95 Civic EX. D16z6 engine.

Timing belt snapped after only 20,000 miles. I know this is an interference engine, however the shop suggested letting them replace the timing belt and water pump as they claimed they have seen many D series engine suffered no valve damage.

After they replaced the timing belt, the engine does start up and run. However, it appears to shake a lot even at idle. I asked them to do a compression test, and the results are 145, 142, 160 and 125. Now, they are saying that the cylinder with 125 psi probably has a loose or bend valve and that's why it runs rough. They say the engine is pretty much done at this point.

What do you think? Should I get a new engine or just have them repair the head? Any advice is greatly appericated.

 

It's a gamble, but if you're having someone else do rebuilding, it can get expensive quick. I'm not even sure you could reuse the head if there was seat damage, which you wont know till they spend time to open it up.

Being a 95, your bottom end is probably towards the end of its life before requiring a rebuild anyway, so I'd lean towards buying a new engine to swap in.

 

My D15B1 engine with 220,000 miles had bearings like they were new,,, well not that good. But I felt good not to replace them upon reassembly. This engine is low powered engine so this does not apply to other higher powered engines.

The action for OP to take will depends on how many miles the engine has and hoe many more miles he plan to run after repair. What is the cost of doing cylinder head rebuild on existing head vs the cost of whole engine replacement to another. If it was used engine, you are introducing new uncertainty to the picture.

But first, let the tech find out where the leak is occurring on that low compression cylinder by performing leak down test or differential compression test. This will tell you how to go about your problem.

 

You might look into just picking up a junkyard z6 head. That would be the cheapest gamble.