308gt4 engine noise

Wow... I've seen a lot... Never that though..

If you don't need to go up in size on the Pistons, we've got a set of std JE 10:1 on the shelf. Recent build needed custom and JE goofed and made a stock set. 10wks later we got the ones we needed. Kept the stock set on hand in case somebody needs a set. Lead times on engine internals is crazy right now. Gudgeon pin is 0.748" though.

Engine looks clean... That's a plus.

 

That's for sure. But I'm confused how the reversed head gasket caused damage. Oil supply holes weren't blocked, just the return. For sure coolant passages weren't right. But did that lead to damage?

 

Pete- thanks for sharing and posting the pictures, bummer regarding initial expectations, but sounds like it’ll be great when you’re done.

Just to clarify, it looks like the first picture posted is of the right (rear) bank with the head gasket correctly installed, and the second pic appears to be with the head gasket reversed… Is this correct? v/r Paul

 

The dowel pins supply the oil, they act as a needle valve of sorts. The gasket would have to be rotated 180*, flipping it won't work as the dowel pins holes are not in all 4 corners.

Very surprised the oil/water didn't mix and make milkshakes. But the oil return blocked would lead to severely reduced oil flow, that'll wipe bearings and wrist pins real quick. Must've been puking oil out the breather, surprised it didn't push out seals on the cams. Couldn't run very long with blocked return.

 

Sorry if I'm being slow. What's the mechanism for this? All nine quarts won't fit in the cam cover. Why would there be reduced flow?

 

Since the return was blocked wouldn't it lead to low dipstick readings and subsequently overfilling?

 

Oil at pressure is fed to both the mains and the cam journals. From there it gravity feeds back to the sump. The cylinder heads have no other return path then those 2 drain back holes. If they are blocked, the head will fill until pressure builds and pops a seal. Flow to the heads is not huge, those dowel pins control the rate. Would take some time to fill up. It would eventually happen though. 4k miles should have been suffecient though, I'd be looking at oil passage flow in the heads as well.

The galled gudgeon pin is proof that oil starvation was occurring. It really would have gotten worse with time. I'd check the cam journals for scoring.

Yrs ago we got an engine in that a previous shop had the cylinder heads glass beaded to clean up... Yeah bad idea... Passages gummed up with fine glass abrasion material. That was not fun fixing.

 

Here's the 328 oil diagram in color, should be similar to the GT4.

https://www.***********.com/attachments/328-1988-us-481-87_nopw-54-lubrication-system-rotated-jpg.34136/

the **** is f....life

GT4 B/W:

https://static-data2.manualslib.com//pdf2/46/4526/452565-ferrari/images/308_gt4_workshop_manual_44_bg.jpg

 

Wouldn't you get some flow back through the dowels when the car was off?

 

Not really no, they are pressure feed ports to the cam journal, very tight tolerance. Really wouldn't want flow to revert thru those as it would mean a "dry" start on the cam journals after every shutdown.

 

Right, and under normal circumstances you wouldn't have any back pressure, but with the heads full wouldn't you have sufficient push back to drain some of the oil out of the heads?

4k miles and 8 years is a long time. Don't know about the maintenance after the rebuild, but it's strange no one noticed the missing quarts.

 

The oil looks pretty clean.

 

It is indeed strange, at a certain point the oil is going to get sucked into the breather port. Then it'll be burning it.

Doh... There is a return path to the sump for the 1-4 Bank.. port between cams feeds to the mid plate (later qv it's the exhaust cam end plate). It's a path, not ideal and will still leave the head filled with oil.

If it was the 5-8 Bank... It would have built up till it pushed out the breather hose.

 

I'm not saying that wrist pin isn't knackered, I'm just asking how the head gasket could have caused it. I think the two aren't related.

 

Here's my take based on rebuilding more of these engines then I recall.
The wrist pin is "splash" oiled. The engine block sits atop the gearbox. Now what's interesting here is the oil return layout. Bank 5-8 feeds right into the sump, Bank 1-4 drops onto a partial shelf before falling the rest of the way into the sump. That means that oil return from bank 1-4 will be closest to the crankshaft and windage tray. There's also the the oil return via the mid plate that feeds at the back of the crankshaft.

Blocking the return to the oil sump on 1-4 would stop the majority of oil "splash" that occurs before returning to the sump.

And there's the issue of reduced capacity since the head is filling up vs returning.

 

Oil starvation was most likely to happen on the first oil change after the rebuild, as subsequent oil changes compensated for the quantity in the head.

Was the first rebuild elective?

 

Nice looking mechanicals!