Bending valves over..and over..

[89_laser_32]

OK I'm getting my 4g63 turbo head back from getting the valves reseated and new valve seals and what not...and I"m kinda worried because my car has bent the valves twice. Anybody give me any pointers on what to be careful with or look for when I get the head put back on that could maybe be causing it to loose timing? COuld the pistons somehow bending the valves? Thanks yall,
Chris

 

[larsenracing]

timing, the head could be decked to far over spec, or to large of cam, the piston and rod combination could have to long of storke, replace the valve springs maby your floating the valves. good luck.

 

[bloody_angel111]

hopefully you arent turning the cams and the crank without having the belt on, because that could cause you to hit the valves and pistons. what you need to do is turn the crank 3 teeth btdc i believe, that way, all the pistons are in the middle, and you wont have to worry about turning the cams and crank and not hit the valves. and yes, i could be that the head was milled to much causing the valves to hit because there isnt enough clearence, or maybe you arent getting he timing done right, could be a number of things really...

 

[Old Mitsu Tech]

My first thought is improper setting of the auto tensioner. You can have your timing spot on and if this is not set right you have a disaster waiting to happen.

I would also do a balance shaft elimination to alleviate that problem.

I can tell you how to properly do the auto tensioner, or you can search on here or vfaq.com. Just let me know.

Never crank the engine by the starter after you put the belt on. Crank it by hand 6 revolutions and see if the marks come back up perfectly, or less than one tooth off.

If it does, see if you can put the pin back in the auto tensioner. If you can't, then it's too loose and you can have a failure.

Also, change the auto tensioner if you did not do that.

Water pump is a good thing also. Helps keep you from going back in for a leaky water pump.

Good Luck

 

[Froyd79]

What was the timeframe between bending valves? I have seen guys lose oil pressure and the cams keep freezing up and they buy another head only to repeat history. Hope this isnt the case but just a thought. Also make sure your tensioner is good you shouldnt be able to push it in with your hand.

 

[Old Mitsu Tech]

To whoever left the negs. I don't mind being wrong occasionally, I don't even mind being told I'm wrong, however, I would appreciate an explanation or a reason.
Thanks

 

[Spyderman7]

If you're doing the timing right and tensioner is good and done right,do what the Old Mitsu Tech said and remove the balance shafts.The oilpump shaft will seize or not spin as freely as it should and cause the timing to skip.

 

[89_laser_32]

Already got the balance shaft removal kit done just so yall know.

 

[89_laser_32]

Ok I want to let you guys in on something I'm suspicious about, but I'm no dsm wizard either. Could a warped cam sprocket...which I do have on the intake side...be bending the valves? Because it's only my intake valves that keep getting bent over and over...and it's never my exhaust.

 

[Old Mitsu Tech]

The cam sprocket would not cause that unless it was causing the belt to either come off or jump teeth. I would however, replace it just to be on the safe side if it is not running perfectly smooth. Too much at stake to let that go.

Good Luck