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Hi,
He reported a clunk(ing) sound so that must mean more than just one CLUNK!
I would be real suspicious of a timing belt issue as well.
The trickiest part is getting the tension roller to-remove all slack or making sure the guide flanges down on the crankshaft are installed correctly.
You cannot put the timing belt on without having covers off and that means the sprocket was at least loosened.
Those thin bevel guide plates must fit flat and behind the bottom sprocket.
If they do not sit flat with the back side “key” engaged through them then the lower sprocket may have cracked and split when torqued down.
The sprocket is made of “sintered metal” as it’s not made from a homogeneous steel stock mainly because of the key and keyways makes for many more machining operations.
This could have cause the timing to jump with a possible clunky sound, since the sprocket would have lost its keyed position on the crankshaft.
Depending on how long the engine ran take a good gander at the edges of the timing belt for scuffing.
Recheck the timing marks to the cam.
The crankshaft bolt receives a bit of tightening. About 110+ lbs in total. First 60 ft lbs and then one hex flat more of which just about maxes out a home air driven impact wrench.
Today’s knuckle busters avoid using hand wrenches and grab air or electric tools way too readily. IMHO
The only other thing that may have happened is the camshaft locked up in the heads journals.
A Bad fit during reconditioning or no pre assembly lube or engine oil. Take your pick.
All of that can stall out the timing belt.
This can rip the belt starting down at the smallest sprocket, of which, IS the crankshaft.
Maybe someone has more knowledge or experience in automotive techniques than me from here out!
I have always worried and wondered about what the head’s journal alignment conditions when resurfacing a warped head?
Do they leave the cam in or out during its, so called, “broaching” operation?
Broaching means different things in “tooling” to me.
There is a height dimension between the cams center line and the heads bottom that limits the amount of material removal … to some extent. This head was rebuilt, right?
This dimension is determined for proper combustion chamber depths and the valves reaching out.
In actuality, the timing belt doesn’t care how low it goes it’s adjustable.
So, with no valves or springs the cam should spin freely, in lubricant, with the caps on. Right?
If a head warps wouldn’t the cam journal go out of alignment from end to end?
You know bow along its axis?
A Twisted head is probably of lesser concern.
The call out is up to .020 or less, from corner to corner or you could just put it back on.
Does a rebuilder setup to the journals just before the resurfacing of the combustion side?
I would want to hope so, maybe?🤔
Just another thought …
I hope they kept a float charger on the car’s battery for 3 months or it’s lost a lot of life from sulfates.
Phil
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