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Valve timing waaaay off?  Rating:  Rating
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 Posted: 04-25-2008 07:14 pm
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subwoofer
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Morning, all! Fresh JH owner form Norway here, bought 18711 three weeks ago. It is in fine shape, rust wise, not too bad in the paint department, but needs a paint job in the not too distant future and is in dire need of some electrical work.

The engine didn't want to pick up properly, I thought it was just ignition that was way off, but a closer inspection may have revealed the real problem. The included picture is taken with #1 at TDC, the pink dots on the rims of the cam drives are at the 110 marks (pointed to by arrows). I can't feel any interference while turning the engine by hand, but am I in need of a rebuild, or should I be OK just retarding the cams back to the proper position?

I haven't got around to checking clearances yet, they would tell me if I have bent valves, right?

Attachment: IMG_5973.jpg (Downloaded 84 times)

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 Posted: 04-26-2008 11:13 am
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Ron Mau
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Welcome,

You might try to rotate the crankshaft  one more time around to top dead center. It looks like you are off one revolution. Try that first before you move the belt and cause serious damage to the valves.

 

Ron Mau

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 Posted: 04-26-2008 11:19 am
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subwoofer
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Mkay? If my maths aren't completely bonkers, that would put the timing marks to the outside, but still as off the centre line.

The cams seem to me to be off by two teeth each, but the engine ran with wild ignition and this setup. Not well, though.

I'll go out and turn it one more rev.

Edit: I just did, and my maths was right...

Last edited on 04-26-2008 11:39 am by subwoofer

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 Posted: 04-27-2008 06:35 pm
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Jensen Healey
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To reset the timing, turn the engine to top dead center. Make sure the rotor is pointing at the number 1 tower on the distributor cap. Use a dial indicator (or pencil) through the spark plug hole to verify the timing mark on the crank pulley is good and the key is not broken or missing.

Mark the position of the distributor pulley.

Back the crank about 90 degrees so none of the pistons are at the top of their stroke to prevent any of the valves from coming in contact with the pistons. Loosen the timing belt and remove from the cam pulleys. Verify the intake pulley is marked Int 110 and the exhaust is marked Ex 110. Line up the timing marks on the cam pulleys. Move the #1 piston to TDC and re-install the belt. Check the timing and distributor pulley marks again after the belt is tightened.

Do a compression check.

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 Posted: 04-27-2008 08:44 pm
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subwoofer
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I tried to figure this one out by myself this afternoon, and did more or less what you described, except I made a note of how many teeth the cams were off at TDC, then moved moved the cams the appropriate amount with the engine turned 90ยบ, put the belt back on - and voila, correct (I hope...) timing.

Confirming the timing mark on the crank pulley was my first check. Unless there is a was of setting the cam pulleys off, or some PO has installed some really weird cams, the engine should be right now.

Still have some problems to work out, though. It wouldn't catch when I tried to start it, tried a few more times. Then I found the ballast resistor bypass had fallen off the starter solenoid. Sound while cranking changed a bit, but still wouldn't catch. Pulled one plug and found it soaked, so I must have drowned the poor thing properly. Left the plug out for now, at least one cylinder should dry out overnight.

Needless to say, being a complete amateur, I have changed several things at once, static setting the ignition, having the carbs apart changing diaphragms and gaskets and of course moving the cams.

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 Posted: 05-01-2008 06:17 am
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subwoofer
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One thing out of the world, at least: The cams were two teeth too early, so the alignment marks were right, confirmed by visual inspection of the cam position with the covers off.

Engine still not running, but at least one variable is eliminated.

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 Posted: 05-01-2008 01:42 pm
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subwoofer
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Oh Joy!

It is running again, a new coil fixed the last problems. It is now revving like it should, idle is back, ignition still needs fine tuning, but at least I have a running car.

Miraculously, it seems to have survived having the valves leading by 36 degrees (two teeth). It must have been a close call...

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 Posted: 05-01-2008 08:48 pm
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Greg Fletcher
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Glad to hear it's running. The gears can be off by quite a bit before a valve will bend, I'm forgetting what that is exactly but I remember being surprised by it.

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