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

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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

I had a hand built electronic ignition in at one point but that was before the rebuild. I did notice it performed better at higher RPMs than points although I wasn't having this issue. I might have played with wires also prior to the rebuild so I might as well try that again. If you read back in this thread you'll see the comments from the dizzy rebuider who says the dizzy is fine even with points.

There's no budget to buy anything or I would just hand it over to Malcolm and have him figure it out. Still there's greater satisfaction in fighting through on one's own. Good learning lesson.

I'll just keep hunting for an analyzer. Someday I'll get a dual AFR setup. There's a company who's website I had bookmarked that can do a dual gauge that will show both carbs/info.
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Re: You Have Described

Post by VWNate1 »

Floating valves to a 'T' ~ ' hitting the wall ' means too many different things to different people .

I'd say it's time to check the valve timing and then the valve spring tension , amazingly , I have owned/worked on/repaired/scrapped quite a few engines that did this run out of power at a specific RPM that , once I slowed down to check , I discovered a weak valve spring that was discernable by simply depressing the valve retainer by my thumb , once that cylinder was @ TDC with the valves unloaed ~ no need to take anything further apart than the rockerbox .

Just a thunk for simple home testing you've indicated you want to do .

From here on , assuming you've checked the full spark advance # 4,500 RPM's and it O.K. , I'd say further ignition fiddles would be a red herring .

OTOH , what do I know ? I mostly work on junk and used cars .
-Nate
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

I simply do not know. Sean Brown just did the head and tested the springs which I believe are all new.

I'll look into all of it but there's so many variables that at this point I may just take a break rather than chasing too many red herrings like I have been chasing. I need a bigger brain I guess to solve this one.

BTW Nate sorry to hear about the results of the leak down.
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

max71 wrote:I had a hand built electronic ignition in at one point but that was before the rebuild. I did notice it performed better at higher RPMs than points although I wasn't having this issue.

I'll just keep hunting for an analyzer. Someday I'll get a dual AFR setup. There's a company who's website I had bookmarked that can do a dual gauge that will show both carbs/info.
Gary, it's not just any electronic ignition that would work as a problem solver, that's why I wrote "Jacobs". The built-in diagnostics would tell if something's, um, amiss, in the system.

Also, whether it's a single, dual, triple or quadruple AFR won't much matter. You can use a dual gauge and read cylinders number 1 and 4 if you mount the sensors in the correct parts of the manifold...or, you can mount one sensor farther down in the downpipe and see what the engine as a whole is doing (effectively "showing both carbs/info") . Unless only one carb is jetted hopelessly wrong you won't learn much more from having separate sensors.

I'm leaning (no pun intended) towards cam timing at this point. If for no other reason because it's the most work to correct.
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 »

I posed the question to the person who re-flowed the head and did a complete valve job:

We re-used the dual springs you had (looked like standard County brand springs) and I did shim them. I seem to recall that the exhausts tested around 100 pounds on the seat and the inlets were up around 110 (I put the weaker springs on the lighter weight exhaust valves).

I have a lot of customers who have used the County springs with the cam you have, so it's doubtful that is the problem. You could try tightening the valve lash up considerably for a short duration test run and see if that smoothes it out or not.
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Okay, so it's probably not valve float due to weak springs.
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. :|
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Jimmy wrote: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.
Out of curiosity I went to their website. Nothing for an MGB.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Martin Keller »

max71 wrote:
Jimmy wrote: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.
Out of curiosity I went to their website. Nothing for an MGB.
I do not know about Jacobs Electronics but Moss Motors carries the following:

Pertronix Ignitor Electronic Ignition

Now available in both positive and negative ground versions. Completely self contained. No external control boxes to mount. Easy installation, only two wires to hook up. No permanent modifications involved. No points to set or change. Engine timing remains “spot on” far longer. Hall effect sensor is impervious to dirt, dust, moisture, or vibration and retains stock advance curve. Unaffected by distributor shaft wear, maintains firing accuracy to within 1/4°, reduces spark scatter over the full rpm range. One year warranty. You must order by the Lucas model number stamped in the housing near the vacuum advance. Model years below are approximate.

Part # Price Description Application Qty
Rqd Qty
222-415 $108.95 Pertronix Electronic Ignition
Note: Neg. ground, Lucas 23, 25D6 distributor
MGC 1
222-560 $120.95 Pertronix Electronic Ignition
Note: Pos. ground, Lucas 23, 25D6 distributor
MGC 1
222-555 $120.95 Pertronix Electronic Ignition
Note: Pos. ground, Lucas 23, 24, 25D distributor through 1967
MGB 1
222-405 $108.95 Pertronix Electronic Ignition
Note: Neg. ground, Lucas 23, 24, 25D distributor through1974
MGB 1
222-435 $108.95 Pertronix Electronic Ignition
Note: Lucas 45D4, Moss 143-110 distributors, 1975
MGB 1
222-425 $119.95 Pertronix Electronic Ignition
Note: Neg. ground, Lucas 45DE4 distributor, 1976-78
MGB 1
222-475 $119.95 Pertronix Electronic Ignition
Note: Lucas DM4 distributor, 1979-80
MGB 1


Hope this helps and your new used 25D is in the mail as of about an hour ago.
Martin Keller
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

Thanks Martin!

I do know about the ones one Moss. I prefer points. I think Jimmy was interested in the diagnostic aspect of the one he mentioned. I don't trust electronic ignition in the MGB. I've seen a lot of people have break downs and when they go they're gone. No warning.
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Jacobs ignitions aren't vehicle specific, or even number-of-cylinders specific.
Add 12 Volts and go.
On the fancier ones you can go back to stock ignition with a switch in or under the dash, whereas the OmniPak requires that you switch the coil wire back to where it used to go, and pull the fuse for the OmniPak.
Unfortunately, the new (well, since ten years ago) owners of Jacobs aren't all that good, and the OmniPak long discontinued - which is why I bought three extras when I found out.
One of my motors wouldn't even run for more than two hours without one.

Then again, I don't think your problem is ignition, so let's worry about upgrades once you fixed "the wall".
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 »

I really want to thank everyone for all their suggestions and aid. I do appreciate it. I hope if I ever solve it the fix will help others with this problem. Or am I the first one in history? :hammer:
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

You're probably the first one that hasn't checked the cam timing by now...hint, hint.
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 »

Very hard to do as far as I know. I mentioned I have a dial gauge if you know how to do it without tearing into the engine. Really although my last thoughts are fuel it makes sense the cam could be too advanced. I asked APT this long, long ago. They said they might be able to check it without pulling the head.

I think a gas analyzer is in order before anything crazy. And if it comes down to the cam I'll just leave it until there's a reason to pull things. Once again, I had the engine on Steve's floor with no head for weeks. Should've called someone over to check it....
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

I don't think you'll need anything fancy to check the cam timing.
Use a screwdriver, or something that can't fall into the combustion chamber, to find TDC.
A caliper, or even a stick and good eyeballs, could be used to measure at the valves.
You'll need a new valve cover gasket (I bought the reusable kind so that I never would have to remove the cover again), but not much else.

If you're off a tooth or two, precise measurements shouldn't be essential.
But whatever and however you do it, do not trust the marks on the vibration damper.
And I still think it's retarded, not advanced, based on your off-the-wall descriptions.
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 »

Its not off on the teeth if its off. We did put an off-set key in after making the calculations. Then we got the key in and it was way off and we ordered a different key. Finally getting the right measurements.

According to my dizzy guy I was using retarded (here's your opening Jimmy) when I should've been using advanced. If the cam is advanced it would give more low end power and then top out. If it was retarded I would get less low end power and more up top. Anyway, according to him that's the right terminology.

I had the dampener rebuilt and I'm very suspect they put it back correctly for the mark to be in the right place. I had ordered a TDC tool which the guy forgot to send when he sent back the dizzy. In doing searches on the net all the references poo poo'd the idea of a screw driver in favor of a liquid filled gauge sort of a hydrometer or manometer. It made sense and if I wanted precise TDC that would be the fool proof way.

Here's two vids on the subject:






OK, so I find TDC. Then what? I would need to put the cam timing degree wheel on it to see where it is, right? If its wrong it means I/we did it wrong. So me doing it alone I'm sure I would come up with the same number I/we came up with. IE I would need an expert or confirm to dispute this as an issue.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Alrighty, then. If you absolutely must use fancy tools, drill out a spark plug and stick a "something" with a snug fit through the hole.
Or, buy a simple, inexpensive, threaded tool made for the purpose. That's about as simple and fool proof as it gets.

Either way, since you apparently reused just about everything but the cam (and its timing) it'd be a damn good place to start.
And besides, when the cover first comes off, why not do the Nate-suggested thumb test on the springs?
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 »

The threaded tool is what was supposed to come back with my dizzy. I don't know how you would use it honestly. If its threaded how far down do I know to screw it in before I insert it into the spark plug hole and screw that part down? Its a fixed shaft at that point, no?

I assume you're referring to this: http://advanceddistributors.mybisi.com/ ... 38932.html

I once had someone put a cam in and they engine wouldn't rev right AT ALL. Turns out after he called Joe Huffaker at 1AM (this was one of their race car drivers who did the work. He admitted later he knew more about driving that engine building) Joe told him he must have the cam off a tooth or two. Which is was. I'm confident it is not off a tooth. I witnessed how that engine runs badly being off a tooth or two.

I can't see how those springs would suddenly lose tension but of course I'll try it. I trust Sean Brown. He's really the state side expert on flowing and rebuilding MG heads. He works closely with APT so he knew exactly what to do when he heard the cam I was using.

Still begs the question.

I find TDC. Then I need to put the degree wheel on to see if the cam timing is off and how much....
Last edited by max71 on Mon Jan 11, 2010 4:10 pm, edited 1 time in total.
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Jimmy
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

With my slow computer (not sure how he did it, but Steve really slowed it down for me) I'm not looking up any links or videos, but anyway; keep turning the motor over CAREFULLY as you back out (or in) the threaded part of the tool - heck, it comes with instructions, I'm sure.
Sean knew what the springs were like BEFORE you drove the car.

And then...yes, you'll need CORRECT cam specs to make use of your findings. Come to think of it, maybe not even that.
If your numbers come up as a 5/4 race cam, something's not right.

Or buy a Prius and be done with it. Okay, maybe not. But buy Malcolm's Jag - he may even take your pile in trade, since it's smaller and he needs the space.
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. I updated the post. above.

I'm sure it has instructions (tool). This is the cam I have. http://www.aptfast.com/cam_chart/Cam_Chart.htm

Scroll down and you'll see the VP-11. Anyway, we're going in circles. I would need to take it to someone like Malcolm to see if the cam was timed right. Remember, I didn't just line up the dots. I used an off-set key.
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Jimmy
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Plus, a Turbo S (with a damn roof) in the household.
And three Mercedes on 20" wheels.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Now you're assuming that the markings on the cam chain gears are correct.
Most likely they are, but...
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 »

Owning this car since 1973 and never having a problem with the gears I doubt it. Never an issue before. I guess anything is possible at this stage.
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Jimmy
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Plus, a Turbo S (with a damn roof) in the household.
And three Mercedes on 20" wheels.
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by Jimmy »

Uhh, you're running 500,000-mile gears still???
Well, if it ain't broke, don't fix it, I guess.
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 malcolmr18zoy »

Hey Gary,
Why did you use an offset key?
Malcolm
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max71
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Re: Did someone throw a boat anchor behind my car at 4500?

Post by max71 »

In the instructions for timing the cam. I forget how many degrees they wanted it at the moment.
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