I admit, i've been ignoring my car more than trying to find this problem, but I thought i'd go back to one of my original theories.

I got me a skip. It skips at any RPM. Kinda like a minor shake.
Like a bad plug wire. This has happened since day one.

I built the motor in the spring. Complete overhaul, nothing
used in the block including injectors. I used trickflow 23* heads with -2 spring package, but immediately changed them to -3 springs because I was afraid they were not heavy enough.

So I never ran it with the lighter springs. Here is what I've done since I built the motor this spring, to try and solve the problem:

Tried rich tunes, lean tunes, add spark adv, take away spark adv
Tried Various plug heat ranges and gaps
New dizzy + cap + rotor
New ECM, bins, etc
New plug wires
New intake, throttle body, fuel rails, etc
New roller lifters (Melling)
New rocker arms
New headers + y-pipe

So i'm kinda wondering if maybe the springs are too heavy
for my cam after all. The -2 spring options are for MAX .540 lift, which is where my cam is .540 on the exhaust. So I went with -3 springs for MAX .600 lift.

-2 Spring specs:
1.470" o.d. single with damper
120 lbs. @ 1.780" installed height
300 lbs. @ 1.280" open
360 lbs. per inch rate
.540" maximum valve lift

-3 Spring specs I installed:
1.460" o.d. double with damper
125 lbs. @ 1.780" installed height
376 lbs. @ 1.180" open
420 lbs. per inch rate
.600" maximum valve lift

Camshaft specs:
230/245, .533/.540, 114lsa 112ctr hydraulic roller

Anyone think these are too heavy or am I being silly again?

I've done compression tests, but I need to obtain a leakdown tester. My ring gaps are .022" for forced induction, but I wouldn't think that would cause a skip. Unless I broke a ring and didn't notice.

-- Joe

 

I'm not sure that's the kind of thing I'd go posting around on the web.

Thos are fairly high rate springs, but I wouldn't expect the "skip" at higher RPM as a result. Unless one (or more) of the lifters is leaking down under the pressure, it shouldn't be that noticable. Then again, you seemed to have tried everything else except a cylinder leakage test and vacuum testing the heads.

 

Have you ever been able to get it to change?

try removing the radiator cap? the PCV? plugging all the vacuum lines? running with the blower belt removed?

How about checking the end-play at the front end of the camshaft?

I know it's all unlikely, but just wondering if these have already been eliminated.

 

I'm trying to locate someone with a leaktest gauge set. Thats about the last thing I can try. Still though, I don't know what's considered 'normal leakdown' for my ring gaps either.

Kinda sucks ya know? Thats why i've lost interest lately. That and my oil pan is leaking. That thing was a pain to get around the oil pump pickup on the engine stand, no way i'm doing it with motor in car.

-- Joe

 

Out of curiousity, what fuel pressure are you running?

 

38psi with 42# injectors.

I did the leakdown test. They all are 15-18%, which from what I've read is just peachy.

Check this out.

I hold throttle at say 2500rpm. It runs rough for a few seconds, but then the RPMS start to fall drasticly. The motor sounds like it's loading up like your going up hill, and then it pops.

I'm starting to wonder if my brand new ford injectors aren't bad. Infact, I'm considering sending them out to Rich tomorrow for testing.

My wideband goes nutty from 10:1 to 19:1 afr, in OPEN LOOP. Thats a huge swing. Somethings not right.


-- Joe

 

just a thought,do you possibly have 1 of the valves adjusted a little too tight ,causing it not to close completely.this will give you a skip at all rpms

 

I've re-adjusted like you wouldn't believe.

-- Joe

 

Fuel pump going south?

 

Your AFR is wandering all over, and no-load RPM just falls away? Are you running an EGR system?

 

Or a leaking block off plate for the EGR.

Man, your issue sounds almost exactly like what my Formula is doing.

Not really a miss, more of a skip/intermittent issue.

U notice it a idle and see stupid AFR on the wideband same as me.

I've been sick and its cold here so I've been hibernating.

Interesting to here someone with almost exact symptoms of my car.

I'm gonna go poke around and reseal the blocked EGR( would think it would be a constant issue) but its worth trying.

later
Jeremy

 

Yes, and no, its a holley singleplane manifold, no EGR.

-- Joe

 

Maybe it's our milodon oil pans getting back at us..

Check out tonights testing:


I did a compression test tonight with a brand new tester.
started with right bank, and did cyls 2, 4, 6, 8.. came up
with 200, 200, 170, 185.

So then I did the second bank (cyls 1, 3, 5, 7), and came up with pretty much 170-185 accross the board.
Then I re-did the first bank, and came up with between
170-185. like on the second bank

So I said hrmm. I sprayed a little oil in #2 to check for
bad rings. still 185. So I said. "why the hell did this cyl
show 200 earlier!?"

So I took the valve cover off, backed the valve off a
little.. 195 psi .. backed it off so there was about .050 between the pushrod and rocker cup. 200psi.. so I figure, the lifters were bleed down when I did the first two cyls from sitting over night when I did the first two,
but then the oiling system pumped up for the remaining cyls.

So at 0 lash, the rocker holds the valve open a hair.
So I'm thinking, maybe the stock-length pushrods are too long for the decked block + trickflow heads, and when I adjust lash it pushes the valve open a hair rather than centering the plunger, because there is more leverage twords the valve. The roller never walks off the valve stem, but maybe still the pushrods are too long. I wonder.

Or maybe I stumbled upon another problem..

 

A quicky test for the pushrod length to see if it's close. Pick a cylinder that's at TDC firing (cam will be on base circle for both valves). Remove rockers, wipe oil of roller and valve tip, and color the valve tip with a black magic marker. Reinstall the rockers at zero lash and wiggle them. You might have to put some slight pressure on the roller tip to get a good mark. The line should cross the valve tip roughly 1/3 of the way down from the intake side.

I don't think improper length would hold the valve open. I've never looked when adjusting my valves to see if they open a tad when lashed. The force on the lifter plunger has to be much less just sitting there versus the engine actually running.

I would check your injectors (or throw in an old set to see if it changes anything).

EDIT I just thought about this again. I think the higher compression test results from the lifter being bled down or from backing the rocker nut off are due to less overlap, not the valve being open.

 

Check this out.

I backed off all the rockers until there was decent lash (loud clicking). probably about .040".

Fired car up until it got warm. turned polylocks by hand until almost all lash was removed.

Car idles steady, vacume is 15hg, no skips, no breakdown when you hold the throttle.


5 of the 8 rockers don't squirt oil, even though I checked ALL of them and the pushrods and they are not clogged.

When the lifter is pumped up, it is ROCK SOLID. Normally, in my experience, hydraulic lifters are a little spongy and you can push down ont he pushrod. These are SOLID, no give. Which is why when you attempt to adjust lash, it doesnt push on the plunger, it opens the valve.

Wtf.. ANy ideas?

-- Joe

 

Throw a set of stock ones back in.

Does melling make a stock replacement solid roller lifter? I would pull one out and take it apart. Something is seriously wrong if it's not squirting oil from the pushrod.

 

I'm running hydraulic roller lifters.

The lifters I'm running right now are Summit brand.
I'm not sure who makes them for summit.

-- Joe

 

Saw a reply (this board I believe) that Crane supplies them.

So you reset lash and skips are gone? Did I read that right? Valvetrain noisy at all?

My dads car has little to no oil at the pushrods at idle, takes some serious excess lash to get any real oil jumping out. Have to bring the RPM's up and run them a bit loose to see much of anything. Havent had any valvetrain issues though, so it must be fine.

 

Yeah, I can't adjust it to a point where it doesn't tick (no lash), yet runs smooth. Normally you would get it to 0 lash, then go an extra 1/4 turn. I can't, it just opens the valve. But with it "close" to 0 lash, and being ticky, it runs like a top!

I dunno. I was always under the impression that you should see a good steady flow of oil. Who knows.

But either way, this lash problem is an issue. And I don't know what to do. The thing is, I replaced my comp lifters with these summit ones a few months ago to "solve the skip". (I said melling in the first post, but I checked my reciept and they are summit house brand). So either I have two bad sets of lifters, or something else is wacky.

-- Joe

 

I think I found my problem in this thread:

https://www.thirdgen.org/techbb2/sho...lifter+plunger

Second from last post. I did the same thing, soaked them in oil overnight. I wonder.

-- Joe

 

EDIT-found a thread on how it lifters works. Learn something new everyday.

http://www.chevelles.com/forums/show...68&postcount=3

 

And this

 

Ugg. I didn't want to take the intake back off.

Maybe this is a good time for me to yank the motor and change out the oil pan too.

-- Joe

 

I've had the same experience last fall when trying to get rid of a "miss" on my roller.
The more I adjusted, the worse it got.
Started with 1 or 2 and by the time I was done it was qty 5-6.
Bought a new Comp set to go in this winter because I couldn't make them adjust and didn't want to carry the problem forward.
Good to know all I needed to do was drain the lifter.

Sooner or later the filling of that chamber is inevitable.
Isn't the fluid in the spring chamber metered out somewhere?

 

Yes.

There are numerous holes in a lifter, I dont know how soaking them in oil could 'ruin' them personally.

I have always wondered about exceeding the limits of the spring and fluid pressure in a lifter with the valve spring pressure and where exactly that point is. Thats one of the upsides to solids.

 

After doing some research on the net, I think joe's lifters are defective or clogged. The oil under the plunger sets the lash but bleeds out the pushrod. His aren't bleeding out, instead they're pumping up the lifter and opening the valve slightly.

 

I just spoke to the crane guy on the phone. He said it's common with there lifters (even read the part # to me before I could tell him what application).

They said there is no way it will bleed out unless I put pressure on each lifter, slowly. So I'm gonna go give that a whirl.

-- Joe

 

Hmmmmm

Never thought of that, lol and I always soak them too. I soak anything thats gonna spin when it gets started.

I could see it happening. In the same vein u can preload them even when full I've done that too.

Could be certain manufactures(only 3 companies make lifters, might only be two now) are mor eprone to this. I'm almost posive mine are made by Eaton as well.

Either way, after the car sits for a few days it shouldnt matter if set it cold as most would find its way out by than.

Might shove mine in the garage and let it sit for couple days and try it.

later
Jeremy

 

I tried that and after 3 weeks the miss was still there, finally just tore it down for the winter.
I think you have the answer there, to actually over tighten them slowly to get the oil forced out of the spring chamber. Probably best to do with motor off and manually rotating the crank.
Then go back and reset them.

 

Seems like an issue with Crane (eaton), that Crane has published. We have the same symptoms, same lifters. Interesting.

I don't think they're gonna pump out themself. I think i'm taking the motor apart and taking the lifter apart.. I bet that will solve it.

Tonight I measured rocker travel to verify correct pushrod length. I'll post a picture, but it looks perfect. I dunno

-- Joe

 

Isn't Summit rather close proximity to Comp Cams?

From my experience with Comps retro-roller lifters, they seem to like VERY little or as close to zero preload as you can give them. If you use the wrong preload I think that the oil-bleed holes no longer line up for it to operate properly.

Which of the 5 didn't squirt oil? was there a pattern?

edit: certain base-circle diameters on cams can cause problems with the lifter oiling. Just something to check.

 

After doing some online investigating, it seems to be the difference in the inner diameter of the lifter and the outer diameter of the plunger that sets the "bleed down" rate. There is no "hole" to perform the function as I previously thought.
If the clearance gets closed up by varnish etc, the bleed down rate decreases and the lifter can go solid.
With the lifter at the bottom of the bore (on the base circle of the cam) the oil pressure is directed into the lifter by a port in the block that lines up with the lifter at that point. Oil pressure extends the plunger to remove the lash in the system.
The lifter is forced upwards by the cam lobe and the fluid hole is then blocked. This causes high pressure to build under the plunger in the spring cavity to push the valve open.
At this point the lifter is slowly loosing volume by bleed down.
As the lifter drops to the base circle again it is refilled for the next cycle.
Makes sense that if beed down does not occur, then the lifter is just solid.
Excessive bleed down will cause the vavle to close early due to lack of volume holding the lifter extended.
With only an 0.020-0.060 preload recommended there is not really that much room for improper bleed rate.
Lots of good reading out there. Never gave them much thought until now.
HTH

 

Here is what boggle's my mind. If you load them by overtightening the lash, it should bleed them down. Every time you shut your engine off, a couple off valves will be open, in essence bleeding down those lifters. Run the engine a couple of times, they should all be bled. If you adjust them with the engine running, when you go past zero lash and the valve clatters, the lifter is fully pumped up. You adjust it and everythings peachy. Why should these lifters need to be taken apart to fix this? I would label these as JUNK and move on. If you spend money with summit (which we all do), call and complain to customer service. You'll get a summit $$ card out of it, and put it towards some better lifters (comp-R); they'll price match too (got mine for 200). Speeddemon sells them for that price:

http://www.speeddemonmotorsports.com...trainFLT1.html

 

Thats the part that makes no damn sense to me.

I've set lots of lifter/cam/valvetrain up in my life and never run into something as stupid as this.

Even if u soaked them in oil, as u set the rockers up yadda yadda, u roll the engine over with other rockers on it(how i do it). They should all bleed down since its almost impossible to have the pushrods not apply pressure at some point in the arc or rotation.

I'm gonna do some diggin and talk to a few hardcore engine guys and see what I can find out.

Maybe it is, maybe it isnt, but the damned unexplainable flutter we have. Curious George I is

Hey anetheses, u got that part number handy?

JP86SS, u have some links for the info that you found?

later
Jeremy

 

Same here, but I'm not a lifter expert. I went down the shop tonight, and NO AMOUNT of pressure will bleed these down..


CRN-10530-16

Which is the same as:

SUM-HT214


Cranes website about not soaking them:

http://www.cranecams.com/?show=faq&id=3F


-- Joe

 

This is all very interesting, but regardless of whether they were soaked overnight, a fortnight, or 20 years, they cannot possibly have more oil under the plunger than if you were to set the lash by running them hot. When backing off a lifter to the zero lash position, they fill with oil - Period. Unless the plunger bore in the lifter body has some taper, they should bleed off at the same rate along the full plunger travel distance.

IK would presume that 300# springs would be adequate to bleed off some of the oil unless you are using SAE 50 and never getting it to operating temperature.

FWIW, ¼ turn is usually a safe place to set preload with a 24-pitch rocker stud, perhaps 3/8 turn with 7/16" studs.

 

Didn't keep them, just Googled for a couple hours.
I've done plenty and never had this happen before either.
This went on for several weeks and adjusted hot, cold, on and off with no change in how they reacted. Over tightened, set real loose. Had me so PO'd that I couldn't get them to work, Thought I had something major wrong and pulled the heads.

I'm chalking it up to varnish or other contaminates closing the bleed down clearances. Bought new Comps R's so I don't have to worry about it in the future (hopefully)

 

Well I dunno what to tell you. Crane seems to think it's possible enough to have a snipit on their website.

Either way my new lifters are not bleeding down, so either all 16 are defective, or Crane is correct.

I guess I can call comp and ask them what they think.

-- Joe

 

I called comp. They said they've had some lifters do that, and they've actually seenit happen. Plunger stuck al the way up. He said try lightly tapping the rocker with a rubber mallot on the pushrod side at lift, and if that doesn't work RMA them.

Unfortunately, I'm using "Summit" lifters, not comp or crane, so I'm on the phone with summit trying to figure out if I can rma them or not.

When I explained my problem he said "Hrmmmm" and put me on hold..

-- Joe

 

I would say, Hrmmmmm, here's my problem caused by your part, and all the stuff I've spent money on trying fix it (purchased from summit racing, of course), and give him that nice long list at the beginning of this thread. And then mention how valuable your time is, etc etc etc.

 

He told me to send them back. I asked if they were under warranty, and he said "No, but, I think you should send them back and .. I will credit you twords some crane or comp, or any other brand". I'm like "uhh.. ok. Cool!".

Apparently I bought them in July.

-- Joe

 

Backing off the rockers seemed to solve the issue.

R u going to be putting the new ones in as soon as u get them?

This is getting just really weird.

I wont swear off on anything anymore. I was in the field long enought to see all manners of stupidity and everything that shouldnt fail, has lol.

later
Jeremy

 

Yes, i'm taking the motor out to change the oil pan and pickup back to stock as well. I wish I didnt have to but, I fear if I don't do it now it will haunt me later.

I'm gonna go with comp roller lifters this time.

It ended up being tight valves, because of lifter failure/problems. Although I adjusted valve lash a million times, it was dismissed. I checked it again after yzinger1,
and that is when I realized the problem.

 

yzinger1? typo?

Now I'm all worried too lol

Have to see what I can dig up

later
Jeremy

 

Jeremy,

Is this the Formula?

RBob.

QUOTE]Originally posted by 3.8TransAM
Backing off the rockers seemed to solve the issue.

R u going to be putting the new ones in as soon as u get them?

This is getting just really weird.

I wont swear off on anything anymore. I was in the field long enought to see all manners of stupidity and everything that shouldnt fail, has lol.

later
Jeremy [/QUOTE]

 

Rbob,

When I was talking, yes I meant the Formie.

I havent played with it lots since the powwow and havent had a concentrated effort on it yet.

But like anethese, I have pretty much ablsolved it of any ignition or fueling(injector) woes and the compression all came back good when I did it.

Thinking about trying the same thing.(backking off all the rockers)

Sounds an awful lot like what a couple other people here experienced and we all have the same lifters in common and it started a s a skip and gradually got more noticeable.

I'll definitely report back when I get some time and $$$ to toss at it.

later
Jeremy

 

Any resolution to this...I have been looking for the cause of a ruff idle for a long time with no luck???

 

Mine was faulty lifters. They would pump up and open the valve. Never pump down.

-- Joe

 

What is the resolution to the problem? Did you have to replace all the lifters or could you just try to bleed them out with them installed? I have used stock replacements and Comp R that I have in there right now. I put that red assembly lube in the cup and on the pushrod for start up portestion on both sets...could this cause them to get stuck? I dont get any oil squriting from the pushrods at idle at all. Also can I just tighten all lifters untill they bottom out and then rotate the engine over by hand to bleed them all teh way down...I really dont wanna pull the intake a 5th time.......

 

Joe - you mentioned something I've wondered about for a long time:

I've noticed the same thing on SOME of my lifters, too. However, it's not all of them. I've been chasing a split BLM problem where the pass side is 1.0-1.5 AFR richer than the driver's side and have done the same laundry list as you trying to run it down. Now I'm starting to think my problem may be in my lifters as well.

One wrinkle about the lifters in my motor (please excuse the log explanation): I've got a 70's era 010 hi nickle content 4-bolt 2 pc RMS block. And it has roller lifters. EXCEPT the guy who built my engine did something funny with the roller lifters. What he used fr lifters was standard non-GM replacement lifters for a mid-90's 3.1L v6 motor with the standard 2-hole retainer to keep them from rotating and the standard "spider" to keep them in the bores. He did not use the retro-fit lifters, probably trying to save $$ would be my guess. Suspecting that may be my problem, I've got a new set of GM roller lifters for a 350 on hand. I got to comparing the 350 lifters to a "spare" v6 lifter like he put in my motor. First off, the v6 lifter is 0.350 inches shorter in overall length than the 350 lifter. Diameter, both across the flats and around the circumference is the same. But, the small oiling hole on the side of the lifter is also at a different location - the 350 lifters have the hole 0.259 inches higher up the lifter body than the v6 lifters. That oiling hole is also at least double the diameter bigger on the 350 lifter. And the oil grooves on the lifter body start 1/16th inch higher on the body and are roughly 1.5 times taller than the groove on the v6 lifters.

Is there any way these v6 lifters can be correct in this motor? I doubt the standard GM 350 rollers are either otherwise there would be no need for the retro-fit rollers to exist, right? Is there any chance the spring rate on my Sportsman II heads is such that the lifters are not working right? I can adjust the valve lash with it runnng by backing off till they click and then going 1/4 to 1/3 turn past the point where they stop. I also use a scrwedriver touching the polylocks to feel when they are clicking, seems a lot more sure and noticeable than strictly just listening for the clatter.

If necessary, I'll move this to a different post, but I fear it may be related to Joe's discovery about his lifters....

Don't know if it matters or not, but I've got a Comp custom roller, small base circle cam. Cam specs: 218/224 duration @ .050, 112 LSA, .495I/.502E lift with 1.5 RRs but he put 1.6 RRs on the intake for a lift of .520 or so there.