Replaced head on 280z and camshaft sprocket mount is different

[camaro-guy]

My son and I bought a rebuilt n42 head. We have replaced the head, but when we went to install the cam sprocket, we noticed the end of the cam is different. The first Pic is a pic of the head we took off and the second is of the head we put on the car. The place where the sprocket mounts is different. Got any ideas on how we should tackle this problem?

camaro-guy

[siteunseen]

I don't see the differnce?

I'm sorry, talked too soon. Looks like the cams are of different lengths.

Edited September 21, 2019 by siteunseen

[siteunseen]

California Datsun?

[camaro-guy]

site unseen,

               Yes, I wasn't going to use their name, but yeah

 

camaro-guy

 

[Dave WM]

just assuming the cam bearing and lobes are in the right spot? I cant recall right  now how the camshaft is retained from walking for and aft. Can you get a pic of the top of the head with the lobes showing.

[grannyknot]

What Dave WM said, just looks like the cam is 1/4" too far back, as long as the cam is all lubed up you should be able to tap the back of the cam with a rubber mallet.  Or you could install the cam gear and pull the cam forward with the cam bolt, just be sure the locating pin also lines up.

[Jeff G 78]

Agreed, the cam is just slid back.  Look at the back end of the cam.  It should be flush with the rear tower and yours likely sticks out the back.  The retainer only keeps it from sliding too far forward.  The gear and accompanying bolt keep it from sliding rearward.

[camaro-guy]

You guys are absolutely correct! I have been pretty nervous about this whole head swap and I completely over looked the obvious. We will try to tap it forward this morning with a rubber mallet! Project is back on the move! Thanks again!

Camaro-guy

 

[jonbill]

Are the rockers in? If not it really shouldn't need force or mallets to get the cam in the right position.

[Captain Obvious]

1 hour ago, camaro-guy said:

I completely over looked the obvious.

Well therrrre's your problem.   

Glad it was a non-issue.

[gundee]

3 hours ago, camaro-guy said:

You guys are absolutely correct! I have been pretty nervous about this whole head swap and I completely over looked the obvious. We will try to tap it forward this morning with a rubber mallet! Project is back on the move! Thanks again!

Camaro-guy

 

You should not need any mallet. It should easily move forward by hand and not tight.

If not, you have to find the problem. Head warped? Towers not torqued properly?

[Dave WM]

good point with all the valve gear out of the way make sure the cam shaft spins easy with no tight spots. I don't have 1st hand info on this, but much has been written about having head work done and the effects it can have on the alignment of the cam bores. Obviously you would want some assembly lube on the cam journals as well. Have to check it with the rockers not engaging the cam lobes. If its tight at some spots I would think over time it could lead to metal fatigue and cam shaft failure. Again reading tells me the correct way to fix a warped head is to either attempt to straighten it (heat and pressure) or machine it bottom AND top, then use shims as needed to correct geometry of the rockers by shimming up the towers. Followed up with careful torqueing of the cam towers while test spinning the cam shaft. A lot to read up on but its out there.

Edited September 22, 2019 by Dave WM