Lifters bleeding down.

[bcjjones]

I have a 355 with a Lunati bare bones cam with the lifters that came in the kit. Cam makes more power than the Comp XE268 that I had in it prior, but the lifters seem to bleed down while driving. Starting up they sound great, I drive on the highway about 25 miles to work, and when I get there they are fairly loud. Tapping like they're out of adjustment. If I sit and idle for a minute or two, they go back to normal and sound like a sewing machine again. Anyone run into this?

 

[Erik the Awful]

Did you adjust your rockers while hot?

 

[bcjjones]

Yes I did, but it's very abnormal, in my experience, that they quite back down. Usually if they are too loose at running temp (adjusted cold) than the noise is constant.

 

[Erik the Awful]

What weight oil are you using? What does your oil pressure read when hot?

 

[bcjjones]

It was 5w30 and I knew that was a little thin. So I switched to some castrol conventional 20w50 I had on the shelf and the noise is gone. A little thick, and maybe some 15w40 would be good next time its due. Oil pressure is always 25-40 psi at idle when hot. Damn GM sending units aren't the most consistent/accurate!

 

[Erik the Awful]

25-40 is good. Did you use fast-bleed lifters? If so, the clatter is normal.