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Discussion Topic:
Fresh Rebuild 8 B-A
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FLTHDCPE |
12-11-2011 @ 2:47 PM
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Member
Posts: 24
Joined: Dec 2011
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I have a fresh rebuild on a 8B-A. Starts & idle fine, at approx.900 RPM and above it will "pop/pop/pop out the left tailpipe.With the engine up to operating temp you can physically hold your hand on the left side exhaust system.? It has a original distributor with a "PerTronix" conversion. One new "Super 97" carb from "Speedway" In a attempt to trouble shoot the problem we performed a cyl.leakdown test which it passed on the left bank.! This is a fresh engine and has not been run very long because of the above problem. Any suggestions or previous experience with this type of problem would be appreciated. Thank You,Steve.
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carcrazy |
12-11-2011 @ 3:40 PM
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Senior
Posts: 1674
Joined: Oct 2009
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Does the engine exhaust popping occur at all engine operating speeds? If so, I would suspect either a sticking or non-closing exhaust valve, miswired spark plugs or spark jumping between secondary ignition wires.
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supereal |
12-11-2011 @ 6:49 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Substitute a known good stock distributor. Conversions are often the source of that type of trouble. We have found that more than once.
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flathead4rd |
12-12-2011 @ 6:31 AM
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New Member
Posts: 169
Joined: Oct 2009
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I haven't heard anything good about the new speedway 97's. You might start there.
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TomO |
12-12-2011 @ 8:34 AM
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Senior
Posts: 7256
Joined: Oct 2009
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I agree with both of the above posts. Unless you have an engine oscilloscope, your best bet is to swap in a good rebuilt distributor with good points. Set it up on a distributor machine to make sure that you do not have point bounce or dwell variation. I would also go with a quality rebuilt 94 carburetor. The 97's may look cool but they do not have the correct vacuum port for your distributor.
Tom
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supereal |
12-12-2011 @ 11:04 AM
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Senior
Posts: 6819
Joined: Oct 2009
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Tom is certainly correct about the advance vacuum tap. The original Ford distributor used plain manifold vacuum to operate the retard plunger in the distributor. If you are using the later "posthole" distributor in your 8BA engine, without the mechanical advance, you will have incorrect or no advance. That distributor requires a vacuum port situated above the throttle butterfly in the carb. That would explain why the engine balks above idle. FYI: Edlebrock is now produced new 94's. They are on page 65 of the Jeggs catalog.
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shogun1940 |
12-12-2011 @ 5:22 PM
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Member
Posts: 464
Joined: Feb 2010
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check the engine with a vacuuum guage, a weak valve spring could cause the popping, and still give a good cyl. leakdown test
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FLTHDCPE |
12-13-2011 @ 10:18 AM
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Member
Posts: 24
Joined: Dec 2011
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My Thanks to everyone for my request & suggestions to locate & solve our problem. I think that we are all on the same track,now it's on to futher testing & trouble-shooting. That's how we learn.!! Thanks Again,Steve.
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