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| twr7cx |
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Why didn't ford use cam bearings in the SOHC i6?
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| Andrew J |
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Because the aluminium being soft provides a good enough surface? What suprised me was that there is nothing but the lifter holding the cam in place. I was expecting the rocker arm supports to play some role in keeping the cam in position
_________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?
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| Disco Frank |
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wtf the cam and ally head are teh bearings
also the rocker gear hold the cam in place not the lifter
_________________ RIP SCOTT |
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| stockstandard |
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The rocker arms hold the cam in place, and they are held in place by the lifters.
edit: and of course the timing chain holds it down pretty good 2
_________________ Stoke me a clipper, I'll be back for Christmas |
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| twr7cx |
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Disco Frank wrote: wtf the cam and ally head are teh bearings
also the rocker gear hold the cam in place not the lifter Which is exactly my point, since no removable bearings were used if for any reason either gets damaged means a replacement head and/or rocker gear! |
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| stockstandard |
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have you ever seen a damaged cam/head though? i havent even heard of it happeneing
im just glad its 1 less set of bearings I have to buy when I rebuild an engine.
_________________ Stoke me a clipper, I'll be back for Christmas |
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| smiley235 |
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saving costs I could only imagine. they probably figured that by the time that kind of damage occurs, there's gonna be know chance off left over warranty.
_________________ 178.3 rwkw
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| twr7cx |
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stockstandard wrote: have you ever seen a damaged cam/head though? i havent even heard of it happeneing
unlikely to damage the cam as there bloody hard, but the head is very soft, so that's obviously gioing to get damaged. Yes I have seen a 94DT (ie EF XR6/Tickford head) with scratchs were the cam rolls in the head. |
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| Walker |
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twr7cx wrote: stockstandard wrote: have you ever seen a damaged cam/head though? i havent even heard of it happeneing unlikely to damage the cam as there bloody hard, but the head is very soft, so that's obviously gioing to get damaged. Yes I have seen a 94DT (ie EF XR6/Tickford head) with scratchs were the cam rolls in the head. Of course it can scratch, i've done a s**t of different alloy OHC engines and haven't seen one with bearings yet. And the rocker gear "DOES NOT" hold the cam down. Look in the tunnel of the rocker gear next time you remove it, it's a rough casting and doesn't touch the top of the cam... The 4.0 is definately the first and only i have seen that doesn't touch the cam. |
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| justfordima |
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I was just about to point that out Walker, the cam doesn't run in the rocker gear, the rocker gear just sits on top of it all.. not touching. And the cam rolls in the head, on oil..
The fact is, it works, and works well.. Cheers
_________________ ;++JustForDimSim++;
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| smiley235 |
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so basically, if you run out of oil, your gonna cause some serious head dmg.
_________________ 178.3 rwkw
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| glenneaux |
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Yeah but if you run out of oil everythings gonna be hurting so thats a given!
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| Rapier |
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well yep this all makes sense considering the head twr7cx has seen is off his own car that used to be mine, and the oil pump shat itself and seazed bottom end hence why i sold the head off it.
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
i have only seen one alloy head that also runs a removable bearing.
it an old SHOC mazda 4cyl and since we all want to put 5c on what holds the cam in. it's the downward pressure from the rollers on top of the cam. also damage to the bearing surface can be fixed if need be. By welding the the all the bearing surfaces and line honing back to spec. minor scratches are not a problem |
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| The Dog |
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You beat me to the punch Tickford.
I have repaired these and VL *shudders* heads in the cam tunnel. Simple as welding them up and line boring. About 5 hours work including pressure testing. And yes it is the rollers that hold the cam in which when you think about it means the valve spring pressure actually holds the cam down. I was a bit taken aback when I saw this for this first time too!!! 
_________________ You'll ride a black tornado across the western sky
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