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Datsun Camshafts & Valve Timing - A MUST READ!


C.A.R.
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Guys,

This is a MUST READ topic for ANYONE interested in selecting a performance camshaft for their L series engine.

Baz from Datsport was kindly given permission to reprint this on his website for all us fortune people!

It does go through the basics at first, but I found it refreshing to re-read it all again.

I suggest you only read it a few chapters at a time to let the info sink in...

 

Enjoy ;)

 

http://www.datsport.com/racer-brown.html

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  • 10 months later...
  • Administrators
It is an ABSOLUTE NO-NO to remove the cam towers from the cylinder head because it is nearly impossible to restore correct cam bearing bore alignment after they have been removed.

 

I have heard this before also. I think its important to point out. I've seen a couple of members recently showed pics of engine heads with no cam towers on them.

 

Can anyone else verify this?

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I have heard this before also. I think its important to point out. I've seen a couple of members recently showed pics of engine heads with no cam towers on them.

 

Can anyone else verify this?

 

 

I have been watching Ztherapy's tuning videos and he also mentions not removing the cam towers for the reasons mentioned above

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I did some time in an engine reco shop and there can be problems with the cam binding if the head has been over heated and the towers are not re installed in the same order.

 

Always mark each tower and base with a centre punch before you remove them and you should be fine, however it was good practice to only remove the towers when absolutely necessary.

 

Shims are mainly used to maintain the timing (distance) between the cam and crankshaft. An adjustable cam timing gear will do a similar thing only better.

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  • 3 months later...
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Used to work, I hope someone saved the file.

I was going to read it when I was closer to an engine rebuild.

 

Archive.org baby!

 

http://web.archive.org/web/20080721214115/http://www.datsport.com/Racer_Brown_Menu.html

 

If that doesn't work for you, let me know

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  • 1 year later...

I Know this is an old post, but I thought I'd add to what Lurch said about cam tower changes.

 

It absolutely is an old wives tale that you can't do it! I took the towers off my early 240 head and put them on a late model N42 head so I could retain the spray bar oiling system....therefore not only did i take the towers off, i put them on a different head!

 

There was never a wiff of a problem....I just kept turning the cam as I torqued the head down, and no problem emerged, and when the bolts were all done up it turned just fine and then I put the rockers back in, and it's been going for many years now with no issues.

 

Cheers

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  • 3 months later...

Removal of the cam towers will not cause a problem. A common cause of the camshaft binding in the cam towers is a warped head due to a blown head gasket. If the head is surface ground on the gasket surface it is essential that the top surface is also machined or the cam towers will be out of alignment. Alliteratively appropriate thickness shims can be placed under the towers to bring them back into alignment.

 

If the head is bent more than .005" it should be straightened to within .005" prior to machining.

 

Gordon Dobie

Datun Racing Team Chief Engineer (Retired)

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  • 3 weeks later...

Removal of the cam towers will not cause a problem. A common cause of the camshaft binding in the cam towers is a warped head due to a blown head gasket. If the head is surface ground on the gasket surface it is essential that the top surface is also machined or the cam towers will be out of alignment. Alliteratively appropriate thickness shims can be placed under the towers to bring them back into alignment.

 

If the head is bent more than .005" it should be straightened to within .005" prior to machining.

 

Gordon Dobie

Datun Racing Team Chief Engineer (Retired)

thats right gordo ,and if you do mix them, wack em on a flat bed and stick a straight edge through the middle of them all, if it rocks tis not good.  ps  this is a very old topic tisnt it
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