My '71 340 with the 305/.525 Comp cam with matching lifters/springs ran fine prior to my indexing my new bellhousing this weekend. Granted, I did have to "feel" my way around that process as it was my first time doing it, so the engine spent quite a few revolutions being turned by hand. Once I had the car all buttoned back up today (the car sat 2 weeks during this time as well) upon firing it up, the lifters wont pump up and are making some very loud clatter. I only let the engine idle for 20 seconds the first time and then another try I let it run at 1500 rpms for about 60 seconds and still the clatter continues, Loudly.

How long do I need to let it run before the lifters start to pump up again? I really don't want to hurt this engine as I have less than a year's run time.

THANKS!!

Are you getting good oil pressure when you started it? Both heads getting oil? Right sized pushrods? If so it could take a minute or two to pump up a completely dry lifter.

You shouldn't hurt anythign with that rattle until they pump up. Don't be afraid - but be sure that's the source of the noise.

Before you start it again you can always pull the valve covers and place a good amount of oil on each lifter to speed the pump up too.

Yea, I've got 74lbs of pressure with Mobil 1 15w50 oil in her. She ran great before the bellhousing indexing this weekend. I pulled both valve covers and checked that every lifter with no load could easily be pushed down 1/4 or more with just my fingers. I was just worried that running it that way might hurt something and I didn't know how long it might take before the lifters would pump back up. How long of run time would be too long with still hammerin' away?

Have you ever let your engine sit for two weeks? Was it fine? I can't imagine you messed anythign up with your recent bellhousing work.

On a new build I have heard it can take 2-3 minutes to pump the lifters up. I'd say if you are sure that's the cause of the rattle, then let it run up to four or five minutes. If it's still doing it I would shut it down and investigate further. I know that rattle, and it sounds ugly.

If I'm not mistaken you can squirt some oil on the top of the lifter and actuate the plunger with the pushrod to pump a little oil in there to speed things along.

But again a loose pushrod won't mess anything up it will just affect performance. Of course if it's waaaay too loose it could jump out of place and cause some damage to the parts in that area or bend the pushrod itself.

Hey guys, thanks for the help. You're right HitIt, that is one UGLY sound when all 16 of those guys are hammerin'. I did just bite the bullet and let her run another 4 minutes or so and she quitened right up. Mystery solved. I guess all those rotations without oil pressure milked the lifters dry, taking around 4 minutes of run time to pump 'em up again.

Thanks for the input, the last thing I wanted to do was run it and cause any further damage.

btw, the new Centerforce DF with the now properly indexed bellhousing is SWEET! .016 off and I was having all kinds of trouble.

Thanks again!

Right on, glad to help.

It won't hurt a thing as long as the y pump up in a reasonable time. Very common in 265/283 GM engines to have rattle on start up.