Aftermarket valve spring discussion

[Cat_rebel]

Doug's are 175 lbs of seat pressure.

He also has some available that are stiffer then that. 200 I think

Who is running them in a 7.3L?

 

[jwlandry]

I will be the first I'm pretty sure

 

[Big Bore]

I will be the first I'm pretty sure

I'm still concerned about them being too heavy for some of the other valvetrain components. I'll be watching yours. At this point I'm still leaning toward the 92120's. They can be installed to [email protected]" and can go to 185lbs. and still be in spec. I'm definitely learning more as I go here and the cam lift is one area where I'm lacking.

 

[jwlandry]

The 7.3 lifters are similar to the 6L and those will turn 5K and have to open 2 valves. Im not really worried about the single valve in the 7.3 nor the springs.

 

[907DAVE]

Doug's are 175 lbs of seat pressure.

I would have to double check my notes, but that is about what the Crowers came out to also.

 

[jwlandry]

Dave, how long you been running the crower springs? Have you had any trouble with valvetrain issues?

 

[907DAVE]

ZERO valvetrain issues so far.

The motor has been together almost a year now? Might have 12k on it, I will have to look.

 

[jwlandry]

ZERO valvetrain issues so far.

The motor has been together almost a year now? Might have 12k on it, I will have to look.

Then i rest my case about the fact that the 175# springs causing an issue.

 

[Big Bore]

The 7.3 lifters are similar to the 6L and those will turn 5K and have to open 2 valves. Im not really worried about the single valve in the 7.3 nor the springs.

Yes, you made the same comment in the other thread and it's an interesting and theoretically valid point. I'm watching yours for sure. Unfortunately I wont have time to watch you put 100K on it lol.

 

[jwlandry]

I cant wait till its done. The goal is TS and if everything keeps going like its going, it WILL be there. I need to start a build thread i guess.

 

[Chvyrkr]

Yea I knew what the seat pressure was, I was more wondering what the installed height, bind and spring rate was. I can't remember if it's in the other thread, and didnt see anything on Go Go's site.

Am I wrong in thinking taller installed height and shorter bind is better?

Max lift height on 26120 is 1.25. Max recommended install is 1.80@. Subtracting leaves .55 of travel. Does this correspond with cam lift?

Stock cam lift is .481...

Stock installed height is 1.833, compresses to 1.352.

Found a copy of my book.

 

[Big Bore]

Stock cam lift is .481...

Stock installed height is 1.833, compresses to 1.352.

Found a copy of my book.

That wasn't actually my question, however that's because I didn't word it properly, and your post answered a lot of other pertinent questions.

What I was trying to ask was if the amount of valve travel would correspond directly to amount of cam lift via the rockers based on stock rocker arm ratio. IOW if the cam lifts .50 in., does the valve travel .50.


Awesome info.

 

[Hotrodtractor]

if the cam lifts .50 in., does the valve travel .50.

No. there is a rocker arm ratio that multiplies the cam lift by a certain amount. I'm not posting a ratio at the moment since I need to verify something - I've been told two different rocker ratios for the stock setup in recent history and I know only one of them is right and I don't recall off the top of my head which one it is.

 

[09stroker]

IOW if the cam lifts .50 in., does the valve travel .50.
Awesome info.

If the rocker arm ratio was 1:1.

 

[Chvyrkr]

I see.

As you may already know, cam lift doesn't equal valve travel.

Think the stock cam lobe is .295 or so on the intake.

On edit: They just answered, ratio was the term I was looking for.

 

[Chvyrkr]

Ok I was a bit off, intake lobe lift is .2535, exhaust is .2531.

So, with .481 of valve travel, the numbers are there for someone to find the ratio.

 

[Big Bore]

If the rocker arm ratio was 1:1.

Uh yea, I'm aware of that.

 

[Big Bore]

Ok I was a bit off, intake lobe lift is .2535, exhaust is .2531.

So, with .481 of valve travel, the numbers are there for someone to find the ratio.

Ok, but that assumes the valve actually travels .481 during operation. From what I'm seeing on the charts, that is simply max compression on the spring? The chart you posted is giving the spring pressures at those heights, but it doesn't delineate whether that's actual valve travel. Or am I missing something? If it is then that's great, if not it just deepens the mystery.:fustrate:

In any event it will be fun to use those numbers and see if they correspond with what HRT comes up with.

 

[Chvyrkr]

That's the ford engine manual I'm pulling that info from. And I'm pretty damn sure that .481 is valve travel, and they're giving you the spring pressure at open and closed in that graph.

 

[09stroker]

Uh yea, I'm aware of that.

Just sayin cause that's exactly what your question was asking.