Interference engine

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Aug 26, 2019
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2005 Hyundai Sonata (4 cylinder)

1. Purchased Sonata for $600.00 with broken timing belt, I had forgotten about interference engine technology.
2. Replaced timing belt, Sonata runs rough.
3. Perform compression test: cylinder's 1-2 no compression, cylinder's 3-4 good compression.
4. Removed cylinder head; purchased 4 exhaust valves and 4 intake valves to replace bent valves, cleaned cylinder head and surfaces.
5. Perform valve lapping and install new valves.
6. Install cylinder head
7. Engine cranks over but doesn't start
8. Go out another day to redo compression test 2 cylinder's with no compression and 2 with good compression.
9. Go out another day engine does not crank over, new battery, does not crank over, it just has a loud click!

I have been working on cars all my life. I was a mechanic in the National Guard and I worked full time for the NG in Atascadero. I attended Allen Hancock College in Santa Maria for Auto Mechanics (4.0 GPA 1 semester) I feel like I am a good mechanic but I have worked in Construction for the past 30 years.

Why would the engine crank over but now it is locked up?
Why would there not be compression in 2 cylinder's?
I appreciate all responses!!
Thank you
D.J.
 
You probably know more than I do.
However, did you think that maybe the damage
from the broken timing belt was a little more serious
than you first thought?
Bent valves indicate smacking against the piston
Could the piston have cracked?
Or could the valves not be seating?

Just a thought
 
You probably know more than I do.
However, did you think that maybe the damage
from the broken timing belt was a little more serious
than you first thought?
Bent valves indicate smacking against the piston
Could the piston have cracked?
Or could the valves not be seating?

Just a thought
Thanks for the reply, when I had the cylinder head removed I checked the cylinders and the top of the Pistons and everything was fine. There was one valve that I could not get good lapping on...
 
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