454 Head back on engine started #7 piston noise

[trop-a-cal]

Now with full compression on both heads the 43,000 mile 1997 454 vortec has the same noise that it had prior to it shutting down completely. The noise was checked by removing spark plug wire and hearing the noise change. So off comes the pan and a check of the bushing on the piston for signs of it spun or a piece of the distribution worm gear stuck in the oil intake at the bottom center of the rod cap. This noise occurred after a slight ticking started back in New Jersey in September. It progressed to a knock South Carolina. It was preceded by a pinging in New Jersey, just after a 55 gallon fill up. That pinging we think was the antifreeze in the 3 and 5 cylinders just in front of the 7 on the right bank. It caused the distributor gear to grind on one side and perhaps drop some metal down to the pan where it got hung up in the #7 bushing as it was dropping down the oil throat of the rear mounted distributor which is just above the # 7 piston. We are going to check all piston bushings and torque on the piston caps when pan is off. All metal and other particles will be cleaned from the pan and the oil pump intake will be checked for metal stuck in the screen, which pumps to the upper end of the engine. So far with two tows, parts, and labor we are at $2,300. Not close to the opinion of replacing the entire engine at $8,500. No problem with down time as it is a mostly summer driven RV.

[trop-a-cal]

Called shop and they are backed up with work and I'm getting better pricing with being fill in work as it's not needed until late Spring.

[okhmbldr]

If he took his hearing aids out he wouldn't hear a thing, and then drive it another 50,000 miles.
When we're going down the road, my wife says "do you hear that noise?", I reply "What noise", and just keep driving!

[willald]

C-Leigh Racing wrote:
One thing he will know in the end, with as much of a job as that 454 engine has to do, he would be way ahead of the game just replacing the engine with new, than trying to patch what he has up.
Now if he did like Dave & went the 502 route, he would probably be one happy camper afterwards.

Haha, its always easy to recommend the most expensive route (crate motor), when its not your $$ being spent.

I wonder how many would see this issue quite a bit differently than posted here, if the cost for the repair (or replacement) was coming out of THEIR wallet. 🙂

Will

[C-Leigh_Racing]

One thing he will know in the end, with as much of a job as that 454 engine has to do, he would be way ahead of the game just replacing the engine with new, than trying to patch what he has up.
Now if he did like Dave & went the 502 route, he would probably be one happy camper afterwards.
Neil

[Daveinet]

Or wrist pin.

[JimM68]

connecting rod bearings typically knock "at the top"
If you rev the engine briefly, the rod will clatter near the peak of the rpms and a lil on the downhill side.

A connecting rod knock = excessive clearance between the rod bearing and the crankshaft. the rod bearing may be worn to copper or worse, and the crank may be worn as well.

A "spun bearing" = the bearing shell has come loose in the rod, and moved. This will ALWAYS damage the crank.

[PaulJ2]

My experience has been--A knock when cold but quiets down when warm is piston related. A double knock sound is usually a piston pin problem. A knock that quiets with the plug wire removed is usually a rod bearing (too much clearance).
Keep us posted what you find.

[FunTwoDrv]

No holes in the rod caps...Oil enters the rod journals via the crankshaft. The hydralic question could certainly have some impact. (No pun intended.)
On another thought, it isn't unusual to hear a little piston slap at startup on some of these engines.
Looking forward to what you find once the pan is off.

Good luck,
Gary

[topflite51]

Back in the good ol' days of automotive repairs, repairs like this were performed all the time. Some worked and some didn't. Good luck!

[trop-a-cal]

Yes spark plug wire was removed, no exhaust gasket is not problem, the pinging preceded the tick which became knock after 1000 miles. Liquid does expand into vapor, it also contracts, we shall see what exactly the problem is with pan drop. Yes the dizzy probably was worn and had little to do with end problem, but did cause performance problem. Worms are a type of gear, bushing, bearings, one is static, other is dynamic,( moves). A worn bearing rubbing a bushing, is what I'm referring to. Holes in rod caps take on oil and release heat from rod cap, does the 7400 Gen VI L 29 have them ?

[PaulJ2]

If I read this right, water got into the #3&5 cylinders but the knock is in #7 cylinder? A heavy knock, or a light ticking? And it changes with the plug wire pulled? Sure it's not a stupid exhaust manifold leak that sounds like a knock?
Does engine warm or cold make any difference? Just curious and trying to help here.

[Daveinet]

Hydrolock an engine, and now it knocks. I would be thinking bent rod. Something must give, as liquid can not compress. If that resulted in noise afterword, something is bent. I don't think the dizzy is an issue, worm gears are known to wear, so it very well could be that was bad long before this incident. Your noise is probably side to side movement, not up and down. Just curious if you have pulled individual spark wire wires while it is running? Removing the load may help isolate the location of the problem.

[trop-a-cal]

That's what we do, worry, about unresolved issues. I resolve by using most probable subjective thought followed by objective fact which is it has only 43K, and full power, just a little knock at idle. So we shall see, it could be a problem, but I'm willing to wait and see.

[BillofPA]

It seems to me there are a lot of "MAYBE this happened or it MIGHT have been that and so it SHOULD be OK because it PROBABLY, etc.,etc". Man, I would be a nervous wreck after the repair to go on a trip with it.