Who else gets a half second to a second of bearing rattle at start-up and is there anything you have done to try to eliminate it? I have changed oil, and went back to using an AC oil filter but the situation is the same. Engine is an '89 TPI 305 with about 70,000 miles since rebuild.

 

sure it's a bearing or not just a lifter that is slow to pump up?

 

If it worries you, you can buy a preoiler. Bit expensive though.

 

The AC filters suck they they are under a new maker.

 

try a different filter- maybe they have a bad anti-drainback valve... does it sound like "dry knock?"

 

Yep, it is dry knock. I've tried both Purolator and AC filters. Right now it has an AC PF 25. As far as the anti drainback valve is concerned, on a small block Chevy engine, since the way the filter is positioned, it is impossible for oil to drain back out of the filter since the opening to the engine is all the way at the top. I've heard other eigines do this from time to time, and I don't think it is of great concern, but I was curoius as to what others think also.

 

Try using synthetic oil to see if that helps. Couldn't hurt.

 

Whats the oil pressure like when cold, and then as it warms up? Do you have pressure cold, then lose it as it warms up?

 

Oil pressure is 45 to 55 psi at cold start-up depending on ambient temperature and about 25 psi at idle when fully warm.

 

So the oil pressure doesn't fade to nothing at idle when its warm? You mentioned its a rebuilt motor. Do you recall what was done. You may have some piston slap at the bottom of the bores if the bores are tapered from use. See anything in the oil or filter (assuming you cut it open)?

 

The oil pressure seems normal when warm. The rebuilt engine was done by a company like Jasper (it wasn't Jasper, but I can't recall the name right now) so who knows what all they did. No foreign material in the oil filter.

 

go to autozone or advance and get ya a bottle of lucas motor oil additive try that i know i use thier additve for the transmissions in my t-bird and wow what a difference in the way it shifted that will quiet you car on start up and i used it in my motor to for the t-bird a tired 200,000 mile motor helped it out to thick stuff when its cold but works wonders lol

 

Thanks, I'll give it a try.

 

n/p hope it helps also they have that slick 50 to. my bro -in law used it in his cavalier think he got it at walmart tho but i think the lucas willhelp the best and they say it wont void new car warrenties either guess that jus supposed to make ya feel good LOL bout buyin it

 

Bearing clearance is getting excessive. Pretty common but not the best if you are beating on it. Take it easy with it and it will probably run forever though.

 

Lucas does more harm than good. All it does is allow more air into the oil. Its snake oil.

 

well mayb it does or it dont but all i know is worked wonders for my t-bird put it in at 128,000 miles im on 201,000 miles now and i havent done a thing to it but drive it but opinions will vary but then again its my opionion and i will swear by the stuff

 

what weight oil are you using?

 

287000 on my wife's Tahoe,been using Lucas since 20,000.If it's snake oil,I guess I'll take it,cause it's still as strong as it was when it was new,50psi of oil pressure warm,using a half quart every 3000.I'd say it hasn't hurt me any.

 

I really don't think you have a bearing issue. If the bearing is bad, its bad, period. I think you've got some piston to wall clearance issues (skirt slap) or a piston pin starting to tighten up. How full of a rebuild was it 70000 miles ago?

 

For a dying engine I might try that lucas crap. For a performance motor I'd never put a drop into anything of mine or that I work on. Here is a three page 'discussion' on Lucas. Decide for yourself...

https://www.thirdgen.org/techbb2/sho...hreadid=258774

 

Interesting,Id never stumbled across that 3 page mess.All the BS should be cut out and the useful stuff posted as a sticky.I'm still a user,but to be truthful,I have only used it on my daily drivers,and in the oil I put in all the flat tappet engines I've built.Great luck,as stated earlier,on the DDs.
I build engines on the side,and have always made sure to dot every I and cross every T,and not be paid to build anything I'm not 110% sure of my own capability to build.But as careful as I could be during assembly,I can't always be there for initial fire up/cam break in.Since I started adding Lucas to every flat tappet build,I've not had 1 cam failure.
That post does make me think,though.

Sorry to rob a post,here