Intake cam starved of oil, catastrophic failure.
01-01-2012, 05:22 AM
#11
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Guys...the camwheel bolt coming loose was the cause. The OP even stated he found it loose. The camwheel is pressure fed. Once that bolt comes lose, all head pressure is lost through the port in the cylinder head behind the camwheel.
So the car I have sitting here had the same issue. The head has slight damage, but not enough to change the position of the camwheel. So the head remained in plalce. I replaced the upper and lower cam caps (this must be had as a 10 piece matched set) 2 camshafts, camwheel bot and camwheel. I RE-USED the VTEC rocker assys, as my inspection of them deemed them healty.
Car fired up and ran perfect. Took it down the road, no VTEC. Further inspection revealed the thrust bearing in the engine is shot. I don't know if the two problems are related. Check your crankshaft end play with a dial indicator...this will help both of us
The engine is otherwise unharmed. Starts up quiet and runs nicely.
So the car I have sitting here had the same issue. The head has slight damage, but not enough to change the position of the camwheel. So the head remained in plalce. I replaced the upper and lower cam caps (this must be had as a 10 piece matched set) 2 camshafts, camwheel bot and camwheel. I RE-USED the VTEC rocker assys, as my inspection of them deemed them healty.
Car fired up and ran perfect. Took it down the road, no VTEC. Further inspection revealed the thrust bearing in the engine is shot. I don't know if the two problems are related. Check your crankshaft end play with a dial indicator...this will help both of us
The engine is otherwise unharmed. Starts up quiet and runs nicely.
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Charper732 (10-12-2018)
01-01-2012, 05:28 AM
#12
Moderator
If it isn't as Billman250 described it could be a plugged oil passage too. Judging by the varnish on the top end you may have some build up or sludge that affected the oil passageways. It could also be some wear metal from other parts failing and plugging the oil passageways.
. That is cooked engine oil. The cams turn with no oil, and become hot enough to MELT the cam towers. The cams I have here are BLUE. I figure this happened over the course 5-50 miles.Trust me. The loose camwheel bolt is the cause.
01-01-2012, 05:33 AM
#13
Moderator
I also see some of your cam tower bolts had to come out with the valve cover. This happened to this car here as well. The cam caps melt so much, the bolts loose all torque. When you turn the valve cover bolts, the cam tower bolts come out with them.
01-09-2012, 12:29 PM
#14
Thread Starter
Originally Posted by Utah S2K' timestamp='1325374225' post='21276366
Currently collecting data as most run 10-30 but Manual says 5-30. Oil orifices on the F-20 C are comparatively small.
Utah
Utah
IOW: oil was not the cause of this.
The varnish is a typical sign of years of dino use.
Varnish settles on high temp & low oil pressure & flow area's, not in oil passages.
We should not use the OP's misfortune to promote 0W or 5W oils.
This has nothing to do with oil.
OP: do you remember seeing the oil pressure warning light at all?
The loss of oil pressure was probably low enough to not trip this light but high enough to cause this damage.
The darker color of the varnish could also mean it happened instantly instead of a slow leak over a longer time.
Even in a couple of miles are a LOT of revs, and revs without oil means lots of heat.
Still my question remains,would I be safe swapping the cam caps/towers and cams (as a full matched set), and be good to go, assuming no other damage is found after the removal of those?
01-09-2012, 12:35 PM
#15
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01-09-2012, 02:47 PM
#16
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Checking the bolt is a fantastic idea.
Yes you could change the needed caps and parts and be good to go. As long as the head is not damaged where the camwheel sits.
Yes you could change the needed caps and parts and be good to go. As long as the head is not damaged where the camwheel sits.
01-09-2012, 07:48 PM
#17
If it isn't as Billman250 described it could be a plugged oil passage too. Judging by the varnish on the top end you may have some build up or sludge that affected the oil passageways. It could also be some wear metal from other parts failing and plugging the oil passageways.
01-10-2012, 02:43 AM
#18
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Bill id suggest you replace the cam chain as well. (though i know you now have a deeper issue to resolve) And to anyone else who has this issue. The amount of strain that was placed on that cam chain to turn those cams at that temp, the chain is now toast.
This is good info though. *takes notes*
This is good info though. *takes notes*
01-10-2012, 03:59 AM
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01-15-2012, 12:00 PM
#20
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I am about to start pulling the head today. Rather than just swap the towers, cams and caps i'm gonna replace the head and probably freshen up the bottom end while i'm at it, since I don't trust that there may or may NOT be metal slivers throughout the engine now. I'll take a look at the thrust bearing for you guys as well and update you on that later. I'm leaving for some military training on tuesday and wont be back til Feb so I won't have time to pull the whole engine out til then, unless a miracle happens and I can pull it out tomorrow Thanks for all the help thus far.
Thanks for all the help thus far.