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Hi,

I have an 99 LHS with broken engine (timing belt skipped due to the broken tensioner bearing) on the road (after overtaking),we found that there is no compression in the LH bank (interference engine >> damaged valves).

Assuming that there is no any defect happened to the pistons and parts under, what are the parts I need to replace?

In my opinion:
  • damaged valves
  • damaged hydraulic tappets
  • valve stems
  • (cylinder head gasket)
  • (cylinder head screws - upon the status)
Of course, some machine shop jobs must be done before assembling the engine (e.g. valve seats grinding).

Anything more to buy?


Thank you,
Csaba
 

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Welcome to Allpar. The head will have to come off first to see which valves are bent (4 per cylinder). I have found that usually only the intakes take the hit and the exhausts are OK, but diagnosis first.
The pistons, hydraulic lifters and valve guides should be OK if just the stems bent. It can be assessed at a machine shop. I have reused head bolts if they aren't 'necked' and it is the 1st time apart.
Replace the water pump when you replace the belt and tensioner pulley.
 

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It would also probably be wise to inspect the head and cylinder walls for gouges. There's a lot of force involved in one of these valve-piston collisions, and, while it is unlikely, something could have splintered or broken and gouged something. It doesn't take a whole lot to dramatically affect compression. The valves may also be of a harder material than the head and, if they hit in the right spot, could have made a hole. You may do well to just pull a junkyard head. These vehicles are fairly common in the yards nowadays.
 

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You can get another head at Pull-A-Part for around seventy bucks. Actually a little less, even with the ten dollar core charge. At least at the Nashville location. I don't know if there's one near you or not.
 
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