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  #16 (permalink)  
Old 09-19-2010, 11:04 AM
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Eric did you check the HEI shaft end play, I just read a bit about timing variations of 4-5 deg with an out of the box HEI. And in one of your other threads on this problem I mentioned that your vacuum advance can may not be fully in but rather floating around near max travel with slight changing vacuum pressure. Combine these two together and you could have a gremlin.

What does the timing light tell you when this miss occurs?

Did you measure the vacuum pressure it takes to get the full rod travel of the vacuum can rod? maybe just make sure its fully pulled in at about 2 "hg below the engine idle vacuum pressure and check the HEI end play.

2 more of my cents

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  #17 (permalink)  
Old 09-19-2010, 05:26 PM
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I read a lot of what is going on here and it really sounds to me like a lifter problem.I had a 460 ford several years back and it had tune ups and carbs and all that and everything imaginable.We tore it down and replaced the lifters and the problem went away.
I dont mean to step on anyones toes or offend anyone by saying this as a lot of the guys contributing here are very sharp and I have respect for you all. just putting in my 2 cents for what its worth.
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  #18 (permalink)  
Old 09-19-2010, 06:44 PM
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Well guys some awesome stuff here. Well first off my distributor end play was just fine and within spec. I have had two other ones in it as well and still same thing.

Also as far as the intake goes I previously had a edelbrock rpm performer intake and still had the same problem. I changed to the eps cause of the idle to 5500 rpm range and the statement of it being tuned for peak torque curve around 3500 rpm and it was better matched to my cam. I also was wondering of the rpm performer was just a little too high with the carb spacer.

Also I am already using a one inch 4 hole spacer on my engine.

Also custom 10 I will have to buy a hand vacuum pump to try out the vacuum advance. I also disconnected it and just ran with initial timing and readjusted the carburetor and it still had the miss in the engine so it should not be that causing it.

Also when checking timing it is still the same within one degree when it does that. Also to answer the other question on the lifters I just checked all them since I did a cam swap and they are all just fine. I was not able to get my volt meter to test my output at the battery to see how mv's I have.

I just recently swapped out alternators too and it has done this problem since I have had the motor and really is noticeable now since i went from a lopey fair idle cam to a smooth idle cam. I just got another 1850 600 holley that was a reman from ebay on the way so I can put it on and see if it just might be something in the current carburetor I have.

I want to be able too rule that out as well. I am also going to eliminate the one inch spacer and see if there is any change after doing so. I will report tomorrow on the digital multi meter and see how many mv's it reads.
Eric
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  #19 (permalink)  
Old 09-19-2010, 08:32 PM
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You can disconnect the alternator and run the engine temporarily off the battery if you want to eliminate it as a cause.
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Old 09-20-2010, 10:12 AM
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Thanks guys for some more things to check but in the last year I have had three different alternators on this thing and it's always been there. First one did not charge enough and the second one the bearings where bad in it.

Current one works good so far but anyways I did some looking over my carburetor and put my finger over each idle air bleed or the bigger ones if I got it named right but anyways it will cause the engine to almost quit so I know they are not clogged with anything but I did notice on the rear of the carb when putting my finger over the idle air bleed buy holding it there I started to hear a slight intermittent tweedy bird whistle sound like tweet tweet and also by putting my finger over both rear idle air bleeds it would do it as well.

It would not happen all the time but here and there. You could barely hear it. Any suggestions on what that might be?
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