spottedog Posted January 18, 2009 Report Share Posted January 18, 2009 My #2 intake seat is receding into the head, for some time now I will set the valve lash to spec and in about 500 miles the clearance closed up and had to be adjusted again. Many times. Now I am at the bottom of the threads on the lash adjuster so I am convinced the valve seat is receding into the head and/or is actually loose in the head. No loud mechanical sounds (yet), compression still good across the board. My question is this, my #2 plug now runs real dark, looks like oil fouling. Do you think I just have a valve guide failing or could this be something uglier? (I am not driving this truck until I fix/ have fixed whatever this is, I don't want to hole a piston, only about 5K on this build) Quote Link to comment
datzenmike Posted January 18, 2009 Report Share Posted January 18, 2009 Look below the lash adjuster at the part that screws into the aluminum... maybe it is unscrewing outward, out of the head???? Quote Link to comment
spottedog Posted January 18, 2009 Author Report Share Posted January 18, 2009 Look below the lash adjuster at the part that screws into the aluminum... maybe it is unscrewing outward, out of the head???? I checked that, they are REALLY tight. 'Got on it pretty hard, they do not move. Quote Link to comment
datzenmike Posted January 18, 2009 Report Share Posted January 18, 2009 Take it and another rocker off along with their lash pads and try to measure the height of the valve tips and compare them. Seems inconceivable that the valve is sinking, can't be stretching.... If it measures higher then it must be. Quote Link to comment
Jason Posted January 18, 2009 Report Share Posted January 18, 2009 Does your head have the old style valve seats or the new style steel ones. On my old L16 head the soft material gets worn pretty bad sometimes and the seat gets pounded into the head. Quote Link to comment
spottedog Posted January 18, 2009 Author Report Share Posted January 18, 2009 Take it and another rocker off along with their lash pads and try to measure the height of the valve tips and compare them. Seems inconceivable that the valve is sinking, can't be stretching.... If it measures higher then it must be. Yep, the #2 intake valve stem stands 0.106" higher in the head compared to the other seven valves. I have taken a lot of notes on this issue, watching it get worse. :( Since this is a Frankenstein engine it is more difficult to work with such as having to drill extra holes in the new head gasket to match several water passages. :eek: Quote Link to comment
datsunfish Posted January 18, 2009 Report Share Posted January 18, 2009 Sounds like you need to find a new head or take it off and have new seats installed and a valve grind if the valves are still good. What head is it? If its a 210,w53 or a87 it probably has bronze seats that smoosh down. You should be using a u67 head for the largest intake port size and optimal compretion ratio. A w58 would also do well but not typically desired. Quote Link to comment
spottedog Posted January 18, 2009 Author Report Share Posted January 18, 2009 Does your head have the old style valve seats or the new style steel ones. On my old L16 head the soft material gets worn pretty bad sometimes and the seat gets pounded into the head. Yes, I think it does, my A13 engine did the same thing and the same valve (#2 intake) :confused: I had hard seats installed and a valve job on the A13. Quote Link to comment
Jason Posted January 18, 2009 Report Share Posted January 18, 2009 Sounds like it's time for head (work) then spotted dog :D! Quote Link to comment
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