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Adam
Site Admin
Joined: 04 Oct 2001
Posts: 682
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 Posted: Tue Jan 23, 2001 7:01 pm Post subject: Changing camshafts. |
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FIRST: bring the engine to TDC on number 1. (this is important)
Next remove the aircleaner and rocker cover.
Undo the camshaft sprocket retaining nut. Be careful not to let this fall down the timing chest into the sump. It happened to me, and you can leave it in the sump, but it is not recommened. Dont take the sprocket off yet. On the distributor side of the camchain there is a tensioner. You need a torch, it looks like a screw. Should be white, but probably yellowish brown with age/heat. Put a screwdriver into the slot and PUSH DOWN before turning clockwise about half a turn. These babys break really easily, so be careful.
The cam chain should be de-tensioned now. Before you pull the sprocket off, loop some wire through the holes and get ready to tie it back around the radiator cap. Pull the sprocket and chain off as one, being careful not to jump any teeth. Its not the end of the world if you do jump a tooth, thats why the engine is set to TDC #1. Because the cam has a dowel which lines up with the sprocket, you can retime everything. Undo the bolts that hold the rockers in and lift out as a set. NOTE: these are matched, so dont mix them up. (The rockers, not the bolts!)
Now the cam will come out with a gentle bump. Put your new cam in, remembering to grease the lobes and journals with a molybendium grease to protect it for the initial startup. Do everthing in reverse to complete. *NOTE*!!: You must reset the valve clearances as the new cam will have different lift values. If you don't do this the engine probably wont start, but if it does, you will burn your valves! Set them when the engine is completely cold. Inlet: 0.15", Exhaust: 0.25"
I have heard that you can adjust the valve timing to get more performance by shifting the sprocket one tooth, but I dont know anyone who has done this, and personally I dont think its a good idea. Too easy to bend a valve. If there are any mistakes in this, its because I was doing it from¦ memory, in front of a computer not a Gemini, so - sorry!¦ |
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old forum
hod rodder
Joined: 04 Oct 2001
Posts: 15499
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| Posted: Wed Apr 11, 2001 4:39 am Post subject: valve clearances??? -(Terry Neilson) |
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| The valve clearances specified in this tip should be 0.15 and 0.25mm. I think 0.25" would rattle a bit. |
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TXcoupe
petrol head
Joined: 05 Oct 2001
Posts: 1675
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| Posted: Fri Nov 23, 2001 5:50 pm Post subject: valve clearance |
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| when putting in a new crow cam just remember you cant get rid of the tappet noise cause the profile is aggresive i have noticed it wioth both opf my cams and i do them tothe spec stated in the notes |
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TXcoupe
petrol head
Joined: 05 Oct 2001
Posts: 1675
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| Posted: Fri Nov 23, 2001 5:50 pm Post subject: valve clearance |
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| when putting in a new crow cam just remember you cant get rid of the tappet noise cause the profile is aggresive i have noticed it wioth both opf my cams and i do them tothe spec stated in the notes |
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gemcrzy
newbie
Joined: 11 Jan 2002
Posts: 2
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| Posted: Sat Jan 19, 2002 2:25 pm Post subject: retarding the cam |
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| retarding the cam timing will let the old girl rev higher but DONT FORGET TO CRANK THE ENGINE OVER BY HAND BEFORE YOU START IT. In my case it gave me an extra 400 rpm before it redlined, it went from 6800 to 7200 rpm |
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