Anyone have Mercury Dyno Charts.

[lmannyr]

Can't seem to find dyno charts on Mercury's site on current production products much less the older models. I am more interested in the '83 vintage 5.0L and todays 5.7 MPI dyno charts.

I'm looking at these long blocks and like to compare curves, etc...

350/290HP
350/355 HO

 

[Don S]

Re: Anyone have Mercury Dyno Charts.

Merc does not publish any torque charts, neither does Volvo. They won't even allow dealers that information.

 

[180shabah]

Re: Anyone have Mercury Dyno Charts.

That second one might scare me a little with the "unique, aggressive idle".
Sounds like it might be a water sucker

Remember this is going in a boat when you make your cam choice. WOT under 5000RPM, and you don't want to deal with reversion so watch the LSA.

 

[lmannyr]

Re: Anyone have Mercury Dyno Charts.

Remember this is going in a boat when you make your cam choice. WOT under 5000RPM, and you don't want to deal with reversion so watch the LSA.

In other words I need to shoot for a max of 5K RPM? What should I look for in the cam to prevent reversion? Please elaborate this in detail on how and why this would happen.

Thanks..

 

[Don S]

Re: Anyone have Mercury Dyno Charts.

Reversion (Valve Overlap) happens with even the best MARINE cam. But ways past it are designed into the engines.
With that overlap, it causes water (used to cool the exhaust in boats) to suck back into the cylinders.
Marinizers work hard to find the best grind and work past the overlap. It doesn't always work.
What may work on a car, doesn't mean it will work on a boat. Two completely different operating parameters.

 

[lmannyr]

Re: Anyone have Mercury Dyno Charts.

Reversion (Valve Overlap) happens with even the best MARINE cam. But ways past it are designed into the engines.
With that overlap, it causes water (used to cool the exhaust in boats) to suck back into the cylinders.
Marinizers work hard to find the best grind and work past the overlap. It doesn't always work.
What may work on a car, doesn't mean it will work on a boat. Two completely different operating parameters.

How does one know this is happening? Block seizes? How can I plan for this during my paper engine building?

 

[Bondo]

Re: Anyone have Mercury Dyno Charts.

Ayuh,...

Keep the LSA between 109?, to 112?......

Find a copy of Dennis Moore's book SBC Marine Performance... It's got alot of Great Info.....

 

[lmannyr]

Re: Anyone have Mercury Dyno Charts.

These are the specs right from the GM Performance Parts Catalog

GM Cam part number 24502476

Hydraulic Flat Tappet

Duration @ .050" Lift (deg):
I: 212 E:222

Maximum Lift (in) w/1.5 rocker:
I: .435 E: .460

Lobe Centerline (deg):
112.5

How do I figure LSA?

thanks!!

 

[Bondo]

Re: Anyone have Mercury Dyno Charts.

Duration @ .050" Lift (deg):
I: 212 E:222
Lobe Centerline (deg):
112.5

Ayuh,......

The Exhaust Duration is Awlfully Long,+ the LSA is Above 112?......

You'll need a Smaller Cam......

 

[lmannyr]

Re: Anyone have Mercury Dyno Charts.

How do you figure that out?

 

[Bondo]

Re: Anyone have Mercury Dyno Charts.

Well,.....

Most Marine cams top out around 214?/ 218? exhaust......
And,.....
I believe that 112.5? is in fact longer than 112?......

 

[lmannyr]

Re: Anyone have Mercury Dyno Charts.

Any way around the reversion? besides changing out the cam on the crate engine. I'd hate to get a crate and swap out the cam? I've heard of people using riser spacers. Does this prevent reversion by buying time or degrees on the LSA?

Bond-o

thanks for your patients. Cams is one area I never really understood in all my years of working on engines. I always just hoped for the best. I'd rather not "hope" with this build and be certain there will be no reversion. THANKS again!!!