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Jag Daddy 05-17-2004 07:13 PM

Engine runs like krap after valve lash adj. HELP!
Ok I admit it, I guess I don't know what I'm doing. Here is what I did.

Ran engine at idle with oil restrictors, backed polylock off until rocker started ticking. Re tightened rocker until noise went away then 1/4 turn more. repeat 15 more times. Now I have a huge miss, and the engine runs like crap. What's up? Here is something weird. When I went to loosen the valves it felt like the polylocks were all the way down on the threads, could that be right? Am I trying to fix some big screw up now the the normal valve lash wont work any more? what else could it be. Please... I was trying to get the car ready for the "Rod and God" car show here, but alas I don't think I'm going to make it now. (unless there is a miraculous healing or something).:smash:

Mark the dismayed:(

Jmark 05-17-2004 07:42 PM

Hmmm, doesn't sound good Mark.

first off, the allen screw is usually way down when it gets tight, atleast mine were.

Second, did you build the original engine? or did you buy it all done? The reason I ask is if you have a solid lifter cam, doing the hydralic adjustment method will leave all of them way too tight, and not let the valves close all the way, making it run like crap and almost impossible to re-start after you shut it off.

Any chance you have a couple of wires crossed? Done it many times myself.

"another Mark"

Jag Daddy 05-17-2004 08:03 PM

Hi Mark,
The engine was in the car when I bought it. It might be that they are to tight. If it did have a solid lifter cam what is the adjustment procedure for that? I don't have allen screws just the standard rocker nuts. I can't afford a new motor right now so I hope I didn't mess it up.

I'm feeling pretty dumb right now :confused:

Any help is appreciated.


lluciano77 05-17-2004 08:11 PM

Loosen all of the rockers arms untill they are are at least on full turn from zero lash. Then run the engine and let the lifters pump up. You may have bled a couple down all of the way. Now they may be feel like solid lifters.

I had some trouble at first with my Chevy lifter adjustments. It seems like the Chevy lifters bleed down a lot faster than a Ford lifter.

Once the lifters are pumped up all of the way, you should adjust them with the engine shut off. I never have agreed with logic behind adjusting hydraulics with the engine running.

sbchevfreak 05-17-2004 08:30 PM

I never have agreed with logic behind adjusting hydraulics with the engine running. [/B][/QUOTE]

totally with you on this one. i've seen the "running" adjustment cause engine failiure due to trashed valves and seats. the adjustment actually pushed the valves open, and burnt the sh1t out of 'em.

jimfulco 05-17-2004 10:40 PM

Be sure your rocker nuts are in good condition. The stock ones cease to be lock-nuts after a lifetime of heat, and if they lose their tension, they will un-adjust themselves quickly.

Here's an easier way to do a running adjustment that avoids the stumble when tightening past zero lash. Loosen each one until it taps, then tighten it until it stops tapping, but no further. Then do the other 15 the same way. Then shut off the engine. Then tighten each nut one full turn. Or a half-turn, if that is your preference. (the factory recommends one full turn, but not everyone likes to use that figure)

Jag Daddy 05-17-2004 11:45 PM

Thanks everyone,
I'll give it a shot tomorrow night, I had to step away from the vehicalfor the rest of the day. It was very discouraging to see it run so bad. I also spent most of the day making a spacer for the EGR valve to get it above the new valve covers.

Also, what do you do about the PVC valve do you plug it to get you vacuum back or adjust it open. I'm also having a hard time finding a big enough PVC grommet to seal on my Valve covers.

OK I know it more complaining but I want to make sure I'm not chasing my tail


lluciano77 05-18-2004 12:13 AM

Always set your mixture under real life conditions. That means PCV connected.

roys63 05-18-2004 04:20 AM

You made a spacer for your EGR? Are you sure you have no vacuum leakage between the two ports, or the valve is stuck? This can cause a massive Vacuum Leak.

Jag Daddy 05-18-2004 07:25 AM


You made a spacer for your EGR? Are you sure you have no vacuum leakage between the two ports, or the valve is stuck? This can cause a massive Vacuum Leak.
Well it runs the same with or without the spacer so I would think it's not causing the problem. The valve was fine before that


Jag Daddy 05-18-2004 02:37 PM

I pulled some of the rockers and looked at them and I have some wear issues on some of them. Looks like some have a worn spots in the slots. Looks like I'm going to have to replace them for sure. Looking at some stock replacements. I don't know if the wear is just from age or improper adjustment. Any ideas?


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