Valvetrain Problems

[osu32]

Quick background: I picked up a 5.0 out of a wrecked '92 from the junkyard a little while back. The donor car only had 104k on the odometer and looked pretty clean (aside from having been shiny side down just prior to being sent to the junkyard). I don't know the history, except that the intake had been removed at some point because the bolt nearest cylinder 1 was broken off in the head. Fortunately I could get to the back of it and successfully drilled it out without chewing up the threads. Since the motor was out of the car, I decided to do a quick preventative maintenance/refresh on it. Pulled everything off, replaced head gaskets, front/rear seals, timing cover gasket, pan gasket, etc. I didn't touch anything on the low end. Crank, cam, pistons all stayed put. Bores were good and clean.

I plopped the heads back on the other night, dropped in the push rods, and went to tighten the rockers back down when I realized that most of the valves had lash caps (11), but some didn't (5). Further investigation showed that when I torqued down the rockers on some of those with lash caps, it actually dropped the valve open slightly. For some of those valves with out the caps, you can easily wiggle the rocker arms around, both side to side and up and down.

I took some detailed measurements on cylinders 1-4 to give you a better picture of what's going on. The valves with an * next to them indicates that the lifters were soft enough that I could easily depress them with my thumb. This explains the lack of preload even with the cap in place.

I'm trying to figure out what the best plan of attack is at this point. It's obvious that I need new lifters. But after that, do I get the adapter kit so I can run adjustable roller rockers on my pedestal-type heads? Should I get a full set of new lash caps and grind each one individually to get the proper adjustment? Should I just say to hell with it and buy new heads altogether?

Money is a factor here, so the last option, while tempting, is my least favorite at this point. What do you guys and gals think?

 

[osu32]

One other thing to note here is that the guys at the junkyard said the motor "ran real good" when the car showed up. Of course, these were junkyard guys, so I'm not sure they had a real keen ear for valvetrain noise when they were revving it up, yee-hawing at each other, and slamming Busch Light cans against their foreheads. Just thought I'd mention that it previously ran in this condition...and no, I didn't lose the 5 lash caps during the teardown, cleaning, or re-installation process.

 

[osu32]

Nobody has any thoughts? Was it the yee-haw and Busch Light comments? I'm from Nebraska. I'm allowed to pick on my kinfolk. Also, I drink Busch Light, I'm just too sophisticated to slam the cans against my head. Barely.

Any help would be appreciated.

 

[osu32]

Calling all engine specialists! I could really use some input here.

 

[03ghoststang]

well these have hydraulic lifters to begin with so getting all valves at zero lash shouldnt be dificult given its a stock top end. if u r missing some caps then replace them with new ones, and u should be rotating the motor so that when u are setting the lash its on the base of the cam

 

[osu32]

All of those measurements were taken with each valve at base.

 

[03ghoststang]

oh ok just get the caps and set everything to spec and you'll be ok cause once the lifters build up the oil pressure inside them it will eliminate any minimal lash left but u may also have a collapesed lifter i would check those out also and replace them if needed

 

[osu32]

I guess my biggest concern is that with the caps, some of the valves end up being compressed to the point that they open anywhere from 2-5 hundredths of an inch, even on the base of the cam lobe. Seems like I'm gonna have compression and other issues with that going on. I can always grind the caps down, I guess.

 

[osu32]

So after talking this over with several folks, I decided against trying to grind down the lash caps. It seems I would be damaging their structural integrity to the point that I could quickly end up with shattered caps and a broken heart/motor. I pulled all the caps off and double-checked to make sure my valve tip heights were uniform across both heads and they were, so I'm not sure what the previous owner was thinking/doing.

The solution I came up with is to use the Crane Cams 36655-16 rocker arm conversion kit (Crane Cams 36655-16 Crane Cams Rocker Arm Guideplate Conversion Kits) and Harland Sharp 4003 roller rockers (Harland Sharp 4003 Harland Sharp Aluminum Roller Rockers).

The new problem I have is that the roller rockers' fulcrum binds at the pedestal before I get to zero lash. The conversion kit was advertised as not requiring any head machining...but this is obviously not the case for me. I'm gonna get on the horn with Jegs tech support tomorrow to try and figure out what might be going on, but I was wondering if anyone here had similar previous experiences.

 

[Boydster]

I'm not an engine specialist, but I'm pretty familiar with the 5.0 HO pedestal valvetrain setup.

#1. When going for the torque, you should be able to compress the lifter before the valve starts opening. If not, you'll need to either bleed down the lifter, disassemble and clean the lifter or replace the lifter. The valve should not start opening unless the lifter is bottomed out (the spring in the lifter being much softer than the valve spring) or you're not on the base of the cam lobe. You MUST be on the bottom of the cam lobe when setting the torque. Oh, and make sure that although they are bled down, the plunger in the lifter is all the way up against the snap ring.

#2. Anyone can correct me if I'm wrong, but I dont think the stock 5.0 pedestal system had lash caps at all. The only reason to install them would be a cam with a smaller base diameter, too short of a pushrod or possibly using titanium valves. Outside of that, it's beyond me why you would have lash caps at all.

#3. With this engine being all stock, it should have pedestal mount rocker arms, not adjustables. You don't mention the valvetrain being converted over to an adjustable system. The adjustables should have hardened pushrods or guideplates or use rail-type rockers that maintain alignment on the valve. The guideplates you bought are used in adjustable systems to maintain valvetrain alignment... pedestal mounts don't need them. Also, the rocker arms appear to not be pedestal mounts... usually new pedestal mount arms come with matching pedestals and use bolts. The HS rockers have a locknut, which is used on studs, not like the bolt of a pedestal system. You seem to be mixing parts from 2 different valvetrain systems... correct me if I'm wrong.

#4. Like I said, you don't mention having adjustable rockers. If you do, all this goes out the window and you need to figure out what the PO did to the engine. Adjusting pedestal rocker arms... With the engine set on TDC of #1 cyl, you can adjust intake 1, 4 & 8, exhaust 1, 3 & 7. Make sure the lifter will compress. Hand tighten the lifter bolt to zero lash... just touching the top of the valve and not compressing the lifter at all. Just take the clearance out of the pushrod. Use a torque wrench and see how far you have to turn to get 20 ft/lbs. I like to shoot for between 1/4 to 1/2 turn, but up to 1 full turn is allowed. If you go more than 1 full turn, you'll have to install shims under the pedestal or use shorter pushrods. If you go less than 1/4 turn, you can get longer pushrods or sand a small amount off the bottom of the pedestal. Rotate the engine CW 180*, then do intake 3 & 7, exhaust 2 & 6. Rotate engine 270* CW (3/4 turn) and do intake 2, 5 & 6, exhaust 4, 5 & 8.

With everything stock and with all components in good condition, she should fall right into place.

If I'm stoopid and totally missed what you've been posting, my apologies and just ignore all this.

 

[osu32]

Thanks for the reply boydster. I'll take your items point by point.

1) I ended up getting new lifters. A few of the lifters were very soft (too soft), but most of them were rock hard. This wasn't helping the pre-load issues. There was obviously something wrong with them, so I erred on the side of caution and bought new ones.

2) It is beyond me too. What's really beyond me is why there were 11 lash caps, not 16. It just doesn't make sense, but then again these are the problems you get with junkyard motors.

3) I do have stock, pedestal style heads. The Crane conversion kit I got (Crane Cams 36655-16 Crane Cams Rocker Arm Guideplate Conversion Kits) is designed "to convert engines with pedestal-mount rocker arms into adjustable-type valvetrains, without machine work or cylinder head removal", per Crane's own product description.

4) I'm so irritated with the PO right now. They obviously did something stupid with the top end and it's making my life difficult. I'm nearly at my breaking point with this and am considering new aftermarket heads. If I'm going to keep putting money into this, I might as well reap the benefits of better heads.

I wish it would all just fall into place. I've got 10 other projects that I need to be working on. Thanks again for the thoughts!

 

[Boydster]

Wel... there's no reason to go full adjustable rockers.

If it were me... I'd get everything back to basically stock and see what ya got when you go to torque them. Return the Crane kit and the HS stud mount rockers. Get stock pushrods, a nice set of 1.6 roller rockers with new pedestals and a box of shims. Since money may be an issue, Comp Cams sells non-roller rockers that are designed to be stock stamped steel replacements. Put it back together with no lash caps and see how the torques come out.

Crane Cams 36758PS-16 - Crane Rocker Arm Pedestal Stands - Overview - SummitRacing.com
COMP Cams 1235-16 - COMP Cams High Energy Rocker Arms - Overview - SummitRacing.com
Ford Racing M-6529-A302 - Ford Racing Rocker Arm Pedestal Shim Kits - Overview - SummitRacing.com
Lunati 80761 - Lunati Bracket Master II Pushrods - Overview - SummitRacing.com

Of course, you could always clean, roll and measure the pushrods to make sure they're straight and the right length... 6.250".

I'd go back to what you know is supposed to work, instead of tossing conversion kits and mixed parts at it. But that's just me.

Sounds to me like the PO didn't know how to set pedestal rockers, and tossed some old school at it. Mixing doesn't work.

 

[osu32]

That's not a bad thought. I'll double-check the pushrods to make sure they're true and correct lengths, bolt it all back up with the fresh lifters in place (don't worry, they've been soaking in oil for a week) and see what I get. If things are still off after that, I'm buying new heads. I could try lash caps, shims, etc to try and get things right, but I'd rather just throw money at the problem and buy some confidence in the motor.

I was planning on doing the Trick Flow Twisted Wedge top-end kit next year anyway, so I might just get the heads now and grab a piece or two of the rest of the kit every month until the spring. It ends up being a couple hundred bucks more expensive that way, but so would putting it on my credit card and paying interest on the balance. I'd rather Summit or Jegs had that couple hundred bucks than CitiCard.

Then again...maybe the new lifters will have magically fixed everything! I'll report back with the results.

 

[Boydster]

Yeah, please do post back when you find out what is going on. Keeps the thread going for people that do searches in the future.

 

[osu32]

Pushrods all appear to be straight and stock (6.25"). So here's what I did and the results:

1) stock rockers, no lash caps - way too much lash

2) stock rockers, with lash caps - zero lash and about 1 turn of preload on the lifters. Valves do not appear to be opening since the lifters are taking up the preload. The only concern I have with this is the geometry. The contact patch seems to be shifted back toward the pedestal a little bit. Not sure how big of a stink I should makes about this since the other issues are corrected, but I know the geometry is fairly important.

 

[Boydster]

Well shims wont help ya. You either have wear on the cam or a valve height problem. You can sand the bottom of the pedestals to bring the rocker down.

You can also get slightly longer pushrods, but we're just covering up what the bigger issue is.

 

[1987stangman]

One question comes to mind. Any chance there is not a stock cam in this motor you got from the j/y?

If I remember when I was still using stock valve train parts I don't remember there being any lash caps and bolting everything back together with the same stuff was a no brainer.

 

[osu32]

I think you both might be on to something. I believe now that I'm dealing with either shorter valves, a non-oem cam, or both. When I was cleaning up the motor I pulled the timing cover off due to leaking gaskets. They had obviously been off before because there was black rtv everywhere. Perhaps the cam was swapped before.

So my two options here seem to be
1) Longer pushrods
2) New, matched Trick Flow heads, cam, and pushrods. Anyone got $1,500 they don't need?

I hate this motor.

 

[Boydster]

Well at least you're getting down to what the real problem is and not just tossing some patch on it.

I work on airplanes for a living... I hate patchwork crap.

Now with that out of the way... if the issue is consistent across the engine, then we could say that it is likely cam design and simply longer pushrods might fix it. If the issue seems to vary from valve to valve and cylinder to cylinder, then we could say it's wear and something needs to go. Unless you want to measure and order individual custom pushrods for each valve. That really would be the wrong way to do it.

I really hope for the sake of coil bind that it's not shorter valves...

 

[osu32]

I think, at this point, I'm just going to spend some money and replace the top end. I could try longer pushrods, new cam, this, that, and the other thing, but that feels a little too patchwork-ey to me. I'm not going to feel good about giving this motor the beans if I've got a mix-bag of parts in there.

Thank you for all the help, and please keep being OCD just in case I'm ever on a plane you work on!