2002 XC70 bent valve possibility

jimmydean012 · Post by **jimmydean012** » 05 May 2024, 17:30

I bought a 2002 XC70 with 190K, I knew it needed a timing belt based off of inspection but after purchasing a large oil leak was apparent from the cam seals. PCV issue was confirmed with a glove test, something I neglected initially. I decided to fix all issue due to the condition of the body and interior (immaculate.) I bought all the parts for the complete PCV overhaul, including breather and crank breather hoses, timing belt/water pump/idlers/tensioners, oil pump seal/gasket, cam seals, VVT oring. Disassembly went well but during attempts to removal of the crank bolt there was an issue.

The crank locking tool from Amazon appears to have mushed/slipped and allowed the crank to move. When I went to return the crank to position I encountered valve contact issues that prevented me from lining up the TDC marks. I was able to get the crank back to TDC by removing the cam lock and manipulating the cam. This tells me it might have bent a valve. I am going to check compression after reassembly and inspect with a bore scope. If the valves are bent, will it require me to remove the head to fix or can it stay on? Maybe it's worth it to remove anyway to do the headgasket.

Post by **jonesg** » 06 May 2024, 03:21

it takes more than contact to bend valves, i know because i had a cam slip when turning the crank by hand.
after torquing everything turn it over by hand twice to check, if theres no interference it is all set.

Post by **abscate** » 06 May 2024, 04:10

I’ve touched valves to pistons with hand tools many times. As long as you didn’t gorilla it, you will be fine.

dikidera · Post by **dikidera** » 06 May 2024, 05:57

I really doubt it. I've had much worse happen. I think you will be fine.

Post by **vtl** » 06 May 2024, 09:06

No harm was done. Volvo valves are tough.

jimmydean012 · Post by **jimmydean012** » 06 May 2024, 09:32

Well this is all very encouraging, thank you. If the compression test is good, could I be fairly certain there is no damage to the valves?

Post by **erikv11** » 06 May 2024, 16:39

Yes a compression test would be highly informative, as you suggest. If compression is low with the cylinders dry then be sure to add a little oil and test them wet, given how long it has been sitting. But probably will check out fine first time.

Also, be sure it passes the hand-crank test that jonesg mentioned up there, before you check compression.

jimmydean012 · Post by **jimmydean012** » 06 May 2024, 22:01

Well I think there is bad news. I got the timing belt on and set the vvt, everything is lining up and tension is good. I've lost compression on cylinders 1 and 4. I have a leak down tester coming to confirm but it's not looking good.

Also I completely spaced that of course the head will have to come off to replace any valves... Worth it? I am leaning towards repair

dikidera · Post by **dikidera** » 06 May 2024, 22:12

Did you hand rotate several crank revolutions to make sure there was no piston to valve contact prior to putting on the belt?

Also just as mentioned did you squirt some oil, very little is needed. Also, did you correctly set the timing? It's not all about marks, I don't encourage people to set the timing based on marks.

I myself had made a very bad mistake the very first time I was taking off and putting back the head after a HG replacement. I had put the camshafts 180 degrees out of phase relative to one another and even managed to close the cam cover and torque it down like that with an audible pop! Only after hand rotation did we realize the mistake after I got piston to valve contact when rotating. So we, just like yourself had to manually rotate the crank and each camshaft separately until we got it correct, without having to remove the cam cover.

jimmydean012 · Post by **jimmydean012** » 06 May 2024, 23:06

Rotate the crank prior to putting on belt? Am I wrong in thinking you don't want to do that? I am fairly certain it is correctly timed right now, basically how it was before I took the belt off.

What happened is the crank lock I was using yielded from the force of the breaker bar and allowed the crank to rotate independent of the cams. At this point piston 4 contacted the intake valves at probably 40 degrees ccw crank rotation. I think it bent the valves here and went to probably 60 degrees ccw (as the ratchet/breaker came off the nut)

Looking at the position of the pistons/valves through ccw crank rotation I can only conceive of the possibility of contact of piston 4 with the intake valves. There is evidence of contact on the face of piston 4 intake side seen with a bore scope. The valves look fine and don't let any light through when in compression. Not sure why cylinder 1 would have a problem.

I am very upset about this, especially the deal with this crank tool. After if yielded I stuck a 3/8 ratchet extension in the hole and it held fine. Im still waiting on my leak down tester but man it's not a good night.