I went by a Ford Dealer today while I was out and about which happens to be in another town. I was checking out his 08' inventory and happened to see an 08' Screw with the 4.6 2v motor. I had the guy get the key and to my amazement, when he opened the hood there sat the 4.6 2v with not only a plastic intake manifold but also plastic valve covers. What the h-ll is Ford doing here? Looked very similar to Nissan's 5.6 Endurance engine. I can see using a plastic intake manifold but going to plastic valve covers. I can't see anything good by using plastic valve covers. Am I wrong? Is this plastic as durable as the metal covers they have used since day one????? The darn engine looked like a plastic engine for crying out loud.

 

It's only going to be a matter of time before we have plastic heads and blocks.

 

my 97 4.6L has plastic valve covers. but its got an alumnium intake. yeah soon everything will be plastic.. ITS SO FANTASTIC!!!!

 

Dang it Shifty_85, You are absolutely right!!!!!:o I had to go out and check my 04' 4.6 to see and you are correct. It only looks metal. Why they choose to put an aluminum intake and plastic valve covers is beyond me. I could have gone without knowing though. LOL. Too bad though now the 4.6 has both the intake and covers in plastic.
Must be OK b/c these 4.6 engines have a history of being reliable. Funny my 5.4 3v has metal covers but plastic intake(or at least it looks metal) yet it doesn't have as good a history as the 4.6. I'm sure both pieces on this engine will be plastic soon as well.

 

The plastic/composite intakes and valvecovers dissapate heat better. So even though they are plastic, the perform better in high heat than the aluminium heatsinks that used to be.

 

I wonder how long it will take for the manufacturers to make everything mostly out of plastics and carbon fiber type materials for engine blocks and such with ceramic liners for cylinders. Some of the new compounds of plastic are quite strong.

 

Well chevrolet was, key word, working on an all carbon fiber v8. Word was it made 400hp and around the same torque, it worked great on the engine dyno, but once the trans was bolted up, all the torque caused the engine block to crack around the bellhousing, and they couldn't get a design to withstand the torque.

 

Plastic may have its advantages, but you can't port plastic pieces too well...

 

I don't think that's quite rite. Plastic is usually a good insulator. It doesn't tranfer or dissapate heat well. The plastic intake should stay cooler than aluminum, since aluminum transfers/conducts the heat from the heads into the intake.

 

I agree. Problem I see isn't short term tolerance but rather long term hot to cold, cold to hot. I can't see plastic being able to tolerate this for 8-10 years without cracking and leaking, esp the valve covers. I mean, look at the darn plastic window regulator pieces that are cracking and failing after just a few months to years in Ford's vehicles, not just the F150. Some things need to be metal for longevity and I would think valve covers would be one of them.