8V71TI Insulated Risers

[whaler23]

Per Pascoe
"Most of these boats through the early 80's had upsweep, water jacketed risers. Which means that if the riser leaks, as it eventually will, the water runs into the engine. Many of these systems were revised, others were not. Best to look for one that has insulated risers"

In referring to the 53 Hatt's. How do you recognize insulated vs. not? How do you tell if the M20 gearboxes that most of these boats had have been "fixed" as Pascoe further refers to them as potentially being inadequately oil cooled...?

 

[Nonchalant1]

What you're looking for is "dry risers" which were actually not that uncommon. The difference is readily noticeable because dry risers have a large bulky fabric or foil covered heat shield wrapped around them.

The riser is the exhaust pipe connecting the engine exhaust manifold to the turbos, one on each side. The manifold is water jacketed, but the riser should be heat shielded, not water jacketed metal (which requires no heat shield) to be what you're looking for.

Re: the M20s. I would assume that any M20 still running OK now has been fixed or was OK to start with.

Doug

 

[REBrueckner]

"Most of these boats through the early 80's had upsweep, water jacketed risers."

I'm not sure that's accurate....not from what I have observed...dry risers seem more common....???

The dry risers (from the back of the exhaust manifold on each side of the engine up to exhaust level) are covered with soft cover heat blankets, wire wrapped and or button on, and get to 600 or 700 degreess or more and are solid un painted (rusty surface) cast iron. The water jacketed risers are copper alloy or stainless alloy and either painted or ss shiny...and are simply warm (raw water) to the touch. This is potentially the closest raw water gets to your inner engine.

 

[MikeP]

I agree, RW is injected at the shower head which is downstream from the turbo and even if the whole thing failed, water would be running downhill toward the exhaust collector, not back toward the engine. I would call those "dry risers" as well and I can't see any danger at all of RW being ingested by the engine.

 

[rsmith]

more applicable to the n engines the PO had rybovitch replace ours with insulated dry stacks right from the get go.

 

[Tim Powell]

I agree, RW is injected at the shower head which is downstream from the turbo and even if the whole thing failed, water would be running downhill toward the exhaust collector, not back toward the engine. I would call those "dry risers" as well and I can't see any danger at all of RW being ingested by the engine.

mike doesn'T that apply to the six seriase as well//I have seem some black insulating naterial looks like a composit that was wrapped around some exaust //my cousin has a 54 viking with mans they put new risers and axaust .It left here with the insuration wraped around came back with what looks like black tape wraped in its place. IT is so so neat can we do that with the detroits eaven though mine are new they still look messy you know all whired up tim

 

[Nonchalant1]

Pascoe's stated concern with wet risers failing is that a hole in the exhaust side pipe can let raw water leak into the exhaust pipe before the turbo and it will run backwards when the engine is off and get into the engine.

Doug

 

[rsmith]

Pascoe's stated concern with wet risers failing is that a hole in the exhaust side pipe can let raw water leak into the exhaust pipe before the turbo and it will run backwards when the engine is off and get into the engine.

Doug

In the old days with the n engines everyone rolled the engines over with the shutdowns pushed for a few turns to make sure the back cylinders didnt have hydraulic lock from the risers leaking