steelmesh

Been trying to understand the lash adjusters / lifters in high power high rpm builds. I am laying out what my current understanding is in hopes it will be corrected.

Available Parts:

Ecotec build books recommends Jesel KLA-81500 lifters and KLA-81555 shim assortment, you may be required to run the Jesel followers too.

Defunct? BLE made them (PN: GM00116), but my research mostly people in forums suggested they made three types: machine to fit, shim, and adjustable. I called a supplier and questioned their description about these being adjustable without shims, my guess is they are the machine-to-fit type though.

Looking into the lifter bores and also confirmed by the internet, you cannot run shims [on the bottom of the lifter] because they will fall out. This leaves only a machine-to-fit type and an adjustable type if that even exists. *update*: Tru Motorsports confirmed with BLE the adjusters are adjustable with a nut, but you really only need 8 for the exhaust side, I guess you can sell the other 8 though.

Compatible camshafts versus lifter type:

1) Hydraulic Lifters should go with Hydraulic Camshafts
2) Hydraulic Lifters should not go with Solid Camshafts
3) Solid Lifters should go with Solid Camshafts
4) Solid Lifters should work with Hydraulic Camshafts

Thinking outside the "bore":

1) Oil pressure behind the "piston" of the lifter takes up slack creating zero lash. The force the lifter exerts on the follower/valve spring is proportional to engine oil pressure. The idea is to increase oil pressure (shim the spring or bore out oil restrictor) to increase the force the lifter exerts.

2) Bore lifter bores larger to install larger lifters [with a larger area "piston"]. Without changing oil pressure, this would increase the force because laws of physics.

3) Close clearances of the lifter / lash adjuster to reduce leak down (I have some cerakote dry lube coating advertised 0.0005-0.0010" thickness, but also advertised that cylinder bore clearance changes are unnecessary.

4) Reduce exhaust valve spring pressure. You compress springs, put in oven 5 minutes at 350F then check, but can play with compression force/time/temp dont exceed 400F. In small batch performance spring production the recipe was developed, but production operators were quite involve being the feedback loop to adjust force/time. It's really that simple to get the target seat pressures, the production process always ends with a longer free length to then be baked to the right seat pressure.

When are they needed and other notes:


- Need them on the Exhaust side more because cylinder pressure (intake has boost behind it)

- Worst case running collapsing lifters, you lose significant power but no permanent damage. Or can followers fly out?

- If you increase valve spring pressure, you are already over powering the stock lifters

- Ecotec build book chart shows at 700 hp is when upgraded followers are needed.

- Page 8 of build book for Sportsman implies they ran upgraded springs and production valves to 500 hp

- Page 37 under the Pro Ecotec build level verbatim:
"For applications above 42 psi of boost, a dual roller rocker
from Jesel is used. The recommended valve lash is 0.0059
at the valve.
At lower boost levels, the production intake rocker arm can
be retained. Bates Engineering offers a cast rocker arm for
use with the Bates Engineering solid lifter. The
recommended valve lash is 0.0059 at the valve. To adjust
lash or roller to cam clearance, the bottom of the solid lash
adjuster is machined down in a lathe until proper lash is
achieved. For each 0.00259 machined-off the solid lash
adjuster, there should be a 0.0019 increase in lash or roller
to cam clearance."



What are your thoughts, experiences and opinions?

63 Nova SS

iTrader: (3)

Message Mr Belvedere, aka John Walters as I believe he has experience on this.

steelmesh

Modified original post. Confirmed BLE is selling actual nut adjustable lifters, GM00116 and called Tru Motorsports can order from them if anyone was wondering.

I'm still doing research and understanding the options here.

Sharkey

iTrader: (1)

non adjustable lash adjusters with shims can only be used on the early l61 head (02-06), im not sure about the 07-08 head. the oil passage that feeds the lash adjusters is smaller in those heads and the shims will stay in place. im running shims with my solid lash adjusters in my l61 head, no issues.

i should also note that i am running solid lash adjusters with comp cams XE246THR-13 cams with my solid lash adjusters. no issues, no signs of wear on the cams in about 2500 km of driving, a bunch of dyno pulls, and beating on it anytime i get a chance.

steelmesh

Do you know what the difference between a solid grind cam vs. hydraulic? My brain keeps saying roller vs. flat tappet cams which most of us know about. Thanks for sharing your insight on your L61 build.

cw383

iTrader: (6)

I had a follower come apart at the bearing, presumably due to a stage 2 lash adjuster ( ZZP/LNF ) collapsing? I had my valve cover off investigating a Subaru sound and at first glance all the rockers seemed in place so I went on investigating other possible causes. After awhile I figured I had better look closer and opened it up again. Here the follower was sitting right where it was supposed to be but the center bearing portion was completely MIA. Had to look in a weird angle to see that, who would of thought...

Problem is, when the follower pops out it can wedge in the camshaft and scratch it up. Or worse. I did notice a mark I could feel with my thumbnail upon closer inspection. I layed a rag under the cam and did my best to micropolish the lobe with various grades of wet sandpaper and WD40. Crude, I know, but the scratch wasn't that bad, and it seems to be working. Plus I didnt want to scrap a $400 Stage 2 exhaust cam over a little scratch. I ordered all new exhaust lash adjusters and followers so I plan to throw them in soon.

I am unsure if my problem was caused by

1: Faulty follower
2: Faulty lash adjuster
3: Just dumb luck or simple abuse hitting 7400rpm

I am using ZZP Valve springs and Ti retainers, so this is good info : )

Sharkey

iTrader: (1)

the biggest difference is a solid lifter/adjuster cam is usually ground on a billet core, as a billet steel cam will take more abuse than a cast cam. a hydraulic grind will typically have a softer valve open ramp to help prevent the lifter/lash adjuster from collapsing, and the closing ramp is quite steep to allow the lifter/lash adjuster to almost "unload", allowing it to fill with oil that was lost during lift. a solid lifter cam can open far quicker than a hydraulic, some performance is lost running hydraulic cams over solid cams because of this.

the reason im running hydraulic cast cams with solid lifters is because i bought the cam and lifters "used (they had been put in a head but never run), and when i got them i discovered they wernt actually billet cams like i was told. after much research i couldnt find a reason not to actually run it, and so far everything is happy.

USMCFieldMP

iTrader: (1)

I've been looking into running Solid Lifters this time around and came across this thread during my search. I figured that since a couple of the contributors are still around, I'd thrown in my two cents.

On the first point - I can confirm. I had 3 or 4 stock lash adjusters collapse at 8k RPM. PTE5557 at 25 PSI. Stock cams, ZZP 82# Springs. All collapses happened on the exhaust side.

On the second point - when mine collapsed 2 or 3 of them were essentially fine afterwards... but one of them, I'm guessing, collapsed in a way that held the valve open. Piston to valve contact happened, which then shot the valve up faster than the spring could keep up, which allowed it to release the locks, allowing the spring and retainer to unseat. Luckily, the only damage to the head was a couple insignificant scratches around the lash adjusters and I needed new valve guides installed.

I am curious as to where people have gotten their grinds from. I'm not seeing a lot of availability, even for staged hydraulic cams.

Sharkey

iTrader: (1)

the problem right now, for the l61 and lsj, is there are no cams, unless you find a store that has them on the shelf. i had a set of comp cams on order since january, and after being screwed around by the vendor for 2 months on when they are supposed to ship i emailed comp directly. apparently comp has no exhaust blanks, and they arent expecting to get any till late april at the earliest, and then they will take 2 weeks to grind them and get them shipped. to add to this, im pretty sure our 2 major vendors that have their own line of cams are having them ground by comp cams, meaning they wont have any cams available sooner either. so like i said, if its not on someones shelf its going to take a while. as far as i know, no other cam manufacturer in north america does ecotec cams. i know there are some available in europe, but i have a hard time sorting it all out, and they are very expensive.

now as far as grinds go, if you come up with specs you want, comp can grind them for you. additionally, have a look here https://www.compcams.com/lobe-catalog at page 151 and 152, there are 10 intake cams and 8 exhaust cams that arent off the shelf. these get pretty wild.

all of the above is to do with l61 and lsj cams. if you have a vvt engine (le5 or lnf) pretty much all i know of is zzp. im sure they could get you any cam specs you want, thats assuming they are actually willing to.

USMCFieldMP

iTrader: (1)

I did some talking with an old forum member yesterday who told me that mrbelvedere is apparently the man to talk to about getting solid cams. I'm not sure how often he hops on here anymore (looks like last activity was 6 weeks ago), but I have him on facespace.

07blackg5

iTrader: (8)

comp will not grind a solid profile ecotec cam