Possible bent valves?

Tiny
EPIPHANY101
  • MEMBER
  • 2001 MITSUBISHI DIAMANTE
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 210,000 MILES
The saga continues. So, after getting the wrong firing order offline and subsequently timing the motor wrong, and then trying to start it, being an Interference motor, I can only assume I bent some valves since a compression test netted 1-100lb, 3-80, 5-95, 2-28, 4-28, and 6-60lb respectively. What should the pressure be? Taking the valve cover off I could see nothing wrong but am sure the bend would be at the valve opening. Thoughts? Thank you in advance, if I had only got the firing order from you guys to begin with. Also, how many teeth should the timing g belt for this car have? The one I got is 190 and I'm a half tooth off on having it timed.
Wednesday, October 19th, 2022 AT 1:22 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

It sounds like you bent them. As far as the compression, are you certain it is correct now when you test compression? If so, pay attention to the valves with the covers off. Are they moving fully? If they aren't, you will likely need to remove the cylinder heads to check for damage.

As far as the pressure specifications, the minimum is 127 psi, and there shouldn't be more than a 14 PSI difference between the highest and lowest. See pic below.

Let me know if you are sure the timing is correct.

Take care,

Joe

See pic below.
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Wednesday, October 19th, 2022 AT 8:35 PM
Tiny
EPIPHANY101
  • MEMBER
  • 13 POSTS
Yes, the timing is as close as I can get with the crank and front pulley spot-on and the back pully a half tooth off. With the top pulleys I can't get both spot-on, only to within a half tooth. I have a feeling I was given the incorrect belt for this vehicle. Which explains why it sounds like it does when it starts. I was pretty sure they were bent. Will get a set ordered and go from there. Hopefully not to psych ward.
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Thursday, October 20th, 2022 AT 10:41 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

Before ordering valves, remove the head to make sure the valve guides are not damaged and there are no cracks in the heads. Also, confirm there is no damage to the piston tops.

Let me know what I can do to help.

Take care.

Joe
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Thursday, October 20th, 2022 AT 6:31 PM

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