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Old 04-26-2014, 12:10 AM   #1
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Default Vvt motor Interference engine

It started out simple enough, I was going to swap vvt gears with the parts car I have to see if that cured the cel and some other issues I mentioned in my other thread.

I was checking out a few things before I put it all together when I noticed I could not rotate the intake camshaft an entire revolution with the crank at tdc. After closer examination it appears that valves on cylinder 1, 3 and 4 will contact the cylinder when their piston is at tdc. #4 is by far the worst. I check the valve lash and everything seems to be in spec.

any thoughts as to what is going on? The only thing I can think of is I stretched the rods. The motor is bone stock and I know the rods are weak, but I would not consider my spirited drives to work to be as abusive as what many on this site do with their cars.

Any insight is appreciated.
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Old 05-04-2014, 11:28 PM   #2
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You may have deposits on the valves and pistons that use up all the clearance. If you have a borescope, you can look down into the cylinder and see if you have excessive buildup. You can use substances like Mopar Combustion Chamber Cleaner to get rid of some of the deposits. Also, check the valve lash on the affected cylinders. If it is too tight, you may be opening the valves further than intended.
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Old 05-07-2014, 10:43 AM   #3
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Old 05-08-2014, 11:42 AM   #4
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Having just actually read your initial post properly... I'd measure the height of #1+4 and compare. Maybe also try putting the belt on and compression test it - if the piston is closer to the head it'll make more cylinder pressure.
You'd have to have some pretty shitty carbon build up to stop the cam spinning at TDC.
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