Archived help daily driver 12valve running rough after visit to 4,000rpm

[DDarmos]

I missed a gear an was up around 4,000rpm I have been there several times before though. I have a 4k kit with heavy valve springs from piers. It runs real rough at idle and I hear something like a woof coming out of the air cleaner. At Idle boost gauge bounces from o to 2lbs. Above 2k it smooths out but still runs bad. White smoke at times and does not like acceleration. Checked timing, it is good. Looked at valve springs with covers off. Any suggestion would be helpful? I am afraid it is a bent intake valve, so I am going to have a friend check my cylinder pressure. If that is the problem any suggestions on head removal and estimate on cost of parts. I plan on fireringing head what is an average cost for machine work and where should I purchase it? Plus while head is off what else should I look into upgrading.

Thank you for any help, Darin

 

[Will24]

Check the shaft in your turbo





-Will

 

[JoshPeters]

Good call Will.



If you are pulling the head..... In your area I'm not sure who has a register plate and the cutter head for doing the Grooves for Fire Rings. I believe Haisleys has a pretty good price on the Fire Ring gasket/ring set. It sounds like you have the upgraded valve springs..... if your willing to spend big bucks... ship your head to Piers, Haisleys or Scheids and get the head ported and polished... . outside of that... there isn't alot you need to do.



Pulling the head is pretty easy..... there are 2 plugs above cylinders 5 and 6 for pulling the long head bolts and the pushrods. Everything else is pretty straight forward.



Josh

 

[Hohn]

Bent valve is my vote.

 

[WMowat]

bent push rod. Happened to my 98 when the wife downshifted, I pulled the head anyways and everything was ok.

 

[bmoeller]

Sounds like a bent push rod to me also.



Ran into that with a Deere 4440 tractor once. Not sure what caused it though. No high revs. Had the same symptoms.