russell-t

I am going through my first ever engine teardown project. MY 215 V8 was

making loud valve train noises,and decided a cam change was in order.

Removed the heads to get them checked at a machine shop,and saw

this strange looking damage. Cleaned carbon from #7 and saw the pock

marks on the piston in the 1st picture. The other 2 pictures are of pistons

#3,and #5 before cleaning them. All of the pistons are showing some type

of pockmark damage,but none as extreme as #7. What has happened here

that would cause this type of damage?

Rickman48

I would say that motor sat for a few years, and the rust got at it!
What I'd be more concerned with are the marks around the edge of the pistons!
The pics look like they hit the head - and they distorted the top of the piston!!
I hope you're taking it all the way down, as there's more amiss than valve noise!!

svnt442

I agree that it looks like rust, but would they really use cast iron pistons in an aluminum engine?

Allan R

Did this engine have a head gasket go on it? Pitting like that I've only seen on rusted items. Even my 455 I tore apart this summer didn't have damage like that on the pistons, although it had a ton of rust in the block. That damage almost looks like the piston was starting to disintigrate. That's why I asked bout the head gasket leak or overheat?

BTW, what does the other bank of pistons look like? Same or good?

oldcutlass

The rust was like said above from an engine that probably sat at some point in its life. I too am concerned about the marks on the outer face of the pistons.

russell-t

Would water sitting in the cylinder for a long period of time make this kind of pitting

in an aluminum piston?


The engine did have head gaskets on it and was running a week before teardown.

The other bank of pistons does not look as bad,but they still have minor pitting on the

surfaces. I'm taking it to a machine shop to check everything out,and will get some

new pistons in it.

64Rocket

I'm leaning towards detonation. Like this is the high compression engine and regular gas was used. under small loads it was just enough to detonate a little and create hot spots. If it was water siting for period of time the cyl wall would have considerable amount of rust. It does look somewhat like water, it would have sat sometime to pit the piston like that, and rusty cyl walls would be very noticeable. So my thought detonation from today's bad gas or regular gas when hi test is needed. Or both bad gas and small amount of water in the gas.
How long has the car been driven, or has it sat for long periods of time between driving?

Gene

russell-t

To Gene: I bought the car in April 11 from the 3rd owner who said he bought it in

2003. He put approx. 9000 mi. on it during that time. Papers he gave me showed an

engine rebuild at 43,000 mi. No specifics on what was done. Told me the car sat for

long periods between being driven. The car had carb problems that would not allow it

to stay running. Replaced the spark plugs with new Champion plugs from parts store.

Comparing old plugs to the new ones, the electrode on the new ones are longer,

meaning they burn hotter. Timing was set to 10btc.

Your post makes sense to me, as the cylinder walls had no rust damage to them.

Bad gas in the tank, carb not adjusted right, too hot plugs, too much advance, valve

train noise and whatever problems that may cause; makes me think that the pistons

were the victim of ALL these issues combined with a little water. And abuse.

Would lean carb settings would work to cause detonation? Ran engine for long

periods of time after carb rebuild (10 to 15 minutes) then test drove at highway

speeds. Hoping this history can show those who know about this stuff what they

need to tell what has happened here.

allyolds68

Have you ever used ether (starting fluid)? I've seen similar pitting on diesel pistons from ether use

64Rocket

From what you say, it all sounds about right. What does the heads look like? Can't tell by the pic's. if there any marks to show over size pistons. To me it looks like all the did was a re-ring job. Just rings, rod brgs and mains.
I would just whiz-wheel the block and pistons. Blow all the dirt from the top of the piston down to the first ring. Pull a couple of lifters and see what they look like. Replace cam and lifters if there is any cupping of the lifter. Everyone I every worked on had bad lifters. Check for broken valve springs and replace valve stem seals. Finish it up and down the road.
Now if you feel you need to do the whole engine, "Kanter" and "Egge" are maybe the only ones with pistons. They should have everything else or maybe local parts can get some parts. Good luck.

Gene

russell-t

to allyolds68:

I never used starting fluid on this engine, but it's possible the previous owner did

seeing he was having problems starting it due to carb problems.

To Gene:

Have taken the engine to the machine shop,and now will be suffering high anxiety

till I hear what the TOTAL amount of cash will be. After seeing this damage I've

decided to have everything checked out. Pay me now, or pay me later.

Many thanks to all of you who have replied to my post. Helped me come to a

decision on what to do.

Russell-t

Rickman48

I know that motor wasn't the 'peppiest', back in the day - had a '62 Special wagon as a DD for a while.
Maybe someone tried some 'NITRO' in it!!

russell-t

At this moment the block and heads have been gone through by the shop

and an explanation of what happened has been revealed to me.

The pockmarked pistons are a result of antifreeze from a head gasket leak

or other problem sitting in the cylinder for a long time before the 1st rebuild.

When breaking down the bottom they discovered thread marks on the crank

from careless removal of the pistons to hone the cylinders and change the

rings. The block and heads are now back together and I'm now waiting for

them to break it in.

Allan R

So I was right.

rustyroger

I've seen a lot of similar damage on Rover v8 engines, essentially the same engine.

Nearly always caused by not keeping the antifreeze up to strength leading to electrolytic erosion, the first symptom normally being a blown head gasket.

I'd have the block and heads very carefully checked for this before you start paying machining bills.

Roger.

russell-t

I've had the entire engine rebuilt by a reputable machine shop in my

hometown.They replaced all the pistons and bearings,redid valves and

valve seals,camshaft,timing chain and gears,and oil pump. Tested it on

an engine run-in stand before giving it back to me. It's back in the car

and I'm now sorting thru all things involved to get it to run right.

Thanks to all of you for your input on this post.

Russell-t