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Got a tough one here. What makes noise only when hot. Sounds a grinding/rubbing noise in a rhythmic pattern. Changes(increase in frequency/noise) with RPM and is only heard through the opti distributor cap with a stethoscope?
Failed lifter or Cam bearing or oil pump drive gear?
Why have you ruled out the opti... if you are hearing the sound THROUGH it.?
I only ask, because one of my DYNASPARKS was a NOISY MOFO... sounded like a "baby" rod knock.....
Yes. I have tried 3 different ones. All 3 are quite on cold starts. The 2 that have seen a up to temp engine both make the same noise. 2 new AC Delco units and an old AC Delco with CMS Cap and rotor.
Thanks for the quick reply.
bad crank bearing
I sure hope your wrong LOL Thanks for chiming in.Quote:
Originally Posted by sinistr
Sure seems like a main bearing:(
Are the cam retainer bolts tight im just throwing something out there . Hopefully it's nothing serious. What about the water pump drive is the bearing in good shape.
Thanks everyone.
The cam retainer is new, and the bolts should be tight. They were torqued and blue locktited. I tried tugging on the cam/gear when I had the Opti Off. It wouldn't budge.
Hate to say it but this is going to be one of those situations where you need to start taking it apart looking for signs of abnormal wear.
There was a guy who broke is flex plate once and it made a ton of noise when it warmed up but it was more of clicking. I am leaning to you cracked the plastic oil pump drive and when it heats up it allows it to flex and skip. But I am probably wrong. I just cant imagine a bearing making a grinding noise but I have been wrong many many many times before.
That's 2 for cracked flex plate and 2 for major failure... I'm going to do some more investigating Friday. I cant bring my self to go work on the car again tonight. Too much invested to be rebuilding after 50 miles.
I forgot to mention that I have an electric water pump and have removed the drive gear from the block. Noise does not change with or without accessory drive belt on. I did use Stainless steel bolts on the cam retainer plate. I don't think stainless is "that" weak and would have failed in that application. Oil pump drive shaft is a solid ARP unit.
Another odd note, the car wouldn't start after the opti swap. I had to crank it over with the fuel pump off to clear the rail and cyls. Then re install and it would start up like normal. Hot start would just flood out. After I confirmed the noise was still there I decided to start it one last time before going home and it fired right up. Seems like there are numerous problems afoot.
I do fear the engine is going to need to come back out. So much for perfect paint huh :(