Rod knock

wvumtnbkr wrote: I have some previously used lifters from another sbc that I could put in. Would I still need to go through the break in process?

Yes. From what I understand. I think to avoid that you need to keep the lifter paired with a cam lobe.

What is the break in process? I will google it, but I like to get my info from this board.

Thanks!

Rob R.

wvumtnbkr wrote: What is the break in process? I will google it, but I like to get my info from this board. Thanks! Rob R.

Ask 50 people, you'll get 50 answers. Long story short:

Fresh oil with extra ZDDP or additive

Don't let it crank too long, don't let it idle at all

Use lighter valvesprings if they are strong

some amount of time at some RPM etc

Change oil afterwards.

apparently, I am better off just taking the ones I have and cleaning them thoroughly.

I will try a little MMO in the oil also. Then maybe I will let it run for more than 5 minutes.

Thanks!

I will report my findings later today!

Thanks again!

Rob R.

wvumtnbkr wrote: apparently, I am better off just taking the ones I have and cleaning them thoroughly. I will try a little MMO in the oil also. Then maybe I will let it run for more than 5 minutes. Thanks! I will report my findings later today! Thanks again! Rob R.

The googles should help you, but yes, cleaning the lifters is a good idea. I have always heard to soak them in ATF or engine oil for a while prior to putting them in, as well. Note which came from which lobe and you should be fine.

Rob,

Get a mechanics stethescope.

http://www.harborfreight.com/mechanics-stethoscope-41966.html

Isolating the source of your noise will be much easier and you won't have to pull off any belts to use it.

Dashpot wrote: Rob, Get a mechanics stethescope. http://www.harborfreight.com/mechanics-stethoscope-41966.html Isolating the source of your noise will be much easier and you won't have to pull off any belts to use it.

I have used this on valvetrain parts with great success. Actually, no, I have a real live medical grade stethoscope that I use. That being said, I have been extremely misled by it when attempting to use it on rotating parts.

before you mess with lifters - pull timing cover and check the chain. or pull the dist cap and spin the crank back and forth by hand to see if there is slop before the distributor starts spinning.

chevy used an ingenious nylon toothed cam gear that can wear enough for the chain to slap the block, and it can sound just like a rod knock. i had one do that, with the stethoscope it sounded like a bad rod in the #4-6 area, and it was just the gear missing a couple of its nylon teeth.

patgizz wrote: before you mess with lifters - pull timing cover and check the chain. or pull the dist cap and spin the crank back and forth by hand to see if there is slop before the distributor starts spinning. chevy used an ingenious nylon toothed cam gear that can wear enough for the chain to slap the block, and it can sound just like a rod knock. i had one do that, with the stethoscope it sounded like a bad rod in the #4-6 area, and it was just the gear missing a couple of its nylon teeth.

This is a great idea. Distributors can also wear in their bushings. I had a bud who could not set his timing. I thought he was being stupid, but the darn thing was wobbling all over the place.

I got a video of it. How do I upload it?

I have not checked the timing area.

The distributor is new.

I can tell it is the # 5 or # 7 piston area. Fairly low and near the back of the drivers side.

In reply to wvumtnbkr:

Low and back would not tend to indicate valvetrain.

You can't upload video here - upload it to youtube and link us there.

I would agree with you on that. The only thing that is keeping me from thinking it is a rod knock is that I just changed the rod bearings. The sound is pretty much exactly the same as before. I thought it was maybe quieter, but I think that is wishful thinking.

Also, there is a metallic rattle associated with the same 2 pistons that sounds like a quarter bouncng around in the valve cover. This only happens sometimes when the motor is revved and then allowed to idle. The noise goes away after a few seconds.

I took the valve covers off to check this out (figuring I had a pushrod or pieces of a rocker arm) bouncing around. Everything looked fine. I even re-adjusted the rocker arms by backing them off until they made noise and then tightened them back down.

The noise still comes back every now and then when revved.

I am having a hard time getting the video off of my droid onto the computer.

If you adjusted the rockers while running and could hear the noise independent of the clatter, than we're out of the lifters and all of the valvetrain altogether. Now I am back to flywheel/converter bolts or a main bearing. Here's an idea, oil pump or driveshaft. You may have screwed the interface up when you installed the distributor onto the shaft. Possibly the distributor is adjusted too far out of the block and missing the key or something. Does this thing have oil pressure?

about 50 psi of oil pressure.

The clatter noise does not happen while adjusting the rockers. The "original" noise happens ALL the time.

It can't be driveshaft (car not moving) unless you mean oil pump driveshaft (brand new oil pump).

If it was flywheel / clutch bolts, I would expect it to make noise while cranking without firing.

I am going to take the transmission off and inspect later today.

I also had somebody suggest it may be something under the intake (like a socket). I wouldn't think something under the intake would be consistent.

Thanks again for the continuing help!

wvumtnbkr wrote: about 50 psi of oil pressure. The clatter noise does not happen while adjusting the rockers. The "original" noise happens ALL the time. It can't be driveshaft (car not moving) unless you mean oil pump driveshaft (brand new oil pump). If it was flywheel / clutch bolts, I would expect it to make noise while cranking without firing. I am going to take the transmission off and inspect later today. I also had somebody suggest it may be something under the intake (like a socket). I wouldn't think something under the intake would be consistent. Thanks again for the continuing help!

Actually a tool in the intake could be an issue, but that's a bigger job. What I am talking about is the interface between the distributor and the oil pump driveshaft. It's easy to get wrong. New distributors also can suck, as can new oil pumps. Did you retain that little plastic sleeve that slips over the two of them? Does the distributor have an adjustable collar? Did you reuse the original OEM pushrod? Did you seat it well in the new pump? Check to see if it was bent?

seriously - check timing chain slack first.

my uncle is a mechanic, had the stethoscope, and was all like "you got a spun main" and then i asked another older mechanic who was well versed in the small block and he said "your chain is slapping the block go pull the cover and check it"

don't forget to check the timing chain

But why would you have to pull the tranny to look at the converter bolts? Don't you have an inspection cover?

Edited because Pat did.

I have had loose converter bolts sound like rod knock

No inspection cover. The only "hole" is where the clutch linkage goes. I can't really see in it.

I took off the tranny and found nothing wrong.

I swapped out the motor for another one. I should get it finished and loaded up today. I checked the bearings and valve train as best I could before putting the new motor in.

See you guys tomorrow (if this new motor sounds good).

wvumtnbkr wrote: I swapped out the motor for another one.

Well that's one way to fix the noise...

Read the whole thread and I was just about to say just replace the whole motor. Since it is a Chev 350 they are as common as dirt in most parts of the country. Just go get another known good running one from the Junk Yard and move one. Consider the old one a pile of spare parts or a potential rebuild for after the race. Best of luck at the race

You mean "Rod Knock" isn't only something that happens when you go looking for a condom in the dark?

That's what it feels like to me right now.

RossD wrote: You mean "Rod Knock" isn't only something that happens when you go looking for a condom in the dark?

wvumtnbkr wrote: That's what it feels like to me right now.

Turn on the lights, find the damn thing and get off the internet then.

It was NOT a rod knock. I got to experience a REAL rod knock 5 laps into the practice day on Friday. Very similar noise, just not exactly the same.

we had to put new rocker arms on this motor before we started it. The rockers were in poor shape.

WE adjusted them the best we could before starting the motor. We then adjusted teh rockers after starting the motor also.

Apparently we berkeleyed up! We had the # 7 intake valve hitting the # 7 piston. Not enough to hurt the piston, but enough to make some noise.

There was black soot from incomplete combustion in this cylinder as well.

We will change the valve, check all of the bearings (again), and check the wrist pins. Once we do that, we will re-assemble.

Thanks for all the help!

P.S. We swapped to motor # 3 the day we left for the track. Motor # 4 was swapped in on Friday night after the practice day. We won "Heroic Fix".