to .060" over as it is currently at .040".
Question is can I go to .060 over or is that too thin for the cylinder walls?

Thanks

 

[Scott Danforth]

1996/97 5.7LX A1 gen 2, closed cooling 0K158784
Severe blow by and time to to rebuild. ~ 580 hours on a rebuild (PO), not original block.
Had head issues last season and tuliped a valve, replaced all the intake valves. Compression and leak down test were ok and piston (#3) looked ok.
Not original heads either.
However I suspect the oil rings have collapsed due to heat. Now burning oil... severely!
Going to pull the motor, and see if machine shop can bore to .060" over as it is currently at .040".
Question is can I go to .060 over or is that too thin for the cylinder walls?

Thanks

check with your machine shop, need to run a bore gauge down the holes and do a sonic check

every block is different. generally, .060 is doable on most blocks, however core shifts, etc happen

 

[AKJohne]

check with your machine shop, need to run a bore gauge down the holes and do a sonic check

every block is different. generally, .060 is doable on most blocks, however core shifts, etc happen

Will do, what is a sonic check? Thanks Scott

 

[Scott Danforth]

Will do, what is a sonic check? Thanks Scott

where they sonically check the wall thicknesses prior to machining

you to know that a new block is less money than a line-hone, re-size of mains, deck, bore and hone of a used block

 

[Bondo]

Ayuh,..... For the money, 'n talent it takes to do what yer sayin',.....
You could be boltin' yer accessories onto a brand new long block motor,.....
Perfect time to up date to Vortec heads,.....

 

[AKJohne]

Ayuh,..... For the money, 'n talent it takes to do what yer sayin',.....
You could be boltin' yer accessories onto a brand new long block motor,.....
Perfect time to up date to Vortec heads,.....

Bondo, I think your on to something here, I thought I would at less explore my options locally (Alaska).... Any suggestions for a good source?

 

[achris]

5.7L (350ci) Vortec Base Marine Engine (1996-Current Replacement)

5.7L (350ci) Vortec Base Marine Engine (1996-current Replacement)

www.michiganmotorz.com

 

[Scott Danforth]

Bondo, I think your on to something here, I thought I would at less explore my options locally (Alaska).... Any suggestions for a good source?

with a boat that big, I would probably go with a 6.2 (377 cubic inch)

6.2L (377ci) STROKER Base Marine Engine (2002-2009 Replacement)

6.2L - 383 c.i. \"Stroker\" Base Marine Engine

www.michiganmotorz.com

or you can build it yourself
heads https://www.summitracing.com/parts/sum-151124
short block https://www.summitracing.com/parts/hpe-sp15
add the cam kit of your choice, marine gaskets, etc.

 

[AKJohne]

Thanks guys, the boat is heavy, does OK with current power, more is always nice, running a Alpha 1 Gen 2 and should I be concerned about using the 6.2L with the A 1? Currently can cruise at 3200 RPM between 22 and 28 MPH depending on sea conditions. WOT is just under 40. Averaging about 2 -2.2 MPG.

Which intake should I be looking at?

 

[Bondo]

Thanks guys, the boat is heavy, does OK with current power, more is always nice, running a Alpha 1 Gen 2 and should I be concerned about using the 6.2L with the A 1? Currently can cruise at 3200 RPM between 22 and 28 MPH depending on sea conditions. WOT is just under 40. Averaging about 2 -2.2 MPG.

Which intake should I be looking at?

Ayuh,....... You should probably pay close attention to what yer doin' with yer right hand, but that combo ain't necessarily, inherently a bad thing,.....

If yer raw water, in salt, go for a cast iron, vortec bolt pattern intake,.....

 

[Scott Danforth]

running AF, you can run any type of intake (aluminum, aluminum/bronze, or cast iron)

 

[achris]

Which intake should I be looking at?

Edelbrock 2516 Edelbrock Performer RPM Vortec Intake Manifolds | Summit Racing

Free Shipping - Edelbrock Performer RPM Vortec Intake Manifolds with qualifying orders of $109. Shop Intake Manifolds, Carbureted at Summit Racing.

www.summitracing.com

If you do go the 6.2L route, make sure you under prop (a prop that will allow the engine to rev higher rather than lower). That will decrease the torque load on the drive. And I know that sounds counterintuitive, but it's not...

Chris...

 

[AKJohne]

Edelbrock 2516 Edelbrock Performer RPM Vortec Intake Manifolds | Summit Racing

Free Shipping - Edelbrock Performer RPM Vortec Intake Manifolds with qualifying orders of $109. Shop Intake Manifolds, Carbureted at Summit Racing.

www.summitracing.com

If you do go the 6.2L route, make sure you under prop (a prop that will allow the engine to rev higher rather than lower). That will decrease the torque load on the drive. And I know that sounds counterintuitive, but it's not...

Chris...

Thanks makes a lot of sense, I figured I should be slightly underpropped with a new motor until I figure out where I need to be. The boat performs quite well with the existing motor, Is it safe to assume a new 5.7 Vortec would be the same or better... expecting better. Its great to cruise a 30 MPH when conditions allow, I guess that would be the main advantage of the 6.2. Instead of running the 5.7 at 3800/3900 to go 30 I could drop a few RPM at the same speed with a6.2.... Its a good theory anyway. Potentially saving fuel at typical cruise speeds.... talking about saving fuel and boating in the same sentence is a bit of a oxy.....

The lower comp ratio and 87 oct fuel is a plus for the 6.2..... usually I can control the right hand............although there are times... when one has to show what a old boat can do...!

 

[Scott Danforth]

yes, a vortec 5.7 would be about 20-40hp more than your motor (induction dependent)

a 6.2 will be above that (about 340hp to 360 at crank)

the issue with a 6.2 in front of an alpha is that you should run a rev limiter that drops the RPM. if the boat leaves the water and returns (small boat jumping a wave) its the re-entry that is hard on the alpha gear sets

 

[AKJohne]

yes, a vortec 5.7 would be about 20-40hp more than your motor (induction dependent)

a 6.2 will be above that (about 340hp to 360 at crank)

the issue with a 6.2 in front of an alpha is that you should run a rev limiter that drops the RPM. if the boat leaves the water and returns (small boat jumping a wave) its the re-entry that is hard on the alpha gear sets

I have read wave jumping is hard on the drive, I can honestly say I avoid, which has been easy as I have not found myself in those conditions. I also wonder if the San Juan HE is adequate to cool more HP....

 

[Scott Danforth]

I have read wave jumping is hard on the drive, I can honestly say I avoid, which has been easy as I have not found myself in those conditions. I also wonder if the San Juan HE is adequate to cool more HP....

Call SJE (i think they are under a new name now)

 

[AKJohne]

I have been talking to a Devin at Michigan Motorz, pretty helpful. Shipping will run about $825.00, checking on another carrier. Hoping they will forego the $250.00 core charge.
He suggested this motor
https://www.michiganmotorz.com/5-7l-vortec-marine-silver-package-315-hp-1967-current-replacement
As it comes with a intake, fuel pump, and carb and ignition which I dont need, rated at 315 HP.
Claimed MM prefers the Delco ditzy... I got to looking and found this one rated at 325HP.

MerCruiser 350 GEN+ Crate Engine

5.7L MerCruiser 350 GEN+ 325 hp Crate Engine 2013

www.michiganmotorz.com

4 B Weber and T-Bolt ignition which I have hmmmm, appears to be the same base motor (5700).

Thinking I will stick with the 5700 LB base that Chris recommended. Its got to have more than my current motor. Personally I like the T-Bolt, other than the parts and the fact it is corrosion magnet.

And sage advice here?
Lastly, 2516 intake not the "GAP"...?

 

[Scott06]

I have been talking to a Devin at Michigan Motorz, pretty helpful. Shipping will run about $825.00, checking on another carrier. Hoping they will forego the $250.00 core charge.
He suggested this motor
https://www.michiganmotorz.com/5-7l-vortec-marine-silver-package-315-hp-1967-current-replacement
As it comes with a intake, fuel pump, and carb and ignition which I dont need, rated at 315 HP.
Claimed MM prefers the Delco ditzy... I got to looking and found this one rated at 325HP.

MerCruiser 350 GEN+ Crate Engine

5.7L MerCruiser 350 GEN+ 325 hp Crate Engine 2013

www.michiganmotorz.com

4 B Weber and T-Bolt ignition which I have hmmmm, appears to be the same base motor (5700).

Thinking I will stick with the 5700 LB base that Chris recommended. Its got to have more than my current motor. Personally I like the T-Bolt, other than the parts and the fact it is corrosion magnet.

And sage advice here?
Lastly, 2516 intake not the "GAP"...?

I bought a 5.0 silver package plus manifolds and elbows off Them six years ago When i repowered from a 4.3. They tweaked the kit to eliminate the fuel pump and substituted a tbolt distributor for the delco, maybe they will do the same for you? I just preferred to stay with stock merc ignition so not to splice my harness for the delco.
not sure your last question gap? I assume you are asking about the performer vs the cast iron intake they offer? This cast iron intake works really well on my 5.0 nice midrange throttle reponse.

if you have components to swap over just get the base , intake and swap them . I was able to use a lot off my 4.3 in terms of accessories saved a bunch of money for me.

 

[AKJohne]

I bought a 5.0 silver package plus manifolds and elbows off Them six years ago When i repowered from a 4.3. They tweaked the kit to eliminate the fuel pump and substituted a tbolt distributor for the delco, maybe they will do the same for you? I just preferred to stay with stock merc ignition so not to splice my harness for the delco.
not sure your last question gap? I assume you are asking about the performer vs the cast iron intake they offer? This cast iron intake works really well on my 5.0 nice midrange throttle reponse.

if you have components to swap over just get the base , intake and swap them . I was able to use a lot off my 4.3 in terms of accessories saved a bunch of money for me.

I can use everything off of the existing motor, when I asked about the 6.2 the rep suggested the 315 hp with delco and 600 cfm carb, yet they offer a 325 hp version with a 750 cfm weber and T bolt ignition, makes me think he doesn't know the product very well. Probably all due to covid.

 

[Scott06]

I can use everything off of the existing motor, when I asked about the 6.2 the rep suggested the 315 hp with delco and 600 cfm carb, yet they offer a 325 hp version with a 750 cfm weber and T bolt ignition, makes me think he doesn't know the product very well. Probably all due to covid.

The 325 is a mercruiser crate engine intended for bravo drives. The silver package is a partial engine MM puts together from a new base engine. If you have an alpha drive the 325 hp one wont work due to lack of shift interrupt with the bravo TBV ignition module. I think merc makes a 300 hp version for the alphas