Valve Overlap Specification Methods
 

Hi ALL, I would like to state the Valve Overlap Amount Specification I use for quality engine performance.

I invite other methods to be shared, to help LS-1 tech Members.

I often fit a camshaft of 180/188 .525" on a 102 C/L
This engine operates at WOT for 25K hours.

MY Overlap specification is based on time spent at PTO vs WOT under the Mode of engine operation.

THUS at PTO there is a LOW overlap requirement. (low port air density)

The fact that runner lengths MUST also match is a major consideration.
The Exhaust Pressure (E-MAP) is a great concern for correct spectfication.


Other Thoughts ?

Lance

Hi Lance! First, just to clarify, PTO = Part Throttle Opening ?

What is an engine operated as above used for? Stationary industrial comes to mind. 25K hrs is a LOOONG time! lol

We have large forklifts get there at the mill. They're 40k lb lift capacity at 4' away from mast and run non stop. Approx 7800 hours per year. We had one that the hour meter stopped at 14,981 and has been stuck on that number since 2011. That's our "little" one. It only has 33k loft capacity at 2'. It's much more maneuverable.

A cam like lance proposes makes a lot of sense in this application. These motors never exceed 2500 rpm or 20 mph.

I was thinking large stationary engines, but totally see it in a forklift! Long hours accelerating and decelerating, revving to lift, a super-mild cam would sure do it!

1 Million Mile Engine
 

Hi ALL, yes this is a 1 million mile engine@40 MPH average.

True, the application is for CPS in Paris, Texas.
A Natural Gas pump, engine running on NG.
The engine is maintained, oil changes/filter changes WITHOUT ever being stopped !
This type of engine is fitted with my IGN-8 and ignition coils.
This engine's MAX RPM is 1800.

The Oil Pump is the first item to wear out.

To ALL, a good guess though the Overlap question requirement was not addressed ?

Lance

i would be interested to find out. can you elaborate? btw, 180/188 @ ? lift?

Lance hasn't posted here since August of last year, and is no longer a sponsor.
You might try to contact him at his business-
Pantera EFI
1-949-250-1797

thats a shame. i enjoyed his posts. actually his last post was on my birthday. didnt he have an internet page?

Lance is a clever man, plenty of experience and like most inventor creative types his communication output OS flies a brand of its own. Hope all is well

He's got panteraefi.com but I get the impression that most of what he does / what he sells isn't listed there.

It's a shame he's off the forum now, the guy had a lot of really interesting insight.

Yeah, I got the feeling PanteraEFI is a side operation, just the tip of Lance's iceberg.
I think his fingers extend to many different pies...

Lance is a boat man iirc. Builds boat race motas

I have a feeling that's not all.... I bet if it's powered, he's involved with it.

Definitely a very smart man, although sometimes I think he talks in riddles ! Can be hard to understand sometimes.

But in terms of skills and abilities, he's well into top racecar territory.

I have a feeling that he gets so deep into stuff, that he has to scale the tech talk down enough for us mere mortals to understand, and the talking in riddles sort of evolves out of that.
Just my little theory....