i was finishing up my engine build when i noticed my rear (6 cylinder) cam tower had a shim on it. I didnt notice it until i started on the exhaust valve of the 6th cylinder. The pivot point for the rocker arm was way higher than the others. I also noticed the lash pad was different color than the others. As of now i have the valve lash on that one valve correct but im worried that if i ran the car i would have BIG issues. Now if i were to remove the shim, would adjusting the lash pad be back to normal like the others. And also would i ruin my headgasket by taking out that one head bolt in the rear in order to remove the cam tower shim?

Be very very careful here. Any alterations to the geometry have been made for a reason.

I'm confused why only one tower has been shimmed, perhaps we need more info on the engine. Was it running before in this condition & did you have the head sent out.

In any case, if you choose to remove the shim you may [will] find that the cam will not rotate freely. My advice would be to leave it alone.

HIH

One can only guess why only one tower has a shim. The only thing that really matters is if the cam can be rotated freely. It may be a bit more work but I'd back off all of the rockers and check to see if the cam is binding or not. It's important that the cam not bind in its bores as binding will destroy the cam towers in very short order.

sorry i forgot to add this but the head was bought from ur-gelis (restored) on ebay. From that, the guy i bought the head from installed a schneider stage 2 cam with adjacent lash pads. My guess is that the rear valve was not addressed and he might have installed the shim on accident... well i spoke with him and we're trying to get this settled. As of now with that one shim, the cam rotates freely without bind. However, i have never heard of having just one cam tower shimmed.:devious:

Given what you've just written, I would guess that the head is a "bitza" made up from at least 2 heads. As long as the cam rotates freely and the wipe pattern on the cam lobe is even, then the head is usable.

  Zedrally said:

Given what you've just written, I would guess that the head is a "bitza" made up from at least 2 heads. As long as the cam rotates freely and the wipe pattern on the cam lobe is even, then the head is usable.

thats a big relief... now my problem lies with the lash pad, it looks as though the guy who installed the cam accidentally installed the stock pad instead of the adjacent lash pad for the cam.

The stock pad should be OK. The shim only brings the tower to the same height as the others.

You can check by using a permanent black marker pen on the cam lobe.

Rotate the cam several times and check the wear on the lobe. It should be even on both sides. If it isn't then you will need to adjust by using different pads.

Has this head already been run on this engine?

If the cam is still new then you should be able to fix the lashpad/rocker to obtain a proper wipe pattern. But if the engine has been run for a while already then the cam lobe has already seated on the rocker. And changing anything might cause premature wear on your camlobe, rocker or both.

That Seller has made a habit of not disclosing what it should be obvious a buyer would want to know(and will after recieving the item), changing the story after the auction ends-and NOT knowing the difference between restored and modified. The facts here prove he wasn't even careful in assembly.

There is only one reason I can think of the limit access to feedback-and it is up to you to weigh the risk before entering into an agreement with him.

Good luck in getting that situation corrected.

WIll

  Ed said:

Has this head already been run on this engine?

If the cam is still new then you should be able to fix the lashpad/rocker to obtain a proper wipe pattern. But if the engine has been run for a while already then the cam lobe has already seated on the rocker. And changing anything might cause premature wear on your camlobe, rocker or both.

the cam was transfered from a P79 head onto the "new" n42 head. I just spoke with the mechanic who did the transfer and he claims the shim on that one tower was already on the n42 head with stock cam. He just transfered over the cam to the n42 head.

Now what im wondering is, since it appears the lash pad (round disc with square cut out) <--- i believe is the lash pad... is stock compared to the others... maybe it got lost or whatever.

Now my rocker arm is raised a good number of threads. Im worried the geometry is gonna be harmful since its raised so high.

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okay lame picture but thats what it kind of looks like. I wish i had a digicam on me but i dont. The rocker arm isnt as drastic in angle as in that diagram but more like a 60 degree angle i suppose.

I know this is off topic [slightly], but I wondering if there were different cam towers with differnt model heads? I've always assumed all towers were identical.

If they were, then how one managed to get shortened is most interesting!

I bought a head from that same guy on ebay, an N-47 when I got it in the mail the cam had fallen out and ruined the cam towers, the rockers were everywhere in the box along with the lash pads. He also forgot or didnt put the dowels under the cam towers so the towers werent aligned and the cam was also ruined. Just to let you know what a great seller he is, He told me "it must have got messed up during shipping" and that was it. I paid 380.00 and got free shipping so I didnt get insurance on the package. Sorry to stray away from the topic at hand but I had to vent :sick: