Weird noise under intake.

[87chrisss]

Im having a weird noise problem.. It sounds like an exhaust leak but no exhaust leak is apparent. Im running E85 so seems like my valvetrain has been a bit noisier since i did the conversion some time ago. I started adding some Benol Oil to the fuel very small amounts just to help lubricate. I have been using ONLY Rotella oil with ZDDP additive..Seem's the noise became apparent to me a week ago while i was driving i thought i blew the header gasket so i popped the hood but no exhaust leak of no sort bl's are normal.. int's also normal Engine vacuum is fantastic oil is clean and so is rad. water no blowby but i have yet to do a compression test though..That is my next step to figure out what's going on. It sounds like its on the Driver side but right under the intake literally right underneath the lower intake. Sounds like a sticky lifter but goes somewhat away when engine is rev'd @ operating temp @ around 170+ But under 165 deg seems its alot more apparent. It actually goes away when engine is rev'd a little higher than 1800 rpm but. Just fyi i did pop the valve cover off and turned car on and all rocker's were 'rockin' normal so i didnt wipe a lobe... Oil pressure is very high @ idle and while cruising. The car still pulls great even @ 27psi no stutter or 'issues' of any sort no knock etc.. Im a bit picky and not sure if i like the 'noise'. When the car turns on cold its a tick tick tick right under the intake could i have bent a pushrod? what is the symptoms of a bad cam bearing and or bent pushrod? Would i still be able to go up in rpm and run such high boost with a bad cam bearing and bent pushrod? It's definitely in the valvetrain somewhere under the intake im assuming lifter cam or pushrod? Any signs to look for? Again my oil looks clean and oil pressure is high all the time? Any suggestions? I'm gooing to try a Compression test later tonight possible HG failure blowing compression into intake side? The car runs great though??

 

[87chrisss]

Im just going to have to break it down, and change the cam, lifter's and pushrods, i cant take little noises... not my cup o tea.

 

[chopped39]

What kind of heads are on engine? egr ports blocked? Could be a small leak at intake gasket. Do you have a stethoscope If so check around center of intake gasket and see if you can hear it with that. You can use small vacuum line as well. If not try spraying brake clean down intake gasket and see if idle flares. It may not . Watch your fuel trims when you do it as well.hope this helps. good luck

 

[87chrisss]

Chopped my BL's are normal they aren't pegged, so i dont have a vacuum/exh leak.. plus my Boost gauge / plogger shows a hell of alot of vacuum @ idle.. so i think im ok.. Im just going to go thru the steps.. I have let the car parked for about 2 day's now, and will drain oil tonight and use a mesh filter to catch any particles the might be in the oil to investigate if any metal in oil i will pull the intake and Vcover's off to take a better look @ lifter's,Cam.. If i dont see any metal in oil or filter i will try other options, Again my oil pressure is close to 70 on a cold start and while driving its near 30-40# of oil pressure.. its really really good and its been pullin hard still so im kind of confused if i were at a loss of power of popping @ high boost i would lean towards wiped cam lobe.. i might just pull intake off and take a look @ everything,

 

[dr_frankenstein]

i had the same once...

It turned out I had left a 9/16 wrench under the intake.

 

[87-WE2]

i had the same once...

It turned out I had left a 9/16 wrench under the intake.

Yikes!

 

[87chrisss]

Just drained the oil looked ok, i thru in some new rotella 15/40 with some lucas oil stabilizer i havent cut open the ac delco 1218 oil filter yet but i plan that to be my next approach..Same thing when i turned it on noise apparent,until 167 degrees and noise drops and is barely noticeable..Oil Pressure @ 175 degrees is close to 40 on gauge, when fan kicks on it drops a bit to about 35 and will go back up to 38 almost 40. Oil pressure is great.. Really hate noises and its really only apparent when engine is cold i think i have a bad lifter.

 

[EYE-OPENER]

Sounds like it could be the lifters Chris...might have one not wanting to pump up. If it were a cam I believe you'd hear it'll the time....mine was doing the same thing and I'm definitely putting all new sealed powers in it while she's yanked apart.

 

[87chrisss]

Seems im trying to avoid the fact i have to break it down.. Im acting like its going to magically disappear with an oil change, i have to stop whining on here and take the f*#ker apart already and see what really going on.

 

[EYE-OPENER]

I had mine apart a year ago to replace the gm head gaskets and it was quiet as a mouse before I tore it down....afterwards it tapped and wouldn't go away. I added Lucas and it went completely away...just every once in a while it clacked at start up...and once or twice for about a minute....damn sure sucks but better than hearing that crap

 

[Buick Mark]

Why are you running such thick oil?

 

[87chrisss]

I have always ran 20/50 but Rotella doesnt have 20/50?! At the parts store they seem to only have Rotella 10/30 which might be a little to thin for me, engine has 88k miles.. They have 40w and 15/40 i have decided to use 15/40. What do you run?

 

[trailinjake]

I had a vacuum leak at egr block off plate and another on back side of DH. My idle vacuum was 15-17 with these leaks so don't dismiss that. Do a pressure test to make sure you don't have any vacuum leaks.... then if not... rip her down. good luck

 

[trailinjake]

and I use 15-40 in the summer months as well

 

[87chrisss]

It's weird because my BL's are normal, even when driving..I checked compression on all cylinder's and they were all inline 150 + - all the way around. Once i give her some gas noise goes away? Really bugging me. I can get on the car without any hesitation all the way up past 27# of boost no burping or hesitation when roasting the tires. Car turns on fine and once it reached operating temp noise quiets down significantly? I just dont get it? My vacuum is around 17-20 inches of vacuum on idle b/o on my gauge and powerlogger map rdg. i have no other choixe but to tear her down

 

[87chrisss]

Need some help folks.. So i popped the intake off, and i dont see anything out of the ordinary took of the rocker's and brought the pushrods inside and rolled them on a flat surface, all seem to roll fine. One seemed to have more wear than the other's though had a little ridge of wear i will post pic.. Once looking around i noticed My head looks cracked?!?! But seem's to be a factory defect on the head's it looks cracked but it really isnt..I think? What other crap should i look for oh i did pop the lifter's out and they all seem flat and good no low spots by touch, Could it be a cam bearing? Could a broken rocker arm retainer also be ticky" i saw one of the plastic reatiner buttons had broke off.

 

[turbov6man]

What head gaskets are on it? Have you pressurized each cylinder with an air compressor and see if the head gaskets are leaking.

 

[87chrisss]

No i haven't but i did do a compression test all the way around, 150 + - 5 on all cylinder's