Your wording still seems backwards. An all aluminum engine will “GROW” the lash about ten
If Crane wants 22 hot then room temp is twelve. Different cam companies shape their lobes to safely run with specific clearances
Steve is only referencing tight lash. Which are quiet stable and easy on valve train parts.
And there is no blanket yes or no to your magic “more” question
Manipulating the lash specs can simply change the rpms where it makes its torque. Too far either direction can wreak havoc on parts and usually points towards the wrong grinds specs for the build

 

It would seem that most of the low-lash stuff compromises something in some way, out of some necessity; otherwise plenty of the full-race stuff would be low-lash too. My guess would be, intensity near the seat is lessened.

 

Let it go man. SEVERAL People in this thread told him and told him the correct way to set lash, and he still doesn’t get it, although he said he understood.
And then he comes back in and calls someone a clown, after he ranted and said goodbye. I say let him set it big. He will figure it out very quickly at that point. Hopefully he will get it beforehand however, and set the lash correctly to save himself unneeded work.

 

Yes, I think you are on to something. Also, if adjusting the lash to add more torque for instance is wanted, why use a fixed system. Wouldn't it be easier to tweak the lash with adjusters than shims.?

 

Hi ALL, I truly DOUBT if MANY here have EVEN designed a Cam Lobe.
I do and have Andrews Software.

I truly DOUBT if MANY here have ever used a Cam Doctor tool ? ( I have done so)

The FANCY name for HYD lobe is JUST a TLSR lobe (Tight Lash Solid Roller)

I have been AWAITING for someone here to make that statement !

Lance

 

We are probably the most unique in that we have our own custom lobe design software as well as having designed and built our own CNC cam grinders. We have been designing camshaft lobes for 40+ years, long before computerized lobe design was a thing.

I can tell you that in the early days, many folks ran solid lifters on hydraulic profiles when using an iron block. Since the lash only typically grew about .004" with an iron block and aluminum heads or not at all with an iron block and iron heads, this can absolutely be done and has been successful for decades.

However, our modern profile are designed for slightly more lash so that they work good on alumnum block or iron block engines. I would not want to run a hydraulic lobe with solid lifters on an all aluminum engine with .010" hot lash. This would get into a faster part of the take-up ramp and would be harder on the valve-train than I would recommend.

 

It is absolutely more convenient to adjust lash with an adjustable rocker arm. Typically guys who use other methods are doing so because of budget, rules or parts availability.

As for lash adjustment. Increasing lash will reduce seat timing significantly. About 4x as much as it will reduce valve timing @.050". This will improve idle quality and vacuum as well as improving torque in many cases, however there are limits.

For our lobes, we generally do not recommend loosening lash more than about .004" greater than the recommended lash setting. When you go too loose on valve lash, you start to get into the faster part of the lobe's ramp and this is very hard on parts.

 

You do not need to use a fixed or shimmed system. You can use adjustable rockers. **** you can use adjustable on a hydraulic lifter.

The main reason in my mind to use shims over adjustable rockers is if you daily drive it and want the solids. It is one less thing to think about.

@Lance - to my mind, the only advantage a hydraulic lifter offers is maintaining zero lash. Other than that, every advantage goes to the solids.

But to those of you thinking it seems gimmicky, it is not. It is hard to describe how much better the engine runs on them. Especially at high rpm. As to the topic of regular solids - yes, they are faster off the seat. Just like LLSR is likely faster off the seats than hydro. But high rpm stability, I bet is the same for both regular and low lash solids. Imo the only "compromise" you make on LLSR vs regular SR is the low lift ramp ramp rates.

 

I totally get both the theory and real-world sides of LLSR. In fact the ONLY reason this could not be a very wide-spread method is the hassle of setting it up PROPERLY. I love the set-and-forget aspect! Hence the PROPER part of the equation! It just seems a bullet-proof way of setting up a valvetrain.

 

Here is an interesting example to consider. This is a buddy of mine's Silverado with a 408 LS. Originally, he had a Comp hydraulic roller spec'd by someone else. Then, just for fun and curiosity we threw in my old LLR out of the Skylark that was about 14 degrees less net duration to see how it would affect performance. Here is the break down.

Vehicle Silverado standard cab street/strip truck #4025
408 LS 13:1 comression on E85
GM CNC LS3 heads
Super Vic
4500 throttle body
Holley engine management
Glide
4.10 gears
29" Drag Radial tire
Currently runs about 10.80s on motor and mid to low 9 on an 82 jet.

His original camshaft: Comp Hydraulic Roller 259/279 on 114+4 with .652"/.632" valve lift
My old Skylark camshaft: Cam Motion LLR solid roller 250/268 on 111.5+4.5 with .688/.671 gross lift. For those of you familiar with LLR cams, this is the equivalent at the valve of a 245/263 with .678/.661" valve lift.

Here is how the valve events break down:



As you can see, the LLR has 14 degrees less intake duration at the valve and 16 degrees less exhaust duration at the valve. The LLR enjoys about .026" more net valve lift.

Here is what happened on the chassis dyno between the two camshafts:




In this graph, the RED line is the LLR camshaft, the BLUE line is the hydraulic. As you can see, they both make about the same peak power and they both hold the power the same to about 7300 RPM. But, the LLR has a bunch more torque (about 40 ft lbs) down low.

It is not surprising that the smaller camshaft made a lot more torque, but it is pretty amazing how a camshaft with 14 degrees less duration and a 10 degree earlier intake valve close event can match the much larger duration hydraulic up top.

On the track, the car picked up about 3 MPH in the 1/8th on motor going from 96.98 MPH to 99.95 MPH with going to the the LLR. We did not get a comparison on nitrous as he was having trouble with his system when the hydo cam was in the truck.

In addition, the LLR idle quality is much better and a lot less rowdy due to the reduced overlap and seat timing.

 

Do standard-lash solid-roller setups have any advantages over low-lash solid-roller setups?

Or is low-lash just the only rational way to do solid rollers nowadays?

 

Both of your questions are answered in detail, on page 1, first post.

 

I Love me some LLR as much as Darth,Hammer, &
Speed, Obviously using one in my build.

Your "Skylark Cam" was perfect!

But... that hydraulic for comparison is WAY to BIG
for the combo and RPM range IMO.

I understand you didn't spec it. I believe it would be beneficial to see a comparison ~ equivalent to duration & lift adjusted for lash.

 

The hydraulic camshaft was spec'd for a 400 shot of nitrous. And judging by the graph, I would say the guy was on the right track for the customers intended RPM range. Nitrous camshaft strategy is another often misunderstood art. I should probably do a write up on that next.

 

Bah, you're making me reconsider my next cam which I'm about to order.

I've settled on a 238/244 114.5+3.5 recommended by Steven. HR.

If I went SR, I'd need to buy a whole lot more stuff... and honestly, I don't know if it'd be worth it if my goal is a street car up to 6500. Even talked to Steven about doing LS3 heads, but since my RPM isn't lofty, I don't know if an equivalent SR would be better than HR throughout the range. Mind you, I also have Johnson Short-Travel lifters I'll be reusing, so they help the HR uptop. If I were going to go max effort on the 416, LS3 heads, FAST medium runners, and the LLR would be a no-brainer. But for a daily cruiser with a/c. I don't know.

 

Whatever you decide, it's good to see you back in action.

I think that cam will be a good all around performer. One small comment -- on that 416, don't worry so much about torque. It'll make torque - even if it's on accident. IMO, you can err a bit to the top end side with fewer ill effects vs a 346.

 

Yeah, I know. If anything, going to an LS3 top end and LLR would shift the focus up more. And I do love revving it out. But that's with a looser stall now.

I don't know if that triple disk 3600 will work as well with such RPM.

 

Can we make this a sticky?

 

 

It was for n/a, but not necessarily for a 400 shot.