Valve stem seals crushed, LS7. More spring?

[mdrew]

...pictures of the witness marks...

Any pics of the alleged victim stem seals?

Alleged....lol

An intake that was not hammered for comparison purposes also in the pic. All the hammered seals have a similar state of death appearance to them.

[Newold1]

Hard to make out exactly but some of the spring bases in the background appear to have much different wear patterns on them than others. Was there a marked different wear pattern on the spring bases from the intake versus exhaust springs. I've seen valve seals such as these on come off the guides and once one does the action of the springs and valves opening and closing at rpms will trash them like this in short order. On the LS engines the standard valve guide seals are hat type seals where the seal base is also the spring base. Why did you not use that type seal on your heads. In your pics there is a pic of a beehive spring. Is that the springs used on the head when it destroyed the seals? I may be a bit confused from the pics as I think the pic showing the rockers appears to have a straight spring.

[Newold1]

Sorry , I got the pics in my mind confused with another pic on another post on a LS7 head thread. You obviously have a dual valve spring setup and if those seals are .501 ID they measure about .550 OD with the metal jacket. With a .654 ID inner spring ID if the inner is moving with valve train harmonics it could pretty easily get over against the metal jacket seal side and lift it off the guide and the rest would be history. The only hole in this theory would be that the exhaust and intake springs are the same dimensions, so why didn't it do the same on the intake seals? But if those wear marks are different on the intake and exhaust spring bases then one might surmise the exhausts were doing things differently than the intakes. Sorry for the ramble, I am thinking to much as I am writing.

[MadBill]

The way that seal is beat up looks like it came off the guide and then was trashed by the inner spring. Surely when you removed the spring the seal was floating around loose rather than fitted over and bottomed out correctly on the guide?

[wyrmrider]

sorry I missed the pics of the witness marks
wish everyone had them as dead nuts on as you do
perhaps my little rant will help someone else
It was after a whole series on geometry and I should have gone back and reread from the top
I've seen in other threads ls folk cutting spring seats for BBC/MOPAR size springs- have you seen anything on that?
cheers and happy new year

[mdrew]

The way that seal is beat up looks like it came off the guide and then was trashed by the inner spring. Surely when you removed the spring the seal was floating around loose rather than fitted over and bottomed out correctly on the guide?

Your assumption is correct sir. The seal remnants were not still on the guide. I am currently in the process of dropping the pan to roll out the bearings, because some pieces of the seals surely made it to the pan. I'm hoping that between the pump pick up strainer and oil filter on this faux dry sump system, hard parts didn't go through the engine.

Here's a pic of the locators. I really don't know what to make of the different wear patterns....



Still waiting on UPS, dangit.... I really need to know what shape the springs are in. Regardless, at this point I'm pretty convinced the exh springs went bonkers and pulled the seals off the guides, then beat the crap out of them. The intake seals took a good deal of effort to remove with channel locks, so I'm pretty confident I installed them all correctly.... As RW has said several times, the system is not happy. The exh side more unhappy because of the added valve weight than the intake valves, and it didn't help, probably, that I set the exh side up 0.0010" higher than the intake side.

[MadBill]

From the apparent shine/wear in the pix, it appears likely that both the inner and outer exhaust springs have been dancing up a storm, plus possibly the intake inners. How do the retainers and collets look?

[RW TECH]

The way that seal is beat up looks like it came off the guide and then was trashed by the inner spring. Surely when you removed the spring the seal was floating around loose rather than fitted over and bottomed out correctly on the guide?

Your assumption is correct sir. The seal remnants were not still on the guide. I am currently in the process of dropping the pan to roll out the bearings, because some pieces of the seals surely made it to the pan. I'm hoping that between the pump pick up strainer and oil filter on this faux dry sump system, hard parts didn't go through the engine.

Here's a pic of the locators. I really don't know what to make of the different wear patterns....



Still waiting on UPS, dangit.... I really need to know what shape the springs are in. Regardless, at this point I'm pretty convinced the exh springs went bonkers and pulled the seals off the guides, then beat the crap out of them. The intake seals took a good deal of effort to remove with channel locks, so I'm pretty confident I installed them all correctly.... As RW has said several times, the system is not happy. The exh side more unhappy because of the added valve weight than the intake valves, and it didn't help, probably, that I set the exh side up 0.0010" higher than the intake side.

It's obviously out of control on the exhaust. The mutilated seals & fretted locators scream that. It's in the cam.......Promise.

[Newold1]

With the smaller diameter dual springs on a LS head and the proximity of the inner spring even with just some normal spring hysterics you could have the inner spring oscillating enough possibly to ride up against the seal and work it up off the guide and the rest is history. There are a couple of things I would look at also. You mentioned possible seal fitment differences? Have you measured the actual OD on the two different guide types, intake, exhaust? It could be that the original build on the heads had used two different spec. valve guide diameters and if those press on seals are not good and tight on the exhaust, the problem could have been amplified. Those are apparently machined aluminum spring bases and show a lot of valve spring rotation. I like to use steel spring bases and on LS or LSX heads whenever camshaft valve lifts will allow I like to see the top hat combination spring base-stem seal type units. ( see pic)

Happy New Year to You, may it be healthy and prosperous to all Gear Heads! https://www.speed-talk.com/forum/posting.php ... milies&f=1#

[wyrmrider]

Couple of things on dual springs
On Mopar and some BBC we saw a lot come in with the small OD seals on the 3/8 valves-- the guides crack so don't do it
still would like to see a larger springs discussed

[wallbrett]

RW TECH,
What's your opinion of Katech's 501 cam for the ls7?

[RW TECH]

RW TECH,
What's your opinion of Katech's 501 cam for the ls7?

My opinion is it won't do the stuff we're seeing in the pictures in this thread if you use K501 cam with ALL of the ancillary items Katech used when they verified it to be stable.

Matching your performance requirements in terms of durations, timing points, etc. depends on too many variables so I don't have a comment. Best bet is to call them & get their opinion.

[mdrew]

Too hung over yesterday to do anything.... This getting old crap sucks. Cute little bench tester from LSM showed up. Had to use a wheel from my Sunnen seat runout checker to compress these little LS springs.



True coil bind at full compressed height of 1.175 is 0.060".

Load on the exh with 1.835" install height:

1) 119/462
2) 122/469
3) 119/470
4) 121/472
5) 122/455
6) 119/472
7) 122/469
8- 121/469

Load on the int with 1.845" install height:

1) 124/459
2) 128/470
3) 129/465
4) 121/469
5) 126/471
6) 127/471
7) 129/469
8- 129/468

Those are bound to be a wee-bit off, as I am reading an analog gauge, but not by more than a pound or two. Gave all the springs a few taps after compressing them too.

I've inspected all the retainers and locks and nothing is glaringly obvious. They look pretty normal to me.

[MadBill]

How many miles on the springs? The difference isn't "yuuge", but the intake seat load average should be 5# less than the exhaust, due to their greater installed height. Instead they're 6# more, perhaps pointing a finger at exhaust spring abuse...

[mdrew]

Roughly, 10k miles of use. I usually go for PAC, but in this instance, the guy I got the cam from suggested I use these Comp springs. They seem to be doing well.