I have a 97 F150. I recently tore the PS head off the truck to fix the leaking valves in the head. Turns out I had 3 leaking intake valves, and 1 leaking exhaust valve. I replaces 1 intake valve, and 1 exhaust valve. The rest I just re lapped in.

When I pulled the cam gear off, I roped it up to the PS fender in hopes that it would not slip and I would not have to re time the engine. I thought I had prevented it from slipped and I put the motor back together. I turned the motor by had 2 rotations and did not hear any valves contacting the pistons. I also pulled the ignition wiring and fuel pump fuse out and cranked the motor over and again heard nothing.

When I fired it up for the first time, it is making horrible noises. It sounds like valves are hitting pistons. I shut it down and checked the compression of a few cyls and they are all sitting around 175-180 psi. The truck runs smooth as silk, but something is not right.

I could be a tooth off causing the valves to hit the pistons and have not caused any major damage in the shot amount of time it was running? I dont understand how I cant hear the noise when cranking the motor, have perfect compression, and it run so good with valves hitting. It basically sounds like a coffee can with a lot of rocks in it when it idles. Thanks for any input.

 

Good day,
Those are the hydraulic lifters still getting to the proper level... Did you happen to pull more than a few of them out while doing the head work? Did you only pull that cylinder head? Is the noise only coming from that side? I'd pull the plugs and prime the oil system using the starter... I have a spare T-45 bellhousing in my garage to do this before installing the motor back in the truck...

Here is a pic of my last motor rebuild... This was a 01 motor that went into a 97 4x4... Flat top pistons and almost 10:1 compression...



It should smooth out as the oil pressure pumps the air out...

Cheers!!!

 

I was thinking it was the lifters as well at first. I let it run for about 3 minutes. At one point, the noise went completly away for about 2 seconds, and then came right back. I only pulled the PS head which just this morning I was thinking that even if the chain was off, it would only be off on that side but i hear the noise on both sides.

It is just so loud that I have a hard time beliving it could be the lifters. I am wondering now if the EGR tube that connects to the DS header could be leaking bad enough to cause that much noise. It seemed very loose when I unhooked it and it also seems very rusted.

 

It could also be the chain tensioners... Or primarly the PS tensioner... That could sound like it is on both sides... It is hard to identify without actually hearing it, but I know mine bothered me for a day or so... It finally went away and didn't return... I was nearly convinced the flat top pistons were tapping the valves... I'd hate to say let it idle until the oil pressure fills all the items it needs to, only to have something mechanically wrong... You could verify the timing on the PS, but you have to pull the valve cover...

 

Yeah I think I am going to pull the PS valve cover off tonight and see if I can see anything wrong. My dad is betting it has something to do with one of the guides or the gear rubbing on the cover. The guides looked ok when I put everything back together, but at this point that is about all I have left to check.

I may also try to record the noise and see if anyone has any other ideas.