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I hear you!! Made good progress today. Drained the coolant, pulled the intake, unbolted the passenger side header from the head and both collectors from exhaust X pipe. Then I removed all 15 nuts and washers from the head studs. Then....I just ran outta gas!! But the head will be off tomorrow and then I'll go over to the drivers side to unbolt the headers from drivers side head and remove the 15 nuts and washers over there. I'll pull that head tomorrow, too. Just to be clear, I'm not complaining about being 70. It's just obvious you have to make a few adjustments to your work schedule. Wife has a little sign by her garden. It says old Irish proverb "Do not regret growing old-Many are denied the privilege!!"
Thought Id also post a couple pictures of the #8 exhaust valve Ti retainer. Due to the wear of the guide, the rocker was slamming the exhaust valve stem toward the exhaust side then slamming it the other way .080" (at least!) towards the intake side. This had the effect of an impact wrench, but instead of rotational forces, they were horizontal. Check out the attached photos of the Ti retainer. It actually has the spiral helix of the valvespring worn into it!!!!!
Did your head shop actually replace the valve guides with longer ones or just replacements? If they did the job right then the solution is as simple and as difficult as figuring out why you have no lubrication, too much heat, or God knows what else.
AFAIK, they are AHP's hardened PM guides, stock length....
Most impressive in this sad situation is the strength of the Ferrea valves, PAC springs, and PAC Ti retainers. I am 100% convinced if I would've had the OEM valves, I wouldn't have an engine.......
Thats what she said!! Anyway, I finally got the drivers side head off. It was ready to pull at 1:30. But.....I forgot what an absolute PAIN IN THE *** removing the alternator bracket is. Had to get the power steering fluid out of the resrvoir, so I used a turkey baster, which I remember doing before. Then removed the hose from the reservoir and where it attaches to the pump inlet. Had to do that so I could access the last bolt that held the bracket to the head. Draining the reservoir best I could and removing the 4 bolts holding the bracket on took me 2 damn hours. Wish the engineers who designed this mess worked on this stuff!Had to give it up for today. Back said NO MORE!! But both heads are on the bench now, and all springs, retainers, and the valves will be out tomorrow. Will post results and pics......
OK guys, got the heads disassembled. Surprisingly, the #8 guide, first one I checked several days back? It was the worst one, by far. All 8 intakes were pretty darn good, with 2 or 3 having virtually no wiggle/wear, and the worst 2 or 3 probably near, or just over the service limit. No, I don't have the means at my home garage to check the guide I.D., partly because I sold most of my toolmaker/machinist tools. Intake stems all mic'd .3135"-.3137", as new. So I figure even though the wiggle test has become redundant (to some), I say if they hardly wiggle, or move, they must not be worn. However, as I removed the #3 and #5 exhaust valves, they felt- IDK how to explain it any other way-gritty. So I wiped the exhaust stems off, and they were galled pretty good!! So then I cleaned the other exhaust stems off, and every one of them showed galling!! Shockingly, the #8 exhaust stem, the one in the worst worn guide of all, was in the best shape of all the exhaust stems! Only reason I can figure is maybe it got a bit more oil due to the extreme wiggle. Who knows?? When I mic'd the exhaust stems, they all measured same as intake stems. Would love feedback on this development....
Last edited by grinder11; Jun 15, 2024 at 07:27 AM.
Ok guys. Here is a pic of the galled #5 exhaust valve stem. Identical to #3 exhaust stem, and worse than #8. None of the 8 intake stems exhibited any galling. #3 and #5 both felt gritty as I removed them. The pic really doesnt do justice to how nasty the galling is. These 2 valves, #3 and #5 exhaust were the only 2 that felt gritty. They were also the only 2 that would not fall out on the bench from gravity. I had to pull them out by hand!
The other 14 valves all smoothly fell out of the heads after they cleared the guide seals.
Ya know what, guys? The thing that thoroughly pisses me about this situation, more than all the $$$$ and all the work, is this; I am going to lose yet another summer to downtime. I know I've mentioned my age, probably too much. But the bottom line is I only have so many summers left to enjoy this car. This will be the 2nd summer in the last 5 that I don't have the car. Even Bezos doesnt have enough $$$$ to buy back lost time. It really sucks.....
Im going to post a couple pics in the next hour of my rocker trunnion mounts. Some look very similar to main saddles moving around/fretting. You be the judge......
@Che70velle@old motorhead and anyone else notice anything like this on
LS7 rocker mounts? Pics are marginal, but if you zoom in you can see some are exhibiting some kinda strange marks on the scallops. When I tighten the rockers on each mount, I use one hand to wiggle the trunnion in a slight twisting motion, using my thumb and index finger to help "nest" the trunnion in the stand as I tighten the mounting bolt. Do this same thing on all 16 pedestals. Not all the stands exhibit these weird patterns. What say you???....
Mike, with 100% certainty I can say that the pedestals flex on the GM LS7 heads, as I and a few other have mentioned in the past. It’s a documented fact. Nothing new there. But here’s something to add to this discussion that might bring some light to the witness marks in those saddles…
In my time spent in the industry, with the R&D work we did for Cup teams as well as other professional Motorsports teams, we did a lot of internal video work. We studied windage under “glassed” valvecovers (along with other areas of the engine) with dry sump oiling systems, to determine what the internal atmosphere looked like in the top end, at 8k+ rpm. The footage was very high quality for the 90’s and we slowed it down to very low frame rates, so slow in fact that we could see rocker flex, rocker shaft (Jesel) flex, valvespring disorientation, etc.
To go slightly off-topic here in an effort to clear up some past discussions on the subject of the rocker wheel sliding across the valve tip…it does NOT slide. The wheel rolls in both directions accurately and precisely as long as lash is kept in check by the valvesprings doing a good job. I’ve seen hours of live footage up close and personal and I’m tired of seeing bad info out there…rant over.
I have no doubt that as those LS7 pedestals flex at very high speed, there is also rocker bolt stretch and the trunnion is likely moving around some in the saddle. To add insult to injury here, this also introduces harmonics into a valvetrain that’s already being scrutinized. Any increase in spring rate along with the associated increase in RPM will only make this worse. And for the guys that have had their LS7 castings ported, which removes material directly under the rocker pedestal, this issue at hand is made much worse.
I'd assume the YT full roller rockers on their short shaft mount system would help stabilize this problem.....somewhat. It would at least tie/girdle 2 pedestals together....
Mike, with 100% certainty I can say that the pedestals flex on the GM LS7 heads, as I and a few other have mentioned in the past. It’s a documented fact. Nothing new there. But here’s something to add to this discussion that might bring some light to the witness marks in those saddles…
In my time spent in the industry, with the R&D work we did for Cup teams as well as other professional Motorsports teams, we did a lot of internal video work. We studied windage under “glassed” valvecovers (along with other areas of the engine) with dry sump oiling systems, to determine what the internal atmosphere looked like in the top end, at 8k+ rpm. The footage was very high quality for the 90’s and we slowed it down to very low frame rates, so slow in fact that we could see rocker flex, rocker shaft (Jesel) flex, valvespring disorientation, etc.
To go slightly off-topic here in an effort to clear up some past discussions on the subject of the rocker wheel sliding across the valve tip…it does NOT slide. The wheel rolls in both directions accurately and precisely as long as lash is kept in check by the valvesprings doing a good job. I’ve seen hours of live footage up close and personal and I’m tired of seeing bad info out there…rant over.
I have no doubt that as those LS7 pedestals flex at very high speed, there is also rocker bolt stretch and the trunnion is likely moving around some in the saddle. To add insult to injury here, this also introduces harmonics into a valvetrain that’s already being scrutinized. Any increase in spring rate along with the associated increase in RPM will only make this worse. And for the guys that have had their LS7 castings ported, which removes material directly under the rocker pedestal, this issue at hand is made much worse.
There was a lot of good, high-end info in that post. Thank you for sharing!
Well damn! Hate you're having to mess with repairing and not driving. I can sympathize with not being able to spend hours bent over leaning into an engine bay. I can do it long enough for minor stuff. My back hurts even thinking about cleaning deck surfaces.
At this point, I'd go in another direction. What's the definition of insanity? I have no experience with LS7 stuff. I will say that my LS3 build has over 50K miles on it. The heads I sent to Tx Speed for porting, milling, and valve job had 10K miles on them. I don't believe Tx Speed touched the valve guides. The cam is a .620 lift Cam Motion custom grind. It's had two set of stock rocker arms along with two sets of BTR platinum dual valve springs. Both changed out at the 30K mile mark. The old rockers looked and felt perfect at the swap. While not LS7 power, 500 at the wheels moves a 3200# Vette around nicely.
I understand that going to an LS3 top end will cost you some power. If you do decide to go the LS3 route, I have an LS3 intake manifold laying around if you need it.
Well damn! Hate you're having to mess with repairing and not driving. I can sympathize with not being able to spend hours bent over leaning into an engine bay. I can do it long enough for minor stuff. My back hurts even thinking about cleaning deck surfaces.
At this point, I'd go in another direction. What's the definition of insanity? I have no experience with LS7 stuff. I will say that my LS3 build has over 50K miles on it. The heads I sent to Tx Speed for porting, milling, and valve job had 10K miles on them. I don't believe Tx Speed touched the valve guides. The cam is a .620 lift Cam Motion custom grind. It's had two set of stock rocker arms along with two sets of BTR platinum dual valve springs. Both changed out at the 30K mile mark. The old rockers looked and felt perfect at the swap. While not LS7 power, 500 at the wheels moves a 3200# Vette around nicely.
I understand that going to an LS3 top end will cost you some power. If you do decide to go the LS3 route, I have an LS3 intake manifold laying around if you need it.
What a nice offer!! Thank you. I'm so far into LS7 stuff that at my age I'm going with the same LS7 heads, but with Tony Mamo reworking them this time. He believes that with his guides, valve job, the full roller rockers and them being shaft mounted, which ties two pedestals together, they will last a lot longer. We shall see. If I was still in the workforce (younger!) I'd go aftermarket, TFS, Brodix, etc. If I get 45,000-50,000 miles out of it, they'll probably last me 8-10 years, as I won't be driving it as much anymore......
What a nice offer!! Thank you. I'm so far into LS7 stuff that at my age I'm going with the same LS7 heads, but with Tony Mamo reworking them this time. He believes that with his guides, valve job, the full roller rockers and them being shaft mounted, which ties two pedestals together, they will last a lot longer. We shall see. If I was still in the workforce (younger!) I'd go aftermarket, TFS, Brodix, etc. If I get 45,000-50,000 miles out of it, they'll probably last me 8-10 years, as I won't be driving it as much anymore......
Tony will do you right. A friend of mine worked with him to get his C6 Vette's act together and he wasn't disappointed. He's very good with support after the sale.
Ya know what, guys? The thing that thoroughly pisses me about this situation, more than all the $$$$ and all the work, is this; I am going to lose yet another summer to downtime. I know I've mentioned my age, probably too much. But the bottom line is I only have so many summers left to enjoy this car. This will be the 2nd summer in the last 5 that I don't have the car. Even Bezos doesnt have enough $$$$ to buy back lost time. It really sucks.....
I can sympathize with this, though maybe to a lesser extent because of my age, but it's been 2 of the last 3 for me. It sucks because cars are the one hobby I really get into. It wouldn't be so bad if we had good driving weather year round, but going all winter in Michigan looking forward to car season and then getting shafted right away at the beginning is a kick in the nuts.
I can sympathize with this, though maybe to a lesser extent because of my age, but it's been 2 or the last 3 for me. It sucks because cars are the one hobby I really get into. It wouldn't be so bad if we had good driving weather year round, but going all winter in Michigan looking forward to car season and then getting shafted right away at the beginning is a kick in the nuts.
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But the head will be off tomorrow and then I'll go over to the drivers side to unbolt the headers from drivers side head and remove the 15 nuts and washers over there. I'll pull that head tomorrow, too. Just to be clear, I'm not complaining about being 70. It's just obvious you have to make a few adjustments to your work schedule. Wife has a little sign by her garden. It says old Irish proverb "Do not regret growing old-Many are denied the privilege!!"
) towards the intake side. This had the effect of an impact wrench, but instead of rotational forces, they were horizontal. Check out the attached photos of the Ti retainer. It actually has the spiral helix of the valvespring worn into it!!!!!
Had to give it up for today. Back said NO MORE!! But both heads are on the bench now, and all springs, retainers, and the valves will be out tomorrow. Will post results and pics...... 
