Did someone throw a boat anchor behind my car at 4500?

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max71
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Re: Field Test

Post by max71 »

VWNate1 wrote:Bad plug wires usualy create a miss , not low overall power though .
I seriously doubt its the wires. I agree I would see other issues aside from what I'm seeing.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Steve Simmons »

Doubt all you like, but you have to eliminate things before you can move on. You've been fighting this for a really long time and there are still really simple things you haven't tried yet, like plug wires! By the way, I've seen wires cause high-speed missing as you describe. Be sure to use a new cap when you swap the wires out.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Didn't say I wouldn't try it. Its a brand new cap in there right now from Jeff so that's out of the equation. The reason I'm doubting is because I've had three sets of wires in there since the rebuild. Never made a difference except the Bosch solid core make the butt dyno happy. Unfortunately it made other things go weird, like the radio and other issues because of the interference they caused.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

max71 wrote: Unfortunately it made other things go weird, like the radio and other issues because of the interference they caused.
Radio?? Is this car remote controlled?
Or did you really mean "radar detector"?
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Don't you have a gas analyzer in your garage??!!! I'll wrestle it away from the creatures.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Indeed I do, as mentioned earlier. I even know roughly where it is.
At this point I only have the required bung for the oxygen sensor on my Jeep, but I should weld one onto some other cars, too, now that you mention it. If for no other reason, to see just how hopelessly rich the V8 B runs at idle.
So, go ahead and weld on a bung, then we can have an AFR day.
(The gauge itself mounts like any 2-inch instrument, but I never permanently installed it)
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Mentioned earlier? When? In a dream. I don't see any mention......

Oh, so its not the kind that shoves up a tailpipe? Oh well. I always dreamed of one but with the twin SUs I wanted a sensor per SU or I thought it was fairly difficult to match them with one sensor.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Ah, you're right. It was Malcolm that fessed up...I tried keeping mine secret.
Either way, you'd be hard pressed to use an AFR (a buzz word from the late Eighties, by the way, speaking of previous posts) on an MGB motor to see what each carb is doing because of the way the exhaust ports are configurated.

And besides, if you're dreaming about showing things up tailpipes, I'm outta here!
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Oh yeah, I remember when I joke about dreaming it makes you nervous from other posts. Ok, Jimmy, knowing how conservative you are I'll make sure I just make my posts as boring and square as possible. :lol:
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Steve Simmons »

max71 wrote:Didn't say I wouldn't try it.....The reason I'm doubting is because I've had three sets of wires in there since the rebuild.
So you HAVE tried it then. You could have mentioned that before! :hammer:

Ignition is out then, so move on to the only other two things... valve float and fuel delivery. Make tomorrow's project to rule out fuel and you'll have your answer, imho.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Martin Keller »

max71,

PM sent.
Are you still looking for this.
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Martin, that indeed is a nice distributor.
Although Gary may not want it if he finds out that I fondled it today.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Jimmy. Keep your Finnish hands off my British Dizzy!

Ooooh AAAhhhhh. That is one nice dizzy. Ok I'll check my PM.

Steve. With the changes I would feel more comfortable trying the wires again to rule them out even though I have had different wires on it. But since then there's been some changes.

How could I have valve float at 4500 RPM? Especially after Sean redid it. I think its suddenly running too lean. Need to get my hands on a gas analyzer.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Steve Simmons »

Don't suddenly doubt yourself. If you tried three sets of wires then it isn't the wires.

Valve float can happen no matter who did the head. Mistakes happen and springs can be bad. I don't know what the problem is, but you seem to have tried everything but valve float and fuel starvation. Doesn't really sound like fuel starvation to me. It wouldn't happen only at a specific RPM, regardless of load. I have no other ideas here.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

I think a gas analyzer will confirm or disprove needle problems. Otherwise if its not needles then all I can think of is the cam is too advanced.
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Re: High RPM Miss

Post by VWNate1 »

Remember that valve floating doesn't produce a miss , it simply makes the engine run out of power... one of my junkers did this when the intake valves sacked from old age , customers cars would come in with weak valve springs that allowed float at normal RPM's .

I *thought* I'd been following this thread closely but maybe not ~ at this point you've replaced all the various ignition parts at least once with the same problem remaining ? for a high RPM miss it is time to look at points bounce (if so equipped) or maybe lean mixtures , this too I had in my old MGB W/ HS4's , ~ they idled *perfectly* and the exhaust was clean but at high RPM's I had a miss under load and a rythmic backfire (carby popping) when revved stationary , lowering the jet bridges a tiny bit cured it .

Just another thought , I'm old enough to think a two gas exhaust analyzer is ' The Shit ' and the buzz word back then was
' EGA ' , wish I had one now as my ears are no longer sufficient to set up multiple carbys :(
-Nate
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Steve Simmons »

Problem is, we still don't know if it's actually a miss or not. That's a big part of the puzzle that needs to be addressed.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

I don't know if I would call this a miss. It just hits a wall and struggles to go any further.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Well, now that you finally described what really happened, it all makes sense.
Hitting a wall is completely different from missing it. If then the wall is substantial enough, the car will indeed struggle to go any farther, either from resulting mechanical damage or due to debris stuck underneath.
At least it works that way with a Jeep, and I see no reason an MGB would be much different.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Throwing a boat anchor I would imagine translates into hitting a wall. I never described anything that could be considered a miss. That's Steve's theory. And all we can do is theorize. I feel its like the engine goes from rich to very lean which is why I'm hot to find a gas analyzer.

What's odd is it did this in every gear including first. Then when I replaced the coil first was ok. Its still ok. That's why makes me wonder on incorrect cam timing as all gears should exhibit the same issue.

When I said its like it runs out of gas that's it as well. Like no more gas suddenly however, I still imagine if I had fuel starvation once I upshifted it would stumble right away. That isn't the case. Run it up to 4500 in 2nd and quickly shift and it pulls fine right away in 3rd up to 4500 and then hits the wall.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Steve Simmons »

Missing isn't my theory, it was just a possibility, as was valve float and fuel starvation. I have no idea what your problem is, all we know is that a new coil reduced the problem.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

I know. We're all guessing and eliminating possibilities.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Sounds like a classical case of "hit and miss" trouble shooting to me.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Agreed. Any brilliant ideas?
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Well, I'd throw a Jacobs Electronics on the ignition (they're easily installed and removed without any cutting or splicing) as that would pretty much rule out ignition problems - or at least point them out.
Then I'd weld a bung onto the exhaust downpipe (for an inexpensive AFR unit) and get a feel for what the fuel mixture is doing.
Either that or good old systematic trouble shooting (plug reading, valve spring tension and cam timing check, etc.)
But I'd probably do the former simply because I'm lazy, not because it's the right way.
In baseball, running into someone is apparently a "collision".
But doing the same thing in a car somehow makes it an "accident".
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