TOC

Friend took his 'stang down for a PI conversion (heads, cams, inlet manifolding).
Had a small coolant leak (external..shop fixed a casting defect in a head).
Suddenly he had fluctuating oil pressure, then good. Took it back.

The oil pump was full of plastic shavings. Okay, that happens when the guides and tensioners wear, but vehicle has 44K of analy maintained miles.

Shop pulled it down...chain and guides shot on drivers side.

They fixed it (not yet ready to release it), we had a meeting (I got called in), have the parts.

The rear chain (driver's side US) has numerous (over 1/4) of the forward links broken. The rest have curved wear marks in them. The broken links sawed through the tensioner (not the guide, surprisingly) like a chain saw.
New oil pump, cleaned pickup, cleaned pan, new chains and tensioner kit.

Shop claims that they have seen exactly one other like this, and no idea what caused it.
I can obtain photos if that would help, but it appears the forward chain (passenger side US) had something rubbing the rear chain.

Anyone seen this before, and any ideas?

I searched for this on the forums, maybe not the right words, didn't find anything in half a dozen pages.
If I missed it, sorry..I tried.

Never had any timing chain issues on my Flathead V-8's...ever...
Dave

TOC

swarthyfellow

I have never seen anything like this before, but it looks scary. At least it didn't fully snap. Maybe it was a defective chain to start with? Is there a chance it wasn't getting proper oil? Cam and crank gear Ok?

TOC

44K, only change was heads. You can see from the RH guides that wear was minimal. Less than 200 miles since head replacement. Something isn't right. It looks like something got jammed between chains at crank. Puzzling.

TOC

Over the last several days we have run this past several machine shops, and through several points of contact at Ford.
Nobody has ever seen it, which most likely indicates an operator error at the shop.
Car is repaired, running, and home to owner.
Since we were not present at teardown, we will probably never know the exact sequence of events.

TOC

Here's the latest. Late last week, negotiations were completed, car picked up, driven home. Owner stopped by, asked me what that noise was. I told him to CAREFULLY drive it home and park it...and call the shop.
Wrecker coming to pick it up today.
Rod.
Not out the block, but geez, it's bad.
I'll post what was found later after they yank it.
Al that shredded plastic that plugged the oil pump and filter, probably lifted the internal bypass on the filter and filed the oil galleries and probably the crank ports.
Not good.
Dave

swarthyfellow

So it was fixed and is making noise again?

TOC

Well.....the chains, guides and oil pump were fixed. My concern was the finely ground up plastic/nylon from the guides/tensioners that plugged the oil pump, necessitating replacement of that item, and the possibility of said plastic plugging the oil filter and lifting any internal filter bypass...filling oil galleries and crank with said plastic bits.

Sure enough. 34 miles later, we have one horrendous rod knock. Bad enough not to drive.

Waiting on results of teardown inspection now.

Dave

swarthyfellow

Wow... I wouldn't have driven it at all untill i made sure everything was cleaned out after that.

TOC

Wasn't me call. They assured the owner it was cleaned out.