Yes, I have the shop manual and I used the search but I get different answers.

My newly rebuilt 2.8L V6 has developed a knocking sound that changes with RPMs and the is most pronounced when cold. It disappears or nearly disappears when the engine is at operating temp. Otherwise the engine runs strong.

I took the engine out today and wanted to adjust valve lash again. Now is there agreement on the adjustment procedure yet?

in my handy dandy "how to rebuild your GM 60* V6" book, it says to tighten the nut while turning the pushrod. tighten just until the pushrod slips through you fingers, then tighten the nut 1.5 turns more.

although, my grip and your grip and someone elses grip on the pushrod will all be different, so it seems that's not a really good method. i did mine by tightening until i juuuust, took up the slack play in the pushrod, then went 1.5 turns more. we'll see how that worked out later down the road. good luck anyway, hope this helps some.

I've tried so many ways and none have produced satisfactory results. I tried turning until it just had minimal resistance and I even tried moving the pushrod up and down until there was no more movement. It still sounds loud.

After checking the lifter plunger travel I went with 3/4 turn on my 3.4. I used the advise from the Crane Cam doc and measured the travel of the plunger and went a little less than half the travel from 0 lash.

[This message has been edited by Dodgerunner (edited 11-11-2006).]

quote Originally posted by Dodgerunner: After checking the lifter plunger travel I went with 3/4" on my 3.4. I used the advise from the Crane Cam doc and measured the travel of the plunger and went a little less than half the travel from 0 lash.

Details please? Were you measuring from a certain point? Have you heard it run yet?

No have not heard it run yet. Will fire it up within a week. (I hope)

The cam doc talks about measuring the amount of preload for fixed rockers so I used part of that.

If I had a dial indicator would have just set them.

I adjusted the lifter for 0 preload. (used the wiggle rotate method feeling for the clicking to stop.)
Put a straight edge across the valve cover surfaces and scribed a mark on the push rod.
Then I slowly adjusted the rocker down while feeling the normal preload until the plunger just bottomed out. (just until I felt the pushrod lock from the max preload) Have to do it very slowly so that the lifter can bleed off.
Marked the lifter again.
Backed the rocker off and reset for just about half.
I have new crane lifters and they say to have .020"-.060" of preload.

Little unorthadox but since I didn't know how fast the thread pitch of the rocker studs sets the preload didn't know how many turns would really be the right preload for the lifters. Crane says 1/2 to 1 for the v6's.


Camshafts
Part Number(s) All part numbers
Instruction Number 214E
http://www.cranecams.com/?show=install&heading=Cam+%26+Valve+Train%3Cbr%3E%28Includes+Sport+Compact%29#Camshafts


Page 4 THE FAST AND EASY WAY TO CHECK HYDRAULIC LIFTER PRELOAD

[This message has been edited by Dodgerunner (edited 11-11-2006).]

Sounds more like piston slap since it goes away as it warms up. Wish the engine was still in... you could fire it up cold, verify the noise, shut it down, pull the plugs, squirt a bit of oil in each cylinder and fire it back up... if the noise disappears for about 15-20 seconds then comes back... it's piston slap.

Other things to check for... is the noise at crankshaft speed or cam speed? Remember the valvetrain is operating at 1/2 crank speed so those noises are slower in repetition. You can pull a plug wire and see if the noise syncs to the spark or 2x the spark. 2x means it's in the bottom end.

But since you have it out... this stuff isn't going to work.

How loud is the noise? Is it there just at certain rpms? More, less or same in or out of gear?

Valve lash info towards the bottom of the thread...
https://www.fiero.nl/forum/Forum2/HTML/077913.html

I have had success with both 3/4 turn and 1.5 turn. Your problem is not your lash, but your oil. Switch to Rotella 5w30, no more ticking on start up.

i always go .5 to .75 of a turn after zero lash, just like a sbc. 1.5 seems way to much to me

1.5 is what it says in all the various manuals, and there has been a lot of discussion here about that figure. IT IS WRONG.

1.5 turns past zero lash will kill your cam in relatively short order, according to what I've heard here. 0.5-0.75 turns past zero lash is considered acceptable.

Ed

quote Originally posted by edhering: 1.5 is what it says in all the various manuals, and there has been a lot of discussion here about that figure. IT IS WRONG. 1.5 turns past zero lash will kill your cam in relatively short order, according to what I've heard here. 0.5-0.75 turns past zero lash is considered acceptable. Ed

That's also what I've heard. When in doubt, better too loose than too tight.

Even the Haynes manual says 1.5 turns past zero lash. However, the instructions that came with my Edelbrock cam (which includes lifters) say 0.5 turn past zero lash. I followed Edelbrock's instructions, and am glad I did.

What is "Rotella"?

quote Originally posted by p8ntman442: I have had success with both 3/4 turn and 1.5 turn. Your problem is not your lash, but your oil. Switch to Rotella 5w30, no more ticking on start up.

quote Originally posted by yellowstone: What is "Rotella"?

Rotella T is oil for diesel engines. Supposedly has more additives to help with flat tappet cams. Sold at most part stores, even Wally world...

[This message has been edited by Dodgerunner (edited 11-12-2006).]

Never seen that over here...

But they sell oils for diesel engines - first time I hear it's a good idea to use that on a Fiero.

quote Originally posted by Dodgerunner: Rotella T is oil for diesel engines. Supposedly has more additives to help with flat tappet cams. Sold at most part stores, even Wally world...

The problem with 1.5 turns is that it is for NEW equipment. It assumes breakin.

When I was doing my rebuild, admittedly I didn't have the plenum to deal with, (carb) but, I used some tuneup clips which attach over the push rod on each arm to block off the oil squirting. You then idle the engine with the valve covers off and back off each hold down nut one at a time until you hear it rattle. Then tighten it until the rattle disappears and then about 1/4 turn more. This is the formula for SBC engine studs, (which I used) however, you will likely find tightening no more than 1/2 turn max on the stock studs you will be pretty close. In theory, it would be about 3/4 turn past 0 lash. I actually made up a pair of slotted Fiero valve covers to put on while doing this, but found I didn't need them. You need to have the engine warm, then take off the valve covers and go to it. I know this is a PITA on the Fiero engine, but it will get you to a really close to perfect setup.

Having too tight rockers will flatten out your tappets and even cause catastrophic failure of your push rods, not saying anything about poor valve seal. Too tight and you'll loose power plain and simple. If it is too loose, the valves will just rattle on you.

Hope this helps.

Arn

I did the lash on both a 2.8 and again when I later upgraded to a 3.4. I was using new 1.6 roller rockers, new pushrods and new lifters. In both cases I adjusted the lash to where there was no up or down play in the pushrods followed by tightening an additional 3/4 turn. The engine fired up and ran perfectly with no lifter tapping noises both times.

[This message has been edited by NewGT (edited 11-12-2006).]

quote Originally posted by Blacktree: Even the Haynes manual says 1.5 turns past zero lash. However, the instructions that came with my Edelbrock cam (which includes lifters) say 0.5 turn past zero lash. I followed Edelbrock's instructions, and am glad I did.

If you compare the procedures in the Haynes manual to the Factory Service Manual you will see a lot of procedures repeated word-for-word. The 1985 FSM says 1.5 turns past zero lash for the V6 and I don't know if the error was ever corrected--or if, as is mentioned above, 1.5 turns is desired for factory new engines.

Ed

the point of this thread is that he has a knock. valves/rockers dont' knock, they tick and clatter. a knock is a deep sound, and not generally associated with the valvetrain.

and you can;t compair a sbc adjustment with a 3/8 24 thread to the stock stud which is a much finer thread.
on a stock lifter, 1.5 turns gives you .040-045 preload as measured at the cup. the preload shouldbe set to the lifter specs, especially with aftermarket lifters.

Then I'm using the wrong word: the sound I have is not deep, so tick/clatter would describe it well...

So, is 0.75 turn past zero lash the answer most agree to?

quote Originally posted by tjm4fun: the point of this thread is that he has a knock. valves/rockers dont' knock, they tick and clatter. a knock is a deep sound, and not generally associated with the valvetrain. and you can;t compair a sbc adjustment with a 3/8 24 thread to the stock stud which is a much finer thread. on a stock lifter, 1.5 turns gives you .040-045 preload as measured at the cup. the preload shouldbe set to the lifter specs, especially with aftermarket lifters.

quote Originally posted by yellowstone: What is "Rotella"?

Shell Rotella, used because it has a zinc additive which helps with breakin and wear on older motors
like ours. Even though it is a little more expensive I prefer a product that you add to the oil that is
made by GM, it is called EOS (engine oil supplement and is high in zinc) I add a bottle ever time I change the oil.
It is also mention in Tom Currao's book "How to rebuild your GM V-6 60 deg Engine".

quote Originally posted by yellowstone: What are the symptoms of a "killed cam"?

I had to work on my 3.4L 3 times after my rebuild. 1.5 turns was to much the first time.
So I went with 1 1/4 turns the second time and then I had a lifter fail and destroy a lobe on the cam.
Mine was on the exhaust side and in the beginning sounded like an exhaust leak that kept
getting worse (it was exhausting through the intake) then the metal to metal noise got awful !!

I ended up talking with crane (I have the crane 272 cam with crane lifters) they recommend 1/2 to 1
turn. I went with 1 turn and haven't had any problems. 3/4 to 1 turn is what I would recommend.

[This message has been edited by Zoom88 (edited 11-13-2006).]

quote Originally posted by yellowstone: Yes, I have the shop manual and I used the search but I get different answers. My newly rebuilt 2.8L V6 has developed a knocking sound that changes with RPMs and the is most pronounced when cold. It disappears or nearly disappears when the engine is at operating temp. Otherwise the engine runs strong. I took the engine out today and wanted to adjust valve lash again. Now is there agreement on the adjustment procedure yet?

the "valve lash" spec is more accuratly the "lifter pre-load" - and it is variable with the lifter. now, the good news is there is LOTSA room for slop. hydraulic lifters are WAY more forgiving than solid lifters. anywhere from 1/2 turn to 1-1/2 turns works. one of the keys to setting the lash is finding the "zero" lash spot. basicly impossible for a man and his fingers. just about EVERYONE overshoots. thats why1/2 turn and 1 turn seems to be what evevryone recommends - because they overshoot zero. the "ideal" method is to actually measure the depth of the plunger when the lifter is sitting on the base of the cam.

OK, I did 0.75 turn on what I considered to be zero lash and tomorrow I'll see how that went..

Something I found during the 3 rebuilds that I have done is that if you're not measuring the plunger depth, you have to make sure the lifter plunger is not depressed. You can set the lash then go back later to double check and find that half the lifters seem loose because they don't always fully recover from being depressed. If you try to readjust them, you're liable to end up with 2 or 3 turns on them. Also, when using the lash method, make sure that none of the lifters that haven't been adjusted yet get depressed while turning the engine over. Without oil pressure to keep them pumped up, they may not fully expand and you'll end up adjusting them too tight. If you want to readjust them, and the intake is still on, it's best to back off all the rockers and use a drill motor to spin the oil pump using an extended distributor drive shaft to pump up all the lifters. Then readjust according to the book.

How are your exhaust manifold gaskets? I have a 66 Mustang that had what I'd call a knocking sound. I adjusted the valves three times with no effect. I replaced the exhaust manifold gaskets and the sound disappeared.

[This message has been edited by Formula Owner (edited 11-13-2006).]

Those lifters not being fully pumped up is a real bugaboo. I had 3 like that even after I had the engine primed. I expect though, that with Yellowstone's engine already running, it should not be a problem for him.

Good luck Yellowstone. You likely have your lash right now. If you hear ticking at idle, just raise your idle a bit and if it disappears you are ok. If not, you are a little loose.

Arn

Like has been mentioned already, the biggest problem with setting lash is determining where the 0 lash point is. All the manuals I see say to twist or twirl the pushrod and feel for increasing tightness when zero lash is achieved, but in practice with new, lubricated parts the difference in rotational friction is so small that it is almost imperceptible, especially for someone with limited experience doing this.

What I do is to push the pushrod up against the rocker to take slack out of that end of the valvetrain and then move the bottom of the pushrod back and forth in the lifter poppet socket, this produces a clicking that is easily felt and heard. As the rocker nut is tightened the clicking and range of motion decreases until suddenly it's gone. Because the hand force is pushing up rather than down it doesn't matter if the lifter is pumped up or not since the poppet isn't being pushed down at all. The transition from click to non-click, or zero lash, is very discernable when done this way.

By the way, I dismantled one of my old lifters and measured the poppet travel in the lifter's internal bore, and considering the thread pitch of the rocker adjusting nut the number of 1.5 turns to mid-travel of the lifter poppet is correct as published in the various service manuals. Wear causes the lifter to travel away from the pushrod and the poppet to rise in its bore, so if there isn't enough depth of the poppet then it will decrease the time that the adjustment is valid.

JazzMan

The way I did it was to rotate the pushrod while turning the adjuster screw until it went from easily turned to just very hard to turn at all. The transition is very quick: 1/20 of a turn of the adjuster screw maybe. Then 3/4 turn...

I have a new head and all new valvetrain parts. I will put in the engine today. Hope all goes well.

[This message has been edited by yellowstone (edited 11-14-2006).]

quote Originally posted by yellowstone: The way I did it was to rotate the pushrod while turning the adjuster screw until it went from easily turned to just very hard to turn at all. The transition is very quick: 1/20 of a turn of the adjuster screw maybe. Then 3/4 turn... I have a new head and all new valvetrain parts. I will put in the engine today. Hope all goes well.

that should be fine
there is much room for slop - thats what hydraulic lifters are all about
consistancy is actually more important than if it was 1/2 turn, 1 turn or 1-1/2 turns

quote Originally posted by yellowstone: The way I did it was to rotate the pushrod while turning the adjuster screw until it went from easily turned to just very hard to turn at all.

If you actually reached the point of "very hard to turn at all," you have bottomed out the lifters. This is not the correct adjustment you want! Running the car this way will result in poor performance and burned exhaust valves, since the valves will not be able to seat fully in the closed position. You don't have to take my word for it ... you can confirm it with a compression check.

What you should have felt was a transition from a small amount of play in the pushrod to no play at all, but the pushrod still should have been very easy to turn at that point. JazzMan is correct (as usual) on several items. His method of finding the zero-play adjustment point is probably the best for someone who hasn't done it before. He is also correct that the purpose of the whole exercise is to set the lifter to the center of its range of adjustment.

I agree with Jazzman that the published adjustment value of one and one-half turns is correct ... as long as the zero-play point was correctly determined in the first place. Anecdotally, after going through the same decision process under way here I used one and one-half turns when I installed my new otherwise-stock 3.1 V6 engine more than three years and 20,000 miles ago, and the valve train is still relatively quiet and has had no problems whatsoever.

Finally, I agree with the others who have said that the knocking noise you describe is probably "piston slap" due to slightly high skirt clearance when cold. If so, it probably won't cause any problems as long as you don't flog the engine until it warms up.

[This message has been edited by Marvin McInnis (edited 11-14-2006).]

Jeez this is a mishmash, however, here is my take. The twisty style of guaging "0" lash is not the best way. It is extremely hard to get "0" lash that way. I did it that way initially and got my valve lash too tight.

The way is "up and down". That was the closest. That way I got all of them right except for 3 which were still too tight. The final way, and the best is with the clips. I can appreciate however, that with the plenum this is problematic.

How is it running Yellowstone?

Arn

quote Originally posted by Marvin McInnis: If you actually reached the point of "very hard to turn at all," you have bottomed out the lifters.

I think he did it right, and just typed it wrong
his mentioning the transistion being very quick made me confident he did it right

quote Originally posted by Pyrthian: I think he did it right, and just typed it wrong his mentioning the transistion being very quick made me confident he did it right

Maybe so, but I had to assume that "very hard to turn at all" is what he meant. From personal experience, the transition in either case will be pretty abrupt.

As I suggested, a compression test (preferably a blow-down test) will confirm whether or not the valves are seating fully as currently adjusted. Doing a compression test now will be easier than having to readjust the lifter preload with the engine in the car.

[This message has been edited by Marvin McInnis (edited 11-14-2006).]

Well, the engine is in the car and it did start up without any problems. Runs smooth and without any noise. Almost, that is: the engine is sucking in air somewhere (not the throttle body), resulting in a huge hissing sound. If I cup my hand over the air intake, the engine doesn't react at all (when it should stall).

Too late to check today, will continue tomorrow...

Maybe there are suggetiond for the usual suspects to check... I do think that I connected everything up again.

With a small leak you would see some difference covering the intake so it just about has to be either the idle tube that plugs into back of the TB, the PCV hose that plugs in underneath or, the brake booster hose on the right side of the intake but, that one would be obvious.

It was the idle tube - thanks...

Now I checked compression and I have virtually none in the No. 3 cylinder. The others are close to 13 or 14 bar. Sqirting oil into the cylinder increased compression from 1 to 2 bars. The engine runs fine, no weird noises and no vibration, even when revving it up.

Back to start?

quote Originally posted by triker: With a small leak you would see some difference covering the intake so it just about has to be either the idle tube that plugs into back of the TB, the PCV hose that plugs in underneath or, the brake booster hose on the right side of the intake but, that one would be obvious.

[This message has been edited by yellowstone (edited 11-15-2006).]

quote Originally posted by yellowstone: ... I checked compression and I have virtually none in the No. 3 cylinder ... Back to start?

Time for a blowdown test. Set the No. 3 cylinder to TDC and apply compressed air (~80 psi) through the spark plug hole. (You can buy adapters for just this purpose, or you can make your own. Make sure the crankshaft doesn't turn when you apply the air pressure.) You should now hear the hissing of air escaping from the cylinder. If the hissing is loudest in the intake, the intake valve is leaking; if loudest in the exhaust, the exhaust valve is leaking; if loudest in the crankcase, the rings are not seating properly.

Assuming your heads were reworked (i.e. "valve job") while the engine was out ... if either valve is leaking, it is probably because it is not seating fully due to too-tight pushrod adjustment. If the heads were not reworked, a burned, bent, or worn valve or valve seat are other possibilities.

If the rings appear to be leaking (loudest hissing in crankcase), it is possible that you have a cracked or broken piston that is also the source of your knocking noise. But this doesn't seem likely since a cracked or broken piston almost always results in lots of oil smoke out the exhaust.

Once you have some idea of what's going on in cylinder No. 3, you should probably repeat the blowdown test on all the other cylinders, too. I hope this helps.

[This message has been edited by Marvin McInnis (edited 11-15-2006).]

Did you use engine assembly lube on your piston rings? If so, thats probably why you have no compression on a cyl. The rings are not sealing. Could also be an improperly adjusted valve that wont allow compression to build. What is the exact reading?