What happened?
Junior User
Joined: Aug 2014
Posts: 98
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on my 68 f250/360 c.i. when driving on the highway.. the engine went from v8 to a v4 instantly. limped back to the shop........ pulled valve covers and found the rear 4 cylinders were not working!!! Broke down the engine and found a broken camshaft and a crack at the valley. needless to say total rebuild short block.
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Joined: Jun 2018
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Logistics Pro
Joined: Mar 2009
Posts: 4,828
Likes: 592
From: Minnesota
Wow, I had a 360 that did that while warming up one day. Destroyed a rare rear sump FE oil pan in the process. Block was unusable as the cam section fell down and the crank slammed it into the side of the block.
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Mountain Pass
Joined: Jul 2010
Posts: 122
Likes: 5
Dang -- what caused 3/4 of your camshaft to evaporate?
There are a lot articles out there opinionating about today's oils not having zinc or phosphate in them because those items can damage a catalytic convertor and therefore the additives were phased out over time. But as the story goes, older engines especially those with flat tappet cams become susceptible to camshaft failure since there isnt a strong enough oil film between the cam and the lifter at cold startup, which the zinc and phosphate supposedly provide. Here are a few articles -- even Hemmings weighed in:
https://www.hemmings.com/stories/2012/09/21/hemmings-introduces-zinc-rich-motor-oil-formulated-specifically-for-classic-cars
https://www.hagerty.com/media/archived/classic-oil/
https://www.bellperformance.com/blog/tips-for-choosing-the-best-motor-oil-for-your-classic-car
https://blog.amsoil.com/do-older-vehicles-need-high-zinc-motor-oil/
https://lucasoil.com/products/hot-ro...w-30-motor-oil
https://inrccca.org/product/classic-car-motor-oil/
There are a lot articles out there opinionating about today's oils not having zinc or phosphate in them because those items can damage a catalytic convertor and therefore the additives were phased out over time. But as the story goes, older engines especially those with flat tappet cams become susceptible to camshaft failure since there isnt a strong enough oil film between the cam and the lifter at cold startup, which the zinc and phosphate supposedly provide. Here are a few articles -- even Hemmings weighed in:
https://www.hemmings.com/stories/2012/09/21/hemmings-introduces-zinc-rich-motor-oil-formulated-specifically-for-classic-cars
https://www.hagerty.com/media/archived/classic-oil/
https://www.bellperformance.com/blog/tips-for-choosing-the-best-motor-oil-for-your-classic-car
https://blog.amsoil.com/do-older-vehicles-need-high-zinc-motor-oil/
https://lucasoil.com/products/hot-ro...w-30-motor-oil
https://inrccca.org/product/classic-car-motor-oil/
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Tuned
Joined: May 2017
Posts: 414
Likes: 40
From: C-town,MD
I think it was just a weak cam. I used the oil with the higher zinc content. The cam bearings looked better than I expected. The cam probably only had 5 thousand miles on it. Maybe not even that.
Cargo Master
Joined: Oct 2011
Posts: 2,233
Likes: 297
From: Kenner,La.
Cam breakage
It may have been dropped sometime between the manufacture and when you got it.
I had a brand new 429 PI cam in the tube that I bought from Ford and had squirreled away for future use and when I opened it I had a 2 piece cam!
I had a brand new 429 PI cam in the tube that I bought from Ford and had squirreled away for future use and when I opened it I had a 2 piece cam!
Tuned
Joined: May 2015
Posts: 413
Likes: 52
Take a close-up picture of the fracture itself from the end. That will often tell you the story of where the problem initiated and how long it took to break. A sudden fracture looks very different than the propagation of a small crack or manufacturer's defect.
Yer killing me Moose