Aftermarket valve spring discussion

[TrailerHauler]

Yeah, you shim to achieve desired seat pressure, relative to installed height.

And I'd bet attention to properly gating boost/BP would go a long way.

Aggie's block and heads were bone stock at 300k correct? No way those valve seats were in the shape required to get away with non shimmed springs.

Height of the spring from the seat to the top of the spring right?

And yes, both chargers were properly gated and yielded very reasonable backpressure numbers from what I can remember. But I'm not sure at what mileage the truck was first modified. I do know that he had over 400k on the truck when it came apart for the 12v and it still ran good as far as I know, which I thought was rather impressive.

 

[907DAVE]

Just a guess but engines could also show no signs of contact because they are so worn out.

If the valve seats are worn the valves will be sucked up into the heads - thus increasing valve to piston clearances....so while there might not be any contact - there could still be valve float.

 

[Cat_rebel]

Shimmed 910's here on all engines that go out the door....

How much of a shim do you run on your 500hp 11 second crew cab? :fordoval:

 

[Marty]

Lol. I had my valve covers off just the other day installing the 400/400s. You're never going to believe what I did way back when....

I'm going to have to contact Matt Lohouse about what I have in there. Way back when I installed my valve springs I did in fact not use a shim under my valve spring seals. I do not have a picture but what I have under the valve cover is not what I have been doing since then lol.

 

[907DAVE]

As long as it gets your spring to an acceptable(lol) height and stays centered....whats the difference?

 

[Powerstroked162]

Ran 910's and they were ok. The piston tops had some light scarring of valve contact but I'll honestly attribute that to the wrong tolerances from the previous builder.

New motor has Hypermax/WOP valve train.

 

[Tom S]

And the correct shimmed height for 910 springs is?

 

[Marty]

Lol. I had my valve covers off just the other day installing the 400/400s. You're never going to believe what I did way back when....

I'm going to have to contact Matt Lohouse about what I have in there. Way back when I installed my valve springs I did in fact not use a shim under my valve spring seals. I do not have a picture but what I have under the valve cover is not what I have been doing since then lol.

So I'm a total tool.

Yes that is quoteworthy but I'm a big enough man to admit my mistakes.

I got ahold of Matt and I have been running Crower valve springs, not comp 910's. I don't even know anything about them. I will be contacting Crower as soon as Matt gets me his account number so I can find out what I actually have and what the hell the strange top end setup was for.

 

[907DAVE]

Time to update your sig!

 

[Marty]

Will do as soon as I know wtf they are. According to matt they weren't an off-the-shelf setup. I really don't know. I don't have my truck here other wise I'd probably take a valve cover off and snap a picture for you guys.

 

[Big Bore]

910's shimmed to 1.75.....

So Dave, since most people are shimming those to .030, was it just the amount of shimming you did that caused the coil bind that snapped the rocker mounts? What do you think the seat pressure was on those?

I've personally witnesses broken rocker mounts and rocker arms and that is definitely the weak link in the valve spring assy as far as I can tell, and my next motor is going to have those cryo'ed at the least.

 

[02POWERSTROKE7.3]

Marty did you have to cut the valve seat for the crower springs? Is anyone using comp cams 26120-16 springs?

 

[Cat_rebel]

Anyone have exp with PBM springs?

 

[907DAVE]

So Dave, since most people are shimming those to .030, was it just the amount of shimming you did that caused the coil bind that snapped the rocker mounts? What do you think the seat pressure was on those?

There was no coil bind. To get to that height most of the valves needed .060, others were a bit more or less. FWIW I started with the springs shimmed to just a fuzz under 1.8 - and I had contact.

Did not even bother to check seat pressure last time I pulled the springs, but the chart says 134 Lbs @ 1.75.

Here's a link to the chart for anyone who is interested.

http://www.compcams.com/technical/valvespringchart/216-06.pdf

 

[Big Bore]

There was no coil bind.

So what did break the rocker mounts?

 

[907DAVE]

Valves hit the pistons.

 

[907DAVE]

FWIW, that was running the spring to the ragged edge....but I was following direction from a shop that has a ton of experience with these motors and was assured that it would be fine.

 

[Big Bore]

Valves hit the pistons.

Float? RPM's?

 

[907DAVE]

RPM + Boost = Float

 

[Homesteader]

Beehives here.