filmjay

Hi all!

So I've got a bad knock....I was simply cruising along at about 1500 rpm and got a sudden and terrible knocking noise, which slowly started to bleed oil pressure off.

I prayed I'd only broken a valve spring, but no luck. Swapped in fresh springs and still have the knock. But..I DID have 6, yes you read that correctly 6, broken valve springs. Thank goodness for dual v-springs....they'll be in every engineI put together from now on.

Here's a video of the symptom....

A builder friend thinks I bent a valve from all the broken springs...they seemed straight when I swapped the valve springs though. And he's backed up and couldn't get to it for 3 months, otherwise I'd just have him do it. Lol!

I'm praying it's a lifter...I'm totally cool with a cam swap anyway....general consensus definitely says there was too much open spring pressure for the stock lifters (PRC dual .675's on a .625 lift cam....so in the neighborhood of 400+ lbs)

BUT....nothing saying it's not a spun bearing...which is what I'm petrified it is. Not quite ready or tooled up for a new short block...think that's a little beyond my driveway skills and tools.

Tear down starts right after I hit "submit reply"...wish me luck!

Oh yeah...and a handful of broken PRC duals to who gets it correct! :P

icntdrv55

Well, that's a pretty lousy video for sound, but it sounds to me more like an exhaust manifold leak. Sure doesn't sound like a bottom end noise to me.

realcanuk

Doesn't sound like bottom end. I guess lifter.

filmjay

The loss of oil pressure says it's more than an exhaust leak....does sound like an exhaust leak though, doesn't it?

I dunno what's going on with the video...doesn't seem to be playing the full 30 sec clip with the noise following revs...getting faster with more, settling at idle.

FireRoc

I'm thinking there is more than one thing going on. I'm thinking an exhaust leak AND a bad lifter or two.

AIR_RAM

Yeah but the oil pressure loss suggest that it's more than a simple lifter issue,..

Good luck and keep is posted...

filmjay

I know....that's what I'm afraid of.

Got the supercharger and cooling systems off today...no oil in any of the coolant...supercharger setup up for sale...was getting late and had to go to dinner, so saving the cracking of the engine for a fresh day.

sliderbkt

Im going to say lifter too. On mine it was easy to find, there was no preload on that valve. Good luck.

KLLRVET

Lifter

C5kid

nother vote for lifter

1fastbob

Broken piston on #7

tlove32

I hate to be the bearer of bad news.....but your knock sounds exactly like mine. I hoped it was a lifter too, but it turned out to be rod-knock. I sure hope yours is just a lifter.....

filmjay

Well, I finally had time to get all the front accessories off and the rack out. Pulled the passenger side valve cover, and started playing with the rockers.

This was #8 at TDC...https://www.youtube.com/watch?v=wyoObkPs7E0&feature=youtube_gdat a_player
Somethig definitely amiss w/ the #8 rocker...
I hope that's my knock, but we'll see. As far down as I'm taking it though, if short block ends up on the menu, it won't be much more trouble to pull it...and IF I have to pull it, I'll just swap in a stroker. I'll just have to rent a hoist for a couple days.

Rain's coming...more tomorrow.

filmjay

Dammit...YouTube just isn't my forte. Lol.

Video shows the #8 rocker with a lot of wiggle and not even making contact with the pushrod while still torqued down. Removing the rockers and dropping p-rods back in, #8 feels like it falls a little farther than it should before making contact.

filmjay

#8 Lifter stuck in the bore. Any ideas on removing it? ...preferably one that doesn't involve ruining the lifter bore. :P

realcanuk

Sorry to hear. I hope you can get it out but often the bore damaged.

What is my prize.... was first correct answer....

Jimmy C-6

That means I have no idea, but I'm hoping to learn.

MR_JLR

sorry to hear, had the same noise once and Carl Black Chevy ended up replacing the camshaft and all lifters. Good luck with it.

filmjay

Had a surprise family event, so no progress....and many many thanks to those friends that have seen this thread and called to help or offer tips I wouldn't have known right away.

But, I can see the #8 cam lobe through #6 well enough to see the #8 cam lobe is pretty beat up. Already decided on Brian Tooley SLR lifters and fresh trays...now deciding on a new cam...perhaps a few other goodies since it's all apart anyway, if I can afford it. (ie. If the supercharger kit sells soon enough. Lol )
I'm going to do some mild head/port clean up while they're off and I'm waiting on shipping...and since I'm selling my ECS blower kit and going back n/a, I'll be looking for the biggest cam I can run without fly cutting and using the stock torque converter in the A6.

Oh...and the prize...why it's a handful of broken PRC .675 duals. :P

erikszr1

loss of oil pressure indicates a crank bearing gone bad, "spun".