[RESOLVED] Changed lifters now bad knock under WOT

[Nofear20]

Well over the weekend I changed out my lifters becuase they were ticking so bad I was getting knock when cruising. Last night I did a WOT pull and the car bucked and jerked bad, and my knock light came on as well. It didn't do this before changing the lifters. Could it somehow be related or just a coincidence? The car is professionally tuned at 24psi on my 16g.

 

[Calan]

did you oil and bleed the lifters before installing them?

 

[Nofear20]

Yeah I did.

 

[Calan]

did you pull the cams? How does the timing/t-belt look?

 

[Nofear20]

Didn't touch the cams. I used the lifter tool and rotated the engine (clockwise) to rotate the cams so I could get the lifters out.

 

[Calan]

hmmm... well if you didn't pull the cams, there isn't a lot that could go wrong with a lifter change, as long as they were bled properly. Logic would say that you missed something putting it back together

Not the most helpful advice, but I would double-check all vac lines, sensor connections, etc.

 

[paultheninja]

Did you make sure you put them in oil for at least 8 hours?

 

[Nofear20]

From what I've read, you dont have to put them in oil if you are manually bleeding them.

I just can't figure it out. All I did was disconnect the breather hose, the PCV valve (don't see how either of those would cause knock) and took the plugs out. I put everything back together and hooked the plugs back together in the proper order.

 

[Calan]

Did you make sure you put them in oil for at least 8 hours?

ehhh... what?

You don't have to "soak" them. As long as you work the plunger a few times while they are submerged in oil and then bleed them, they will be about as oiled as they can get.

************

The "bucked and jerked bad" statement is what gets me. From a lifter-changing-related standpoint, it could be caused from a timing or t-belt issue, or bent valves due to a locked lifter keeping a valve from closing. But if you didn't remove the cams/t-belt and you bled the lifters down, then neither of those problems seem likely.

How is it running now?

 

[BogusSVO]

has the head been off? been milled? if so how much?
is this a 2g head on a 1g 6bolt block?

 

[Nofear20]

ehhh... what?

You don't have to "soak" them. As long as you work the plunger a few times while they are submerged in oil and then bleed them, they will be about as oiled as they can get.

************

The "bucked and jerked bad" statement is what gets me. From a lifter-changing-related standpoint, it could be caused from a timing or t-belt issue, or bent valves due to a locked lifter keeping a valve from closing. But if you didn't remove the cams/t-belt and you bled the lifters down, then neither of those problems seem likely.

How is it running now?

I bled each and every lifter and made sure that i could compress them with my finger. I also primed them by pulling the engine fuse and cranking the car.

I'm scared to even hit full boost just becuase of how bad it feels.

 

[Calan]

Have you checked your t-belt/timing, just in case? Although it doesn't seem likely, it may have jumped a tooth while you were prying on the lifters and rotating the motor.

 

[Nofear20]

Nah I haven't checked it. If that was the case though wouldn't it run bad all the time?

 

[Nofear20]

I just took the car out for a little cruise. Here's a log. I have no idea why I wasn't getting any knock this time. Last night the knock sensor was picking up quite a bit. I noticed this time its kinda like a popping noise with some bucking and loss of power.. It happened right around 22 seconds on the log which is when I left off the throttle a second later. I can't see anything wrong with the log and even compared it to my old one but I know nothing

Another thing I thought about were my plugs. Not sure if maybe my gap could have got knocked out of place when I took them out? I was careful with them... I'm running the bpre6s or whatever they are and this was the first time I have taken them out since my car was tuned..

But otherwise can anyone see anything wrong with my log?

Thanks

 

[Zex4g63]

Pull the valve cover and make sure all the followers are still in the right place.

 

[Calan]

I think it has to be something you missed... maybe list out EXACTLY what all you did and the process. Who knows... maybe we can spot something (that "can't see the forest for the trees thing )

 

[VETTE_50_TH]

I think it has to be something you missed... maybe list out EXACTLY what all you did and the process. Who knows... maybe we can spot something (that "can't see the forest for the trees thing )

at your analogy there. Haha. I love it. Did you happen to take off any intercooler pipes?

James

 

[Nofear20]

1.) disconnected breather hose and unscrewed pcv from valve cover.
2.) removed sparkplugs
3.) removed valve cover
4.) learned how to use my handy new lifter tool and removed all the rockers that i could get out
5.) jacked the car up, pulled the driver side wheel off, and turned the motor over clockwise so that i could get the rest of the lifters out
6.) bled the new lifters by sticking a paperclip in them and dipping them in a cup of oil while compressing/decompressing. I then took them out with the paperclip still in them, turned them upside down and compressed/decompressed them so the oil would drain out. i then took the paperclip out and made sure i could compress them with my finger easily.
7.) reinstalled them and made sure the rockers were all secure
8.) put the valve cover on, reconnected the pcv and breather reinstalled the sparkplugs put the wires back on correctly.
9.) removed the engine fuse and cranked the motor over for a bit to help prime the new lifters
10.) put the fuse back in and started it up. ticked for a while but no ticking at all now, not even when the car is cold.

 

[VETTE_50_TH]

Only thing i can think of the the wires were going bad and went bad, or they have a bad connection. Or the spark plugs are not gapped correctly or not tight enough in the head. My guess its one of those.

James

 

[Calan]

damn man... that's pretty straight forward and it sounds like you covered the bases.

But...it was fine before, and now it's not... and the only thing different is the lifters. Logic still says you missed something when putting it back together.

I'm at a loss at this point

EDIT:

maybe what James said... double check the plug connections and make sure they are connected firmly.

BTW - James... I still want your friggin VC

 

[VETTE_50_TH]

damn man... that's pretty straight forward and it sounds like you covered the bases.

But...it was fine before, and now it's not... and the only thing different is the lifters. Logic still says you missed something when putting it back together.

I'm at a loss at this point

EDIT:

maybe what James said... double check the plug connections and make sure they are connected firmly.

BTW - James... I still want your friggin VC

I have two. One for my white 2g gst, one for my 1g awd. I had a third but used it as colateral on powdercoating my VC for the gst. The one i jsut got powdercoated is black chrome. Its so sik!

James

 

[Nofear20]

I guess it was just the sparkplugs. I took them out, regapped to .028 (not even sure if that gap is recommended at my boost level) them, and reinstalled them. I opened it up a coupletimes afterwards reaching the full 24psi and it doesn't seem to be happening anymore. Thanks for all the help

 

[VETTE_50_TH]

Please give me cred. Thanks.

James