DoctorJohn

The mechanics who did the head gasket install pinpointed the noise to the driver's side front cylinder. I don't know if they checked the injector, but I will see if I can disconnect it or use a stethescope to determine if it is a noisy injector - that would sure be good knews, as I fear it is an internal engine noise. Thanks John

This does have a shim adjustment on the lifters, and the shims were checked, added as needed and rechecked. The worn cam sounds like its worth looking into, except the noise didn't exist before the head gasket job, and I'm not sure the leaking gasket/overheating would have made this worse. As far as the plugged rocker assembly being a possible cause - doesn't this apply to hydraulic lifters only? This engine has solid mechanical lifters. Thanks again for the ideas - I'm gathering all the info I can and before taking the engine apart again. John

Thanks again for all the replies - the timing belt tensioner/bearings were also replaced. Its more of a tick tick than a knock. If anything, it gets slightly louder after warmup, or at least the same as when cold. When I put my ear next to the engine it sounds exactly like a valve tappet click right above the valve cover on the front driver's side. I'm hoping it is the famous cylinder slap as from what I've read the engine will run a long time with this condition. John

This motor has solid lifters and the shims were set and re-checked over and over to try to get rid of the noise. It is something other than lifter adjustment ......Thanks for the comments so far, I'm still searching for the cause. I guess it could be something to do with the connecting rod (wrist pin?) even though the sound didn't exist before the head gasket job. The engine leaked coolant and maybe this put stress on the pistons as coolant entered the combustion chamber. Any and all ideas are appreciated. John

Yep - lifters were re-shimmed.

My wife's Subie with 105K on it developed a radiator fluid leak and by the time she pulled over the temp gauge was redlined and steam was pouring out - head gasket leak. So we had head gaskets replaced, heads resurfaced, timing belt and idler set replaced, water pump replaced, valves checked (machine shop said they didn't need turning). It runs great EXCEPT there is now a prominant tappet type noise coming from the driver's side front cylinder area. Its there at all times, regardless of RPMs and engine temp. The mechanics I took it to are competant and good people and they went through the valves, shimmed and adjusted, checked camshaft, valve springs. We are all scratching our heads on this one. We didn't get into the engine except to visually check for cylinder cracks, and one idea is that this is a worn piston wrist pin. But, the noise was not present before the top end job. Any ideas ????? Thanks. John