powerpigz-51

That little bit of side to side movement is about where they should be. Since you have it apart, you might as well readjust. Rotate the motor clockwise until the intake valve closes all the way. Tighten nut until pushrod is tight, then extra quarter to half turn. I am thinking it is probably ok. Three threads on top sounds about right also.

vette079

No one has mentioned yet that you can check the injectors cold and hot, do that first.
Calderone mentioned that he had one injector going south.
You can find big differences in readings from injectors cold and hot.
How does it start cold?
If OK, then how does it start when warm/hot?
If it´s harder to start, then it might just be an injector.

Check each injector with a digital volt meter on 200 ohm scale or higher (after you take off the clips) and write down every injector´s readings, both cold engine and warm.

Photomania

Will it be OK to tighten the rocker arms on the driver's side only?

I noticed that each rocker arm nut has two marks. These are like cut marks in the form of lines that run parallel with each other. Most point toward the front center of the car, but two point toward the passenger side headlight. Do those marks mean anything?

I wasn't going to bother with removing the valve cover on the passenger side. I still need to check all of the spark plugs and wires.

I have a feeling my fuel injectors were damaged by Valvoline Water Remover a few years ago. A Chevy mechanic told me to never use anything but GM water remover. The 1990 Corvette and a few other years have fuel injectors that can be damaged by alcohol-based water removal products. Turns out I didn't need to be using the water remover anyway.

powerpigz-51

Yes, you can do that one side only. The marks on the nuts do not mean anything, I believe this is where they dimpled the top thread of the nut to hold it tight on the threads. Alkie can damage the Multec injectors as it corrodes the insulation on the injector coils. You should do a resistance check on each injector with a ohmeter.

Photomania

Hey Michael, Rich, Theo, Brian, Calderone, Chris, Mike, Dan and others,

I appreciate your knowledge and advice. This is a new frontier for me. I've replaced fuel pumps, fuel filters, water pumps, wheel cylinders, master cylinders, shocks, brake pads, mufflers, alternators, distributors, ignition coils and serpentine belts, but I've never done any work on valve trains. As I do the work in the next day or two, I'll keep you posted.

Perhaps even more important, I think it's great to get advice from CF members in Sweden, Chile and Canada, along with members in the United States. Best wishes to all of you. - Eric

Calderone

You're welcome Eric !
Corvette work is like sex poses,there is always a new area to experiment and have fun !
The best thing is that our car delivers,so it deserves,i really enjoy when something breaks because i know the upgrade is coming,and that much more driving pleasure will be available soon !

vette079

Reread the whole thing and saw that Pletzvet already mentioned the injectors as well.

Anyway, cool to hear some thanks from other CF members, even if the tips not always turn out to be the solution.

One very good thing is that the different OP´s also post back when they have fixed their problem, so those threads become really usefull.

Save the wave.

Photomania

Hey guys, I tightened all eight rocker arms on the driver's side today. Each one needed only a half turn to three-quarters of a turn. I made sure I could still turn each push rod with my thumb and index finger. I installed a new gasket from NAPA for $26.

By the way, something I almost overlooked was that it's important to put the transmission in neutral before attempting to turn the crankshaft. I tried a breaker bar but that was too slow. I found that a long handle socket wrench worked just fine. I had to remove the water pump balancer to get to the crankshaft. I also removed six spark plugs.

Then, I cranked up the engine. Checked for oil leaks. No noise until I had driven the car around and the engine was warmed up. I let the car idle in my driveway for 10 or 15 minutes and there was no noise.

This clicking noise sounds like something bigger than valves or rocker arms. It sounds like a decent size piece of metal that's hitting another piece of metal. It doesn't sound any worse. It's the same noise. I don't see how a fuel injector could do this. But the engine is still missing and pulsating pretty bad. It seems to runs more smoothly at 50 to 60 mph. There is no missing or pulsating when I let off the gas and just let it coast.

I just don't understand why it does this only when the engine is warmed up. I wish we could post engine sounds on this forum and you guys could hear what I'm hearing.

The noise still sounds like it's coming from the engine near the firewall.

Any more ideas?

Calderone

Now it sounds like something major,bottom end related
i wouldn't drive it around,can you record the sound and post it here
or youtube link ?

JrRifleCoach

I recall years ago in High School the auto shop teach was telling us about an engine that made all sorts of racket. He ran some Marvel Mystery Oil thru the carb and the noise quite. Turned out there was a significant build up of carbon on a piston top that was now hitting the head. The treatment softened the carbon and the noise quit.

Years later I had the same thing happen and I swear it sounded like a rod knock. Some SeaFoam cured the problem.

I'm not saying this is your problem, but.........

vette079

A clicking noise near the firewall and it wasn´t the rocker arms?

Remove the distributor and check out the gear, I think it´s not seated right.
That would explain the missing also.

Just mark everything before you remove it.

Calderone

vette079 has a point !!!!!!
Check that out !

Photomania

Yeah, I was thinking about the distributor gear, but I didn't understand why it would act up only after the engine is warm. I'll have to check that early next week. I had a Ford Mustang in which the distributor gear malfunctioned so badly that the car left me stranded in a parking lot. It had to be towed to a shop.

Over the past few months, I've put three cans of Sea Foam in the tank at the recommendation of a mechanic. But that was before the loud clicking started. At that time, I was trying to get rid of the slow engine start up s and the pulsation. The Sea Foam some.

I may break down and take the car to him to get his opinion and a paid diagnostic examination.

Calderone

i insist,can you please record that and upload it to youtube ???

Photomania

I appreciate the concern and interest, but I have a dial-up connection. Besides, I don't have a videocamera. I'm a still photographer. The sound would be confusing because the input shaft on the engine is noisy when the clutch is out and the car is in neutral. Apparently, this is the way the car came from the factory and the original owner could have taken it in for an adjustment, but never did.

For about $60, I can get a professional mechanic I've used for years to take a look at it and even run some tests on the car with diagnostic equipment. I will definitely post on here what is wrong with the car. One last thing I'll check before I take it to the shop is the distributor and gear.

Despite all the crazy stuff going on (loud clicking noise and pulsation/missing), the "Service Engine Soon" light has not come on even one time.

Calderone

Service Engine Soon doesnt recognize some failures,it won't tell you if your bearings are going south or other problems.

If the original owner told you that,he lied to you,i seriously doubt that car was coming with a noise like that from Bowling green plant,oh yes,come back later for adjust it ..yes yes

I know you have dialup and you dont have a video camera,but im sure you have a friend with a digital cam,even phones now record video,and im sure you can record that and upload it on some friends house.-

I'll wait !

engle1147

Oil tends to flow "thicker" when it is cold but once the engine heats it up it becomes "thinner" so to speak. Saying you hear "noise" once the engine is warm makes me think your clearances may be "loose" in a spot or 2 down low. Try a heavier weight oil and see if it quiets down.

FICINJECTORS

did you try disconnecting the #7 injector.. I have heard injectors across the shop..The car will run on 7 injectors

vette079

Smart, the sherlock method.

If the buttler didn´t do it, some one else DID.

Very good tip, eliminating one after another.

joe wilson

Could you not put something like an old towel around the head to absorb the oil and run the engine at idle for a few seconds to see if the noise is coming from #7. If it is you might try tightening them slightly until the noise just disappears. I wouldn't tighten them down too much because you may have a collapsed lifter and if you tighten it down until it misses it may do damage to your piston on #7. If you don't hear any loud clicking just put the valve cover back on and look somewhere else, like an injector or spark plug wire.