Is the 460 an interference engine???
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Tuned
Joined: Oct 2020
Posts: 256
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From: San Jose, CA
That list is far from complete especially when it comes to older engines, a 1972 472 Cadillac can bend the valves if the timing chain goes out.
I don't know if a stock 460 will hit because I can't think of one 460 that I ever had come in with a timing chain problem but it seems very likely.
I don't know if a stock 460 will hit because I can't think of one 460 that I ever had come in with a timing chain problem but it seems very likely.
Cargo Master
Joined: Oct 2020
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When you tear into it maybe the first thing to do would be to take off the intake and the valvetrain. Then just make up a plate and vacuum check the intake valves or put air in each cylinder. If it doesn't blow past the valve you're golden.
Please post your results.
Please post your results.
Fleet Mechanic
Joined: Sep 2003
Posts: 1,716
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I don't think the 460 was an interference engine, at least not originally. The early high-compression 460 came out in the 1968 1/2 Lincoln, and in 10.5:1 form ran up through the 1971 Lincoln model year. Compression took a big dive after that. Anyway, the big bugaboo about aged early high-compression 460s was the nylon-overmolded cam sprocket. The nylon would wear with miles and age, and was known to collect and plug up the oil pickup screen, which was about the only killer of the engine. I dutifully pulled the timing covers on my two, and they were both pristine! I went ahead and changed sprockets and chains anyway. I never heard ANY concern that when they got bad enough to slip, that disaster would result. No, it was all about oil pickup plugging.
So unless the later low-compression bigger-chamber design also made a significant change to the overall valving scheme, I wouldn't think interference would be an issue.
So unless the later low-compression bigger-chamber design also made a significant change to the overall valving scheme, I wouldn't think interference would be an issue.
Cargo Master
Joined: Oct 2020
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Cargo Master
Joined: Oct 2020
Posts: 2,701
Likes: 798
That's right. Here's two more that I know will hit, Chevy Vortec 350 and Chevy 235 6 cylinder. The Vortec is known to sometimes hang an exhaust valve and they'll get bent every time. A 235 is bad about a stuck intake valve if they sit around and or have bad gasoline in the tank. I'm still not sure about the 460, it does have more than .430 valve lift on the intake side, is the valve relief, deck clearance along with how far the chamber is recessed enough to make it not hit?
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Tuned
Joined: Oct 2020
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From: San Jose, CA
https://itstillruns.com/list-ford-in...s-8042311.html
This list of Ford interference engines from 1981 to 1995 does not include the 7.5 460.
This list of Ford interference engines from 1981 to 1995 does not include the 7.5 460.
Lead Driver
Joined: Feb 2002
Posts: 7,970
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From: Greater Austin, Texas
I've had that happen on an Olds 350 too
With those dished pistons they run? Not buying it. I worked at an Olds dealer in the early 80s and did several, never had any valve damage.
Cargo Master
Joined: Oct 2020
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Tuned
Joined: Oct 2020
Posts: 256
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From: San Jose, CA
The engine actually wasn't running when it went down. The camshaft broke off while cranking. I believe it was broken off because of a water pump bolt stopping the gear from turning. I refreshed the heads recently so the springs are all in good condition.
Hotshot
Joined: Feb 2004
Posts: 10,851
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From: The Shenandoah Valley
Had a cam bolt fall out of a 400 Pontiac once, fell into chain and busted it, only bent 4 intake and 4 exhaust valves.
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Tuned
Joined: Oct 2020
Posts: 256
Likes: 30
From: San Jose, CA
was it a stock engine or was it built that's the thing