TedH

After installing the Milodon 30701 oil pan, stock volume mellings oil pump and a one-piece Fel-Pro oil pan seal, I started the engine and heard an awful clanging noise coming from somewhere in the engine. I shut it off and shut the garage light off assuming major issues...

I installed a Comp Retro Roller cam conversion this spring. In addition, I had the cylinder heads refreshed with new valve guides and the hardware that came with the cam. I've also installed Ultra Pro Magnum rocker arms.

After over seven months of wrenching, I was tired and frustrated enough to just let it sit until I was ready to 'try again'.

Oh, and I still have to seal the rocker studs as they are passing oil into the intake runners...

Today, I've started to open the engine to find out what the issue is.

So far, the distributor is out and there is no sign of wear on the distributor gear; that was my first thought: distributor gear damage.

I've tried to shoot digital pics down the distributor shaft hole and can't see the cam gear (at least not clearly). Going to have to climb up on the car to get a better view with a flashlight. Hoping the cam gears are not damaged.

Next, I'll be pulling the valve covers to see if one of the rockers has slipped off a pushrod.

I am also concerned that the cam may be walking forward (or backward). I installed a nylon cam button and was very careful to (I thought) set the proper clearance at the timing cover. Perhaps the cam is smacking the inside of the timing cover.

I am also wondering if the oil pan/baffle are in the way of the crankshaft counterweights. The Milodon pan is a strong piece and made in USA. I'd hate to think I have crank clearance issues... or, could I have a faulty oil pump? I noted steady oil pressure but perhaps the internals in the pump are faulty.

Then, there is the replacement fuel pump pushrod with the steel insert that rides on the new cam.

The fuel pump pushrod will come out and then the timing cover will be the last thing I pull to determine if I have cam walk.

Then, I may also have to pull the intake to see if there is any obvious lifter damage (either from cam walking or lifter link failure).

With all of the potential issues, I buttoned it up last month until I was good and ready to go hunting... having just got it all back together, I hate the thought of tearing it all apart again.

I've pretty much ruled out anything to do with the front engine accessories... but, there is the older water pump. I did not notice any looseness in the water pump shaft/bearings. There is no noticeable rubbing of the fan blades on the shroud.

I love my vette but hate to tear into it again so soon.

MotorHead

Hey Ted, did it ever run good after making all the updates ?

Does the Milodon pan have a built in windage tray or is there one in there ?

Have you checked the end of the dipstick for any unusual marks ?

Did you setup the valve train correctly so the rocker tip slides from side to side equally ?

How did you determine the correct pushrod length ?

drwet

I feel your pain. If its any consolation to you, I have had to go back into just about every engine build I have ever done. Usually something minor, but there's always something.

Couple of suggestions. Hard to know what to look for without hearing the noise, but check the flywheel cover at the bottom of the bellhousing. They bend easily and I have had them rub on the flywheel (or ring gear.)

Check that your starter is disengaging from the flywheel/ring gear. If the starter gear is not disengaging it can make quite a racket.

If its not these things, check the easy stuff first. Pull the valve covers and look around. If its not there, I would be dropping the pan to see if there is a clearance problem with the pan or the windage tray.

Good luck and relax. We've all been there.

TedH

Good ideas. The car actually did run good and quiet before the oil pan/pump and seal replacement. It just had a really bad oil leak (old one-piece Fel-Pro seal and cheap oil pan suspected) and I had the blue smoke from the leaking rocker studs.

I had driven the car with the oil leak and smoke for about 200 miles... yes, probably 200 more miles than I should have but I just wanted to experience the thrill of that new bumpstick.

The Milodon pan has an integral windage tray (I think that is what it is) welded into place. The short oil pickup (made for the pan by Milodon if I recall correctly) also went in with the new oil pump/pan.

I had removed the flywheel cover after the pan replacement as I was concerned it was not clearing the flywheel/converter and contributing to the clanging. Once I put it back in place, it appeared to have good clearance from the flywheel. Had to pull both headers off along with the starter to get the flywheel cover out of the car; sure has some sharp edges (leather gloves required). I may remove it completely again if I don't figure the noise out. Perhaps I made it worse removing/reinstalling the flywheel cover. The starter is disengaging but I wonder if I torqued the flywheel cover and got it to close to the flywheel when I put the starter back into place. Will check that out again with flashlight (added to my list). I also verified the three bolts that connect flywheel to converter were tight; I added threadlocker and torqued them just for good measure.

I checked the cam gear and it looks fine. Had to crawl onto the car but got a really clear view from passenger side of the car with a good flashlight. So, the cam gear looks normal as does the distributor gear.

Valve covers will come off next and I'll check all of the pushrods, rockers, springs and valve tips. Will advise shortly...

TedH

I found a clearance issue between #8 intake rocker arm and the baffle in the aftermarket valve cover. It is apparently hitting/scraping on the baffle and wore a spot into the baffle. No apparent rocker damage. This could be the source for the clanging. I installed the valve cover couple weeks before the oil pan replacement. I may have tightened the valve cover bolts at time of oil pan install (they were loose) and that could have brought the cover/baffle in contact with the rocker body.

When I was chasing the oil leak, I thought I had solved it with replacement of the passenger valve cover; but it kept leaking. Otherwise, no loose pushrods and all rockers are centered right on the valve stems. One thing I learned with the DART heads is that some of the valves are not exactly where the OEM's put them; to increase port volume. Therefore, the guideplates are essential and the rocker tips on some of the valves will be a little to the 'right' (not a lot but noticeable) in order to center on the valve tips.

Time to pull the driver's valve cover but this scraping on passenger side valve cover baffle may be the gremlin I am chasing.

MrJlr

You may have lucked-out big time

TedH

Ok. Driver's side looks good. I am going to reinstall the valve cover that I thought had the leak issue as it had no clearance issue with #8. Distributor is back in (I took really GOOD pictures so that I could be assured it all lines up) and going to button it up and see if I've solved the issue.

I may go back in (once I confirm noise solved) and put a final adjustment on the rocker arms to verify valve lash once it is warmed up.

TedH

Ok.

Got it all back together, started it and 'clang, clang', but not quite as noticeably as before. Then, it stopped making that noise and it became intermittent. I moved around the engine bay and found it to be coming right from the area of the distributor. To be honest, it could still be an ill-fitting flywheel cover. May have to remove it to be sure.

Question: Can my distributor shaft/bushings be going bad? I noted some up/down play in the shaft; about 1/16-1/4". Car runs nice and steady with good oil pressure.

One thing I note is that the oil pressure from the 'standard volume' pump from Mellings is not that much lower than the initial pressure from the high-volume unit. About 60-70psi at start-up and it settles down to about 40-50psi at idle once all warmed up. I am currently running 10w-30 dino oil.

The noise is almost non-existent now save for a little noise when I rev it but it still comes and goes.

I will give flywheel cover removal a try. Will mean headers have to come out but I want to resolve this once and for all.

TedH

Now, the noise only occurs when I start the vette. It clangs a little bit and then quiets down. I suspect the starter has something loose inside.

I took the car out for a nice drive and no such noise whatsoever the whole trip. I got a little 'ting, ting' noise when slowing down and not sure if it is related. But, the car ran smooth and strong the whole time. No hesitation, shudder or anything to lead me to think there is something amiss inside the engine. Even goosed it from a standing start and it barked the tires loudly and no hesitation.

It also groans louder (starter) than it has ever before. Before this extended repair cycle (February - October), it always just started the car with no noise or apparent effort.

I am going to replace the starter with hope that solves it. It is a 'palladium' starter from Advance Auto and has served well for the last 8 years; longer than any rebuilt unit I've ever purchased.

Will advise.

427Hotrod

Sure sounds like it could be that cover. It takes very little for them to get out of whack.

9 times out of 10 I leave them off to help converter cool off.

Good luck!

JIM

DM76

I found out where a lot of noises came from in cars with a simple piece of garden hose. Good luck figuring it out.

TedH

Bought a rebuilt starter and will see if that helps with the noise.

procketus

Could be a busted flywheel. Look for cracks around the crank.

drwet

Distributor bushings certainly wear, but I've never known them to cause a problem, and I've certainly never heard of one causing the kind of noise you are describing. With that said, the end play you are describing is typical of stock distributors, but you should still shim the distributor to reduce the end play to about .015" This reduces ignition timing variations due to the distributor shaft bouncing around. There are kits available with the shims you need.

TedH

If the new starter doesn't solve it, flywheel and cover are next. I gave it a good looking at (from what I could see under the car) when I pulled the cover last month.

MidShark

Could it be as simple as one of the exhuast pipes clanging on the crossmember? Just a thought, as I've had that happen before after messing around with things.

lvmyvt76

that oil pan is a high performance part, the L-48 is a low performance engine, it is fighting the presence of high performance parts!!!(lol)

TedH

Yes, it sure IS fighting. I'll swap the starter out but starting to suspect the flywheel. If the flywheel is cracked, engine OR trans will have to come out.

All that is left of the L48 is the block, crank and rods...

Question: I bolted the flywheel to converter when I installed the engine. All bolt holes lined up and the converter was right up against the flywheel; didn't have to work to line up the first converter threads. Is there a secret to flywheel and converter alignment? I just lined the three flywheel bolt holes up with converter threads.

TedH

Expanding my examination of the engine/trans:

1st:
- flexplate cover - will pull it first (have to remove headers to get it out) and see if the noise is resolved. I would like to reinstall if possible to keep debris out of that area of the drivetrain
- starter

2nd:
'bell' housing of the trans
flywheel including the teeth on the perimeter for obvious cracks/breaks
torque converter
rear of new Milodon pan rails

cv67

Got a mallet or deadblow hammer?
Id start smacking on things underneath with the car in the air bet you find your culprit sounds like.

had some noise that made me batzchits crazy.
turned out some rockers were juuust kissing the valvecover when the motor got warm.

Kept replacing stuff finally got wise pulled the covers off started it and silence....least i got good at running lash

Keep us posted!