97 Grand Am Gt 3.1 Lifter Noise

[Avengeusa]

I have the same issue, 1997 GM 3100 V6

I rebuilt it 75,000 miles ago, ran fine

recently developed a lifter rattle, and a loss of power

I did track the loss of power down to the knock sensor, it was picking up the lifter rattle and interpreting it as a spark knock, it was retarding the timing severely, once unplugged the car ran much better

Still chasing the lifter tick....

Loud lifter rattle, took off the manifold and seen that all but 2 lifters were collapsed, so i replaced them all, re assembled, and the rattle is still there..

I removed them again, inspected, and even removed the front head and all looks very well, clean oil, no debris, the inside of the block is looking very clean, no metal.....

I figured oil pressure issues, I reassembled and started the vehicle, still rattles, checked the oil pressure, it is 40 at idle and 60 when the engine speed increases at all

I read the guy who stated that the cam bearings had rotated and blocked oil flow to the lifters.......

I do not understand how they could stop flow of oil......

I pulled the engine anyways, the cam bearings look fine, and all of the holes in the bearings are in the proper spot, and not blocked in any way

no oil galley plugs are missing or leaking, the engine had no oil leaking from the inside to the outside of the engine, so i am seeing what would appear to be a pressure or flow problem... but see no evidence that would give a clue as to the issue, I did see one thing

the distributor gear is worn really well, definitely needs to be replaced, i was thinking it may be from lack of oil to the gear, the cam looks fine....

where to go from here

[xeroinfinity]

Welcome to AF Avengeusa !!

One other thing about these lifters is if the rockers are to tight they'll pump the lifter dry and damage/break the springs inside them.
If they are to loose, it can also cause problems, and a lot of noise from both situations. It is a fine line of adjustment.

So chances are you probly didnt need to pull the motor.

Btw you change the timing chain/gears ?
Any push rods bent ??

[Avengeusa]

Originally Posted by xeroinfinity

Welcome to AF Avengeusa !!

One other thing about these lifters is if the rockers are to tight they'll pump the lifter dry and damage/break the springs inside them.
If they are to loose, it can also cause problems, and a lot of noise from both situations. It is a fine line of adjustment.

So chances are you probly didnt need to pull the motor.

Btw you change the timing chain/gears ?
Any push rods bent ??

the lifters are non adjustable......

no overtightening them..... torqued to spec

may be a piston rattle, it is constant, with no change when warmed up...

[xeroinfinity]

oh yeah the 97 under were just 89 in lbs.

Do the rocker bearings look and feel ok ?

Also did you pre prime the new lifters with oil ?
If you didnt, they all could be damaged.

[Avengeusa]

Originally Posted by xeroinfinity

oh yeah the 97 under were just 89 in lbs.

Do the rocker bearings look and feel ok ?

Also did you pre prime the new lifters with oil ?
If you didnt, they all could be damaged.

not damaged, oiled ahead of time, all is well there

rockers feel great, the bearings in them are excellent....

push rod length is fine with little wear, so they are not too short and rattling......

i am still thinking i had multiple noises, the pistons may be the culprit, rocking in the bores i bet

[xeroinfinity]

Were the heads reworked ever ?
How many miles on this GA now ??

On the piston noises you are reffering to is called piston slap. It typicaly only does this on start ups when the engine's cold.
If it's doing it more often, then a rebuild or engine replacement might be in store.

[Avengeusa]

Originally Posted by xeroinfinity

Were the heads reworked ever ?
How many miles on this GA now ??

On the piston noises you are reffering to is called piston slap. It typicaly only does this on start ups when the engine's cold.
If it's doing it more often, then a rebuild or engine replacement might be in store.

I shaved the heads, did a valve job, and did a complete bore/rebuild 75 k ago......

I think the pistons went south..... too much clearance

[xeroinfinity]

If the block was bored out I dont see that being an issue unless the pistons/rings were the wrong size. 75k miles on the rebuild isnt good at all!
It is pretty earsy to tell how much slop they have. With the head(s) off and with a piston at the top of the cylinder, see if it has a bunch of play side to side.
Or if you have an inside micrometer you can measure the bore.

What all did you replace in the heads/valve train ?

[Avengeusa]

Originally Posted by xeroinfinity

If the block was bored out I dont see that being an issue unless the pistons/rings were the wrong size. 75k miles on the rebuild isnt good at all!
It is pretty earsy to tell how much slop they have. With the head(s) off and with a piston at the top of the cylinder, see if it has a bunch of play side to side.
Or if you have an inside micrometer you can measure the bore.

What all did you replace in the heads/valve train ?

there is slop in the piston/bore..... too much, i have to measure it, there is scuffing of the piston skirts, some are pretty bad, not horrible.....

all valves and springs were replaced when the rebuild was done, the heads are near perfect, all of the bearings in the whole engine are just beginning to be polished, the engine is clean as a whistle, the oil galleys have been inspected and are perfectly clear, no debris, or anything like that, it appears the sealed power pistons i used have just began to wear prematurely

the bore is great......

the pistons upon the build were installed and the freeplay in the bore was at the minimum limits, this was a perfect rebuild.....

crazy.....

[tiso_us]

Originally Posted by Mullinsports

Problem found:
Cam bearings spun and blocked the flow of oil to the top end. The lifters had no oil to pump up the hydraulic pressure. The result was collapsed lifters causing slop in the rockers. The loose push rods (6 of 12 were always loose) caused the noise and loss of power.
I purchased a remanufactured long block from Murray's Discount Auto parts for about 1600 and it works great. I looked everyplace for a replacement engine and it was a best deal. It only took 1 day to get it delivered to the store.
Good luck to anyone else out there with this issue.
Thanks to all who helped with feedback on my question!

Thank you for the Information, I kinda got tired trying to pull the hair out.

Instead of making a new post, I decided this is the same problem i'm having at the moment and decided to post here.

I did a oil pressure check and had a reading of 40 psi on warm up, dropping to 15-18 psi when warmed. removed head and cleaned all the lifters of all oil build up and inspected each piece......all functional.

While running and with the valve tapping, i noticed the valves not oiling as good, just seeping out.

I then thought it was a weak spring, until i ran across this subject, yes it brings back old memories to.

This vehicle is not mine but someone i'm trying to help, they have no money due to layoff, but that's another story.

Question: Could the oil pan be removed to change the bearings instead of pulling Pak(engine)?.

Again thank you for this OP.

PS....2001 Grand Am GT - 124,000 miles

[xeroinfinity]

If you are talking about the cam bearings, the engine should be pulled to change.

If you are talking about mains and rods you should be able to change them with the oil pan off. It's going to be tight in there though.

Having that big of a pressure drop sounds like you have a oil pump issue. You'll probly find a gunked up oil pan too.

Hope that helps!

[Avengeusa]

cam bearings cannot stop oil pressure from reaching the lifters

[tiso_us]

Originally Posted by xeroinfinity

If you are talking about the cam bearings, the engine should be pulled to change.

If you are talking about mains and rods you should be able to change them with the oil pan off. It's going to be tight in there though.

Having that big of a pressure drop sounds like you have a oil pump issue. You'll probly find a gunked up oil pan too.

Hope that helps!

I took off the oil pan, it was a little difficult to do this while still in the vehicle , but i did removed it.

After further inspection of the main bearings i have located the problem (i think), the center main bearing was gone and had spun wearing down the main. the other mains were good. looks like oversize bearing time.

After using that Plasticgage to determine what the oversize would be(can't recall at this minute what it was), but with the new bearing(standard) inserted, it still had excessive play.

This problem could explain why the tapping noise and thinking it was a lifter......the piston traveling further and in turn slapping the valve.

I hope this helps those having tapping problems.

[xeroinfinity]

You may be onto something... with the main bearing, that would knock more then tap Id think.

Gm has been building loose engines for several years.
This problem cuases piston slap, see this link for more info.
http://pistonslap.com/

[tiso_us]

Originally Posted by xeroinfinity

You may be onto something... with the main bearing, that would knock more then tap Id think.

Gm has been building loose engines for several years.
This problem cuases piston slap, see this link for more info.
http://pistonslap.com/

Good read!!...Thanks, I had no Idea these cars had this kind of problem with them. Here is what i did next.....after replacing the oversized bearing, i put the engine back together, but before i do that i want to make this note about the bearings first, the bearings had alot of play from side to side, something like the width of a dime on both sides.

With that said i'll continue.....after putting the vehicle back together and replacing the oil filter and oil with 5W-30 which was on the oil cap, I started it up, for the first 5-10 seconds it ran smooth like a ribbon, than my worse nightmare came back........tap....tap....tap., this time it was not as bad when ideling, but noticable when the engine was raised.

Now i'm considering pulling the heads off to see if there were valve damage.

Could it be a piston slap!?!?!.