Big Dave

Brian:

I can stop by and have a listen in person tonight on my way home from the office. Let me know if you're available.

I had my fair share of odd noises, from chain tensioners, torque converters to loose distributor rotors. Hopefully it may still be something minor.

Are you planning on coming to our monthly meeting in Royal Oak tomorrow night? I'm certain we can get a group together to help you out.

Dave

camboinc

thanks much dave- tonight would be great. i will be there on thrusday for the get together as well. was hoping to drive the car there but that may not be a good idea until i rule out a few things. just give me a call if you need directions to the house again. thanks my man!

WallyP

Another possiblity that should be checked pretty soon would be the tensioner and timing chain between the camshafts.

Scott M.

If you suspect inner engine noise, remove the oil filler cap and listen.

Another suggestion is to order a oil sample kit from Blackstone. They send the kit to you free and it's only about $20 for the analysis.

Also, some of the shudder my be motor mount related, which will magnify engine noises.

AO

Brian-
Sorry I've been away from rennlist for the past few days - been super busy at work. I'd try to lend a hand, but it looks like Big Dave's got your back. Let's see what he determines and go from there.

Mrmerlin

Hi I forgot to mention that you should also check the rear driveshaft clamping bolt if the driveshaft looks like it is moving forward the only thing is that you have to remove the exhaust system to get to the rear clamping bolt it is also a good idea to replace these bolts when they are removed torque them back to 66 ft/lb use blue loctite on the bolt. (this is the higher torque number from the original 58 ft/lb)
There are also a few other noises that you may be hearing but these have already been covered, first is the freeplay at the rear of the crank, try not to run the car till this is checked,

camboinc

Stan,
on the driveshaft check- should i just grab it and see if it moves forward or back, and then if yes, check and replace the clamping bolt?
Andrew, ill let you know what dave thinks tonight. thanks!
Wally- the tensioner would be checked by removng both timing covers and the timing chains under the cam covers, correct?
thanks guys!

Bill Ball

You really don't have any symptoms of TBF, at least not the classic ones, but releasing the flexplate periodically is a must.

Could be a lot of things with bearing knock being a bit high on the list because you say it is once per rev, right? Twice per rev would move it up into the cam/head area. You said it was RPM related but I actually didn't see if you gave its frequency relative to RPM.

Big Dave has more experience with these motors than anyone should ever have unless he were a mechanic by trade. With a mechanic's stetoscope or a length of heater hose, you guys should be able to better locate the source.

heinrich

I wonder if it could be carbon, once you've checked everything else. With the spurt up to 5000 maybe it dropped some carbon into a valve seat?

Big Dave

We'll use the stethoscope and figure out where it's coming from.

Checking the chain tensioners would require pullng the cam covers. Let's figure out if that's where the noise is originating before diving in there.

Dave

svp928

H may be onto something with the carbon idea- I've had carbon hang a valve open and cause a 'shudder' and loss of power, as well as a tapping sound, because the valve isn't coming back onto its seat, which makes too much clearance at the lifter. Also caused a compression test to show zero on that cylinder... It should not have stayed there for such a long time, though. Usually falls out within a few miles of running. Maybe compression test would help- its not too hard to do...
Unfortunately, a timing belt jumping a tooth or two could also cause these symptoms..

Steve

SharkSkin

Carbon would more likely knock once per rev. The old school way of getting rid of carbon was to trickle water from a hose -- about a 1/4"-3/8" dia. stream -- into the intake while keeping the engine at 1500-2000 RPM. The steam would tend to break up the carbon. While this is easy enough to do on a v8 with a 4bbl, I'm not sure how you'd do it on a non-CIS shark. You wouldn't want to pour water through the MAF. There's a thread here that details a 3-step process, BG cleaners, that has been reported to eliminate carbon and intake crud.

camboinc

bunch of clever buggers! thanks! thanks! thanks! cant get home until 5pm so ill wait for big dave to take a listen- then pull oil filter and flex plate release. the knock seems to be at crank speed (once per rev) and not cam speed. again, waiting for the ol' pro! if noise is not terminal, ill go TB WP R&R as well.

mark kibort

valve noise will have a lower frequency than something in the crank area. valve lifter noise sounds like click,click,click,click (say out loud as fast as you can) . rod bearing or crank related would have twice the frequency at idle.

compression check??

Mk

dr bob

Before you get too far along, make SURE that the car is running on all 8 cylinders. The ignition on the car is split through two coils, two distributors. For casual driving, especially with not much seat time in the car, it's possible the engine is running on only 4. If it is, you are dumping four cylinders' worth of fuel raw into the cats, and you risk a fire if they are doing their job. It's as simple as a loose or broken coil wire, tougher when a coil goes away. Wires aren't real cheap foir the 32V motors so they are often moved to the bottom of maintenance lists. You can use an IR thermometer to check the exhaust temps at each port to see if four of them are cold. If you find that there are cold ones, stop the engine and get to the problem before you do anything else.