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Cam Wear


240260280z

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OK, thanks!

I'll change the rocker and see how it goes. All the others look great.

I'll take pics of the other cam later this week. It is ~ 600km away right now. It "spectacularly failed" and looks mighty ugly.... the young'ns here may not be able to sleep after seeing it.

Edited by Blue
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Same here.....Isky recommends it (VR1). Also, do you fill your oil pumps with oil to prime them before starting a new motor? It's especially critical with a new camshaft. I also crank it w/o the coil wire attached and w/o plugs till I see the oil needle move (you have to look close because it barely moves at that low rpm).

Edited by Diseazd
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New rocker is in. Let's see what happens.

Yeah, I prime the pump like an IV and pour lots of oil over the valve train when first cranking (starter only) until I see oil coming out of the oil holes in the cam/oil bar....then I fire it up.

btw on this car, after sitting over night, it takes 51 turns of the cam (starter driven only) before significant oil comes out of the holes. Is this normal?

Edited by Blue
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Some devil's advocate stuff, and channeling your own intuition. Oil pressure results from lack of flow, the pump pushing against obstruction. You noted very good oil pressure in the first post, but are seeing 51 camshaft turns (102 crankshaft) before oil flows, plus your observation that flow seemed low, just by eye. Seems like you might have some obstruction in the channel to the head. It's small already and wouldn't take much to block it. Some people open it up to get more flow, especially if they're running a spray bar and an internally oiled cam.

That another thing that's common to both camshafts, besides the springs.

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Yes I was thinking that however there is good flow, just delayed flow. The head and block were cleaned by the shop and oil plugs removed in the block to get the main galley.

I am guessing that when the motor is off, oil in the cam and in the head drain back into the pan through the main bearings and oilers in the block.

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Few things come to mind looking at all the evidence so far.

1. Since the cam bearings are supplied by the same oil path as the lobe holes, I'de be curious to look at the #1 cam tower bearing/cam bearing and see if it looks any different (ie worse) than the other four.

2. And along the same lines as #1, judging by the way oil gets to those lobe holes, if its only #1 not getting oil, then its a plug/restriction right there in that hole in that lobe, or #2 would be having problems too, as they share a common supply bore down the length of that cam. Therefore, I think, if you see the same oil volume coming out of #1 lobe as #2 in just-crank condition, then its not a lack of oil supply to just #1 that's causing this.

2. After it runs for few minutes, is there noticably less oil sitting around/on/over that lobe than any of the others? There is such a flurry of oil flying around under there under running its hard to imagine you would able to tell any significant difference. Also says that oil can even get #1 just by splash chance and keep it alive for more 1500 miles...

3. A close up magnified view of the first pic in post #10 of the rocker pad worst wear area is showing breakout and fracturing. I'm thinking the hardening of that particular rocker surface is not up to snuff and it gave out.

4. Also note the wear/damage is not even across that rocker surface, but is concentrated in ~ 25% of the width. Tells me the rocker pad is not flat across its width or is not hardened evenly.

Just some thoughts. hope the rocker switch solves the mystery.

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Thanks Jim,

I checked and all cam lobes are flowing a lot. I could actually see the oil flow start in the middle then move out to the ends. Each lobe behaves the same. I also ran a wire in through the first few lobe holes to see if it stuck or came out with debris....it just had clean oil.

I agree with you that it looks like the rocker is the problem.

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