Valves hitting Pistons?

[Michael]

Appologies if this is posted twice, but I couldn't find the last post.
Thanx again for taking the time to help me out.
I figured out the muffler clamp tool, and it works like a dream. I didn't actually use a muffler clamp, since the local auto parts place was closed, so I had to make do with a ubolt with a flat piece of metal across the open end; however, the flat piece of metal I used bent considerably and I had to reinforce it with another bit of metal, so perhaps in the the future I may use a muffler clamp, since the flat bit is reinforced so that it doesn't bend.
My problem today is this: I figured out why I was having this recurring problem with oil getting in my coolant, it wasn't a cracked block - after all, I was simply continuously blowing head gaskets due to my engine overheating all of the time. I hadn't realized this, since I was relying on a cooling system and idiot light - neither of which were working properly. I installed a proper water temp gauge and discovered that the engine was overheating. The fan wouldn't work due to a hidden broken hot wire to the motor and a bad thermistor at the radiator. I have fixed these items and am ready to go.
However: I had my head resurfaced, replaced the gasket with a new one, got it all back together - torqued to proper specs, turned the engine by hand to make sure nothing was seizing, and started her up. The sound seemed to indicate that pistons were hitting the valves. It seemed to idle alright, just louder than usual. I shut it down, checked my valve clearances and found that half of them were actually a bit out of spec., by .001", on the loose side. No problem there. So, what I think is happening is that slop from worn rod bearings is causing the pistons to hit the valves. I think my next move would be to remove the head, see where they're hitting, and then grind out a tad from the pistons, wouldn't you think? The machinist said he removed .003" from the head, so that shouldn't be enough to weaken the pistons, should it?
Please let me know what you think might be an easy fix for this thing.
I'm planning on removing the injectors, at first light, so that I can easily turn the engine by hand, so that I can get a better sense of this phenomenon.
Whad'd'ya think?
Thanks again.
Michael

[Fatmobile]

Having it too advanced can make it more clackity.
Make sure all the pullys are tight,.. I knew the crank pully bolts were loose on the car I'm playing with but didn't expect a valve hitting piston noise when I started it the first time.
I don't think surfacing the head could make valves hit pistons. When I got a head rebuilt the shop said 2 thou below the surface is good enough.
Turning the engine by hand should let you know if the valves are hitting pistons,... but checking the timing marks might be in order.

[82vdub]

I agree with fatmobile. Turning the engine over by hand is smart, especially when you mess with timing or the timing belt. If the valve would have hit the pistons with any amount of "crush", you would have had a dickens of a time turning it by hand past that point.

Many things can cause noises in the engine. Timing, a bad injector, valves hitting the pistons, a collapsed hydraulic lifter (you don't say what year or engine), piston slap, wrist pins, rod knocks, plus more. I would double check your valve timing and if that doesn't solve the issue, maybe investigate your bottom end. Water in the oil will take out a bottom end in short order if the amount of water and time is involved. You may likely be able to see if you have bearing clearance issues with an oil pressure gauge. Low reading could be too loose of bearings. Also, use a very clean oil pan and drop the oil. Look for any pieces of fine metal in the oil and cut open the oil filter to see what's inside. You may find indication of your bearings on their way out.

[caveman]

When the shop who machined the heads, remove the prechamber shields [i know there's another name for it but i can't remember right now], and replace them? Whatever the case is VW IDI heads really are not supposed to ever be machined. There are others out there who may disagree, but the issue is getting those shields to reseat and stay where they are supposed to. I say there's a good chance one or more has dropped out. If the motor turned good by hand and then got noisy after started then maybe that's the case. Of course if one or more fell out completely ,then the motor will seize and will be toast. Don't want to scare you, but be careful.

[sideburns]

if your crank pully is loose, you likely have spun the timing a bit....

[Quantum TD]

If you felt no contact when you spun it over by hand, then you should be fine in the valve dept. THis is assuming you used the same head gasket (# of notches that is), as what you took off.

Either way, it sounds more like an Injection Pump timing issue, or sticky injectors.

Double check your pump timing and let us know.