Thread: f100 - cams are out...

Not looking good...

Ran without oil to me. The aluminum can grip like no other metal except maybe Titanium. Not sure how you would repair the Head casting but someone might. I will check my Yamaha 4 Stroke rebuilder and see what he says.

Heads out. And to me it looks OK!




And Rojo, I see some heads for sale on Ebay, and guess what, their top cam bearing looks same as mine, bad! lol

This is a snapshot of one being sold on eBay. I'd say mine looks better, at a bit better. Doh

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And here's my bad one above.

The other one of my cam bearing below is gooderer:



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Looks like the bearings were turning in their seats. That happens when ran with no oil.

Originally Posted by Barnacle Bill

Looks like the bearings were turning in their seats. That happens when ran with no oil.

These cam bearings are not separately replacable. The whole head would have to spin! lol


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Originally Posted by Barnacle Bill

Looks like the bearings were turning in their seats. That happens when ran with no oil.

[QUOTE=Slab;These cam bearings are not separately replacable. The whole head would have to spin! lol[/QUOTE]

So like a Ford 5.4 3V Triton overhead cam engine the casting is the bearing. Although vertical Cams are used allowing oil to drain there is no combustion heat to melt the aluminum enough to transfer to the steel camshaft. The heat is just not there. That being said those camshaft bearing valleys in the head casting did Gall on the aluminum side. The Ebay castings galled even further. Ford repairs their head castings by Line-Boring the casting with the clamps in place then installs a new camshaft with .010 oversized journals for the repair. Its a one and done, you buy a new casting the next time. I happen to have one of those engines in my Fishin' Expedition. Respectfully speaking the case must be cracked, Crank & Rods checked for low or no oil operation too. Without doing that you may be pulling the head right back off along with the Powerhead. We may be able to find a complete block, I will call Tuesday as my guy is way too busy with oilfield customers on Mondays. I have bought a ton of good Yamaha F250-F300 used parts from him and all were good.

May just be normal wear patterns. I would think that the cam shaft would have galded aluminum stuck to it if it ran without oil.

Originally Posted by DockShootinJack

May just be normal wear patterns. I would think that the cam shaft would have galded aluminum stuck to it if it ran without oil.

Camshaft side looks fine, smooth as silk.