[kevink1955]

67 Mustang with 79 302 with about 60,000 miles

After being shutdown hot and siting for a few days when it is started it has a lower end clatter like all rods are knocking. It's the same sound you get after an oil change till it builds pressure. Shutdowns and restarts within a few hours to not make any noise

The clatter lasts 1 to 2 seconds and after that it builds normal oil pressure and runs quietly. Originaly had a Fram filter (I know bad choice) now has Motorcraft FL-1A

Question is what (if anything) prevents the oil from draining back in a small block ford

[The Greek]

The oil filter should have an anti-drain back. There's an oil reservior in the lifter bosses to keep the lifters primed and quiet at start up and that's it.

[kevink1955]

Originally Posted by The Greek

The oil filter should have an anti-drain back. There's an oil reservior in the lifter bosses to keep the lifters primed and quiet at start up and that's it.

That's what I was thinking, the oil filter should hold the galerys full of oil that's why I used a Motorcraft FL1 on the last oil change.

The noise is not lifters, it's rod bearings. This engine has 60,000 "old Lady Miles" and is very clean inside so I do not think the bearings should be worn that badly. It has about 50 psi of oil pressure at 3000 rpm and 20 psi at idle hot.

It just seems like all the oil drains back after a hot shutdown when it sits for a week, if you shut it down for a few hours and it starts with no noise. Only makes noise after an extended shutdown.

[Ivy66GT]

The oil filter on a 302 is BELOW the oil gallery and also angled such that even without a valve it would stay 1/2 or more full of oil. If anything I would expect oil to drain INTO the filter as much as it might drain out through the bearings. I doubt the drain-back valve in the filter has much to do with your problem. Lifter bleed-down and clatter is not unusual after a few days or maybe weeks shutdown but I have never experienced anything else.

Are you using synthetic oil? I am told that it does not 'stick' to the parts as well during a long shutdown. Some car clubs I belong to suggest not using synthetics for that reason is you don't drive them regularly.

[cindys_sn95]

both of my 302s do this. one with 120xxx miles and the other has 235xxx.

[kevink1955]

Originally Posted by cindys_sn95

both of my 302s do this. one with 120xxx miles and the other has 235xxx.

That's good to hear, this engine has about 60,000 and runs great but the noise scares me. Just sounds like it is running without oil for the first 1 to 2 seconds.

[cindys_sn95]

a lot of them do this after they set for a while.

[The Greek]

I've owned engines with this condition that ran for years. As long as you're not dogging the engine with high RPM blasts, you should be fine for quite a while. Addition of a Motorcraft or GM oil treatment or suppliment might help to retain a fluid cushion between the bearing surfaces to help quiet the condition. You'll probably have to buy the treatment from a dealer.

[cindys_sn95]

the greek is right, todays oils suck. i do run E.O.S. in everything i have.