Volvo Penta 5.7L needs rebuild - where to go?
 

2003 Volvo Penta GXI 5.7L 320hp.

4 cylinders with low compression. Only 308 hours. The motor is still in the boat and starts but I need a recommendation on who to go to for a rebuild?

Thank you advance for your help.

Marshalls Maine
 

Do you have a bad head or is the short block trashed too? I have used this company with great success on a 350 boat engine- they will install as well, but I would call to see if they install in boats.
http://marshallsmachine.com/list.html

Thank you, this looks like a good option. I'm not sure of the extent of the damage as it was just diagnosed this weekend after the engine wouldn't rev above 2800rpms. The engine will need to be pulled and torn down before I know any other information so I am preparing for the worst.

Go with a replacement short block... plenty of people out there who do this. Rebuilding an existing motor usually is not worth the time, money or down time.....

HOWEVER...

Why are they telling you that your engine is trashed?? Low compression could be valves or rings.... with those few hours you probably only need a valve job, and that does not require removing the motor... just removing the heads.

You might want to seek out a second opinion before you have the motor yanked...

Woodsy

Are the 4 low cylinders on the same side/head?

I second Woodsy
 

Replacing a 7.4 (454) with a 390 short block is a huge benefit. HP to engine weight ratio is better than the big blocks. A lighter boat saves gas!

Just so we do not confuse the OP too much. Short block= Block, Crank, pistons, etc. Long block= short block plus cylinder heads. Big Blocks (454, 496, 502 Chevy, 460 Ford 440 Chrysler) are really just larger dimensionally than a small block (350, Chevy, 302 Ford, 318 Chrysler). Big blocks typically create more torque, but often weigh 30% more than a small block.

Motor Boatin', if you need work on the bottom end, put in a long block, and stick with your small block 5.7 (350) :)

Hopefully you just need a head reworked

I would find someone that can diagnose the problem properly. Low compression could be caused by a number of things. What they will need to do is a cylinder leak down test to pinpoint the problem. I know GM had a lot of issues with cam shafts from about 07 through 2010 where the lobes would wear down and cause all sorts of issues depending on how bad they wore. I agree white the ones that said stick with what you have in there as changing engine sizes will cause more headaches than it is worth. 360 hours in nothing one one of these engines unless it has been run very hard all it's life.

I thought those camshaft issues were resolved back in the 80's. I made quite a few bucks doing cam, lifters and timing chains back then....right in my driveway, nights and weekends. The good old days....

BT

ya, you are correct. but I believe all those engineers have retired and the new ones never got the memo. 07 through 2010 or so had the same issues as they had back in the 80's. I can't tell you how many of these cam shafts I have replaced. it's funny we would see a new model car come in and we would see something they tried twenty years ago and did not work, just to see it not work again. We would just shake our head when we saw these cars come in with the same problems we have seen in the past.