Volve Penta 5.7L RPM Question

[mdecker006]

Hi all -- I just got a reman'd 5.7L VP 350hp put in my 2002 Wellcraft Martinique over the winter. After about 5 times out, seems like it does not have the power out of the hole that it used it. Top speed is consistent with performance before the swap (I had a blown head, scored cylinder and very poor compression on 2 cylinders which necessitated the swap) but seems to take longer to get on plane. The other thing I have noticed is if I hammer the throttle, it shoots up to top end rpm, but then immediately dogs for 3 - 5 seconds back down to 2500 rpm or so, then heads back up to top end. Any thoughts on this? I feel like I might need to get a compression test or something to make sure this swap was done correctly. Thanks for the help.

 

[Don S]

Re: Volve Penta 5.7L RPM Question

Carbed or MPI? Full model number of the original engine would be handy.

 

[Bondo]

Re: Volve Penta 5.7L RPM Question

Hi all -- I just got a reman'd 5.7L VP 350hp put in my 2002 Wellcraft Martinique over the winter. After about 5 times out, seems like it does not have the power out of the hole that it used it. Top speed is consistent with performance before the swap (I had a blown head, scored cylinder and very poor compression on 2 cylinders which necessitated the swap) but seems to take longer to get on plane. The other thing I have noticed is if I hammer the throttle, it shoots up to top end rpm, but then immediately dogs for 3 - 5 seconds back down to 2500 rpm or so, then heads back up to top end. Any thoughts on this? I feel like I might need to get a compression test or something to make sure this swap was done correctly. Thanks for the help.

Ayuh,.... Sounds like it ain't gettin' Good gas flow,...

Which is probably what detonated yer old motor to death,...

Was any forensics done to see what killed the other motor,..??

 

[mdecker006]

Re: Volve Penta 5.7L RPM Question

Volvo Penta 5.7 GXI DPS

The diagnosis was a severe overheat in the past (before I bought it) that weakened the heat. Eventually head failed, and knocking started, scored cylinders on #3 & #5.

 

[Bondo]

Re: Volve Penta 5.7L RPM Question

Volvo Penta 5.7 GXI DPS

The diagnosis was a severe overheat in the past (before I bought it) that weakened the heat. Eventually head failed, and knocking started, scored cylinders on #3 & #5.

Ayuh,.... Which makes a pretty good case that the same issue killed that motor, 'n is why this 1 won't run Right,...
Detonation is Extreme localized overheatin',...

The Fuel ain't flowin' properly, or it's bad fuel to begin with,...

 

[Maclin]

Re: Volve Penta 5.7L RPM Question

What exactly was replaced (long block, intake to pan, etc...), what components are from the orignal engine?