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Replaced head on VP AQ120

P

pugetsounder

Advanced Contributor
New head gasket, do they still require re-torqing after a few cycles of warm up and cool down? If so, Do you experts just do it after a brief warm up?

BTW the number 4 and 3 exhaust ports were corroded beyond repair. There was nothing left. I always flush with fresh water after a saltwater cruise is there a way to prevent this form happening in the future?
 
Exhaust manifold is fairly new. I replaced it two seasons ago. I knew there was corrosion then but it seems to have gotten a lot worse. Funny because I flush the motor out with fresh water in a tub after saltwater use. I'm hoping I can prevent this in the near future. The exhaust mani has a zinc in it. I wonder if that is deferring corrosion to the head?

For my original question do you re-torque head gaskets these days?
 
The exhaust ports themselves are supposed to be dry all the time. A leaky gasket at the manifold/exhaust elbow joint could allow water in the port area. On other makes and models, water injestion, i.e., water getting sucked back into the engine ports from the exhaust system caused this. High speed backing could also be a factor... or a missing or not sealing exhaust outlet flapper (If equipped) or shutters in the exhaust line ( if equipped)
 
sandkicker said:
The exhaust ports themselves are supposed to be dry all the time. A leaky gasket at the manifold/exhaust elbow joint could allow water in the port area. On other makes and models, water injestion, i.e., water getting sucked back into the engine ports from the exhaust system caused this. High speed backing could also be a factor... or a missing or not sealing exhaust outlet flapper (If equipped) or shutters in the exhaust line ( if equipped)
Click to expand...

I think you're thinking in terms of Mercruiser, there is no exhaust elbow on a 4 OHC Volvo Penta. Or inline exhaust flappers. The flapper on the drive is good working order. Corroded #4 exhaust ports are a fairly common problem with these motors, VP even had a portable fix for it back in the day.

Back to my original question about retorquing the head bolts on a new head gasket. It's an Erling brand original volvo gasket but new stock. I've heard that newer gaskets don't need retorquing?
 
Thanks Kim. Getting the boat ready for halibuts on the straights this May and I knew the head was going to have to be replaced before going out. I replaced the ex. manifold two seasons ago and it still looks pretty good when i had it off monday but I knew the port was pretty corroded back then. I just band-aided it until i could replace the head. All fixed now. The battery ground sounds like a good idea. I have both grounds (2 batt system) going to the front of the block.
 
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