marc_w

Hello...

I'm looking to clarify on the procedure to set the initial (pre-setting-preload) 0-lash for adjustable rockers.

The instructions I have for my set here, say to start by setting all the rockers for 0-lash. I take that as no play in the rocker arm body, as felt by my hand, Correct?

It then says to turn over the motor one full revolution, and check the lash again. It says to repeat this for a total of 4 full turns, stopping at every revolution and checking for 0-lash.

Unless I'm misunderstanding this, it doesn't seem like it accounts for rockers who are on a lobe on the cam. Or does it matter, so long as there is no play?

FWIW, In the end, I will be giving each rocker to full turns on the preload nut, to seat the pushrod down in the lifter.

It seem to me that I should find TDC, and start with #1 and rotate the crank a quater of a turn, and alternate cylinders, setting this 0-lash for the cylinders with both valves closed.

Either that or just wing-it and crank it around 4 full turns, checking for 0-lash at every eigth turn. It's easy enough to finger tighten the adjusting nuts.

Woud anyone care to comment on this?

Thanks,
-marc

camrsz

iTrader: (4)

I would follow the directions for setting the initial lash. When you get resistance spinning the push rod with your fingers you have 0 lash. The 1/4 turn method works good to set the preload. Two full turns sounds like alot though. Make sure you are not bottoming out the lifter.
What engine is this for? and what do yu have for rockers? Just wondering thanks

marc_w

Sounds good, thanks. I found another member in here who mentioned that he followed the directions.

These are VHP/Crane accelerated lift rockers - I hear they're definitely on the higher-end of preload, but others are successfully running them.

mrr23

iTrader: (3)

another way to check for valve lash being at zero is to try and pull up on the rocker itself. and it should be 1/4 turn 8 times for the crank. that way you've been around two full revolutions. and you've been through all 8 cylinder's cycles.

marc_w - you must do the full two turns on the preload. do not just do 1/4 turn. it will not be enough preload and you'll get the noisy valvetrain. when i did my heads on the wife's car, i had greg from vinci walk me through it. standing there watching me. what you do once you get 0 lash is turn all of them 1/4 turn. wait about 5-7 minutes or until you pull up on some rockers and have looseness. this is the lifters bleeding down. then do another 1/4 turn. repeat for a total of 7 times. then on the 8th time, you turn the las 1/4 turn while also turning the posi lock. this will ensure the posi locks are secure enoug has not to come loose. on the preloading sequence, you do not turn the motor over.

marc_w

Thanks a lot mrr...

I went through everything, went to start it, and I have some serious, serious problems. The engine is not starting at all - it sounds very sickly. I've got maybe one cylinder firing. The starter sounds as if it's turning over very slowly for some reason. All of my external stuff is hooked up (coil packs and what-not).

When going through the sequence to a "T" these last 3 hours, during the last time around, it felt as if some of the lifters were being bottomed out. The adjust stopped being turned easily, and it was not due to the lock contacting the stud. I did not like that at all, and I knew something was up. I felt for the contact, and backed off a quarter of a turn from that. I'm 100% sure I only did 2 full turns. It felt like these offending cylinders were both on the drivers bank.

I'm not certain on my judgement of zero lash. I did not do things finger tight, but wrench-tight, when I could not turn the pushrods with two fingers stuck around each rocker.

I suspect that some of my valves are not closing, due to too much preload. The motor turns over somewhat normally by wrench, but I can hear some hissing up in what sounds like the intake. Scary stuff. I'm pretty annoyed right now. It's dark, 20*F and dropping. I'm working out of my driveway here.

I'm going to give things another 20 minutes to bleed down before I tear things back down again. It's already been 45 minutes since the last adjustment.

marc_w

Yeah, it's a no-go.

What are the opinions on going through the bleed-down procedure at this point?

Will the lifters pump up again once I take off the adjusters?

Or can I just give them 2 full turns once I get lash all set to finger-tight ie: no loose rockers?

mrr23

iTrader: (3)

sounds like you have most of the valves open. meaning way too tight. do this. back all of them off 1 full turn. then see how it starts. if it doesn't then i've got another way to do it. most people just don't get the zero lash part done right. this in turn hangs all the valves open.

marc_w

Ahh shoot, I got everything torn down already. I just got done getting everything set to finger-tight 0-lash, after two full crankshaft turns, using the 1/4 turn-at-a-time method.

It has/had to be the valves hanging open - I can smell gas in the engine bay, I assume it's whafting (if that's the right word) out of the airbox.

Any recommendation on how to take things from here? It feels like some lifters decided to pump, others I can pretty easily get some actual preload on if I push down on the rocker body.

mrr23

iTrader: (3)

check your PM and call me

marc_w

Just got it - Thank you!!

NASTE_SS

I've never heard of two full turns of preload on hydraulic lifters, and i go to school to be a machinist and engine builder. The rule of thumb is 3/4 of a turn on street motors that go 100,000 miles and 1/4 of a turn on street trip motors, and1/8 turn on race motors. That goes for any hydraulic lifter, there's only .160 travel in the lifter and two full turns would preload the lifter way too much. If you need some help just pm me and i'll tell you anything you want to know.

NASTE_SS

always set your preload on EOIC after the base circle of the cam (exhaust opening, intake closing) so when the exhaust starts to open then set the o lash on the intake valve, and then proceed with setting the preload on the intake. Then when the intake vavle is closing you should do the same for the exhaust valve.

mrr23

iTrader: (3)

ok well there's a thread pitch difference in the studs. could be why vinci/crane says to do 2 full turns. which just happens to equal about .120". after all, it's there product. you'd think they know what they are doing. i did mine 2 full turns per the instructions. been running for almost a year that way. and just redid them in january when the heads went in. and the LS1 isn't like the old SBC.

clif notes: do what the manufacturer tells you to do.

NASTE_SS

no offense, but like i said i'm learning from the best on how to build race motors. I'm not saying it wouldn't work, but how long do you think it's going to last at .120 preload, when the standard for any hydraulic is no where near that kinda of preload. it defeats the whole purpose of runnig a hydraulic. but there's no point in arguing, I go to college to studying this and you rely on directions. So good luck with everything and i wish your valvetrain the best of luck.

marc_w

Whew... Sorry to leave you hanging a bit, Robert.

It's up and running - pretty good too! Thank you SO MUCH, I really appreciate the help.

It sounded like an old radial engine for the first 5-8 seconds which had me worried, but it was just because it was loaded up from before. I had a few ticks and taps for the first few minutes... and a few chirps/squeaks too - which really makes me second guess my ability to pre-lube parts, but after a quick test-drive it's quieter than I can ever remember it being.

The tricks or tips you mentioned for the bleed down REALLY helped. Once I knew what I was really looking for, everything went real smooth.

My problem before was that I took my sweet old time when cranking over the motor and setting the initial 0-lash... and I was using a wrench to get the PR's snug (rotation wise). By the time I'd walk around to double check things, I'd find that the lifters have bled down and I'm thinking I didn't do a good job the first time around, so I snugged them up some more, putting too much initial preload.

Doing things only finger tight is definitely the way to go.

mrr23

iTrader: (3)

it's amazing that you rely on teachers. while i rely on the people that make the product. some wonder if teachers are nothing more than failures in the real life. so, they went into teaching.

wonder how many turns it takes a thread pitch of 1.00mm vs 1.50mm to reach .120"?

marc_w

These things are made by VHP/Crane - they've been in the business plenty of time to know what will work correctly...

mrr23

iTrader: (3)

glad to see that it finally worked out for you. you have my number if you ever need anything else. i guess the whole thing that vinci put up about how the rockers get the barrel oiled must work on keeping things quiet huh?

marc_w

I pulled up an old PM I had from another member who talks with VHP - he says they recommend .060-.080" for preload. I assume that's around the range we end up with with our two-turns.

mrr23

iTrader: (3)

http://www.vincihighperformance.com/...20PAGE%20.HTML vinci's tech and tuning page.