noisy cam follower

[JAMES MEYER]

Hi I was wondering how to diagnose which cam follower is noisy on my front head so I don't have to buy all sixteen.As you know it makes an oily mess if ran with cover off. The noise only occurs when the 4.6 98 seville is at a hot idle.It has new 10w30 castrol gtx in the crankcase. All temps and pressures are normal 68,000 miles one owner very conservatively driven

Thanks James

[JasonA]

very conservatively driven

That might be your clue. How have you actually diagnosed it to be a cam follower? Could it simply be carbon deposits in the cylinder or on the piston? I'd recommend going out onto the highway, put the transmission in 2nd gear, and floor the accelerator until you get to 70-80 mph, then let off completely. Let it coast back down to 30-40 mph and floor it again until you get to 70-80 and let back off. Witness the incredible amounts (probably) of black smoke and soot coming from your tailpipes when you're on the throttle. This is carbon that you're blowing out of the engine.

The Northstar likes to be driven hard. You're actually doing it more good to drive it hard than babying it around. Driving it real easy all the time can accumulate carbon deposits and you can sometimes here these knocking or tapping like you're describing. The reason I don't think it's a cam follower problem is because I don't think we've ever heard of anything like that on a Northstar here before. Ever.

Welcome to the forum!

[JAMES MEYER]

Thanks I will decarbon the engine ,do the top engine decarb,ring decarb,run it hard and then retry. It does have to idle hot to make the noise.If you rev it the noise goes away at idle for about 10 seconds before returning.Also the follwers on the exhaust had some center scoring so I replaced all of them and the cam,whille checkng bore and springs and guides but after putting it together noise was still there. I guess what I was really asking is is there a way to run this thing with the cover off.

Thanks James Meyer ASE L-1 Tech