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Discussion Topic:
setting timing
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tomlud |
05-05-2013 @ 1:46 PM
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Member
Posts: 23
Joined: Jan 2011
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I need some advice from some of you old pros. A friend of mine has repainted the engine and engine bay on my 51 ford custom v8. Now we are having trouble getting the timing set correct as it keeps moving off center so i am posting this question for him. In setting camshaft distributor drive gear is it supposed to be flush with the end of the camshaft ? I hope i am asking this correctly. Many thanks. Tom.
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TomO |
05-06-2013 @ 7:29 AM
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Senior
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I am having a problem understanding your problem. Did he remove the camshaft distributor drive gear to paint the engine? Did you find TDC on cylinder 1 and install the distributor with the rotor pointing to the cap contact for cylinder 1? Is he timing the distributor with the vacuum hose removed from the distributor and plugged as described in the timing procedure? The initial timing should be 2 degrees BTC at 475-500RPM for standard shift cars and 425RPM for automatic trans cars with the vacuum hose disconnected. If the timing moves after driving the car, the clamp holding the distributor in place may be bent or the wrong length bolt may have been used. The bolt should be 1" in length. If I have not answered your question, please describe the changes that you see when trying to set the timing.
Tom
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supereal |
05-06-2013 @ 9:35 AM
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Tom has asked most of my questions. I'm not sure what you mean by "moving off center", either. The distributor drive gear on the front of the camshaft is pressed onto the camshaft in front of the four hole plate that fastens the timing gear to the camshaft. This means the face of the gear is flush with the end of the camshaft with the marks on the gear and the camshaft aligned. Unless the gear has come loose from the camshaft, an unlikely situation, it can't move to affect timing of the distributor. If the distributor was properly inserted, as Tom describes, I would check the driven gear on the end of the distributor shaft. It is held in position by a pin thru the collar of the gear. If it is secure, look for a problem inside the distributor such as a broken or missing advance spring. If the crankshaft pulley was removed for the painting, be sure that the key is in place, and not damaged. I'm having a problem understanding how painting the engine could affect the timing unless, as Tom points out, the clamp between the cylinder head and the distributor is not correct and secure. If the point set is faulty, or the condenser is weak, the timing will not be stable. Occasionally we find the pigtail under the point plate is grounding on the later distributors.
This message was edited by supereal on 5-7-13 @ 5:12 AM
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tomlud |
05-07-2013 @ 10:49 AM
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Member
Posts: 23
Joined: Jan 2011
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I want to thank you for your answers and questions. My friend took the timing cover off and found that the dis drive gear had moved and the marks aren't lined up on the camshaft any more. also the fibre timing gear is worn out. So we never could get it back in time. we have parts on the way now. Thank you very much.
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TomO |
05-08-2013 @ 7:17 AM
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I don't understand how the distributor drive gear could move. It is a press fit and if it has moved, either the camshaft or gear or both may not be correct size any more. You may have to replace the camshaft. If the cam fiber gear is worn, I would also check the crank gear for wear and replace it if any signs of wear are present.
Tom
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tomlud |
05-08-2013 @ 10:43 AM
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Member
Posts: 23
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Ok I will check the crankshaft gear. Lets hope the camshaft is ok. thanks
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rotorwrench |
05-08-2013 @ 12:56 PM
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Posts: 59
Joined: Jul 2012
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The 49 to 51 Lincoln/Mercury overhaul manual that I use for Mercury version of the 8BA, has procedures for removal and reinstallation of the drive gear on the end of the camshaft during overhaul. I never remove them when I overhaul but some one might have in the past on yours. If it is still a good press fit, it should be reinstalled with the marks aligning. This will insure the distributor and the associated vacuum advance line will be in the correct location when the engine is timed to the 2 degree mark at the pointer & lower crank pulley.
This message was edited by rotorwrench on 5-8-13 @ 12:57 PM
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TomO |
05-09-2013 @ 8:03 AM
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Maybe I am missing something, but I see no need to align the distributor drive gear scribe mark with the mark on the camshaft. The camshaft is timed to the crankshaft and the drive gear is a press fit to the cam shaft. The drive gear will always be in time with the camshaft and if the distributor is timed to the crankshaft (#1 at TDC and the timing mark on the pulley is lined up with the indicator), the drive gear relationship to the camshaft seems irrelevant.
Tom
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Stroker |
05-09-2013 @ 9:33 AM
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TomO: You are correct in your logic. As long as the pressed on gear doesn't slip, the distributor doesn't "care" which teeth are being used to drive it. One could randomly press on the gear, and about the only possible consequence of not having it indexed to the cam mark would be the possibility that it is a half-tooth off, which will affect the range of the clamping flange on the housing, and the position of the vacuum can in relation to its' plumbing.
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supereal |
05-09-2013 @ 3:04 PM
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The marks on the camshaft and distributor drive gear are there for purpose, otherwise they wouldn't exist. In this case, they report that gear came loose, which accounts for the inability to get a firm timing adjustment. The only problem of this kind I've seen was with an aftermarket camshaft that had an apparently undersized nose.
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