Sanity Check on 348 Cam Timing

I used the excellent posts by FBB and Ernie on 348 cam timing. My situation is all cams except one are in time and the marks line up. No. 1 cyl. exhaust cam is retarded by approx. 2 degrees. I understand that I need to remove the cam pully lock pin. At that point I am unclear on which direction and how to adjust the pully (CW or CCW) to advance the cam, do I turn the crank to line up to the new hole. Also how do I move the pully without impacting timing on the other cams. And finally if I run out of holes and need to remove and rotate the pully is it necessary to remove the tensioner.

Thanks,

Brewman

 

I made some longer pins and used smaller washers so I could easily remove them and rotate the cam (by inserting the pin in the next closest hole). Once it's lined up insert the orig pins and washers of course. If there isn't a hole that will work, the only choice that I know of is to remove belt and re-located the cam pulley.
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Your have the pins and belt cogs to pick from for timing adjustment. If you can manage what you need with the pins then just spin the cam and line up the pin you want. If you need to jump a cog then pull the tensioner back, lock it down so the belt is loose, secure the belt on the cams you don't want to adjust, adjust the gear, then let the belt go and recheck everything. Repeat until your happy. I'm unsure which direction you need to go as it becomes evident with adjustment in the correct or incorrect direction.

 

What crank degree is the exhaust valve opening at, and what are you trying to set it to? Basically what are your timing specs, int & exh?

Without actually seeing your cam in motion this is just a guess.....the dowel on the 1-4 exhaust pulley would get removed, then I would rotate the the crank counter clockwise. This should cause the exhaust cam to "catch up". Dowel back in, cam pulley bolt back in, then I would turn the crank clockwise at lease four full rotations and recheck.

I don't see why you'd need to remove the tensioner, but you may need to remove the cam belt.

 

The specs I am using are for a car with cats. Intake open at 12 and exhaust at 54 degrees. For the one cam that is out I have not measured it yet. I wanted to be clear on how to make the adjustment first.

The timing mark on the exhaust cam in question is not reaching the mark on the cap. When I rotate the crank and come back to TDC it is failing to reach the mark on the cap by approx. 2 widths of the mark.

This is where I get confused. if I remove the pin and then move the crank which way do I rotate it knowing that the cam mark is not reaching the cap mark.

I'm unclear on how to relieve tension or remove the belt without removing the tensioner. I don' have enough a** too push it back in place. Is there a trick.

Thanks,

Brewman

 

To hold the tensioner in place there was a set screw hole drilled into my tensioner housing. The tensioner gets compressed and then the set screw holds it int the compressed state. Belt removed/replace and set screw loosened.

If I am visualized what you are saying correct, you'll need to remove the dowel on the exhaust cam, hold the exhaust cam in place, with the belt still in place on all the pulleys, then SLOWLEY rotate the engine counter clockwise 1-2 pulley holes (or as needed). With the exhaust cam being held in place and the engine rotated backwards it allows the pulley to "catch up" to the other pulleys because it will spin "freely" on the cam.

Give it a try and you'll understand a little better.

 

So after I move the pully CW do I put the locking pin in before rotating CCW. Also if the cam mark is advanced past the cap mark do I use the same process except go CCW first and then CW .

Thanks so much for your help.

Brewman

 

No, no, no, no, no no.

Line up the three GOOD cams that line up on the marks. Now pull the dowel/pin from the cam that is retarded. Lock the retarded cam in place. With the pin out of the retarded cam pulley rotate the engine COUNTER clockwise 1-2 pulley holes as needed. Replace the pin in the cam, and the retaining pulley bolt. Rotate the engine CLOCKwise at lease four full rotations, and recheck the timing.

 

I don't do any of that. There is a detent on the cam shaft. It holds the pully on the shaft even if the belts are tensioned and camshaft retaining bolt is out. I move the out of wack cam shaft re-pin it, then confirm cam timing.

 

Ernie, sorry to be so dense.

1) Bring engine to TDC , verify 3 cams are still aligned.
2) Remove bolt and pin from cam that is retarded.
2) Lock retarded cam.
3) Rotate crank CCW one or two holes.
4) Reinstall pin and bolt on retarded cam
5) Rotate engine CW 4 rotations minimum.
6) Repeat process until cam marks match and/or spec. is met.

Thanks Again,

Brewman

 

BINGO!

 

Ernie,

Thanks so much for working me through my questions. I really appreciate you sharing your knowledge.

Regards,

Brewman