Water ingestion issues with Volvo 81Gi

"I repowered from a Volvo 7.4l

"I repowered from a Volvo 7.4l to an 8.1Gi and ended up with three damaged exhaust valves. The manifold in the immediate area of exhaust valves showed salt incrustations; it was clear that salt water had gotten to the exhaust valvesd. Volvo covered the damage under warranty. They believe water got in from a leaking riser gasket.

I have been hearing rumors that this engine has had a history of water incursion problems, perhaps due to a partial vacuum created by the choice od valve timing. If there are any related issues, I'd obviously very much like to know about them.
The engine was a direct replacement for a 7.4L, which lived for 10 years and 2000 hrs. The engine beds were raised apprioxi9mately 1" and the engine is well above the minimum waterline-to-riser height called for in the installation manual.
Thanks in advance for any help offered."

"Sounds like you've done y

"Sounds like you've done your homework! Those leaky gaskets are probably the problem, especially the manifold to riser gasket--it's CRITICAL on all marine engines.

Jeff"

"I guess I'm really worrie

"I guess I'm really worried about the reputed propensity of this engine to ingest water through the exhaust system. I understand there was a problem with several installations, notably on Carolina Classic boats, but my information is all second or third-hand. Would anybody know whether the 8.1L Vortec engine is any more likely to ingest water through the exhaust system than other engines on the market?"

"I'd be curious to know wh

"I'd be curious to know what you decided to do about your 8.1Gi. Just purchased a 2001 Carver 396 with twin Volvo 8.1Gi's. After seeing a water leak on the port / inboard manifold, we took it apart and saw very light oil and a lot of rust indicating that seawater was getting in. If you replaced your manifold riser gasket, did that fix the problem? I have elected to replace all risers/elbows and manifolds as a precautionary measure.

Also, how are things holding up now? Looks like it's been 6 months since you posted the problem."