I had my heads rebuilt when I build the motor a couple of seasons ago - when they were done I had all new valves installed. The intake valve stems look pretty good with minimal wear - but the exhaust valves look pretty bad for the most part. I am sure most of this is due to the nature of the beast (turbo) but I am curious if anyone else has noticed thiers showing heavy wear or not..??? It appear they are worn about .002 or so close to the top with very little wear in the middle and lower section..

 

On my stock heads the exhaust valve seems to be turning white.

 

if they are stainless they will lip up after not much use.

 

if you run your timing to low it can burn or wear out the exhaust valves...

 

Interesting.. Never heard that before.

 

That just from the high exhaust heat from the retarted timing.

 

If they're wearing near the top, it sounds like you are experiencing some side loading from the rocker. Have you checked your rocker geometry?

Are there any signs of galling? What kind of guides? Are you running positive valve seals on the exhaust, or none at all?

 

I got to looking a little closer and - it is possible that the two of the four valves I pulled were the old ones (the originals in the heads). When I got the heads all of the stems were no good and had very little run time on them. I had bought all new valves and took them to the shop to get the valve job done. He called me and said a couple of the new valves were no good - I went up there to inspect and found they were bend or out of concentricity so bad that they couldn't be ground. So we had to make a judgement call on which of the old valves were good to use. I think these are possibly the two that we kept. I wont know till I disassemble the other head to see for sure.
There are no signs of galling at all, and the heads have the positive seals I believe. I checked the rocker geometry pretty close a few times and they are fully traveling in almost the perfect center of the stem.... this brings me to another odd point.. The rockers have broken the little "eyes" off of the snap rings on two of my rockers (new set) and a couple of the rockers on the old set.. this would confirm the "side loading" theory solidly... which I hope is NOT the case.. then I would have to install new guides and hope the machinist was good enough to get the guides lined with the rocker stud... and then grind the seat accordingly..
Damn I wish I still worked in a machine shop so I wouldn't have to pay/trust someone to do this correctly..

 

This should not be a problem is they are using a Sunnen or Serdi head machine. Also make sure the roller tips are centered on the valve stem side to side. If they are not you need to adjust your guideplates so that they are. If you cant get them centered, you can cut and weld your old guideplates or buy some Isky adjustable ones. Also check for pushrod to head interference just to be sure.

So. . .what kind of valves are these anyway?

 

Yeah.. I know for a fact he is old school and has a basic air float table - I think it may be a sunnen machine. I completely didn't think about the guideplate adjustment till after the motor had been disasselbled but the pr's are no where near the heads. As far as I remember the rockers were pretty damn centered except for a couple................wait a minute. I remember now (this was a year ago) ....I did try to center the rockers better on the couple that weren't centered. It seems like there were a couple of rockers, on different cylinders, that wouldn't center up. I'd bet the guideplate will need to be cut and welded to make it right - like you mentioned. The valves are crummy Ferrera's I think.. I am probably going to get a set of Race-flo's or something to that effect this time.....

 

Ferrea valves are fine, as long as they are the correct series for the application. I would at least put a set of Manley Severe Duty (or the equivalent Ferrea) valves on the exhaust.