Hi all. Thought i would post on here to get a bit of advice...
I bought a 24' bayliner this past summer, Happy with the purchase... even though the motor needs a bit of tlc...
The boat is a 2000 year and came with a 5.0 and previous owner put in in 2015 a New mercruiser 5.7, roller block with 902 vortec heads. Edelbrock marine intake and 1409 carb, dynoed at 305 hp when installed. Paired with a B3 drive.... Nice combination.... 370 hours since 2015
When put in lake it seemed to run smooth, start easy.. but no power. I ended up replacing the cap, rotor and plugs as they were original from 2015.. I set base timing to 10 btc.. tried again, better but not quite up to rpm at wot so i gave it another couple deg and got it to 4700 ... At that time i was happy but thought it should have a bit more poop....
Now in shop for winter... I pulled drive and motor and I now know that besides oil changes this thing hasnt seen much maint since 2015.. Plus i want to clean and paint bilge, re wire as the wiring is a mess and replace all hoses to black and fresh water tanks...
OK.. Did comp check on motor.... hole 4&6 were at 90 & 140 and hole 5 at 150. the rest were between 160 & 170....
Did leak down and seemed to be leaking via valves... Hard to tell, but hole 4 wouldnt hold any air
Time to tear down... One thing i am very happy with is the cleanliness of the internals... so it looks like oil has been changed and no over heating...
Pulled heads and they look good, a bit of carbon build up, no visible cracking.... I am taking them to local speed shop to get re done.
I was hoping not to touch the bottom end.......
Mic'ed the cyl's and they are not too bad, within 1-2 thou on most, No scoring, No ridges.. But there is a bit of corrosion wear on 4 & 6 and on 5 and minor corrosion on a couple more.... I would say from leaking risers and sitting all winter.. Not enough to sieze motor, but enough to bugger ring seal....
So , I dont think a good hone will work... even with new pistons I think there will be too much clearance..... so Im looking at going 30 over, and new pistons....
Now the ???'s... Its been decades since i rebuilt motors and WOW there are a lot of choices for pistons these days...... I dont want to cheap out....
I have to watch out for my CR as with the vortec heads its real easy to get high comp... I want to stay below 9.5 ish so a dish piston with -12cc..... That will give me a bit of lee way incase the heads and block deck need to be shaved 0.010......
The piston i kinda like is the Keith Black kb 193.030....
others are....dss sx series 8103-4030, wiseco pro tru street pts508a3, sealed power h423dcp
Can anyone give me there opinion or suggestion please.
I am not looking for a hi performance motor, just a solid, reliable runner... will be using boat in ocean, west coast of BC... need reliability....
TIA
Cheers
I bought a 24' bayliner this past summer, Happy with the purchase... even though the motor needs a bit of tlc...
The boat is a 2000 year and came with a 5.0 and previous owner put in in 2015 a New mercruiser 5.7, roller block with 902 vortec heads. Edelbrock marine intake and 1409 carb, dynoed at 305 hp when installed. Paired with a B3 drive.... Nice combination.... 370 hours since 2015
When put in lake it seemed to run smooth, start easy.. but no power. I ended up replacing the cap, rotor and plugs as they were original from 2015.. I set base timing to 10 btc.. tried again, better but not quite up to rpm at wot so i gave it another couple deg and got it to 4700 ... At that time i was happy but thought it should have a bit more poop....
Now in shop for winter... I pulled drive and motor and I now know that besides oil changes this thing hasnt seen much maint since 2015.. Plus i want to clean and paint bilge, re wire as the wiring is a mess and replace all hoses to black and fresh water tanks...
OK.. Did comp check on motor.... hole 4&6 were at 90 & 140 and hole 5 at 150. the rest were between 160 & 170....
Did leak down and seemed to be leaking via valves... Hard to tell, but hole 4 wouldnt hold any air
Time to tear down... One thing i am very happy with is the cleanliness of the internals... so it looks like oil has been changed and no over heating...
Pulled heads and they look good, a bit of carbon build up, no visible cracking.... I am taking them to local speed shop to get re done.
I was hoping not to touch the bottom end.......
Mic'ed the cyl's and they are not too bad, within 1-2 thou on most, No scoring, No ridges.. But there is a bit of corrosion wear on 4 & 6 and on 5 and minor corrosion on a couple more.... I would say from leaking risers and sitting all winter.. Not enough to sieze motor, but enough to bugger ring seal....
So , I dont think a good hone will work... even with new pistons I think there will be too much clearance..... so Im looking at going 30 over, and new pistons....
Now the ???'s... Its been decades since i rebuilt motors and WOW there are a lot of choices for pistons these days...... I dont want to cheap out....
I have to watch out for my CR as with the vortec heads its real easy to get high comp... I want to stay below 9.5 ish so a dish piston with -12cc..... That will give me a bit of lee way incase the heads and block deck need to be shaved 0.010......
The piston i kinda like is the Keith Black kb 193.030....
others are....dss sx series 8103-4030, wiseco pro tru street pts508a3, sealed power h423dcp
Can anyone give me there opinion or suggestion please.
I am not looking for a hi performance motor, just a solid, reliable runner... will be using boat in ocean, west coast of BC... need reliability....
TIA
Cheers