Again? Dang It!

[Bob Cowan]

Last week the car started to run bad while on a trip to Estes Park. I got it home, and found this



I thin I Found the Problem

I took it all apart, inspected everything, and put it back together. It ran great - smooth and powerful, no smoke, no vibrations.

Today I was driving around town and doing some tuning. I was running it a bit hard, getting the rpm's to redline in the lower gears to do some data logging and tuning. After the last hard run, it started running rough and sounding like a sewing machine. Again.

I removed the valve cover, and the same rocker arm is loose. Fortunately, the lifter is still in place so I don't have to remove the intake this time.

If it happens once, I can accept that I made a mistake. I'v adjusted the valves on a SBF many many times over the years. But still, I could make a mistake. When it happens right away to the same rocker arm, I'm starting to think there's a problem - and it's not me.

Anybody ever have this problem before? Any ideas?

Lifter - stock Ford roller lifter, modified by Kieth Craft for high rpm's
push rod - Comp Cams Magnum. Still straight.
rocker arm - CC steel magnum, 1.6 ratio
adjuster nut - CC magnum.
springs - CC double with damper

All parts appear to be in good shape.

[2FAST4U]

Is the stud coming loose?

[Erik W. Treves]

Time to check the valve spring and then replace that lifter I would think...sticky valve?

[Darren]

Originally Posted by Erik W. Treves

...sticky valve?

This would make sense.

[JKleiner]

First thing that popped into my mind is that perhaps a spring has gone soft.

Good luck Bob

Jeff

[Wayne Presley]

Check valve springs and verify you have enough spring pressure for your lift and RPM.

[Bob Cowan]

I pulled the stud for inspection - it was tight

I'll check the springs tonight.

The lifter looks and feels good inside and out. But I may just replace it anyway.

[Don Payne]

x4 on the valve spring

[Big-Foot]

Pushrod troubles
Ford small blocks seem to have a problem with pushrods hopping off on cyl 1.
Many times this can be linked to having the wrong length pushrods. We know this is not the case with yours.

I suspect that the issue is momentary high rpm oil starvation that impacts this cylinder first.

Think about it -*
Zero lashed hydraulic lifters require a supply of oil to suspend the pushrod cup in the lifter.
Oil goes away momentarily
Lifter partially collapses
Pushrod hops off

Their is a growing support of the notion that zero lash buys you nothing in that the lifters today do not pump up, they maintain lash tolerance as set by depth of the cup in the adjustment procedure. *As a matter of fact there have been a couple of articles printed by well respected engine builders and camshaft mfgrs that are now advocating deep-lashing the hydraulic lifters with cup literally buried to the bottom of the lifter. *
This precludes the lifter collapsing to the point of losing the pushrod. This requires a longer pushrod which now enjoys a better angle to the lifter.

At the very least, I would lash it with one full turn pre-load and see how that goes for you.

Well - it's something to think about..

[Big-Foot]

BTW - many valve springs get stiffer as they go bad. It's called work hardening and they frequently BREAK when this happens.

I use 10# as my tolerance at installed height and compressed height.

[tirod]

The deep lashing setup is comparable to what Crane did with their roller lifters - the pump up is reputedly so reduced, the push rod can't separate if they collapse.

Since heavy roller lifters aren't known for high rpm use - Ford chips the EFI at a limit of about 6,200 rpm - it begs the question how far this engine is being revved.

Certainly not questioning experience and skills, but as was recently demostrated to me again in a no-start situation, what we assume to be ok and not the source is usually the cause. As in "I've got air, fuel, and fire, what could be possibly wrong?" Well, I assumed I had air going in, as simple as that.

Not trying to be ridiculous, but how's the cam lobe? Got to admit we just put an inspection camera on the hook at the store, I see how nice it can be having one for just this kind of thing. Point being, don't paint yourself into a corner with "I know it's good to go." when it hasn't been checked, and that is a blanket recommendation on all the parts.

It's a human tendency to evaluate something and then give it a pass after that, because we don't want to go thru all the work of establishing it's credibility every time. And, like a doctor who starts writing Oxycontin scripts by the bushel basket, it comes as a surprise when we discover things aren't what they are supposed to be.

So, if you measure the push rod to check it's actually the same length of the others, I won't point fingers.

[Bob Cowan]

Randy, that's pretty interesting. When I bought my lifters, the guys at KC said to NOT tighten more than 1/3 turn past zero lash. They were quit emphatic about that.

Since I have the tools and parts, I might just change the springs on that valve tonight.

Tirod, you are correct. Never assume, always check. I, too, have been fooled by something I was sure was OK. I checked the cam lobe visually and with a dial indicator when I had it apart 2 weeks ago.

KC tells me the valve train is good to about 7,000. My rev limiter is a dual stage ignition cut out - soft at 6,300 and firm at 6,500. Last night I ran it up to 6,500 a couple of times for the data log. I think I'll lower that limit a bit; all it takes is a couple of key strokes.

[jewels]

When you adjust your stud nut for tension...How much of a turn are you giving it after proper tension has been reached and before you tighten the keeper? Also how much torque are you putting on the nylock nut (keeper)? I have had this problem recently and seemed to have solved it.

[Bob Cowan]

Originally Posted by jewels

When you adjust your stud nut for tension...How much of a turn are you giving it after proper tension has been reached and before you tighten the keeper? Also how much torque are you putting on the nylock nut (keeper)?

I only turn it 1/3 after zero lash, per KC instructions. As for torque on the set screw, it's tight.

I might also try some red lock tite. It shouldn't get hot enough to break that free (??). And it's supposed to be oil resistant.

[Mustang Man]

Are you just tightening the set screw, or are you giving the adjuster a small turn too? I always go about 1/2 to 3/4 turn after zero lash, tighten the set screw, then turn the adjuster a hair to further lock the adjuster to the top of the rocker stud.

Good luck!

Mark

[Jetsbaby]

I see a mechanical roller in your future!! Not like I can predict the future or anything..

[jewels]

Originally Posted by Bob Cowan

I only turn it 1/3 after zero lash, per KC instructions. As for torque on the set screw, it's tight.

I might also try some red lock tite. It shouldn't get hot enough to break that free (??). And it's supposed to be oil resistant.

My engine came from the engine factory and I had a similiar problem.
All my nylocks were at atleast 35ft.lbs. and they "always do a full turn at zero lash" and all nylocks at approx. 15ft.lbs. (mine weren't)according to literature they sent me. When I asked comp cam about this they said 1/2 was there recomendation and 12ft.lbs. on keepers was fine.

I have put 900miles on since the problem, everything seems to be ok, but I use 5800 as my Max rpm.

[canuck1]

Originally Posted by Erik W. Treves

..sticky valve?

I hope it's not, but If I beat on my engine like you do , I wouldn't rule out a sticky (bent) valve.

I'm sure you'll sort it out, you are very thorough.

Sean

[Bob Cowan]

Originally Posted by Mustang Man

Are you just tightening the set screw, or are you giving the adjuster a small turn too? I always go about 1/2 to 3/4 turn after zero lash, tighten the set screw, then turn the adjuster a hair to further lock the adjuster to the top of the rocker stud.

Good luck!

Mark

I never heard of that before, I'll give that a try

Originally Posted by Jetsbaby

I see a mechanical roller in your future!! Not like I can predict the future or anything..

I'v been thinking of that all year!

Originally Posted by canuck1

I hope it's not, but If I beat on my engine like you do , I wouldn't rule out a sticky (bent) valve.

I'm sure you'll sort it out, you are very thorough.

Sean

Yeah, I had considered that. I don't want to rebuild the heads just yet, though. I plan to overhaul the entire engine in November - new pistons, cam, lifters, etc. That's why I'm considering a solid roller cam.

[CraigS]

I like this idea of nearly bottoming out the lifter. I am no expert on these but here is a thought anyway. Lets just say a hydraulic lifter has .100 inch travel in the cup. Why would you want to set it up so you have it at maybe .015 or .020 inch from one end of it's travel? IE: the usual 1/3 to 1/2 turn after no clearance. Why wouldn't you want to set it up so you have it in the center of it's travel? That way it could adjust itself .050 inch in either direction to account for whatever. There are many examples of mechanical assemblies that have a range of travel and are initialized in the center of the range. And then you get to what could most likely go wrong in a valve train? Seems that excess clearance would be a prime candidate for something that would cause failure. That gets you to the idea that a hydraulic lifter should be nearly bottomed out because the probability of something causing too little clearance is pretty small.

[Bob Cowan]

That sounds good on paper, but maybe not in real life. If you turn the adjuster 1 full turn, what happens? We've seen it here on this forum many times. The valves hang open, and the engine won't run well.

I'm not willing to try it until I see more information on it.

[Bob Cowan]

Well, spent the evening in the garage. Everything seemed to check out OK. Couldn't find anything about those parts that were different than any of the others.

I put it all back together, and used red lock-tite on the adjuster nut and the set screw. I used Mark's trick to get it nice and tight, but not too tight (I hope). My oil fill hole is right there, so I can visually see that rocker arm. I put a dab of white paint on the nut, so if it comes loose even a little bit, I'll see it.

I also lowered the rev limiter.

We're racing on sat and sun, so we'll see how this goes.

[Todd Buttrick]

Did you replace that intake lifter when it happened the first time? That lifter breaking free of it's keeper seems a bit odd to me. The spider was designed for just the fault you encountered. Never seen that before. I've got many spares so let me know if you need one Bob.

[srells]

Hi Bob... a number of years ago I had a 302 that I built up with fresh heads. 5 minutes into its first run it started popping out the carb. I pulled the rocker covers to find the same picture as you posted just one cylinder over. My number 7 intake valve was stuck down. The valve guide was galled. My vote is for stuck valve. its probably not your springs unless you are really turning some high revs Good Luck keep us posted

[Bob Taylor]

When I did the 306 race motor , I got it all back from the machinist and what I was told on this issue was use a dial indicator and set them .030 in the hole measured at the back of the rocker arm.. Bob I know you on the ball with inspections and assembly and all , here is something POSSIBLY of use to use and others. Pre lube materials. I have always use lubriplate assembly lube or the nice red moly paste on everything when assembling. About 2 years ago I was freshening a stock rebuild and it came down to lube the valvetrain and prelube the engine. I torqued the stock bolts installed filter and oil primed it up and only had oil out of 14 of 16 rocker arms .Turns out , the lube had plugged the holes ! I was using it sparingly too. One other thing about the stud , could it just be worn out on the threads or even the nut?? Good luck at the track Bob

[trevor]

I think it has something to do with the valve or guide. I run my engine up to 6500. It is there most of the time. The only problem I have is the parts wear quickly. After 2 seasons everything is heavily worn and the last two times I had a problem, the rocker bearing fell apart. This was with both crane gold rockers and orange hartlands.
I always set my lash at a 1/2 turn past when it tightens up.

[Bob Cowan]

So far, so good. about an hour of track time today, and the nut hasn't budged. Why did it do it before, twice? I don't really know.

The fall, the engine gets a complete tear down and rebuild. The only parts I intend on re-using are the crank and rods. Maybe the camshaft, but I kind of doubt it. The heads will get a comlete rebuild - studs, valves, springs, rockers, etc.

But, I'v got to get through a couple more months yet.

[nc1mike]

Bob, On your fall refit and rebuilt since you are a real performance user of the FFR have you given any thought of going to Beehive valve springs. Many articles rave of their ability to control the valve train. Just a thought as I have no experience with them and drive your FFR 300 times harder than I drive mine.

Michael S.

[Bob Cowan]

Originally Posted by nc1mike

Bob, On your fall refit and rebuilt since you are a real performance user of the FFR have you given any thought of going to Beehive valve springs.

Michael S.

Actually, I have. I tried them once on a milder engine, and didn't really notice any difference. At the time, the only one's available were pretty mild. Lately I have been seeing them for high lift solid roller cams, with much higher spring rates. So I'm thinking about them again.

One of the down sides is that they are a single spring. If one spring in a dual spring package breaks, you won't drop the valve into the cylinder. With a single beehive........

[rick8928]

Read an article in "popular mechanics" several months ago regarding a US company having developed world class valve springs which all the NASCAR racers use. Allows them to rev to previously unheard of RPM. Not sure if the benefits transfer to street/occasional track use (there may be longevity side effects?), but worth checking in to.

The Spring that Revolutionized Nascar - 2012 Daytona 500 - Popular Mechanics