Max lift with GM dogbone roller lifters

[CGT]

Talk to Vizard.

Talk to at least 3 builds of mine using those lifters that have been posted on here.

[skinny z]

Fair enough and I have no reason to dispute your successes. I've followed your work and respect your results.
But I very much doubt something along these lines would get published if it wasn't factual. Dimensionally and component- wise the two versions may be identical but the composition of the material used for the lifter body is where the difference lies.
Unfortunately, I have only have one representation that supports that finding.

[CGT]

Dimensionally and component- wise the two versions may be identical but the composition of the material used for the lifter body is where the difference lies.

And I say horseshit, but who cares. Sorry OP

[skinny z]

Apparently, you and I cared enough to have this conversation.
As for the OP, perhaps he can take away something from the following.

Screenshot_20201104-133632_1.jpg

Screenshot_20201104-133728_1.jpg

[mt-engines]

Dimensionally and component- wise the two versions may be identical but the composition of the material used for the lifter body is where the difference lies.

And I say horseshit, but who cares. Sorry OP

Thats why i didn't respond with what i have seen. the nay sayers have their minds already made.

[skinny z]

Thats why i didn't respond with what i have seen. the nay sayers have their minds already made.

I'll take it Mr MT that you share the share experiences as CGT? It's a non-issue?

[CamKing]

The only difference between the old LT1 lifters, and the LS7 lifters, is the bleed rate.
The LS7 lifters have a slower bleed rate.
When GM was developing the LS7, they found that the 1.8 ratio rockers were causing the lifters they ran in the LS1 engines to bleed down at higher RPM's. Whenever you increase the rocker ratio, you increase the force against the hydr unit in the lifter. The higher the force, the quicker the lifter bleeds down.
To fix this issue, GM had the LS7 lifters made with a slower bleed rate.

[CGT]

The only difference between the old LT1 lifters, and the LS7 lifters, is the bleed rate.
The LS7 lifters have a slower bleed rate.
When GM was developing the LS7, they found that the 1.8 ratio rockers were causing the lifters they ran in the LS1 engines to bleed down at higher RPM's. Whenever you increase the rocker ratio, you increase the force against the hydr unit in the lifter. The higher the force, the quicker the lifter bleeds down.
To fix this issue, GM had the LS7 lifters made with a slower bleed rate.

The part number lifter used in the LS7 originally was in use in 4.8 5.3 etc prior to the release of the LS7 itself. I always found it ironic that they ended up being labeled "LS7" lifter....not saying they couldn't have been released prior in anticipation of the 7.0. Im well aware its all about the buck and that could have been the result of financial decisions and consolidation of parts inventory.

There have been many supersessions, part number changes, retroactivity, etc in lifters in GM over the years in LS, and small and big chevy as far as that goes. I have looked at all of them. I have measured some slight changes in overall travel, seen some "country of origin" changes, differences in axles etc. and im sure "valving". But material composition causing distortion causing rpm limitations between the reiterations.... ...I have just been involved and around too many things using all of the different variations not having these issues to stay quiet on this.

[CGT]

1.8 ratio rockers

I have always found it interesting that GM decided to put a higher 1.8 ratio on their "high rpm" hydraulic lifter engine(LS7). I think a lower ratio has some inherent advantages when using full travel hydraulic lifters. I guess they saw it different

[skinny z]

But material composition causing distortion causing rpm limitations between the reiterations.... ...I have just been involved and around too many things using all of the different variations not having these issues to stay quiet on this.

I'm only reporting two things: What I experienced and a change made that had results. That another well respected (?) builder and author would report similar findings and remedies that followed gave some credibility to those results.
I'll ask this and then the leave it alone: Why do they make tool steel lifters? That is, Comp (as an example) went from their normal travel cast body roller to a tool steel short travel version. I understand the short travel aspect of it but the change in metalurgy? Surely not change for the sake of change.
And this, IIRC, is about the same time as Vizard published the article posted above.
Anyway, that's about it I think. I haven't got the experience to qualify it any further than I have and I appreciate all of the insights and information spilled out here.

[rebelyell]

large base circle cam
check out the cam rings & lobes in this P&W double wasp radial aircraft engine; base circle OD must be at least a foot.
https://www.youtube.com/watch?v=EyPvpdy4dgg