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| Moderated by: Greg Fletcher |
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| Valve Timing | Rate Topic |
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| Posted: 06-23-2007 06:12 pm |
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1st Post |
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Bill Member
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I am looking for some advice about the valve timing on my 74 JH. Vin # 16229 with engine # B74 04 6754. I understand the workshop manual p.24 says that for this engine #, the valves should be set at 110IN to 110EX. However, my engine is set at exactly 115IN to 115EX. The engine runs as is, but should I reset and if I do will I cause any permanent damege? Strobe timing is at 12 deg BTDC at 1000 rpm and engine is fitted with 45 Dellortos. Engine was rebuilt (I suspect by a professional shop) in 1985. I haven't a clue how much the vehicle was driven since then. Plugs are set at 25 and engine is fitted with electronic ignition. Any advice would be greatly appreciated. Signed, "Confused in Wisconsin"
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| Posted: 06-23-2007 06:48 pm |
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2nd Post |
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Jensen Healey Super Moderator 
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All JH cams will run at 115, but 110 is the stock timing. The only risk of bending valves is during the pulley change. If you rotate the engine to 90 degrees before tdc, loosen the belt and flip over the pulleys without moving the cams you should be good to go. I assume you have pulleys with both marks on them. Kurt
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| Posted: 06-24-2007 02:44 am |
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3rd Post |
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Judson Manning Member 
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Bill, Consider the old saying, "If it ain't broke...don't fix it". Kurt points out how easy it is to change, but there may indeed have been a method to the PO's madness. Unless you are experiencing a problem, my suggestion is to let sleeping dogs lie. The first US JHs did have 115/115 timing that was later changed to 110/110, then to 100/110 for emissions. Further revisions in cam durations over the years gave us 102.5^ and 104^ lobe centers in the Esprit/Excell engines. None are really 'better' because by now every engine is unique and the only way to tell is to use a dynomometer. Judson
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