Knock/Rattle update - long
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From: Still under the hood in O
Knock/Rattle update - long
Got the pan back on and truck running. There was no evidence of anything abnormal. Rod and main bearings looked fine. No metal shavings at all on the rotating assembly or in the pan. So a new one piece gasket and oil pump with a Ford Racing intermediate shaft, 5.5 qts. of oil and a Motorcraft filter later I'm back where I started.
Ran truck and I still have a knock/rattle when revved after warm up.
Still couldn't pinpoint where it's coming from. But as it warmed up it started getting blowby on the drivers side bank - pretty bad. After it cooled about 10 min or less I checked the compression again on the #8 cylinder (suspecting a hole in the piston). When I pulled the plug it was soaked with oil. I pulled the plug next to it (#7) - it was very clean as expected because they are new plugs since getting it running. The compression still shows about 122psi in ALL cylinders even when it was still good and warm (same as cold). So I can rule out the hole.
What has been replaced so far;
Cam/lifters/pushrods
ALL sensors
Distributor
Cap/rotor/plugs/wires
Cut the Cat off and gutted the pre-cat
Truck runs great cold. Then when warmed up it idles and drives rough at low speeds and starts knock when revved, but not at idle. Sounds more like a diesel. Getting up to speed is great, no problems at all, hot or cold. All the plugs look good except now the #8 is oil soaked (this is new). I just re-routed the PCV and plugged the port at the back of the manifold. When I put the upper back on I noticed oil in a runner. That's when I re-routed the PCV, so the oil soaked plug could have been caused by this. Right now I don't have a new one so I'll see if it continues to get soaked after drying it.
What to make of it??
Well, what it is not (in my opinion);
Rings - No smoke out the tail pipe
Hole in piston - compression checks good
Blown head gasket - again compression good
Cracked or warped head (or block) compression good and no water in oil and no oil in water
What it could be;
Bent or stuck valve - although compression is good
Valve guide or valve seal - possibly caused by weak springs or bent valve? would explain the oil soaked plug
Wrist pin (However highly unlikely since there isn't ANY metal shavings in oil)
Sorry for the thinking out loud here but I'll know more tomorrow. I'm going to bring that #8 to TDC on the compression stroke and fill it with air to see where the leak is. If it leaks into the intake manifold it's the intake valve, the exhaust the exhaust valve, into the crank case it's getting by the piston (or through it). Then, if it points to a valve, I'll take the rockers off to see if it is caused by a too long of a pushrod.
I'm really hoping it is a bent valve that either took out a guide or a seal, causing the noise and oil control problem, of coarse caused by weak springs (from overheating)!!
If you can think of something I haven't let me know. I'll let you know what I find (or don't).
Ran truck and I still have a knock/rattle when revved after warm up.
Still couldn't pinpoint where it's coming from. But as it warmed up it started getting blowby on the drivers side bank - pretty bad. After it cooled about 10 min or less I checked the compression again on the #8 cylinder (suspecting a hole in the piston). When I pulled the plug it was soaked with oil. I pulled the plug next to it (#7) - it was very clean as expected because they are new plugs since getting it running. The compression still shows about 122psi in ALL cylinders even when it was still good and warm (same as cold). So I can rule out the hole.
What has been replaced so far;
Cam/lifters/pushrods
ALL sensors
Distributor
Cap/rotor/plugs/wires
Cut the Cat off and gutted the pre-cat
Truck runs great cold. Then when warmed up it idles and drives rough at low speeds and starts knock when revved, but not at idle. Sounds more like a diesel. Getting up to speed is great, no problems at all, hot or cold. All the plugs look good except now the #8 is oil soaked (this is new). I just re-routed the PCV and plugged the port at the back of the manifold. When I put the upper back on I noticed oil in a runner. That's when I re-routed the PCV, so the oil soaked plug could have been caused by this. Right now I don't have a new one so I'll see if it continues to get soaked after drying it.
What to make of it??
Well, what it is not (in my opinion);
Rings - No smoke out the tail pipe
Hole in piston - compression checks good
Blown head gasket - again compression good
Cracked or warped head (or block) compression good and no water in oil and no oil in water
What it could be;
Bent or stuck valve - although compression is good
Valve guide or valve seal - possibly caused by weak springs or bent valve? would explain the oil soaked plug
Wrist pin (However highly unlikely since there isn't ANY metal shavings in oil)
Sorry for the thinking out loud here but I'll know more tomorrow. I'm going to bring that #8 to TDC on the compression stroke and fill it with air to see where the leak is. If it leaks into the intake manifold it's the intake valve, the exhaust the exhaust valve, into the crank case it's getting by the piston (or through it). Then, if it points to a valve, I'll take the rockers off to see if it is caused by a too long of a pushrod.
I'm really hoping it is a bent valve that either took out a guide or a seal, causing the noise and oil control problem, of coarse caused by weak springs (from overheating)!!
If you can think of something I haven't let me know. I'll let you know what I find (or don't).
