Originally Posted By: Max_Wander
What I do appreciate is the engineer's kindness of an over-built production engine.
Well Max, then you should positively ADORE engines like the Ford 460, Mopar 440, and Olds 350. They just don't come any more "over-engineered" than those old brutes.
The fact that properly breaking in a flat-tappet cam is essential is no different than the "special procedures" (iow, no big deal) for torquing an aluminum head on an open-deck aluminum block in an import engine. Once that cam is broken in, those old engines will run FOR EVER. Even with pretty poor treatment. I once drove a happily purring Mopar 383 in my garage for a valve cover gasket change, and discovered that 3 cylinder head bolts were loose (and don't blame the factory, a shop had done some work on it about 5 years before and screwed up). Neither head gasket was hurt because the heads and block are so d*mn stout, I just torqued them down again and it ran on for many more years.
As I said in another post, I'll wager that the 460 cam or the lifter in the other forum was flawed. Otherwise more than one lobe would have been wiped. As the demand for flat tappet cams has gone down, I think the quality has really plummeted as well. It only takes one tiny flaw in the surface hardening of a flat tappet cam or lifter to grow into an area that lets the wear pattern quickly chew into the softer steel below the surface. Cam makers are out-sourcing more and more, and now its coming back to bite them. It will happen with rollers, too. Bet on it. :-(
Quote:
Perhaps I can't pin this one on FORD (although I don't find cam in block designs to lubricate as well as a OHC where each lobe gets dipped in oil on each revolution)
"Dipped" in oil is nothing. Most hydraulic lifter cam-in-block engines have a full pressure feed to each lifter bore, usually by each lifter bore broaching into the main left or right oil gallery. Each lifter has a circumferential oil groove that lubes the entire lifter/bore interface, and the oil is then sprayed out of the lifter/bore clearance directly onto the cam lobe face as it rotates under the lifter. On top of that (at least in Mopars) all the oil that returns from the overhead is channeled onto the cam as it collects in the lifter valley on the way back to the sump. Finally, many new-style lifters additionally have a centered high-pressure feed hole right in the middle of the contact face. There's FAR more cam lubrication there than on most OHC designs I've seen.
I'm not anti-OHC (I currently own one and just sold another with nearly 260,000 trouble-free miles), but cam-in-block still has a lot of advantages. Otherwise engines like the GM LS series (seen the specs on a Z06 or ZR1 latel?!?) and the modern Mopar Hemi wouldn't turn in the numbers like they do. And its not just raw horsepower- you have to fight REALLY hard (see Northstar :-/) to package an OHC engine of a given power in the same size package as a pushrod engine of the same power.
What I do appreciate is the engineer's kindness of an over-built production engine.
Well Max, then you should positively ADORE engines like the Ford 460, Mopar 440, and Olds 350. They just don't come any more "over-engineered" than those old brutes.
The fact that properly breaking in a flat-tappet cam is essential is no different than the "special procedures" (iow, no big deal) for torquing an aluminum head on an open-deck aluminum block in an import engine. Once that cam is broken in, those old engines will run FOR EVER. Even with pretty poor treatment. I once drove a happily purring Mopar 383 in my garage for a valve cover gasket change, and discovered that 3 cylinder head bolts were loose (and don't blame the factory, a shop had done some work on it about 5 years before and screwed up). Neither head gasket was hurt because the heads and block are so d*mn stout, I just torqued them down again and it ran on for many more years.
As I said in another post, I'll wager that the 460 cam or the lifter in the other forum was flawed. Otherwise more than one lobe would have been wiped. As the demand for flat tappet cams has gone down, I think the quality has really plummeted as well. It only takes one tiny flaw in the surface hardening of a flat tappet cam or lifter to grow into an area that lets the wear pattern quickly chew into the softer steel below the surface. Cam makers are out-sourcing more and more, and now its coming back to bite them. It will happen with rollers, too. Bet on it. :-(
Quote:
Perhaps I can't pin this one on FORD (although I don't find cam in block designs to lubricate as well as a OHC where each lobe gets dipped in oil on each revolution)
"Dipped" in oil is nothing. Most hydraulic lifter cam-in-block engines have a full pressure feed to each lifter bore, usually by each lifter bore broaching into the main left or right oil gallery. Each lifter has a circumferential oil groove that lubes the entire lifter/bore interface, and the oil is then sprayed out of the lifter/bore clearance directly onto the cam lobe face as it rotates under the lifter. On top of that (at least in Mopars) all the oil that returns from the overhead is channeled onto the cam as it collects in the lifter valley on the way back to the sump. Finally, many new-style lifters additionally have a centered high-pressure feed hole right in the middle of the contact face. There's FAR more cam lubrication there than on most OHC designs I've seen.
I'm not anti-OHC (I currently own one and just sold another with nearly 260,000 trouble-free miles), but cam-in-block still has a lot of advantages. Otherwise engines like the GM LS series (seen the specs on a Z06 or ZR1 latel?!?) and the modern Mopar Hemi wouldn't turn in the numbers like they do. And its not just raw horsepower- you have to fight REALLY hard (see Northstar :-/) to package an OHC engine of a given power in the same size package as a pushrod engine of the same power.
I've yet to see a stock rod break, theyre forged & HUGE (nearly twice the size of SR20DET rod). Ford also used the F blocks (in the probe/telstar/courier/ranger international) since the mid 80s. Glad to see the engineers knew a good thing and just updated it. I got worried when Mazda went to the 2.0L FS (Protege engine) as the base engine, the FS isnt a real F engine, it's more of an overgrown BP, glad it's gone! Put short, the L engine is really just an updated F engine with VVT, Al block, reverse flow head, timing chain, balance shaft, and DI. Which brings me to the point that a lot of Ford's successes now are blatently based on their affiliates work (Fusion, Edge, Duratec engines, DI technology, chassis sharing etc), and they have definatly cashed in on the little known engineering powerhouses like Mazda. Ford of America in this day seems like more of an engineering brokerage firm to me, Ford of Europe does most of the Ford engineering, you know except for the trucks and the modulars.
